Renewable Fuel Contenders
Posted by Robert Rapier on September 10, 2009 - 10:15am
Introduction
I got quite a few interesting e-mails and comments following my previous essay: Biofuel Pretenders. I probably should have mentioned - but I thought it went without saying - that pretenders usually don't think they are pretenders and will therefore protest mightily at the characterization. A number of people who e-mailed assured me that they have really cracked the code to affordable biofuels, and that we would be hearing more about them soon. Another person who wrote to me about algae said that he has been following algae since 1973, and he wrote "In spite of all the hype and non-stop press releases, no one to my knowledge is producing algae on a commercial basis for biofuel production."* Ultimately, I would be happy to be proven wrong on this, but I am just calling it as I see it.
On the other hand, there are some renewable fuel options that have either proven themselves as solid contenders, or have not yet demonstrated fatal flaws that would disqualify them at this point. In this essay I will cover some of those. First, I will cover a pair of first generation biofuels that have proven that they can compete with oil on a cost basis, and then a pair of next generation biofuels that I believe will be competitive.
Caveats
There are some other things that I need to point out, but if history is any guide these caveats will be completely ignored by some. First, I am discussing liquid fuels here, even though I am hopeful that electric cars become a real contender.
Second, calling something a contender is not an endorsement – particularly of the first generation contenders. Palm oil can compete with petroleum on price to some extent. The wisdom of using palm oil for fuel is a different matter. So please do not confuse how I see it with how I would prefer to see it.
Third, I am fully aware that there are limits to the biomass that can be removed from the soil. I want to be sure that biomass that is grown and used responsibly. One of the things I am involved in right now concerns farmed biomass that removes few nutrients from the soil. There are even ways to produce biomass that can improve the quality of the soil. Imagine a tree that sends down deep roots, brings nutrients up from the subsoil, and concentrates them in the leaves which then fall off and add to the soil. It is not science fiction, and my new group has people working on these types of biomass.
Finally, for those who go on an anti-car rant any time there is a discussion of liquid fuels: I personally would like to see a big reduction in motorized transport. The basis of our future energy strategy has to start with conservation. But I believe we will need liquid fuels for applications like long haul trucking, airline transport, and marine applications. There will likely be a liquid fuel need for emergency vehicles. So while I am under no illusions that bio-derived fuels can replace our petroleum usage, I believe they can make a contribution for critical applications.
The First Generation Contenders
Sugarcane Ethanol
Ethanol that is produced in conjunction with sugar production, especially from tropical regions like Brazil, has some unique attributes that have enabled it to compete on a head to head basis with gasoline pricing. Specifically, during the production of sugar, the bagasse (sugarcane residue) is pulverized and washed many times. Many soluble inorganic constituents that may normally pose an ash problem for a boiler are washed out in the process. What remains after processing is a pretty clean biomass feed for the boilers. The normally vexing logistical issues aren't present because the biomass is already at the plant as a result of the sugarcane processing. So they essentially have free boiler fuel, which minimizes the fossil fuel inputs into the process. That enables ethanol production that is relatively cheap, and that is largely decoupled from the impact of volatile fossil fuel prices.
There are several reasons we don't this in the United States. Last year I made a visit to the largest sugar producer in Louisiana, and they explained the reasons to me. Ethanol can be produced from sugar (but sugar subsidies discourage this), or from the molasses that is produced as a co-product. (The latter was the basis of the plant I visited in India). For sugar producers in the U.S., the economics of the by-product molasses generally favor using it as an additive to animal feed. If the U.S. had a year-round growing season as they do in the tropics, it is more likely that the animal feed market would start to become saturated, and conversion into ethanol might be more attractive. Further, a bagasse boiler is a major capital expense, so there needs to be a high level of confidence that in the future ethanol will consistently be a more economical outlet than animal feed. For Brazil, this is certainly the case.
The ultimate downside of sugarcane ethanol will come about if the U.S. and Europe begin to rely heavily on tropical countries for their fuel needs - thus encouraging a massive scale-up. First, trading oil imports for ethanol imports doesn't do much for domestic energy security. More importantly, it may encourage irresponsible usage of the land in an effort to feed our insatiable appetite for fuel. I think the ideal situation would be to produce the sugarcane ethanol and use it locally, rather than try to scale it up and supply the world. In this way, sugarcane ethanol could be a long-term contender for providing fuel for the tropics, but not a long-term contender for major fossil fuel displacement outside of the tropics.
Palm Oil
The other major first generation contender is palm oil - which also comes with a lot of environmental risk. Palm oil is derived from the African Oil Palm. The oil palm is a prolific producer of oil, which can be used as fuel (and food). This is also a plant that thrives in the tropics, and is capable of annually producing upwards of 500 gallons of oil per acre. To my knowledge there is no other oil crop that consistently demonstrates these sorts of yields (acknowledging that algae could theoretically produce more).
The price of palm oil over the past 5 years or so has traded in a range comparable to that of crude oil; $50-$75 a barrel for the most part (although like petroleum, prices shot up to around $150/bbl in mid-2008). Palm oil can be used unmodified in a diesel engine, although some precautions are in order (and I don't recommend it). It can also be processed to biodiesel, or hydrocracked to green diesel. The extra processing will generally make the final product somewhat more expensive than petroleum, but demand has still been strong due to biofuel mandates.
The risks with palm oil are significant, though. Palm oil presents an excellent case illustrating both the promise and the peril of biofuels. Driven by demand from the U.S. and the European Union (EU) due to mandated biofuel requirements, palm oil has provided a valuable cash crop for farmers in tropical regions like Malaysia, Indonesia, and Thailand. The high productivity of palm oil has led to a dramatic expansion in most tropical countries around the equator. This has the potential for alleviating poverty in these regions.
But in certain locations, expansion of palm oil cultivation has resulted in serious environmental damage as rain forest has been cleared and peat bogs drained to make room for new palm oil plantations. Deforestation in some countries has been severe, which negatively impacts sustainability criteria, because these tropical forests absorb carbon dioxide and help mitigate greenhouse gas emissions. Destruction of peat land in Indonesia for palm oil plantations has reportedly caused the country to become the world’s third highest emitter of greenhouse gases.
Because palm oil is capable of competing on price, it was originally viewed as a very attractive source of biofuels. In recent years, countries have begun to rethink their policies as the environmental implications of scaling up palm oil production began to unfold. As is so often the case, the biofuel mandates that politicians thought were a good idea have had some pretty serious unintended consequences.
Next Generation Biofuel Contenders
Here is how I would define a next generation Biofuel Contender: A technology that is capable of supplying 20% of our present liquid fossil fuel consumption on a net energy basis.
Yes, 20% is somewhat arbitrary, but it weeds out a lot arguments over many potential small contributors. If you set the bar too low - say 5% - all kinds of things come out of the woodwork and make claims. Too much to discuss or debunk. Set the bar too high - say 50% of our current usage - and in my opinion no renewable fuel can meet that target via biomass. Although the pretenders will insist that they can.
I will focus in this essay on the United States, because I am most familiar with our energy usage and biomass availability, but these arguments should be applicable in many places around the world.
Consider for a moment the amount of energy locked up inside the 1.3 billion tons of dry biomass that the Department of Energy and the USDA suggest can be sustainably produced each year. (Current biomass usage is 190 million tons/year). Woody biomass and crop residues - the kind of biomass covered in the 1.3 billion ton study - contains an energy content of approximately 7,000 BTUs per pound (bone dry basis). The energy content of a barrel of oil is approximately 5.8 million BTUs. Thus the raw energy contained in 1.3 billion tons of dry biomass is equivalent to the energy content of 3.1 billion barrels of oil, which is equal to 42% of the 7.32 billion barrels the United States consumed in 2008.
This calculation tells you a couple of things. First, the 42% represents an upper limit on the amount of oil that could be displaced by 1.3 billion tons of biomass – presuming we could really produce that much sustainably. The actual amount of oil displaced would be much lower because energy is required to get the biomass to the biorefinery and then to process it. So replacing oil with biomass isn't going to be a trivial task, and a process must be capable of turning a respectable percentage of those biomass BTUs into liquid fuel if it is to be a contender. But it is unlikely that we are going to replace anything approaching our current level of energy usage with biomass.
Imagine a process that only captures 25% of the starting BTUs as liquid fuel. The liquid fuel production of 1.3 billion tons would then be 10.5% of our oil usage instead of 42% - and that's before we consider the energy requirements from the logistical operations (like getting that wood to the biorefinery). This is the realm of the pretenders; they waste a lot of BTUs during the production of the liquid fuel. What we really need is a process that can capture >50% of the BTUs as liquid fuels. That's what it will take to be a contender, and quite frankly I don't believe cellulosic ethanol has a chance of pulling this off on a large scale.
However, there are at least two technologies that can achieve net liquid fuel yields in excess of 50% of the BTU value of dry biomass. These technologies are flash pyrolysis and gasification. I will talk about each below. (Hydrocracked oils – green diesel - might get close as well, but the most consistent oil producers are generally also foods).
Flash Pyrolysis
Flash pyrolysis involves rapidly heating up biomass to around 500°C. The reaction takes place in about 2 seconds, and the products are pyrolysis oil (also called bio-oil) and char. The process can handle a wide variety of feedstocks, the oil yield is approximately 70% by weight, and the energy content per pound of oil is similar to the starting material. Thus, approximately 70% of the initial BTUs are captured in the oil before we have to start subtracting out energy inputs.
Char is frequently mentioned as a great soil amendment (as terra preta, for instance), but I don't really know if there is a market for it. As someone recently said to me, it may be like biodiesel and glycerin. In theory there are all kinds of uses for glycerin, but the market was quickly saturated as biodiesel production ramped up. Glycerin suddenly became a disposal problem. Terra preta does in fact appear to be a great soil amendment, but people are going to have to show that they will buy it. It seems to me that the ideal solution would be to use the char to help heat the biomass, unless the ash properties are problematic for the process.
There are definite downsides to flash pyrolysis. Heating up to 500°C will subtract from the net energy production, and while heat integration is possible, it would be more difficult to achieve in a hypothetical mobile unit (which I think could finally provide an outlet for the millions of acres of trees destroyed by the Mountain pine beetle). The properties of the raw oil are such that it isn't suitable for transport fuel as produced. It is not a hydrocarbon and is very acidic. Without upgrading, it can't be blended with conventional diesel. There are various issues around reproducibility and stability, especially if the biomass quality varies. The oil is suitable for power generation or gasification, and can be upgraded to transportation fuel, albeit at greater expense and lower overall energy efficiency.
With those caveats, it is still a contender. It could be knocked out of contention as a viable transportation fuel if the upgrading process is too expensive or energy intensive, but at present no fatal flaw has emerged. There are a number of companies involved in pyrolysis research. Dynamotive Energy Systems has been working on this for a while (I first wrote about them in 2007). UOP - a company that specializes in product upgrading for refineries - has teamed with Ensyn to form a joint venture called Envergent Technologies. The company intends to make pyrolysis oils from biomass for power generation, heat, and transport fuel (this is where UOP's skills will come into play).
Gasification: Biomass to Liquids
The following example is just one reason I think gasification is going to play a big part in our future. During World War II, the Germans were cut off from liquid fuel supplies. In order to keep the war machine running, they turned to coal to liquids, or CTL (coal gasification followed by Fischer-Tropsch to liquids) for their liquid fuel needs. At peak production, the Germans were producing over five million gallons of synthetic fuel a day. To put that into perspective, five million gallons probably exceeds the historical sum of all the cellulosic ethanol or synthetic algal biofuel ever produced. Without a doubt, one week's production from Germany's WWII CTL plants dwarfs the combined historical output of two technologies upon which the U.S. government and many venture capitalists are placing very large bets.
South Africa during Apartheid had a similar experience. With sanctions restricting their petroleum supplies, they turned to their large coal reserves and once again used CTL. Sasol (South African Coal, Oil and Gas Corporation) - out of necessity - has been a pioneer in gasification technology. Today, they have a number of gasification facilities, including the 160,000 bbl/day Secunda CTL facility, which has been highly profitable for the company (but very expensive relative to oil prices when constructed). In total, Sasol today synthetically produces about 40% of South Africa's liquid fuel.
While we can speculate on the source of future fuel supplies in a petroleum constrained world, we do know that two countries that already found themselves in that position turned to gasification as a solution. The technology has a track record, is scalable, and today commercially produces synthetic fuel in volumes cellulosic ethanol or algal fuel can only dream about. We hope various other technologies scale and that technical breakthroughs allow them to compete. But gasification has already proven itself as a viable go-to option. There are presently a number of operating CTL and GTL plants around the world. Shell has been running their Bintulu GTL plant for 15 years, and is currently building the world's largest GTL plant with a capacity of 140,000 barrels/day.
The biomass to liquid fuel efficiency for gasification is around 70% (See Section 1.2.2: Second-Generation Biofuels), a number cellulosic ethanol will never approach. In short, no other technology to my knowledge can convert a higher percentage of the embedded energy in biomass into liquid fuels.**
Of course there's always a catch. Despite large reserves of coal, the United States has not turned to gasification as a solution. Why? High capital costs. At the end of the day the desire to keep fuel prices low consistently overrides our desire for energy security. (There are also greenhouse gas concerns over using coal gasification which should not be an issue for waste biomass gasification).
But biomass is more difficult to handle, so there are added costs above those of coal gasification. So you have a process that is more capital intensive than a conventional oil refinery, or even a cellulosic ethanol plant. But what you save on the cellulosic ethanol plant ultimately costs a lot in overall energy efficiency. Until someone actually scales up and runs a cellulosic ethanol plant, we can only speculate as to whether cellulosic ethanol is even a net energy producer at scale.
Interestingly, one of the "cellulosic ethanol" hopefuls that we often hear so much about - Range Fuels - is actually a gasification plant. (Ditto Coskata). The front end of their process is intended to produce syngas in a process derived from that of World War II Germany. For their back end they intend to produce ethanol, which in my opinion is an odd choice that was driven purely by ethanol subsidies. But this is definitely not the optimal end product of a gasification process. They are going to lose a lot of efficiency to byproducts like methanol (which is actually a good end product for a gasification plant) - and that's assuming they get their gasification process right. They are then going to expend some of their net energy trying to purify the ethanol from the mixed alcohols their process will produce.
The question for me is not whether BTL can displace 20% of our petroleum usage. I believe it can. The question is whether we are prepared to accept domestic fuel that will cost double (or more) what we pay today. In the long run - if oil prices continue to rise - then BTL plants that are built today will become profitable. The risk is that a sustained period of oil prices in the $50-$70 range will retard BTL development. But I don't expect that to happen.
Conclusions
In my opinion, the question of which next generation biofuels can compete comes down to fossil fuel prices. If oil prices are at $50 for the next 10 years, it will be difficult for next generation renewable fuels to compete. Despite the many promises of technologies that will deliver fuel for $1 a gallon, I think that target is likely to be reached only on paper. My view on which technologies will be competitive is based on 1). An expectation of an average oil price over the next 10 years that exceeds $100/bbl; 2). An expectation that we will need to efficiently convert the available biomass. 3). Knowledge of what many of the major players are doing. I expect biomass prices to rise as well, and inefficient technologies that may be competitive if the biomass is free and fossil fuel inputs like natural gas are low-priced will not survive as the prices of both rise.
I am certainly interested in helping promote promising next generation technologies, so if you think I have missed some really promising ones then feel free to add your thoughts. It is possible that a company like LS9 or KiOR will ultimately be successful, but they are going to require some technical breakthroughs. Those don't always happen (I am waiting for a laptop battery that runs my laptop for a week on a single charge). Given the great number of renewable energy start-ups, it won't be surprising if one or more of them eventually makes a contribution, but the odds are against most of them. I selected pyrolysis and gasification as strong contenders because they don't require technical breakthroughs in order to produce large amounts of fuel. The technical aspects of gasification at large scale are well-known. This is not the case with most companies seeking to compete in the next generation arena.
Personal Note on Technology Development
On a personal note, since I have long believed in the promise of gasification as a future solution to our liquid fuel problem, it may come as no surprise that my new role in Hawaii has connections into this area. While several have figured out what I am doing, I still don't have the green light to explicitly discuss it (but I should before year-end). I am not being coy, it is just that we still have some pieces to put in place, and then I will explain why I believe we are building a platform that is unique in the world. I can say that my new role is as Chief Technology Officer of a bioenergy holding company, and the platform we are putting together does not exist elsewhere to my knowledge.
One of the things I am very interested in is developing conversion technologies for woody biomass and crop wastes. I have a number of technologies on my plate right now, but I am searching for other pieces that improve the economics (scalability is important).
For example, in the earlier example of the beetle-infested forests, the logistical challenge of getting the biomass to a processing facility - without consuming a large fraction of the BTU value of the tree - is significant. Biomass has a low energy density relative to fossil fuels, and cost-effective technologies are needed for improving that equation. I am speaking to a number of people with promising technologies around this area, but am always open to speaking to others who have ideas, prototypes, or pilot plants demonstrating their technology. You can find my spam-protected e-mail in my profile.
Footnotes
* Following the publication of this essay on my blog, I had a meeting with someone inside the Department of Defense who is involved in testing fuel for the military. The person said they were able to get some algal fuel to test from one of the well-known names – for around $100/gal.
** I have heard from a couple of people that 70% seems too high, and is likely a result of an improper energy balance. I have personally seen this number several times, but I have not seen a full energy accounting to validate that. One person who is very well-versed in gasification said that total energy balance will probably put the liquid fuel recovery at about 50% of the starting BTUs. (You can't calculate an EROEI from this unless you also have the fossil fuel inputs – primarily from the logistical operations).
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Fascinating.
I would like to push back a bit on the 20% limit. Would you care to mention one or two of the minor contenders that look most promising--some that could probably never supply more than 20% of the need, but that may be useful locally. After all, as you say, liquid fuels will necessarily have to be limited to a much narrower range of critical applications in the future, so a minor source may serve to cover one or two of these niches, perhaps. Which ones would have the best chance of serving this function.
For example, could bio-diesel from, say, rapeseed be effectively used for farm equipment and for trucking food to market? These seem to me to be among the most crucial functions to maintain going forward if we are to avoid mass starvation.
I would like to push back a bit on the 20% limit. Would you care to mention one or two of the minor contenders that look most promising--some that could probably never supply more than 20% of the need, but that may be useful locally.
The next essay will get into that.
even though I am hopeful that electric cars become a real contender
I use a built in 1923/24 electric car several times/week.
Almost half the workforce in Washington DC gets there with with electrical propulsion, etc.
No new technology required.
long haul trucking
Not required (except in exceptional circumstances). Local and even regional, yes, but not long haul.
The primary focus should be on efficient Non-Oil/Non-Liquid Fuel Transportation using mature technology.
Best Hopes,
Alan
Alan,your point about long haul trucking being unnecessary is maybe a little premature but I agree in principle.
Do you have links or references on how long and how much it might cost to get the trains nback into service in to the extent that trucks can really be relageted to local use?How long might it take to realize an energy saving by rebuilding the railroads to such an extent?Do you think it can even be done,given the state of the economy?
RR has done his homework well,has he not?It's going to take a while to digest this article.
Electrifying all mainlines (about 36k miles) and 50k busy branch lines
Double tracking basically all main lines (excess capacity in many cases, but no congestion) (i.e. double tracking expands capacity by x3 to x4 vs. single track and saves time and adds reliability of on time delivery).
Rail over rail bridges when E-W crosses N-S
Grade separating about 90% of crossings (last 10% get difficult price/benefit)
Making all main lines & some branch lines clearance for double stack containers
Many intermodal facilities as well as moving factories & warehouses to rail sidings (or extend rail sidings)
14,000 miles of semi-High Speed rail (freight at 90 to 100 mph, pax at 100 to 125 mph on same tracks)
Time - 20 years (first ten to twelve years at tar sands development pace)
Cost - About 5 or 6 AIG bailouts
Best Hopes,
Alan
Yes. Actually, I think we could get most long distance freight on to the rails (or, to a much lesser extent but not to be ignored, on boats & barges) very quickly, and achieve some very quick energy efficiency gains and corresponding reductions in our need for diesel fuel. The electrification of the rail lines needs to happen and will come, but let's not have the incorrect idea that it must happen BEFORE the freight moves on to the rails. It isn't a precondition, and it is in fact starting to happen right now. Using good old Pareto's rule of thumb, we can probably expect to see about 80% of the benefit with the first 20% of your added investments, so we might not need to wait anything like your 10-20 years to realize most of the gains.
Removing the long-distance truck traffic from the highways would have the further benefit of knocking the support from under the highway construction lobby once and for all, with a consequent reallocation of highway construction funds to better long-term uses.
Kudos all. Revitalizing rail transport is such an obviously logical thing to do environmentally, economically, security-wise that I simply cannot imagine it being allowed to happen. Whatever forces have blocked it for the past many years that that statemen has held true are unlikely to go away.
With the trucks mostly off the roads highway maintainence expense will shrink enormously-another plus for all of us but another nail in the coffin of bau.
This shapes up to be a rumble in the jungle of the halls of congress. Ten years until it is up for a vote maybe?
More efficient trucks could also be employed.
The EU is currently looking at these 'Gigaliners' with a 40 ton payload, which consume 32 liter per 100 km or 7.35 mpg.
This corresponds to 294 mpg per ton of freight.
http://gueter-auf-die-schiene.de/file_download/45/Niedersachsen-Auswertu...
What is the average mileage of big rigs in the US?
The amount of liquid fuel could be further reduced if the engine was at least partially powered by CH4 or Hythane (from natural gas or organic waste).
And then there is probably still some room for aerodynamic improvement.
You can see variations of such trucks on American limited access highways almost any where already.
The guys who drive them call them wiggle wagons.
In Australia they hook up three or four and that makes them functionally almost equivalent to highway capable rubber wheeled trains.
Too bad I know only about a hundred words of German,I would like to read it.
A Swedish project for even longer trucks:
http://www.youtube.com/watch?v=WCZis4-z2Mw
(I hate the muzak used in these promotion videos. )
The fastest growing timber freight is btw via rail.
Hi Rob,
Have you done any calculations into the water requirements of the two contenders?
Here is testimony Michael Webber (you met at last year's ASPO conference) gave to US Senate Committee this past spring.
Michael will be addressing the water/energy nexus at this year's ASPO conference.
Thanks for another great piece.
(I love the Big Island but how long before you go stir crazy?)
RR wasn't specific about the biomass feedstock, but it could include both crop residue and purpose-grown biofuel crops like switchgrass and miscanthus. They can theoretically grow without irrigation, but yields are lower.
If freshwater and topsoil are limited, what are the prospects for growing algae in open saltwater ponds? Not for oil content but strictly for biomass gasification. Would water content cut into EROEI? Would salt be a problem for the gasifier?
Have you done any calculations into the water requirements of the two contenders?
We are very focused on water requirements. As Michael says "depending on how you produce them." This is the key. The water requirements are generally similar to those of an oil refinery, because the back half of pyrolysis and gasification have many common components with refineries. They require water for process steam and cooling. On the feedstocks, nobody I work with is interested in bioenergy crops that require irrigation.
I love the Big Island but how long before you go stir crazy?
Well, it is a Big Island. :-) I have yet to explore most of it. I am in the midst of a mass of green hills and mountains; I could probably hike the rest of my life and not see it all. The other thing is that I will be getting off the Island on a fairly regular basis. I probably have to go to Germany in two weeks, and I will likely be in Chile, New Zealand, and Malaysia before year end.
A while back I watched a TV interview with geneticist Craig Venter, he talked about genetically modifying Algae to find one for bio-fuels. He intimated that he was well along the path.
He discussed the thing in general and I kind of thought of it as brewing fuel beer. If he does get the correct mix he can buy the whole planet and make Bill Gates look poor.
Technically he thought it was possible, but as always the devil is in the details.
Here's a 'back-of-the-fag-packet' idea:
We take a huge coral atol somewhere near the equator, the sides of the atol have a nice steep slope down to 1 or 2km so we can easily pump nutrient rich deep water up via a self-powering OTEC (which also runs the air-com for the 'Paradise-Bay' resort and on-site Engineers apartments ;o).
We take this water and pump it into the atol where it mixes with warm surface waters laced with genetically engineered algae. An explosion of green goo results...
24/7/365 solar powered harvesting trawlers zig zag through the goop scouping it up, dumping it into sun-dryers that compress into bales. Being 25-40% by dry weight oil the algae-bales are processed and extracted oil is exported world wide by supertanker.
I'm sure there are dozens of reasons why this might or might not work.
Nick.
Noutram,
Is your external filter malfunctioning? Please edit your first line.
Fag == cigarette in Britain?
I'm sure you are correct--I had never heard it before. There is a word we use commonly in the US to refer to a hip pack that is considered very vulgar in the UK (I learned the hard way). When in Rome...
Two nations divided by a common language.
I have encountered similar problems using innocent slang from the English Midlands, which had a very different meaning in London, 100 miles away.
When the Internet dies, the sad decline in in our global babbling will be reversed.
I live in a region where "Can you jump me?" is normally a perfectly innocent question.
Cold weather+lead batteries...
Debbie - did you think he was proposing bending a homosexual over and writing on his or her back with a magic marker? Just curious what visual you had that got your hackles up...
Burjoes -
That was funny as all hell!
I almost sprayed my coffee all over my keyboard when I read that.
Yes, one much watch one's colloquial expressions when posting things to a potentially international audience, and I strongly suspect that the there was some intentional mischief at work when the writer used that choice of words.
I always thought you could do a similar thing with seaweed and anaerobic digestion. Large tankers would skim it off the surface of the water and digest it, returning to shore with the nutrient rich digestate and methane. The ship could be powered by a simple steam cycle using concentrated sunlight with the extra heat warming the digestion.
OMGlikeWTF -
I have been seeing a number of comments lately showing enthusiasm for anaerobic digestion as a means of producing fuel on a commercial scale. I think some things regarding anaerobic digestion need to be put into perspective.
First, it was initially used for the treatment of sewage treatment plant sludge in order to make it less offensive for eventual land disposal (raw sewage sludge stinks to high heaven whereas digested sludge has a far less offensive earthy odor). The generation of combustible digester gas (typically 2/3 methane and 1/3 carbon dioxide and other gases was for many years considered a byproduct. Many of the larger municipal sewage treatment plants now use this digester gas (after cleaning it up) to help power plant equipment and thus defray energy costs.
Second, if one wants to run a high-rate anaerobic digester (say something with a 20-day detention time), then the digester must be operated at a higher temperature than normal ambient air, typically 100 to 130 degrees F. Thus, the digester must be heated, and in colder climes that's what a good part of the digester gas is used for: to heat the digester itself.
While I don't have specific number right in front of me at the moment, the amount of digester gas produced per day is not very large in comparison to the required volume of digester required. So, this roving ship you describe would have to be quite large, but would produce relatively little net energy. In fact I question whether it would be enough to run the ship itself.
Third, and this is probably most important, the net conversion efficiency of a digester in terms of BTUs of digester gas produced per BTU content of incoming material is quite low. This should be readily apparent from the fact that digester gas is about 1/3 carbon dioxide, meaning that a large fraction of the reduced carbon in the incoming material was converted into carbon dioxide which has no heating value whatsoever. This is typical off anaerobic processes - part of the original carbonaceous material is converted into more reduced compounds while part of it is converted into more oxidized compounds.
Fourth, and this is also important, not all of the organic content of a bio-mass feedstock gets converted during the digestion process. Cellulosic material and many other organic compounds do not digest well, and that is why some organic residue is still left after the digestion process is completely. So, this further erodes the overall conversion efficiency.
Now having said that, I'm all for using anaerobic digestion as a means of extracting some energy from waste materials already generated, and we should do more of it (the Europeans are way ahead of the US in using this process for livestock waste). However, in my opinion it doesn't appear to hold that much promise as an actual energy production process in which you intentionally harvest bio-mass for the sole purpose of digestion.
There are much better ways of doing this, such as the pyrolysis and gasification techniques discussed in Robert's article above. For that reason, I could much more easily picture your roving algae-harvesting ship having some sort of a gasifier rather than a digester. Still, there are serious obstacles, the main one being that the algae is quite wet (ever after being squeezed in some sort of a filter press), and that moisture content consumes a great deal of energy when the algae is heated.
I
The ship idea was a bit far fetched I admit, but biomethane does have a much better EROEI balance than other biofuels. The thermal requirements for heating the digester are actually quite modest compared to distilation, and this heat can come from the 'waste' heat from electrical generation at the end of the process or ideally solar thermal.
http://dx.doi.org/10.1016/j.biombioe.2008.08.018
Also wet oxidation treatment can be used to break down the lignocellulosic structures
http://www.ramiran.net/doc06/O-12%20Uellendahl.pdf
Biogas (~30-50% CO2)can be upgraded to methane through compression, cooling or pressurised water scrubbing all obviously needing energy inputs but are proven technology.
There is interesting potential for catalytic gasification which could be done at much lower temperatures and with a much higher water content.
http://www.genifuel.com/text/20090420%20Renewable%20Natural%20Gas%20via%...
OMGlikeWTF -
The thermal requirements for a high-rate digester are, of course, heavily dependent on climate. Not too bad if you're in Florida, but horrendous if you're in Minnesota. Regardless of whether you have very heavy insulation, having a stirred liquid at 135 degrees F on the inside of the wall and wind at say 0 degrees F on the outside of the wall is going to result in some very high heat transfer rates. Naturally, the bigger the digester, the smaller the surface-to-volume ratio and smaller the thermal requirements per unit volume. If waste heat is available, heating a digester is an excellent way to make use of that waste heat.
Sure, wet oxidation can (partially) break down cellulose material, but that's adding another expensive processing step that will negatively impact the already shaky economics.
Yes, there are ways to separate the methane from the biogas, but I think this is rarely done if the biogas is going to be used on-site. Though you would have to do it if you want to inject the biogas into a natural gas pipeline.
The catalytic gasification process does indeed look interesting.
One unrelated comment about algae: I am becoming more of the mind that algae may have more potential value as a food source (either directly or indirectly as livestock feed) rather than as a fuel. Don't forget that even if gasoline is selling for $4 per gallon that is still only 57 cents per pound. Mightn't we get more economic value out of the algae (with much lower processing costs) as a food product?
and other gases
Sulfur and Nitrogen containing gases that oxidize into Sulfuric and Nitric Acid.
Now imagine that acid on your energy conversion equipment - say an Internal Combustion Engine. Or cookware. Or .....
Working Stirling Cycle engines with a easy to replace heat exchanging head would be a possible answer. Or at least a better one than an ICE.
So how much longer is it going to be before I can go down to my local lawn and garden store and buy a stirling?
New five horsepower Honda ices are only four or five hundred bucks-and that includes a machine attached to it,such as a pressure washer or garden tiller.
I'd like to have that answer myself.
The last 5 HP unit was the ST-5 and some Japanese bought the rights....never to be seen by us mortals again.
Stirlings simply cannot compete with IC's as long as refined fuel at $2.50 / gallon exists. How high it has to go before a market for them develops I'm not really sure. I do know that SES Stirling Energy Systems - Technology - Advantages is installing stirling generator solar dish units in California which are stated to be 31% overall efficient generating electricity from sunlight, meaning the engine must be significantly better (and also meaning those heater head temperatures must be VERY high). Materials costs due to temperatures, high gas pressures, perhaps trickey gasses like hydrogen, make heat exchangers for these units extremely expensive. Reduce the specs so the materials get affordable and the efficiency drops to where it's useless.
That would be a very good application for solar thermal. A few panels should be able to raise the system temps to those levels, leaving all of the biogas for output.
The non-Rube Goldbergesque alternative would be to skip the atoll, OTEC, harvesting trawlers, dryers, algae balers, bale supertankers..., and just use the solar thermal to heat peoples houses.
However, the atoll and the sunshine is in a nice hot tropical place whereas the place where the oil/energy is needed is somewhere freezing, cloudy, and otherwise non-sunny. Sounds like any method for efficiently bundling up the sunlight's energy and shipping it to the northern climes would be very useful.
Oh, were we just talking about some ship-bourne scheme here? I was refering more to land-based systems - which are what 100% of all anaerobic digesters are now. Yes, solar thermal should be used directly for residential heat, and that will help. However, especially in colder regions it will need to be supplemented, and for many homes that will have to mean some form of gas heat. The NG won't last forever, but biogas is a renewable resource, and indeed is the one "biofuel" which truly makes good sense. Using solar thermal panels to heat the slurry in the digester makes perfectly good sense, too.
Four or five volumes per day for thermophilic. From what I've found most of the larger ones are mesophilic as opposed to thermophilic, fermenters have to be scaled up but are much less finicky. Costs still look good compared to other alternative schemes, about $15K per installed barrel equivalent.
Not always true. Manure is already partially stripped of the structural carbohydrates that the microbes work on, but for ensiled grass conversion can exceed 70%. Forget wood.
Grasses in digesters with some regularity exceed the theoritical maximum output for cellulosic ethanol with the same feedstock. Feeding grain to digesters gives more energy yield than fermenting to ethanol, check out the work of Niamh Power1, and Jerry Murphy in Ireland. It may not have much promise, but it has more than anything else as far as crop fuels go.
One of the reasons it won't work is the energy content of baled algae is going to be pretty small, and the freighters may burn most of the cargo on the round trip.
Using supercritical water oxidation (SCWO) to convert the algae to a bio-oil (much less oxygen than pyrolysis oil, 2-12%) would probably be a better bet. Here is the Green Car Congress post on the issue. I note that the biomass-to-liquids efficiency is claimed to be extremely high (70-90%), and an operation on an atoll could perhaps use solar energy to supply the process heat.
Now all you need to do is get the atoll, get the productivity up there (make sure zooplankton don't eat all your profits), make sure you can harvest it, get the conversion process to shippable product debugged, build a port for the ships... should be a snap. ;-)
Problem: wild type algae will out-compete the genetically engineered algae.
One has to isolate genetically engineered algae in order to use it. One can physically prevent other algae from reaching the genetically engineered strain. Or one can genetically engineer the special strain to only grow in a special broth that a wild type strain can't handle. But in a lagoon you can't do the isolation.
If algal biofuels are not currently being produced on a commercial basis, I don't see how that precludes ongoing efforts at pilot plants from arriving at commercial solutions in the near term. Of course, that doesn't mean they will have no problems getting there, as well.
Some efforts underway, as I mentioned before;
In Virginia, researchers at Old Dominion University have successfully piloted a project to produce biodiesel feedstock by growing algae at municipal sewage treatment plants. The researchers hope that these algae production techniques could lead to reduced emissions of nitrogen, phosphorus and carbon dioxide into the air and surrounding bodies of water. The pilot project is producing up to 70,000 gallons of biodiesel per year. Such an amount is minor from a commercial production standpoint, and it may indeed fizzle at some point, but it currently shows promise, and is an outside-the-laboratory pilot success.
PetroSun, Inc. announced today that PetroSun BioFuels and the Town of Gilbert, Arizona have executed an agreement to commence an algae-to-biofuels wastewater pilot program at the Neely Wastewater Reclamation Facility.
I'd say it's too early to call algal biofuels a pretender, though as I mentioned before, I don't expect it too be a silver bullet even if it is moderately successful. We are simply consuming far too many BTUs/kWhs in fuel, and our expectations of future consumption should be tempered sooner rather than later.
I look forward to hearing more about the biomass effort you are working on. I don't see any one solution being completely dominant at this point; indeed, having multiple options will be one of our best transition risk mitigations.
It may be technically possible to ramp up production but price is still a big issue even if the process problems are figured out. At the cleantech conference in San Francisco earlier this year I spoke to two algae biofuel company CEO's. I asked one in a public forum, "How much would a plant cost to produce 10,000 barrels per day?"
Despite putting on his slide deck that one of the uses of his product was for ICE engines, his response was close to this (going from memory):
"We haven't done those calculations. Let's see, that's a really, really big plant: 420,000 gallons per day. My guess would be $100 million."
That sounded way too low (the cost of coal to liquids is much, much higher) so I asked another CEO in the hallway what he thought of that response and he said, "No way. That's a gigantic plant for us. I would say at least $1 billion."
THAT perhaps is one reason why there are no commercial plants producing this type of fuel yet in large quantities. Until the price of the alternative (gasoline/diesel) is sufficiently high for a sufficiently long period of time (and there is a solid expectation that it will stay high) that investors are willing to place their bets on their competitors, many biofuels will be used in smaller sectors only, like cosmetics (one target market from the first CEO's slide deck).
But with the price volatility I'm expecting for oil (making planning difficult and investors risk-averse) and the recent experience of the ethanol producers (i.e. bankruptcy), how many investors are likely to build these very large plants? Maybe some, but I doubt very many.
Let's keep in mind the possibility that biofuels in our rocky economy may never make a significant contribution. It is more likely to me that our overall consumption of liquid fuels will come down to meet the meager production of these biofuels.
If algal biofuels are not currently being produced on a commercial basis, I don't see how that precludes ongoing efforts at pilot plants from arriving at commercial solutions in the near term.
The reason I call algal biofuels a pretender is not because I see no potential there. Rather they are pretenders because their hype does not reflect their reality. Truth be told, technical advances are going to have to be made before they can make an impact. $100/gallon is so far out of the ballpark that there is no guarantee that they are going to get there. People are making all sorts of claims around production at a much lower price (and Solazyme probably can produce it for a lot less, albeit from sugar), but try to secure some for those prices. The reason for the high costs is pretty fundamental. The logistics are challenging, and some advances will need to be made.
However, I do favor continued research into algae. Part 3 of this series covers algae as a potential niche fuel, and I describe what I think it will take to make it work commercially.
The pilot project is producing up to 70,000 gallons of biodiesel per year.
Here is what I found on that pilot project:
http://sci.odu.edu/hatchergroup/announcements/announce6.shtml
What is the source of the 70,000 gallon claim?
Different project, same researchers at ODU (if the sources are to be believed);
Please stick to hard numbers. "Up to" numbers aren't real. If we don't have the numbers, the discussion is pointless.
Cold Camel
The pilot project is producing up to 70,000 gallons of biodiesel per year
I think someone made a typo. There is no way they are producing at that rate. I will bet money on it right now, no questions asked. There is nobody in the world producing algal biodiesel at that rate. You might write to them and ask them about that quote. My prediction is that they will tell you it was a mistake, or they will talk about what they might do if they can scale their 1 gallon per day experiment up.
I've shot an email off to two of the researchers, and will report back with their response. Another link to the different ODU/Algal Farm joint partnership you brought up lists their goals;
Virginia's first algae farm an experiment in biofuel
I called the phone number on thier website,which has a picture of a race way pond and a paragraph or two of boiler plate,the usual stuff.
The lady who answered the phone would say nothing at all except that she is allowed to say nothing at all but she did refer me to thier lawyer for intellectual property rights.
If I find out anything else I will post it.
You're mixing up feedstocks and biofuels. You put palm oil and cellulosic ethanol at the same level, but they are not.
You left out some very important concepts here. First, actual "fuel" conforms to a standard. Diesel, for example, is ASTM D975, while biodiesel is D6751. Which standard these future fuels intend to conform to is of critical importance. It's not trivial to simply retool from making one type of product into another, so this should be a key part of the discussion.
Palm oil is a feedstock for biodiesel today, but can be a feedstock for renewable diesel, green diesel, synthetic diesel, and lots of other novel technologies. But talking about palm oil as a biofuel is mixing up apples and apple pie. The availability of feedstock for a particular biofuel is just one of the challenges associated with that biofuel. In the case of biodiesel, because it meets the D6751 standard instead of D975, it is not fungible with diesel. Renewable diesel (green diesel, coprocessed renewable diesel, etc) all conform to the D975 standard.
There are ethanol plants being built with biodiesel plants colocated to produce fuel from the distiller's grain left over from the ethanol process. This high FFA oil has been difficult to deal with in the past, but new technology is making this a viable feedstock.
The 20% number you put forth is a good one. A blend of B20 (20% biodiesel and 80% diesel) is likely the greatest blend that will be supported by OEMs, the pipeline, and the rest of the diesel infrastructure for the next decade or more. With demand at 60 billion gallons, 20% is 12 billion gallons.
It's my belief that biodiesel can eventually get there, but that B5 (5% - 3 billion gallons) should be a 5 year goal, with B20 being a 10 year goal.
The other 80% can slowly be replaced with renewable diesel and other variants, which all meet the native fuel specs and don't have the same compromises as biodiesel.
All that being said, I do believe that B100 (pure biodiesel) will continue to be a niche fuel that will have a small but vocal loyal customer base. It can be made with ethanol or biobutanol (?) as a feedstock instead of methanol, which can get rid of the 10% fossil fuel input. Biodiesel is the only fuel today that can be made at a community scale, works in most diesel vehicles in use today at any concentration (with some notable exceptions) and let's an individual drive around on 0% petroleum oil imported from the middle east. That gets people excited about renewable fuel, which helps all the new variants.
Jason Burroughs
DieselGreen Fuels, Austin TX
"let's an individual drive around on 0% petroleum oil imported from the middle east."
I understand that moving from dependence on imported oil to a completely domestic system is a process that must start somewhere and that independence will be a long time coming.
However, let's keep in mind that the whole infrastructure of creating these alternative fuels is still heavily dependent on regular oil throughout its manufacture, 2/3's of which is imported.
To say your clients are using zero petroleum imported from the Middle East is marketing-speak, and if you are the head of your company I understand why you feel the allure of saying it, but on this forum, let's be straight: it's far from the truth at this moment in time. Were I to take away your access to oil right now, your supply chain would evaporate.
Jason:
If we subtract out the diesel fuel going for long-haul trucking (the freight of which must move to trains or to ships and barges), then you are going to be looking at a substantially smaller quantity that ultimately needs to be replaced with some form of biodiesel. Electrify the rails, and replace urban buses with electric streetcars, and you are looking at a yet smaller quantity. Ultimately, I believe that we are going to be looking at just agricultural equipment, heavy construction equipment (and not so much of that needed in the future), municipal and utility service trucks, etc. - only that limited niche of really essential vehicles are still going to need to run on biodiesel. That limited subset probably can eventually be feasibly transitioned over to B100, and we can produce that much B100 without diverting too much cropland. To my way of thinking, we should just proceed with that ultimate goal in mind and not worry too much about fueling things like long-haul trucks. They will be out of the picture soon enough.
One thing to be careful with is balancing demand for gasoline and diesel, or rather fuel for spark ignition vs compression ignition engines. Oil refineries can tweak the mix within a range, but you'll always get both from crude. Up to 20% we could balance it by import/export of refined fuels, but beyond that?
You're mixing up feedstocks and biofuels. You put palm oil and cellulosic ethanol at the same level, but they are not.
Not cellulosic ethanol; sugarcane ethanol. You can certainly use palm oil directly as fuel. I know people who have done it. I don't recommend it, though. In fact, your own site mentions "vegetable oil as fuels for diesel vehicles."
You left out some very important concepts here.
Not for the purpose of this essay. Had the essay been all about palm oil, I would agree.
Palm oil is a feedstock for biodiesel today, but can be a feedstock for renewable diesel, green diesel, synthetic diesel, and lots of other novel technologies.
Here is where I think you have your categories mixed up. "Renewable diesel" covers all of the above. Green diesel can either be hydrocracked oils, or BTL liquids (which I think you are referring to as synthetic diesel). But I can't imagine a situation in which you would use palm oil to produce synthetic diesel. It is already liquid fuel, so I wouldn't break it down to the basics only to put it back together as diesel.
It can be made with ethanol or biobutanol (?) as a feedstock instead of methanol, which can get rid of the 10% fossil fuel input.
Generally, though, there are significant fossil fuel inputs into ethanol (and there certainly will be with biobutanol). I have looked at a scheme like this for a project in Africa, and ethanol always had too much value as fuel itself. It never made much economic sense to use it for biodiesel. You could get far more for it by exporting it to the U.S.
Getting paged to a meeting...
I had the understanding that most of the ethanol used in the deesterfication process was recoverable, so you only needed to add a relatively small amount to cope with the portion that wasn't.
Is this impression wrong, or is the usage of "too much" ethanol including the recovery cycle?
I had the understanding that most of the ethanol used in the deesterfication process was recoverable, so you only needed to add a relatively small amount to cope with the portion that wasn't.
No, he is talking about substituting ethanol for methanol. In that case it would be consumed. Take a look at the graphic in my Renewable Diesel Primer and you can see where it ends up:
http://i-r-squared.blogspot.com/2009/01/renewable-diesel.html
Gasification remains highly dubious IMHO.
Sasol gets 1.25 barrels of oil from a 1 ton of bituminous coal input(24 MJ/kg) or a 30% efficiency.
http://tiny.cc/kD0tv
http://www.newsmax.com/hostetter/Coal_Liquefaction/2008/08/06/119599.html
I saw in one place 1.5 barrels per ton of coal which would be about 36%.
Also gasification requires very high temperatures which are more difficult to produce with wood than with bituminous coal, in part due to the fuel moisture load. Dry wood is about 19% moisture. Dry bituminous coal is about 2.5% moisture. Lignite has about 20% which is comparable to dry wood.
Corn ethanol has an overall efficiency(fuel to total feedstock) of 57% and cellulosic ethanol has an overall efficiency of 45%.
http://www.nrel.gov/biomass/pdfs/39436.pdf
Wood may end up being too valuable to burn in the future as cement and steel require much larger amounts of fossil fuel than lumber.
Corn ethanol has an overall efficiency(fuel to total feedstock) of 57% and cellulosic ethanol has an overall efficiency of 45%.
I am working on a book chapter right now, and I discovered that there were two commercial cellulosic ethanol plants (wood-based) built in the 1910's. Neither could make a go of it, and despite sporadic government efforts again in WWII, they could never make a go of it. Meanwhile, we have several large commercial gasification plants worldwide.
Also, very important to bear in mind that the 45% for cellulosic ethanol is theoretical. Until someone actually builds a decent-sized plant and shares the data, we we are going on a series of assumptions.
Will answer other comments as time allows.
majorian and RR:
We need to keep in mind that NG isn't going to last forever, either. While the recent news coming from the tight shales might be encouraging, that is a short-term encouragement at best. It won't be many decades at all before NG goes into steep, permanent decline. Replacing NG with something more sustainable is AT LEAST as much of a concern as is replacing liquid fuels. Maybe even more of a concern. People can rearrange their lives to take a bus or streetcar to work instead of driving, but if they live in a cold climate, to avoid freezing they are going to need gas, either directly for their furnaces or indirectly via the power plant for the electricity to power their heat pumps.
Thus, while I think it is good to be thinking in terms of these various gassification schemes, I am not nearly so thrilled about the further step of GTL. This is especially true where NG itself is the feedstock, but also applied to the other feedstocks that RR addressed as well. IMHO, we are likely to need all that gas, however produced, to feed into the NG pipelines.
I think the tight shale production will go into permanent decline about twelve hours after we get honest answers about what they're mixing with the water they pump into those wells. Cancer causing agents like benzene are certain and I've seen one report where hexavalent chromium(!) was found. The EPA will have no choice but to toss producers an anvil or two ...
I read the articles you linked to, and see where you got the 1.25 barrels of oil per ton of coal, but I'm not sure if that's representative of the CTL process itself. Sasol produces a lot of hydrocarbon products besides diesel (waxes, varnishes, lubricating oils, etc.) and I believe they also produce electricity. Perhaps the 120,000 tons input is total coal input, while the 150,000 barrels is only the diesel output? At any rate, 30% thermal efficiency for CTL sounds low. From other reading I've done, my impression was that the CTL process itself would be in the 70 - 80% range. I could be wrong, though.
The Germans at Leuna in WW2 turned a million tons/yr of
German Fortuna brown coal(25.4 MJ/kg) into 200,000 tons of products/yr of which 35% was gasoline and 60% was diesel and the rest bottoms/waste.
200000 x (46.4 x 35% + 52.7 x 60%) x 1000/(1E9 x 25.4) = 35.7%
efficiency.
Patzek for what it is worth gives 41.1% efficiency for CTL process alone.
This is less than nrel says for cellulosic ethanol at 45%.
Also cellulosic ethanol requires 19% fossil fuel inputs
http://www.nrel.gov/docs/gen/fy04/36831c.pdf
Take for example corn stover at 18.715 MJ/kg or 7,664 Btu/#, how many gallons per ton does that work out to?
.45 x (7664 x 2000)/75700 = 91.1 gallons per ton.
R2 posted this interview with Mark Stowers of POET,
91.1 gal per ton would appear to be in the low 90's.
However lets also add in the fossil fuel inputs.
I don't have any fossil fuel inputs for CTL but there must be some at least for mining and transporting coal.
(91 x 75700)/(7664 x 2000 + (91 x 75700/5.33))=41.4%
In both cases this is higher than CTL.
Again, I am dubious that BTL can be more efficient than coal as biomass is less energy dense than even brown coal.
You are mixing up several things. The 45% is for conversion efficiency. That has little to do with the net energy. The conversion efficiency can be 100% and your net energy negative if you had to input more BTUs into the process than the biomass contained.
From the interview with Mark Stowers, the BTU of ethanol/BTU of stover is down to 44% before we subtract a single BTU for transport or distillation. Given that his ethanol titers are going to be less than 10%, the distillation energy is going to be huge. This is certainly going to drop the BTU efficiency down into the 30's, and we still haven't considered transportation.
Your NREL numbers are all based on hypotheticals. And I have multiple references to BTL in the range of 50% to 70%. I may find out that it is 45%, but if you do a proper accounting of cellulosic ethanol you will be lucky to be at 25%. More on this later, as I have to run. But look at the USDA studies on how much distillation energy it took to run a corn ethanol plant with much higher ethanol titers...
Conventional gasification, whether of biomass or coal, uses partial combustion with injection of oxygen, along with some amount of steam. Using biomass, with its higher moisture content, rather than coal just reduces the proportion of injected steam. I don't see any reason for the higher energy density of coal to affect the conversion efficiency at all. The ash content of biomass is less than that of low grade coal, so the conversion efficiency might even be higher. (Less thermal energy lost in the form of hot ash.)
A lot of the thermal losses in FT synthesis come from the exothermic FT reaction itself. Overall plant efficiency depends in part on how much of the heat from the FT reactor can be captured and utilized. It's mid-grade heat, a couple of hundred degrees C IIRC, so not great for power generation. But fine for desalination of water, and for production of steam for the gasifier.
Efficiency in chemical plants can be as much a matter of economics as it is process; how much is it worth spending on efficient heat exchangers and heat recovery systems, weighted against the cost of energy?
Coal and biomass are chemically similar hydrocarbons but a coal flame is about twice as hot as a wood flame because it has a lot more carbon and carbon is higher density than hydrogen, etc.
Endothermic chemical reactions move faster with more heat(LeChatelier's Principle)--gasification is endothermic so raising the temperature drives the reaction forward so higher density coal should be more efficient than lower density biomass.
Economically, perhaps, but not thermodynamically. Higher productivity of equipment. But increasing the temperature to drive an endothermic reaction faster increases the distance from equilibrium and results in a greater increase in entropy. That means greater loss of free energy between input and output streams and lower thermal efficiency.
Not that that's likely to matter much. With partial combustion with oxygen injection, you can easily get any temperature you want up to the limits of the reactor vessel.
In both cases this is higher than CTL. Again, I am dubious that BTL can be more efficient than coal as biomass is less energy dense than even brown coal.
Let me take a stab here at clearing things up for you. The report that that USDA published in 2004 that estimated the energy balance of corn ethanol came up with an energy input for the conversion process – that is fermentation and distillation – of 50,000 BTUs/gal of ethanol (average for wet and dry mill). I can tell you without a doubt that the energy requirement for a cellulosic process is going to be higher than for corn ethanol. The ethanol titers are lower, and it takes energy to break the cellulose down into sugars.
So what does that do to the net BTU efficiency of the process? So far, we have an estimate of 90 gallons of ethanol per ton of stover. Subtracting from each gallon of ethanol are 50,000 BTUs to ferment and purify it. That knocks the energy efficiency of the process all the way down to 15%, and we aren’t even looking at transportation energy.
Like I said, you will be very lucky to get to 25%. Today cellulosic ethanol isn’t even there. So yeah, gasification beats that hands down (which helps explain why there are commercial gasification operations around the world).
Cleared up?
You changed the subject--I was talking about gasification versus ethanol.
Hehe.
So can I, so does nrel--did you even read the report?
The nrel report already says that it takes 1.75 Btus of corn plus fossil fuels to get 1 Btu of ethanol(57% efficient) while it takes 2.22 Btus of biomass plus fossil fuels to get 1 Btu of ethanol(45%).
(Geez, I wish I was a betting man.)
If you say so!
Convinced me!
Shall we change the subject, R2?
You changed the subject--I was talking about gasification versus ethanol.
The report - which I have looked over several times - is based on modeling. But why would I look at a model when I have POET's real world example? Anyway, I did not change the subject. I am talking about gasification versus ethanol. You are asserting an efficiency for gasification, which is too low, but I am reciprocating with an efficiency for cellulosic ethanol - which is supported by public information.
We have some information given to us - the NREL model is close to POET's experience - but you have yet to add in the fossil fuel usage. That is what I am doing above; taking the distillation requirements for corn ethanol and applying them to cellulosic. This is an assumption in favor of cellulosic given that the energy will necessarily be higher for cellulosic due to the lower ethanol titers.
If you say so!
I am not saying so. I am showing you. Start with X BTUs of biomass, which is given. End up with X BTUS of ethanol, which is given. Subtract fossil fuel inputs, which I have done above. End up with a net % of liquid fuel BTUs from the starting biomass. Your problem is that you are taking a model from NREL and plugging in a fossil fuel usage based on that model.
Shall we change the subject, R2?
I suspect this is majorian-speak for "I see now that RR is right." In that case, you can just say "OK, I got it." Then we can move on and you can drop the silly assertion that cellulosic ethanol is more efficient than gasification. Just thinking about it should tell you that it is a ridiculous notion. Cellulosic ethanol can't convert the lignin, a large portion of biomass that gets converted in gasification. Then your product ends up in water, which takes a lot of energy to remove. It is no contest.
Corn ethanol has an overall efficiency(fuel to total feedstock) of 57% and cellulosic ethanol has an overall efficiency of 45%.
By the way, I now know who will be the winner of the race to be the first to commercialize cellulosic ethanol:
The First Commercial Cellulosic Ethanol Plant in the U.S.
Turns out it wasn't much of a race. I guess those who cannot learn from history are doomed to repeat it.
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Hi Robert,
Great post. I'd be curious where you would place nut-tree oils in the contender / pretender mix. I've heard a bit lately about using black walnut and chinese chestnut fruits as biofuel feedstocks. Here in Western NY we have about a zillion black walnuts that basically grow as weed trees.
If you become unemployed you can pick up enough walnuts to make a hundred bucks a day if there are lots of trees and a good crop.
Black walnut that grows in the open where it grows fast is not worth much but if you happen to have a big sound tree on your property that has grown very slowly in the woods (where it is shaded and competes for water and sunlight)that weed might be worth a thousand bucks or more.Even the stumps of such trees are often dug up and hauled away for specialty uses such as the manufacture of the stiocks and handgrips of high end firearms.
I reccomend that every body who lives within the normal range of this tree plant a few on thier property if there is a suitable spot for them.The nuts are delicious as snacks,highly nutritious and prized by savvy bakers.They are also are a major source of food for squirrels which also happen to be highly prized by savvy cooks on short budgets.
Domestic hogs can also feed on walnuts if there is no other use for them.
While the wood might not be as valuable, Persian/Carpathian/English walnuts are much easier to work with overall. BWs have thick husks which are a bear to free the nut from; EWs fall out of their husks when ripe. BWs have thick, hard husks; EW's are easy to crack. Wild BWs are relatively skimpy on % of nut meat; EWs have a high % of nut meat. BW nut meat can be hard to extract in large pieces, not so for EWs.
Heartnuts are very similar to EWs, but crack even easier, and are susceptible to only Walnut Bunch disease. Plus, they are able to grow in marginal soils.
Agreed but the black walnut outer husks come off easily once thoroughly dry.The yield of meat per nut or per hour of cracking time is definitely much lower but you would be suprised at how fast you can crack black walnuts if you have a lot of them and do it as a family or friends visiting and talking activity-I can probably get a pound easily while the average novice is getting four ounces.
The extra work is imo justified by the extra flavor and the price premium-some local folks have long term retail customers that pay six bucks cash for thier wild nut meats and drive a good ways to get them.
We do have some English walnuts around the nieghborhood that seem to do ok as shade trees but they never have very many nuts for some reason,possibly the nursery stock was inferior.Definitely both kinds should be on tried homesteads in case one works out better than the other.You can always burn a tree that consistently fails to bear.
Perhaps the biggest plus of the native tree is that its a plant it and forget it local species that usually does well if in good soil well watered.
I definitely would keep the shade off as the nuts from year to year are worth more than a log a hundred years down the road.
If Black Walnuts work for someone, that's always a good thing. Around here, yields are lowered dramatically through endemic walnut anthracnose, while walnut blight hits other regions, both of which are not as damaging to English Walnuts. Add Walnut bunch disease to that list.
And BW give off high levels of junglen, which kills off a number of other plants nearby.
Waiting until the husks dries increases the astringency of the nut meat, though some may have an acquired taste for this if used in bakery products.
The best producing nut trees are grafted varieties, whether BW, EW, or Heartnut; seedlings take much longer to produce and yield fewer, smaller nuts.
One excellent source of information is the Univ of Tenn Extension Home Nut Tree Plan.
Nature is a poor provider without the right seedstock, but I have little knowledge on the specifics. Do you have a reference for this knowledge you can share?
Cold Camel
oldfarmermac -
Maybe a dumb question from a city boy, but if one wanted to plant a couple of walnut trees, would whole walnuts from the supermarket do, or does one need fresh-off-the-tree 'planting' walnuts still in their husks? Are some types considered good for planting while others are not?
Grafted varieties are best. Some optimized for nuts, others for timber.
Relatively few species are best grown from seed. (Papaya is one, I have some seed from a good source).
I will be planting a grafted "Early St. Ann" satsuma orange tree this winter.
Best Hopes for Good varieties,
Alan
Joule,
My guess is that your best bet is to get a few pounds of sound nuts from a local tree known to be a good producer if you want to just plant the nuts and hope for the best-what we do is just drive three wooden stakes around newly emerged or transplanted seedlings to protect then from being hit by a lawn mower etc.This is if your goal is to minimize your investment while hoping for a reasonable nut harvest.
Nuts purchased from a market may have ben shipped in from a long way away.They could even be contaminated with some disease that is not presently known in your nieghborhood. Nurseries are notorious sources of pests-just as hospitals are notorious sources of infections.
But planting local nuts may not be your best choice as there are diseases which do affect walnuts and these diseases may already be prevalent in your nieghborhood-we have been lucky so far where I live,but the prevalence of continious and extensive personal travel and shipping of all sorts of products here there and everywhere probably means that these diseases will hitch a ride to my part of the world sooner or later.
You will do better to consult your LOCAL extension service or state forester.There are lots of good things to be said for cultivated varieties of all types from nuts to fruits to veggies.Most cultivars across the board exist specifically because they are either resistant to some particular disease or pest or because they produce higher yields than thier natural brethen. Other traits can be and are selected for by selective breeding once a cultivar is well established.There is always a tradeoff that might not be obvious in terms of a loss of fitness in some other respect.
By planting local wild nuts you avoid that tradeoff.
The nuts need to be allowed to dry and probably (I have never needed to check) exposed to cold temperatures for several days at least.Planting single nuts where trees are wanted has not worked out very well for us.We scatter then on ground that is moist and sunny but not subject to flooding late autumn and cover then with leaf litter and maybe a little soil and when they sprout they can be moved to the location of your choice.Many will never sprout and some will sprout the second or even the third year.
Handle very gently.
You will have to cover them with hardware cloth or some similar type cover to protect them from squirrels.
I am not by any means an expert either in nuts or forestry-if you are going to invest any significant amount of time or money in your trees you should seek LOCAL professional advice which you can probably get for free.
The importance of seeking local advice in any matter pertaining to production agriculture can hardly be overemphasized.
oldfarmermac -
Thanks much for the advice on walnuts.
The nurseries around here mainly serve suburban decorative horticulture, so I doubt they'd have walnut tree saplings. It wouldn't hurt checking though.
We do have several good-size state parks nearby, and I'm sure they must have some wild walnut trees.
Now all I have to do is find my old guide book on North American trees so I can spot a walnut tree. I guess mid to late Autumn would be a good time to go looking for wild walnuts?
Trouble is: these are probably slow-growing trees, so I'm liable to not be around by the time they get big enough to be real producers.
I don't know where you are but around here a black walnut takes at least ten years to bear say a half bushel of nuts,probably five years longer.I can't be more specific because we don't pay much attention to the walnuts as they are just "plant and forget" trees,not something we do to earn money.
If time is a consideration and space is not buy some cultivated varieties and plant some wild nuts too.If the trees are common in your nieghborhood you can probably pick some nuts up right out of the ditch along a country road or maybe even a city street.Don't plant the walnuts too close to your house as and they eventually get to be huge trees and spread out horizontally for up to sixty feet or more and it can run into real money to hire a treeman to take one out that overhangs a house-and the sap is very bad for house and automobile finishes.They really need to be located well away from any building other than a cheap shed.English walnuts are much better in this respect and will bear quicker but I am seriously prejudiced in favor of the flavor of the black walnut.If they aren't simply delicious they are probably just getting old/rancid.I can't remember ever meeting any one who doesn't like them.We usally eat ours within six months of harvest.You can store them for a while in a freezer.
Grafted trees bear much sooner than seedlings, and will likely yield much more as well. See above for diseases that BW are susceptible to. I'm currently growing English/Persian Walnut and Heartnut, a Japanese Walnut variant that is resistant to everything except Walnut Bunch disease. It grows in marginal soils, is somewhat drought tolerant in it's younger years (and later as well), yield well, and can easily be grown in Hardiness zones 6-7 (5 has been accomplished with extra care). Grafted trees will begin to bear in 1-3 years, with commercial production expected in 6-8 years. Compare that with a seedling Black Walnut that will take 10 years to start to bear and 18 years to commercial production.
I recommend the University of Tenn. Extension Office Home Nut Tree Plan for general planning purposes. Look at different nut tree varieties in there and their bearing schedules.
I don't shop my local nursery, because they just have whatever sounds good. I like to find disease resistant cultivars and have ordered 90% of my 100+ trees/shrubs/vines via well-respected mail-order nurseries.
My biggest feedstock interest hinges around plants that provide food, but that produce a fuel as a byproduct. There are several plants that fall into that category, including a number of nut trees. I really love the idea of growing olive trees for both food and fuel. Note that I don't think olive trees are ideal for this purpose, because the oil is also food. But those are the kinds of synergies I am really looking for. I want something that ends up at a processing plant, and as a result of food processing can be easily converted into fuel.
Those sorts of things aren't common. Bagasse is an example, but there are some issues around bagasse gasification. But that is the sort of model that I am interested in developing.
You mentioned research by your team that involves deep rooted trees(and maybe otherdeep rooted plants such as alfalfa?) that can bring up minerals from the subsoil.
Can you post some links dealing with this type of research?
Thanks!
There's lots of info out there on this:
http://www.agroforestry.net/overstory/overstory61.html
There is a lot more there. They also give a list of good trees for soil improvement. They mention eucalyptus, which we view as very strategic for what we are trying to do. We are also looking at different nitrogen-fixing plants.
Hi OFM,
There's also a ton of information in the Permaculture realm on this: I would recommend Geoff Lawton (Permaculture Research Institute) and Dave Jacke (Edible Forest Gardens) to start.
For nitrogen fixing here in the NEUSA, I use honey and black locust, red bud, mountain and white ash and alders for nitrogen fixing. My knowledge of other tree recyclers / accumulators is a little sparse.
Many pioneer / opportunist (ie. "weed") plants have deep taproots and recycle subsoil elements to surface soils. Mullein, comfrey, alfalfa, dandelions, burdock are some I use, and all have some medicinal application as well. Dogwoods recycle calcium and Bamboo silica.
I've also looked a bit into accumulators for phyto-remediation of lead paint polluted sites in urban areas I do some work in: sunflowers, fescues and cresses seem to be most effective, but not terribly so. Plant material has to be removed and disposed of properly. Poplars are also good remediators.
Paul Stamets (Fungi Perfecti) has some very interesting results using mycelium / mushrooms to remediate e coli and hydrocarbons that he showed at the recent NOFA conference in Massachusetts.
Thank you both RR and Shrimp.
I am up on the nitrigen cycle and locousts,etc but easily located data on the other minerals and trees pulling the minerals up from the subsoil is scarce.
I expect they teach this in forestry school nowadays but I got only an introductory course in forestry and that was forty years ago.
I just sent you an eMail about lead remediation plants. Share the results on-line if you would for others.
Thanks,
Alan
Coconut grows well on most tropical islands, in my place in South India we consume all of it as food, the shell from nuts is powering many biomass based electricity generators-about10MW - for feeding the grid at many placed to avoid transporting husks and nuts using diesel!!
Coconut may even grow at Hawaii ...
Robert,
Thanks for the very interesting article. You show that the Rolling Stone's saying of "You can't always get what you want, but if you try sometimes you just might get what you need" may hold for liquid biofuels.
If we take our average auto fleet mileage, double it, and then drop the number of miles traveled in liquid fueled cars by half (mass transit, bikes, motorcycles, electric/PHEV's, walking, better arrangement of living abodes to work/shopping, telecommuting, or just plain eliminating some travel), we can drop fuel usage by 75%. So our 9 mbd gasoline consumption drops to 2.25 mbd. It's at that point, and with higher and economically sustainable fuel prices that biodiesel/EtOH and cellulose derived fuels can really make a difference.
On the biomass to synfuel stage, there may be ways to lower the energy requirements for purified O2 by hybridizing water electrolysis (makes O2 and more H2) with syngas production. And then there is the direct reduction of CO2 with H2 to make a variety of things. This makes sense where the electricity is made renewably in areas far from where it could be consumed in distant urban areas, and may be a way to upgrade the value of that electricity from the dirt cheap levels (and essentially where no significant value remains in the host community) that will come about from wind farm plantations (big farms) negotiating with large consumers.
And of course, you haven't mentioned the other hydrogen carrier (ethanol, biodiesel, biomass derived hydrocarbons are carbon based hydrogen carriers) - ammonia. As long as you don't have platinum or palladium coated pistons (which would do the Ostwald reaction to make nitrogen oxides), ammonia burns into N2 and H2O. And that Pt coated engine...well that would be a rare beast, and pricey, too. NH3 may not be an ideal fuel in congested urban areas, but it can work on the farm (great for tractors), and is also a great way to store power for peaking plants (such as single stage gas turbines or diesel gensets) when pumped water is not practical (desert and/or flat land areas). But to make either of these work in a sensible manner, the electricity has to be made renewably, which generally means wind, tidal or run-of river. And for Hawaii, onshore OTEC might also be a nifty way to make lots of electricity, given how fast the water gets deep near shore.
Niobium,
I must admit that I lack any real expertise in this area but it seems that we are going to have a hard enough time manufacturing enough ammonia to meet the needs of agriculture and industry,although I know there are some people pushing the concept of ammonia as a fuel.
The basic idea is to use stranded wind power to run the ammonia plants,which could obviously be done but the efficiency of the process is in doubt due to the intermittent nature of wind power.
My guess is that once manufactured it will be worth more as fertilizer than motor fuel indefinitely but it would be possible to divert some for use as emergency motor fuel especially in the midwest where there are ammonia pipelines, people used to working with it,and lots of thirsty farm machinery-and ammonia storage and handling equipment already in place on many farms.
It looks to me as if natural gas prices are going to have to go up substantially and stay up,as well as wind generation rising substantially, for this idea to have any chance of standing on it's own feet.
There is an immense amount of news in this area, but Larry Bruce, chairman of the Ammonia Fuel Network, knows where I live and I'm forbidden to speak until after the fall conference in mid October. I do believe I'm attending the conference and I'll have a tidy update for TOD a few days afterward.
On the biomass to synfuel stage, there may be ways to lower the energy requirements for purified O2 by hybridizing water electrolysis (makes O2 and more H2) with syngas production.
Have you been tapping my phone? :-)
Seriously, I had a long discussion on this just last week. You have to have some special circumstances to make it worthwhile, but there are situations in which it would be ideal. Biggest problem is the required scale of the operation for a BTL plant.
Robert,
No tapping. But I was doing some numbers on how to convert cellulose (= sugar, = starch, empirically speaking) into fuels like MeOH and EtOH. To keep it simple, lets assume that cellulose has the empirical formula of CH2O. Then, "adding" water to it gives Methanol and CO2:
2 CH2O + 0.5 O2 + H2 --> CO2 + CH3OH
The H2O + electricity gives H2 + 0.5 O2
The MeOH can be used as is, converted to gasoline/diesel in Mobil's MTG process, and probably further scrambled to give EtOH, plus some additional H2 in the process.
Then there are lots of variations. For example, burn some biomass with air to give heat and steam/electricity via co-gen. Burn some other biomass in a deficit of O2 with steam as a diluent, to make syn-gas, and shift the syngas as required. There are some catalysts that can make EtOH (MoS via Dow's process) from syngas. Or, and CO2 formed can be converted directly to EtOH via Rh10Se catalyst with H2, and probably other catalysts, too. Or, maybe the syngas can be adjusted with more H2 from electrolysis to give butanols. That would be a fine fuel where it's hot, seeing as it has a higher boiling point than EtOH. That CO2 could also be converted into AcOH, AcO2 and with alcohols, into a nicely burning ester, or just plain higher value added esters.
Anyway, to paraphrase Dire Straits..."That's the way you do it, get your money for nothing...."
Also, since Hawaii is both windy and has lots of hills and nearby ocean water, any thoughts or making a salt water pumped hydro system for short term power storage (also works with wave and solar thermal power, too). Finally, all that biomass could probably use some candy to grow faster....how about some renewable ammonia to speed the growth up a bit?
In general the problem with alternative fuels is this: the crisis is double. It is not only peaking oil, followed by other hydrocarbons and uranium, it is also metals and minerals, not peaking so much, but simply rising inexorably in cost because of the falling ratio of end product to tailings (I forget how to put it properly).
And of course bringing what's underground to the above ground continues the despoilation of the only resource we will have left: the soil, the water, the above ground ecology. It's much too narrow to simply look at energy calculations.
Yes, alternatives have a role, but the amount of waste is SO great and the opportunities for retrenchment and conservation so great that I remain profoundly skeptical of attempts, or what might end up amounting to attempts at prolonging our addiction.
Hi Dave,
Good comment. On one hand I have this utopian vision of conservation (2 billion humans by end of century, few cars - many bikes, etc) coupled with efficiency (mass transit, 100 mpg tiny personal vehicles, passive solar, etc) and then alternative fuels (especially for farm tractors and the like) allowing humans to transition from the current delusion of a "normal" life to a much richer human experience that is truly compatible with a biosphere that can sustain humans and most other species of life.
On the other hand, I witness the daily reality of our culturally improvished obsession with cars, plastic junk, throw-away stuff, and the general ignorance of science coupled with "faith" in all kinds of silly myths. Not to mention our level of political discourse or our ignorance of how things like financial systems really work.
So, it seems that alternative fuel technologies could be valuable tools in the right context - but, it also seems that humans are simply not capable of using our collective intellects to rise above our baser instincts and create a context that is really useful for "life, liberty and the persuit of happiness". At least not for the longer run.
Thanks for the interesting discussion.
I think, though, that we should be a bit more critical of the findings of the so-called "Billion Ton Study." The subtitle of the study is "Technical Feasibility of a Billion-Ton Supply"; although they go on to use the words "sustainably removable biomass", it is quite obvious from reading the whole report that their definition of "sustainable" is not one based on ecological principles--they are simply indicating what could be technically feasible to harvest. Indeed, in the entire report, the only discussion about the impact on nutrients occurs in a bullet on page 54 where it notes: "A particular concern has been raised regarding the effect of removing the nutrients embodied in the biomass", and goes on to suggest it will just require more fertilizer application. This does not suggest sustainability to me.
Further, the bulk (nearly 1 billion of the 1.366 billion tons they identify) of the biomass production is assumed to come from agriculture, including crop residues, but not just with our existing agricultural practices. They assume:
- Yields of corn, wheat, and other small grains were increased by 50% [!!]
- The residue-to-grain ratio for soybeans was increased 2:1
- Harvest technology was capable of recovering 75% of annual crop residues (when removal is sustainable)
- All cropland was managed with no-till methods
- 55 million acres of cropland, idle cropland, and cropland pasture were dedicated to the production of perennial bioenergy crops
- All manure in excess of that which can be applied on-farm for soil improvement under anticipated EPA restrictions was used for biofuel
- All other available residues were utilized.
This is a remarkable set of assumptions. According to the USDA, the US has maintained about about 340 million acres of cropland since 1910; given the commercial exigencies of commercial biomass production, I have to assume the 55 million acres they are assuming will be dedicated to perennial bioenergy crops will be monocropped. (And the idea that all this "marginal" land exists, for example, for growing switchgrass is absurd; switchgrass will indeed grow on marginal land, but you will get at best marginal yields, which is not a commercial goal.)
I think Debbie's point about water needs serious attention. My own study of biomass production in California shows that every drop of available water in this state is allocated; to dedicate land (and irrigation water--it doesn't rain here in summer) to a perennial bioenergy crop means something else has to be given up. This also means that bioenergy crops are decidedly going to compete in price with food through this same water nexus.
Finally, the 1.366 billion (English) tons identified by the study is about 1.25 billion tonnes; and using your same energy content assumption (16 MJ/kg on a bone-dry basis), the total energy content would be about 20 EJ. Total annual net primary productivity in the US is estimated to be about 119 EJ, but only about 75 EJ of that amount is above the ground (roots can account for up to 50% of the biomass of a plant). Since I assume we aren't going to be digging up roots, the study suggests that we could take nearly 30% of annual NPP (not even accounting for the portion we already appropriate through food and wood production) and dedicate it to bioenergy processing. This figure alone tells me that this report has nothing to do with sustainability.
I think, though, that we should be a bit more critical of the findings of the so-called "Billion Ton Study."
To be clear, I am not counting on getting feedstock on the basis of the Billion Ton Study. Primarily I use that study just to show how much biomass that is relative to our oil consumption. Also, I use it to illustrate the importance of capturing as many of the net BTUs as possible, regardless of how big that "billion ton" number turns out to be.
On the other hand, I am convinced that we can sustainably use woody biomass on multi-year rotations and actually improve the quality of the soil at the same time. We have a number of foresters on our team, and they are quite passionate about good stewardship of the land.
Robert The foresters that first planted the eucalyptus trees on the Hamakua Coast did not practice good stewardship of the land when they applied herbicides by spraying from the air, by helicopter I believe, and totally destroyed existing organic farms in the process. Any spraying of herbicides and pesticides should be illegal period. Nobody can control the drift from spray yet they are allowed to do it. It is insane. DeanP
Just to clarify, though, those weren't our foresters. I hadn't heard about what you describe above, but it wouldn't surprise me.
I have looked at those trees along Hamakua. They are not strategically in a very good spot for harvesting and utilizing, which is the same conclusion a number of others have come to as well.
This points up another why perennial grasses and coppiced tree farming are so much better as sources of biomass than annual crops. In perennials, the root system can support new above-ground growth for many successive years; a larger fraction of NPP goes into harvestable biomass. At the same time, the harvest is high in cellulose, low in N, P, K, and various micronutrients. At least it is if it's harvested in winter, when most of the nutrients are stored in sap within the root system.
The nrel/usda reports looks like expert estimates of US biomass potential.
They have not shown all their homework but to me their assumptions are reasonable(the USDA is quite familiar with ag statistics) and the skepticism here at TOD is not justified.
http://feedstockreview.ornl.gov/pdf/billion_ton_vision.pdf
The US consumes about 23 million tons of fertilizer a year;
13.2 million tons of ammonia, 4.6 million tons of phosphate and 5.1 million tons of potassium.
http://www.ers.usda.gov/Data/FertilizerUse/
First there is too much worry about ammonia which we get from natural gas. China has no natural gas to speak of and consumed 23
million tons of ammonia fertilizer alone (out of 47 mllion tons of all fertilizer). China gets it's ammonia from coal and we have twice as much coal as China has.
http://tiny.cc/sCcPm
Of course I am not suggesting that we waste fertilizer only that US fertilizer crisis is quite a ways off. Reducing
over-fertilization is very important environmentally but I don't see the resource as constrained.
They assume:
- Yields of corn, wheat, and other small grains were increased by 50% [!!]
- The residue-to-grain ratio for soybeans was increased 2:1
- Harvest technology was capable of recovering 75% of annual crop residues (when removal is sustainable)
-..etc.
The estimate is for 50% increase in corn and 20% for wheat by 2043 based on past performance, it is more complex than what you state.
In the 997 million ton of high yield ag resources with land use change they include 377 million tons for switchgrass(60 million acres at ~5.5 tons per acres) while on moderate yield they have 156 million tons with smaller acreage.
You say the USDA's estimate is 'absurd'. But do you KNOW anything about agriculture (but don't cite anything either)?
Frankly to live in California or Arizona or the Moon is to live unsustainably. You reject for the whole country a source of renewable energy because you can't use it in California due to water restrictions!
It is YOUR problem to adapt, not mine. One billion tons of biomass cannot meet all the energy needs of the country anyways. I propose that we 'saw off'(in the words of Arizonan Barry Goldwater) those unsustainable, overpopulated states, let them harvest sunshine or whatever to make themselves 'sustainable'.
The report says that biomass can replace up to 30% of US petroleum(high case)which the eia says is 27.8 quads of petroleum for transport.
27.8 x .3 = 8.34 quads or 110 billion gallons of ethanol equivalent(though usda includes biodiesel). The report considers that both fossil fuel and biomass would be used to produce ethanol but since you think fossil fuels are not sustainable you consider them to be liars.
Let's assume that .67 quads will be corn(8.9 billion gallons-~87 million tons grains to biofuels in the report) and the rest, 1279 million tons 911 bt of ag plus 368 bt of forest products will be cellulosic ethanol. If you get 80 gals per ton of biomass that would be,
1279 mt x 80 gallons per ton = 102.3 billion gallons(7.72 quads) + 8.9 billion gallons =111.2 billion gallons of ethanol.
According to nrel
it takes .7 BTUs of fossil fuels to make 1 BTU corn-ethanol and I cited nrel that it takes 1 BTU of fossil fuel to make 5.33 BTUs of cellulosic ethanol.
For which 7.72 quads would require 1.45 quads of fossil fuels plus .67 quads would require .96 quads of fossil fuel or a total of 2.4 quads of fossil fuels.
The US has +300 quads of natural gas and +2500 quads of coal.
You put in 2.4 quads/yr of fossil fuel and get 8.4 quads of liquid fuel out/yr.
Sustainability is sustainability for the next 100 years. Worrying about energy supplies beyond that is nonsense.
According to nrel it takes .7 BTUs of fossil fuels to make 1 BTU corn-ethanol and I cited nrel that it takes 1 BTU of fossil fuel to make 5.33 BTUs of cellulosic ethanol.
But do you understand how they arrived at that estimate? It came from a set of assumptions in a model, some of which may bump up against reality as they try to run their process on lignin that is full of inorganic matter.
I will say this, though. Our discussions here have gotten me very interested in just what the real efficiency of the process is. There is zero literature on this. There have been studies on the energy inputs to grow switchgrass, but beyond that the energy returns are speculation. It occurs to me that POET (or Iogen) is in the position to publish the first definitive paper on a true energy balance for a cellulosic process. It would be a difficult paper, as they would have to get energy inputs for enzymes and such. I have a good relationship with POET; I may approach them to write a paper and make a valuable contribution to the literature.
Corn requires 275 pounds of biologically available nitrogen per acre to reach the current yield of about 150 bushels. About half of that nitrogen comes from stover left on the field and the other half from synthetic ammonia and derivative compounds. There is a small (5 - 20 lb) contribution in the form of atmospheric nitrates, mostly from lightning and fossil fuel combustion by-products.
The relationship between yield and available nitrogen is pretty linear as I understand it. A 50% increase in production means about 400 lb/acre, a 75% stover removal subtracts a hundred pounds. Ammonia prices are $0.25/lb right now so that's a $0.50/bushel fertilizer cost burden.
Tiresome, this math stuff, isn't it, and doubly so when it gets in the way of nice theories?
It takes 20 cubic feet of natural gas to make a pound of ammonia fertilizer so 275 pounds (according to you) would require 5500 cubic feet of natural gas.
There are 90 million acres in the US of corn today, producing 13 billion bushels.
If we increase the bushels by 50%, that's 20 billion bushels.
Let's assume that 1/2 of that goes to corn-ethanol.
10 billion bushels x 2.6 gal/bu =26 billion gallons per year of corn-ethanol(1.4 quads). This would require about 1 quad of fossil fuels (equivalent to 1 Tcf of natural gas ).
Cellulosic ethanol needs only 27% of the fossil fuel that corn ethanol does--which is one reason why the focus is on cellulosic ethanol.
Back to corn-ethanol,
(400 pounds + 100 pounds) x 90 million acres x 20 cf NG/ pound =
.9 Tcf of natural gas for all corn fertilizer--.45 Tcf for corn ethanol.
500#/acre x 90 million acres(all corn)/2000# per ton = 22.5 million tons of ammonia fertilizer.
Note that China uses 23 million tons of ammonia fertilizer(with almost no natural gas). The US used 13.2 million tons of ammonia fertilizer.
Speaking of theories,
For the US per based on awea figures below.
100 GW wind = ~160 Twh. 160 Twh/60 Mwh per ton H2(electrolysis) =
2.7 million tons of hydrogen.
2 NH3 = N2 + 3H2 so 3 tons of H2 = 17 tons of ammonia
So 100 GW 'could' supply 15.1 million tons of ammonia fertilizer,
just counting electrolysis.
All US wind power(20 GW) generated ~32 Twh in 2007, you would have to dedicate ~5 times all US windpower, off-grid to replace natural gas to make ammonia fertilizer.
I support hugely expanding wind but for fertilizer? Pah-lease.
Cellulosic ethanol needs only 27% of the fossil fuel that corn ethanol does--which is one reason why the focus is on cellulosic ethanol.
You keep saying this as if it were fact. You realize what is being claimed is based on a model, right? Also that there were no energy inputs allocated to certain things like enzymes?
Anyway, I wrote to the guys at POET this morning to inquire as to whether they might be up for making a contribution to the scientific literature. Generally companies are opposed to publishing in the literature, but they could make a real contribution to advancing knowledge on the issue of cellulosic energy balance. If it can truly be verified at close to 40% efficient, that would be something. If it is at 25% or less (my expectation) then it will not be viable as fossil fuel prices increase and biomass becomes more expensive.
Wonderfully lucid analysis by RR as per usual.
I must say that while reading it, I thought of another sort of biomass which grows well in Hawaii; the burning of which, in small quantities, causes people to giggle and sit around playing ukuleles. If properly promoted, it could obviate a lot of liquid-fuel use by acting directly on those pesky hominid brains.
The society of sloth has a lot to be said for it.
Yes there's no need to drive to work and back when all you do is smoke pot and collect a welfare check.
In ten more years the ones of us who are still working and toking will be paying taxes on our smoke that will help fund the welfare checks.
We just gotta wait for the rest of the older generation that never indulged to die off and get together politically and it can be a done deal-how many people ten years ago would have thought we would have a black president today?
Thank you for this article.
In my view biofuels from biomass should be produced locally in small scale plants, on the spot where the biomass is produced.
Don't waste fuel on transport to giant processing plants and on transporting back the fuel to the consumer.
Fiftythousands small plants are less vulnerable for disruption than 5 giant plants.
And small scale plants can produce a steady flow of biofuel all year round.
Small is beautiful.
Mr. Rapier in an earlier post some months ago commented on the problems transporting the low energy biomass. The problem with "small" plants is the lower efficiency from being on the wrong side of economies of scale. I suspect in the future balancing transport costs of biomass with plant efficiency due to size will be a major part of the design puzzle.
I suspect in the future balancing transport costs of biomass with plant efficiency due to size will be a major part of the design puzzle.
You are correct. As you get bigger, you benefit from economies of scale, but then the radius you have to go to for your biomass gets bigger. The bigger the radius, the higher the energy inputs into transport. What may work well is a plant with water transport, and biomass that gets compacted/torrefied prior to shipping.
Everything is just fine except maybe we can tinker with this little bit here or substutute one kind of 'input' for another, we don't really have to change anything else.
Happy Fuc-ing days are here again!
This is intellectually dishonest; je accuse! If it's all just for 'marine applications' why not just get rid of the cars and be done with it? Problemo solved!
We would still have rock and roll!
Actually, nothing ever was fine; things haven't been 'Fine' since the 14th century and thing things were fine for a little while after the Black Death had abated. It's been downhill ever since punctuated with various petite Lon Nols and Adolf Hitlers and 'King Mustard' and machine guns, accretions of industrialization which have never really gone away but only added to.
Nothing was ever fine except for the 'winners' ... the lucky few. Now that many are lined up to cross the turnstiles into 'fine' the whole game is shutting down ... I wonder why? Look for a return of Black and other kinds of death. It's going to happen one way or the other, the only chance is to get rid of the cars.
... The final war, the last war, the war between humans and automobiles. The humans are too stupid. Automobiles will win, the humans will be destroyed, any survivors will be slaves.
Death by 'progress', by hubris, by collective insanity and the desire to 'win' at all cost, death by ignorance. Too clever by half you can feed yourselves by cutting off your feet and eating them. Don't you get it? There are no free lunches on planet Earth!
Go ahead biofools! I laugh at you!
14th century eh? Well at least you're more progressive than the wahhabis, they want to take us all back to the 7th century!
Not my call. Don't worry, we'll get there all the same. Blame, if you will, lies with thermodynamics, not me ... nor the Wahabis.
Our (Americans') chances of winding up in the 19th century are slipping away fast. We are set toward a point where there is too little nature left to support anything other than simple, multi- cellular organisms.
Where does that take us to?
Ordovician? Maybe. 200 million years ago ...
The war between humans and automobiles is one of extermination. The automobiles are currently winning. Keep that in mind at all times.
Out.
Well said. I'd type more but I've got to drive home......
Robert states that Algae fuel is not a contender because there is no commercial production in existence. And even though the largest commercial production of liquid biofuel comes from corn ethanol, it is NOT a contender? That's somewhat of a double standard isn't it?
And also, it should be quite clear to everyone by now that corn ethanol production does not increase the price of corn. Ethanol production has gone up, whilst corn prices have gone down.
Robert states that Algae fuel is not a contender because there is no commercial production in existence.
That isn't remotely what I said. Further, I clearly defined my terms to indicate why corn ethanol doesn't fall into that category. It is only enabled by fossil fuels and subsidies.
Nice straw man, though.
Sounds to me like you are agreeing with the person who wrote you the letter. Perhaps I'm reading it wrong?
Oil and gasoline are also subsidized in the US as well (Iraq war, etc.) Solar and wind are also subsidized as well, are they not contenders for electricity generation? And there is no modern farming operation that doesn't use fossil fuels. Although it seems possible for farmers to use biodiesel as a substitute.
Sounds to me like you are agreeing with the person who wrote you the letter. Perhaps I'm reading it wrong?
I am agreeing but that wasn't the basis for calling algae a pretender. My last essay - in which commented - discussed why I call algal a pretender.
Solar and wind are also subsidized as well, are they not contenders for electricity generation?
As I said near the beginning, this wouldn't be about electricity, even though I feel pretty good about some of the electrical contenders.
Robert,
Nice article. I agree with all your major points, including your criteria for "contender" and your remarks about sugar cane ethanol and palm oil.
There's one important category you didn't cover, however: what I would call "enhanced gasification". It differs from conventional gasification in that the energy to drive the gasification, along with much of the hydrogen required for fuel synthesis, comes from externally supplied electricity. The biomass is used as a carbon source, rather than an energy source. There's no CO2 emitted, because any CO2 that would otherwise be produced in gasification reacts with H2 to increase the yield of synthesis gas. So the net yield of liquid fuels is roughly double what it would be if the process energy wers supplied by partial combustion.
One of the neat things about enhanced gasification is that it's a good way to tap "stranded" wind energy. No long distance transmission lines needed, and intermittency of supply is no big problem. It's just being used to electrolyze water, and the resulting hydrogen and oxygen can easily be buffered for steady supply to the gasification / fuel synthesis plant.
Oxygen buffering is easy but hydrogen? Not so much - we'd already see stranded renewables powering such operations if that were the case. H2 is a slippery, disobedient molecule.
It's far better to buffer carbondioxide and use opportunistic hydrogen production to produce various things (methanol) next to a good CO2 supply, say the room temperature/room pressure stuff coming off an ethanol plant.
The only hydrogen buffering scheme I've seen that makes sense is a solution mined cavern - big enough, tight enough, and cheap enough - those Texas wind farms driving production, regional pipelines taking the product to local ammonia production and oil refining facilities ... haven't spent a lot of time figuring on this since I don't live in the region, but there aren't any huge technical barriers.
Good point, although the economics obviously depend on the amount of buffering involved and the period of time. For the simplest type of hydrogen - CO2 reactor, producing a varying mix of mostly CO, CH4, CH3OH, and H2O, the capital cost of the reactors will be low; high utlization at a steady feed rate won't be important. In that case, it's probably best just to use the H2 as you suggest, at whatever rate it comes from the electrolyzers.
In the case of something like Doty's WindFuel scheme, where the reaction conditions are optimized for CO (minimizing production of CH4 and CH3OH), steady flow rates are more important, and the capital cost of the reactor system probably justifies some H2 buffering to achieve higher utilization of the reactors.
Decisions about how much of what to buffer are probably among the trickier and more interesting aspects of chemical engineering. Not that I'm a chemical engineer, but the principles are pretty straightforward. I have a little background in operations research (a course in grad school), and the economic optimization problems in plant design are interesting challenges for the techno-geek in me.
As an example, one of my reservations about Doty's WindFuel scheme is that to show economic feasibility, he has to make some pretty agressive assumptions about cost scaling for electrolyzers. The scheme requires very cheap electricity, which is available from a grid-connected wind farm only around 10% of the time. So with no buffering of electricity, the electrolyzers only see an average 10% capacity factor. That's OK if electrolyzers are dirt cheap, but they're not. So to me, it makes more sense to integrate the scheme with pumped hydro, CAES, or flow battery storage and run smaller banks of electolyzers at high CF.
The same consideration for the electrolyzers would apply for use of wind energy to make ammonia. (He writes blithely, as if he weren't replying to Mr. Stranded Wind...)
I suggest that the universal fuel of the future should not be a liquid but a gas consisting mainly of methane. The energy density should be around 40 MJ/kg. I believe that gas will have a significantly higher EROEI than liquids but I haven't seen real world data.
This universal fuel gas can be made or blended from biomethane, natural gas, methanated syngas or hydrogenated biocarbon via the Sabatier reaction. The hydrogen could come from the nuclear sulphur-iodine cycle, renewable powered electrolysis or perhaps a new method using water directly. It could be
(small net energy X large scale)
beats
(large net energy X small scale).
Work to date appears to be limited and not co-ordinated. That is, the hydrogenation people haven't seriously connected with the gasification people.
This has had everything: informed science, balanced debate, English-American incomprehension, even another of oldfarmermac's wonderful contributions (someone should make up a compendium).
My own back-of-a-gentleman-in-comfortable-shoes-packet calculation is that we should stop chasing liquid fuels entirely. Their manufacture is either thermodynamically dubious, or will deplete the soil, and their use in heat engines will always be inefficient. They are only necessary for transportation - for everything else you can just chuck in the straw and burn it directly. All our efforts should go towards electric transportation: on-grid heavy and light rail, and battery-powered trucks, vans, cars. Whether this will take revolution or evolution in battery technology isn't clear yet, but I would bet my house on this winning through over the next 50 years. Air transport, other than dirigibles, is through.
Solar powered dirigibles. There's an idea!
http://www.popularmechanics.com/science/air_space/4324155.html
Ammonia fueled drigibles with on board hydrogen reformation refilling the flotation as well as providing the accelerant for the ammonia/hydrogen hybrid engine.
It's all good ... till you hit a squall line with it.
RR:
Your pyrolysis contender has this char by-product that you indicate is problematic. Your BTL contender is based on experience in CTL (Coal To Liquid). It seems to me that char is rather more like coal than is raw biomass. Would it not be advantageous to combine the two contenders?
Another thought about char: in the long run, we will have to do something to remove CO2 from the atmosphere and sequester it away from the biosphere. Char dumped into abandoned coal mines is one possibility. This is a social goal which some governments might be willing to subsidize.
Some char might be retained in large piles waiting to be used in CTL. This could be useful as a way to avoid the costs of just-in-time processing. Think of char as a recycled coal...
Would it not be advantageous to combine the two contenders?
Yes, they are synergistic. Although I have had people tell me that there is a great market for char.
Unless I am badly out of touch with reality,any char left from a gasification process will wind up being burnt in most cases.Some might be used as a soil amendment or for other purposes but why would any body bury perfectly good carbon just so they can go dig up some more carbon to burn?
Other than the fact that we are irrational,I mean.
As far as Hawaii ... Have a Brazilian company do sugar cane biofuel for liquid fuel ?
Better to burn biomass to generate steam ..to ..elec ???
UC Berkley/Modesto study says yes.
Hawaii does have a garbage to energy plant, but it only produces a small percentage of electricity. There is also a biodiesel plant under construction that has run into a snag after problems with Imperium. Interestingly, there was a time in Hawaii's history when the island of Kauai received electrical power from a sugar cane ethanol fired power plant. These days unionized AG labor is much too expensive to grow sugar cane for ethanol. Ethanol for the state's 10% mandate is imported from El Salvador. I doubt that biofuel could ever be produced economically in Hawaii. Solar appears to be the leading alternative energy. 1 in 4 homes have solar thermal installed. A recently enacted law requires all new home construction to include solar thermal. Solar PV is expanding too but you see a lot of small systems. A feed in tariff rather than zero net metering would encourage larger systems, IMO. Short distances makes Hawaii an ideal market for EVs.
Sugar cane ethanol is available at any gas station at Brazil, and nearly half the car fleet actualy run on it. Anyway, some of the biomass do go into eletricity.
A very good summary...
My only critique would be:
- low-balling (again) the average Btu content of biomass at 7,000Btu/lb (the EIA uses 8,600Btu/lb)
- your ‘contender’ definition
While the first element is relatively negligible for this discussion (raising the Btu profile of 1.3 billion tons of biomass to 3.8 billion barrels of oil or 51% of US consumption 2008) the second is a bit more complicated.
Liquid transportation fuels i.e. gasoline, diesel and jet fuel are derived from petroleum – not coal, natural gas or methane. Therefore, biofuels or biofuel contenders for that matter should not be measured by their ability to replace fossil fuels. Rather, biofuels should be measured by their ability reduce/remove our exposure to petroleum.
As such –and ignoring the fact that we should technically be examining a production regime as opposed to an individual technology or product per se– I proffer that a more apt description of a next gen biofuel contender is: one with the lowest PIR (petroleum input ratio) possible and capable of displacing 30% of the petroleum utilized for transport in the US 2008.
On terra preta...
Give J. Lehman a call at Cornell University’s Dept. of Crop and Soil Sciences for a discussion re: widespread feasibility of char usage by North American AG.
- low-balling (again) the average Btu content of biomass at 7,000Btu/lb (the EIA uses 8,600Btu/lb)
If you look at this link from ORNL:
http://bioenergy.ornl.gov/papers/misc/energy_conv.html
You will see that they cite 7,600 to 9,600 as the HHV for bone dry wood. HHV is never achieved in practice. They also cite the following:
So I think 7,000 BTU/lb is quite reasonable across a broad range of wood wastes and agricultural feedstocks. Besides that, if you are an engineer you learn to be conservative with your estimates.
I proffer that a more apt description of a next gen biofuel contender is: one with the lowest PIR
That's the whole point of the net energy discussion. Something that requires high fossil fuel inputs is going to have a low net energy, and thus not be a contender.
I spent some time looking into outdoor wood boilers last year. As I recall split, seasoned hardwood is good for maybe 7,000 BTUs/lb. Softwoods were in the 5,000 BTU/lb range. The number Robert picked actually seemed a little aggressive to me, but he is out there actually touring plants.
If you can nail it down to a specific feedstock, you can pin down a better number. Across the range of feedstocks described in the billion ton study, you could have come up with a lot of different estimates, all in the 5-10,000 BTU/lb range. So I grabbed a number in the range to work out the thought experiment. The real number is going to be dependent on all sorts of things like actual composition, moisture content, etc.
Mr Rapier,
Very good article. I have one concern about two of your contenders which may stem from my lack of understanding.
Sugarcane ethanol in Brazil from what I have read is labor intensive with much of the labor one step above slavery. If this is true I question how long this will be a contender. Can this sugarcane ethanol system be mechanized and what would be the effect on the economics?
How mechanized is tropical palm oil production? The photos I have seen show workers tossing bundles of fruit obviously harvested by hand into an animal drawn wagon.
If my impressions are correct how long before the labor to provide these alternate fuels either revolts(Think Haiti at the end of the eighteenth century) or demands a larger piece of the pie?
I realize this kind of question is outside the scope of your article but my opion is that it is a valid concern.
According to Wiki, the latest figures (2008) state that 48% of the sugar cane is now harvested mechanically.
As I understand it, the byproduct char from flash pyrolysis is not particularly good as a soil ammendment. The high temperature at which it is produced apparently destroys the porous cellular structure that makes some other chars good habitats for assorted micro-organisms that enhance soil fertility. The best chars for agricultural use result from slower, lower temperature pyrolysis that produces more synthesis gas and light volatiles, and lower quantities of tars and liquids.
Bio-char is not a concentrated fertilizer. It does retain most of the mineral nutrient content of the biomass it was made from, but on a per-weight basis, that's less than 1% of the content of a commercial fertilizer. Its does serve to buffer any fertilizers that are subsequently applied, improving uptake and reducing runoff. It also increases natural soil fertility, but it takes something on the order of 100 kg / square meter before that effect can fully substitute for applied fertilizers. Not remotely economical, in and of itself.
The solution that Eprida is pursuing is to "pre-load" the char with other fertilizers. Then it can be applied to fields in roughly the same quantities and with the same equipment that farmers use for conventional fertilizers. There's an immediate benefit in reduced runoff and lower fertilizer cost, but not much immediate gain in soil fertility. That builds up after years of small applications.
Or so I understand. This is all from website reading supplemented a bit by correspondence; I've no first-hand knowledge.
but it takes something on the order of 100 kg / square meter before that effect can fully substitute for applied fertilizers
That is 220 lbs per sq meter.
Carbon, solid 2146 kg per cubic meter
1/20 of a cubic meter would have to be carbon.
Charcoal 208 kg per cubic meter
so 50% of the 'soil' would have to char. Not exactly sure how one gets to that point.
The old grand man of vermipost Clive Edwards was claiming that up to 20% of soil mass can be vermipost for the best effect.
Are you sure about that 100kg/sq meter number?
Another benefit of char - it can help hold water in the soil.
Other issues with char:
1) The terra perta might not be from char. Elaine Inghrim notes that charing can happen at normal compost pile temps. I doubted her on that till I noted charing at temps about 135 deg when drying watermellon.
2) To work the char into the soil, one needs to move that soil about. Moving soil is rather energy intensive. Imagine moving enough soil to get the 50% rate calculated above.
100 kg per cubic meter is roughly based on the analysis of tetta preta soils in the Amazon. They range from half a meter to two meters in depth. Carbon content, from all forms of soil organic matter, averages somewhere around 200 kg per cubic meter (~15% of soil, by mass), of which 50% is thought to be from added char. But there's a lot of variation, and a lot of uncertainty as to the actual sources of the carbon.
I think your figure of 208 kg per cubic meter for charcoal is for uncompacted charcoal powder -- mostly air. That's only a fifth the density of water, and a tenth the density of solid graphite. In practice, the powdered char would become well mixed with other soil elements, and would constitute a significant but not dominant fraction of soil mass.
You're right about the high cost of mixing that much powdered char into the soil in one application. That's why I said it would be totally uneconomic. But with small annual surface dustings, continued over many years, the mixing can be accomplished by rain, plant roots, and bugs that live and burrow in the soil.
The North Dakota report on ethanol/gas mileage shows what happens when you take advantage of ethanols' higher octane rating.
I originally posted this comment on Roberts' article "Another Biofuel Scam?". It was my first post ever, one of the last comments on the article and I don't think it was viewed. I certainly expected some kind of responce. Considering what Robert is saying here, I'd like to post it again.
The two Chevy Impalas in the study are the same except one is flex fuel and one is not. Flex fuel vehicles have a fuel compensation sensor or a flex fuel sensor. This adjusts ignition timing. At E10 and E20, the timing is increased toward optimum for the engine. At around 91-93 octane (E20-E30) anymore ignition advance is beyond optimum regardless of octane rating available although I have seen some 98-100 octane tunes that extract the last couple percent of horespower not gas mileage. The non flex fuel Impala followed the expected drop in gas mileage due to the reduction in Btu content. The flex fuel Impalas' gas mileage improved for E10 and E20 because the improvement in efficiency with the timing advance more than offset the reduction in Btu content of those fuels. Beyond E20 gas mileage began dropping because no more timing advance could be added.
All this is similar to my experience with my vehicle. It's a 2000 vintage with 111,000 miles. I sent my engine computer out to be reprogrammed for higher octane (under $100). With no other changes, running E10 before and after from the same gas pump, my mileage increased about 10%.
I live in Iowa, just about to retire from John Deere. E85 doesn't make sense unless the vehicle can take advantage of the 100+ octane. However, E10 to E20 does. Nearly every spark ignition engine of the cars already on the road could be reprogramed to take advantage of the higher octane like I did (some of the higher end vehicles come from the factory already tuned for higher octane. That's where some of their higher horsepower and great gas mileage comes from). Whether higher than E10 will harm older vehicles or if E(any percentage) could or should be made is quite a debate. Politically, there's no way the government could ever endorse such a plan even though I think it would save more oil for dollars spent than the cash for clunkers program.
A lot of hot rodders have discovered E85 as a low cost racing fuel. Commercially available racing fuel can be as high as $10/gallon. But unfortunately, the ethanol industry will not likely see any growth unless the E10 blend wall is moved. And although Obama campaigned as a biofuel advocate, the industry has gone into decline over the past year. 2 billion gallons of capacity are now idled. The blending increase request is tied up at EPA (as is offshore drilling). The biodiesel industry has been especially hard hit, adding to the unemployment situation. You would think unemployment and energy independence would be a priority for this administration.
I put some hope in treatment of cellulose by subcritical water like described here
http://www.greencarcongress.com/2009/08/subcrit-20090827.html
still a long way to go since nothing has been demonstrated yet at a significant scale
To me main problem with biofuel is to find a way to carry all this biomass to the plant, or to bring the plant to the field by putting it on a big truck, probably possible with bio oil.
But in my view there is another issue, what will be the incentive for farmer to grow cellulose in volume, I have doubt that it will ever be economically viable. I think if the farmer could sell the bio-fuel directly he would be more motivated. In that view bio-methane is the best approach, not only it is the less carbonated fuel by energy content, the cleanest, the easiest to make (so it can be made at the farm avoiding carrying the biomass over long distances) and has probably the highest conversion efficiency, but digester can only digest cellulose not lignign. last but not least CH4 can be burned very efficiency in ICE because of its very high octane index. Hard to beat.
I'm trying to wangle an invite to a local plant that uses supercritical CO2, in this case to make beer flavouring syrup from hops. Questions include; does the bio-trash make it harder to seal pressure vessels, is much fluid lost and how much power do the pumps use?
A problem with small scale farm methane is that the feedstock seems to work best when it has been through an animal gut. That is sh...umthing needs to be shovelled. You want warm weather, well feed pigs or cows and not much demand for machinery. Also there will sophisticated technology costs if you need to get from 25% to say 5% CO2 in the gas mix.
Supercritical CO2 seems to be able to be handled with steel at the psi is under 2000 lbs/sq inch. (Al is 1000) So it's "doable" with not all that hi-tech EQ.
I've entertained it as a method of extraction from herbs like rosemerry/thyme/oregino.
CO2 is roughly 100 times as soluble in water as methane, so counterflow through pressurized water will do the job. I am investigating this for a very small setup; the pressures involved are within the ratings of PVC pipe.
I recently viewed a prototype of an on farm system for doing exactly what you describe - I have to jump through some hoops on NDA and all, but I think I get a photo op complete with first farm installation. It'll show up here if I get the job done.
I meant UC Merced ...
Study Suggests Bioelectricity Could Be More Efficient than Ethanol to Power Vehicles
http://www.ucmerced.edu/news_articles/05072009_study_suggests_bioelectri...
Don't show that to majorian, it will prove him wrong and he'll pitch a hissy-fit.
Edit: Damn, am I prescient or what?
I'd read his paper but I'm not going to subscribe to this magazine.
'Could be?'--LOL
Anything 'could be'.
The problem with electric vehicles is they are just over-hyped glorified golf carts, not cars.
The Zap 40 miles
Fisker Karma 50 miles
Toyota iQ 50 miles
Phoenix SUT/SUV 100 miles
Miles XS 50 miles
Nissan Leaf 99 miles
Volt hybrid 40 miles electric
Fisker Karma 50 miles
---------------
Ah...the Super EVs
Lightning 190 mi
Tesla 200 mi
----------------
Actual car
Ford Model T (1916) 250 mi (180 miles on E85)
GM,Ford is pledging to have half their vehicles FFV(E85) by 2012.
Poor stupid brainwashed executives!
Can't they see that the Tesla, Nissan Leaf and the Fisker Karma are the wave of the future?
I'll bet Obama's Car Czar made them say that, etc.
Quick somebody send them a copy of Elliott Campbell's newest paper while there's still time!
I find my electric car quite practical, and beautiful :-)
Alan
What is it's range?
Once from NE of Cleveland through Cincinnati to Georgetown KY as one example.
Many more examples at
http://sbcglobalpwp.att.net/w/i/willvdv/ijmain.html
Best Hopes for efficient, mature non-oil/non-liquid fuels transportation,
Alan
You forgot BYD - 250 miles.
The problem with EVs right now is not the range, it's the lack of recharging stations. Once these stations are up and running, the range won't be that big of an issue. That doesn't mean ICE motors are going away completely. I suspect ICE motors will still be around for another 100 years at least.
Evs will run out of battery material; lithium, nickle, even lead isn't infinite.
Local mass transit, like trams and buses
travel between 7-25 mph and the average single route is 5-15 miles, which even worse than EV that can sustain 60 mph and go for 40 or 50 miles.
This is only a bit faster than bicycles at 9 mph which I would guess are far more efficient BTU/mile than any car, bus or tram.
This is a direct comparison as suggested by Alan's photo.
However I'm not sure you can make a direct comparison.
Many people can't ride bikes.
During the Special Period in Cuba,
they imported millions of bicycles--the people hated them.
I think there is a definite place for buses and trams in urban settings(cities will not disappear post-Peak) but as a 'replacement' for all cars, no.
I think Copenhagen has an interesting balance --people move locally on bikes 1/3 of the time, 1/3 cars, 1/3 trams.
until we address the elephant in the room, this was an interesting but pointless discussion. Numbers of consuming people on a finite planet, and the little problem old Tommy Malthus identified, make the discussion a tad (it's English, oftentimes postceded by pole)esoteric. Lets just get the war or the pandemic over, and the one or two billion of us left can get stuck into what's left.
I flavour the possibilities of backyard alcohol - but acknowledge you do end up walking further...er
I recently gave that elephant a bit of a going over in this - The Dead Gods Of Atacama.
http://www.dailykos.com/story/2009/8/5/762051/-The-Dead-Gods-Of-Atacama
Biofuels are a joke. Nuclear is the real answer.
An absolutely incredible book just came out about why the world IS going to go nuclear this century. The book covers all the themes of peak oil and climate change, energy transitions, alternatives to nuclear, and advanced 4th generation reactors:
http://www.thenucleareconomy.com
The book sums up the whole energy situation in one compact volume!
They're not mutually exclusive. Even if nearly all surface transportation is electrified, there will always be a need for liquid fuels for aircraft, boats, off-road equipment, and portable or backup power generation.
Repeat after me................
BAU, BAU, BAU, BAU, BAU............
Employment will recover and exceed past records.
Governments will subsidize future nuclear with the revenue received from tax revenue gained from full employment, consumer spending and business prosperity. Debts will be managed and and a new era of plenty will arise.
Entrepaneaurs will scramble to build nuclear power stations because the increasing populace (fully employed, housed and fed) will have the money to pay for the power the utilities provide, which will in turn also ensure prosperity for all.
I must confess I haven't read the book, I assume it has a happy ending though.
Agreed. We already have a glut of electricity. Building more nuclear power plants makes no sense to me. Let's build CSP plants instead and allow the coal plants and nuclear plants to run to the end of their lifespan (with an aim to shut down the coal plants earlier).
People really don't get "peak economy" and "peak credit"....
And does the book show how man has been responsible with fission based power?
Does the book cover what should be done when a nation-state gets a fission reactor and later is judged that they should not have a fission reactor? (Because the world was close to this exact condition. If the Shaw of Iran had gotten the fission plants working that were ordered, these same plants might have been subject to attack as the present new fission plants Iran has are being discussed in parts of the internet as subject to attack. What about nation-states that sign the NPT then have their reactor bombed? Iraq signed in march of 1970 and Osirak was bombed by 3 seperate nation-states. Does the book cover reactors being bombed? How about leadership saying they want a fission bomb, that the plant will help them get that bomb while still signed up to the NPT?)
The "peaceful atom" was a con-job you and others seem to have bought as it seems that fission reactors and ownership of fission weapons, based on evidence, go hand in hand. So, in this new 'nuclear economy' - who decides who can have nuclear for the economy?
Those who have fission weapons and don't use them?
Gen IV fast reactors mix materials in such a way that they are dangerous to handle and not suitable for bomb production. They don't chemically separate plutonium, and don't require enrichment of uranium.
For one thing, biofuels are being adopted to supplement oil. There's a difference between liquid fuels and electricity. And in the US, the latest EIA report shows that total energy from renewables has exceeded the total output of nuclear power plants. So right now the trend in the US is toward renewables. First Solar is reportedly producing 1 GW worth of PVs every year. That's the equivalent of a small nuclear power plant. In the US, there is still no permanent, long term repository for nuclear waste. Nobody wants it in their backyard.
Thanks for this series. Excellent information!
The consideration for GHG emmisions is an excellent and important point but I'm very concerned about habitat loss as well. It is well known that biofuels of any type have an incredibly large footprint/btu and every new acre of indusrial crop removes habitat (or replaces food production) and creates a new monoculture. Please share in your next installment how conservation of habitat/bio-diversity fits into the equasions.
On a related note, I just got back from a trip through Illinois. Virtually all of the farmland was in corn and soybeans. I'm curious, how much of that is destined for the biofuels market and how much for animal feed? It appears that little or no space is left to expand. I'm pretty sure from all of those thousands, probably millions of acres, there is almost no food intended for people directly nor was there much non-monoculture habitat.
Those of us here call it the 'corn desert'. There is some difference in policy from Iowa to Illinois - here I don't even find abandoned farmsteads to photographs. It's just mile after mile after mile of corn, less soy, and occasional farmsteads.
Lots of good points in your article, Robert. I was surprised that you didn’t comment on synthesizing fuels efficiently from CO2, H2O, and off-peak wind energy, since you are a chemical engineer with some appreciation for the reverse water gas shift (RWGS) reaction and Fischer Tropsch synthesis. Perhaps you haven’t yet run across the Windfuels website, where we present the science, engineering, and economics in considerable detail. Four peer-reviewed technical papers and two pending patents (containing even more technical detail) are available there for download. Allow me to introduce the concept briefly.
We have shown that off-peak energy (mostly wind, but also nuclear) can be used to recycle CO2 into ethanol, gasoline, jet fuel, and diesel at up to 60% efficiency. These wind-generated carbon-neutral fuels, dubbed WindFuels, will compete when oil is above $45 to $90/bbl. Recycling CO2 into standard transportation fuels using off-peak renewable energy addresses both the oil and the climate challenges, and it completely stabilizes the power grid, no matter how much wind and solar are added.
There is no better way to store massive amounts of energy than in the chemical bonds of standard liquid fuels that flow seamlessly within our current infrastructure. The tank-component cost of storing energy in liquid fuels is over three orders of magnitude less than the cost of storing energy in batteries or in compressed air.
Recent studies show the U.S. potential domestic wind resource exceeds 80 PWhr/yr (more than 3 times total domestic primary energy usage). There are sufficient amounts of domestic wind resources and point-source CO2 to produce twice our current total transportation fuel usage and supply all our other energy needs. The climate effects of wind usage at such a scale appear to be of little consequence.
Annual WindFuels production per land area in good wind regions will exceed biofuels production density in fertile farming areas by a factor of 4 to 30. Wind will not continue to grow quickly without a solid market for its off-peak energy (the price of which has plummeted over the past 18 months) and the ability to stabilize the grid by putting the off-peak energy into liquid fuels.
Detailed scientific, engineering, and economics analyses are available at http://windfuels.com/ .
One of the earlier comments posted by Roger Arnold alluded to something similar to Windfuels but less scalable and actually more expensive (because of syngas clean-up costs): Use off-peak wind energy to enhance the fuel yield of biomass. Indeed that is possible, but it’s better to think big from the outset. There will be no shortage of CO2 available anywhere there’s a market for it, and the easiest way to deliver the carbon needed for fuel synthesis is by pipeline.
We’ve also looked carefully at a number of studies on algae oil and concluded all indicate fuel from algae will cost in the range of $40 to $80/gal even at very large scale.
There’s a lot of sound economic analysis on all the alternatives here http://dotyenergy.com/Markets/MarketsOverview.htm and on the other pages referenced there.
I heartily agree that readers interested in renewable fuels should visit Dr. Doty's web site. There's a lot of good information there about renewable energy resources and fuel synthesis. I personally think that Dr. Doty is a bit too negative on the potential for CAES and other forms of energy storage, but the issues are legitimately arguable.
I also think that efficient, economical gas-to-gas heat exchangers of the type that Doty Energy has patented should be of high value in a broad range of chemical engineering processes, not just for production of syngas from CO2 and hydrogen. That's at the nity gritty detail level, and probably doesn't mean much to most readers here. But heat exchangers are such fundumental technology in chemical engineering that their performance can determine what is or is not economically feasible.
As to whether synthesis straight from CO2 and H2 is more cost-effective than what I referred to as "enhanced gasification", I've no real idea. Enhanced gasification should give roughly double the fuel yield per ton of biomass as conventional gasification, while giving roughly double the yield per kWhr of electricity as synthesis from CO2. It's also a good logistic match, in that some of the best areas for wind energy (e.g., northern plains of the US) are also very good areas for growing low-impact energy crops (e.g., switchgrass).
But it all comes down to issues of capital cost per barrel of oil equivalent. Cleanup of output from gasification of biomass hadn't been on my radar screen as a significant issue, but perhaps it should be. OTOH, the CO2 coming into a WindFuels plant of Dr. Doty's design might have its own cleanup needs as well. Especially if it's produced by oxy-fueled combustion of coal or biomass. That's way beyond what we can address through the kind of generalities and handwaving that we like to indulge in around here.
I don't think that any scheme which requires carbon input other than from the atmosphere deserves the label of "renewable". Even if carbon taxes or caps are never implemented, depletion will eventually strike.
We do, OTOH, have huge amounts of uranium, thorium, wind and sun. Our biomass production is sufficient to supply our use of fixed carbon in things like lumber, paper and plastic. If e.g. Ford gets on the ball and steals GM's thunder with a plug-in luxury car (call it the Lincoln Lightning—they can have the idea, I give it to them), we might set the stage for a radical shift from liquid fuels to electricity as the mainstay of ground transport. Should that happen, bio-carbon augmented by electric energy would be in the running to fill the niches that batteries can't.
Not sure what you're getting at, EP, in regard to carbon input. The WindFuels scheme proposes to use renewable energy and CO2 to produce fuel, and I certainly regard CO2 as a renewable resource. The scheme doesn't depend in any way on the source of the CO2, and every ton that it uses is a ton not released into the atmosphere.
If you're referring to Doty's assumption that the CO2 would be piped to the WindFuels plant from a coal-fired power plant equipped for CCS, then you have a point. But realistically, it will be a long time before we'll be able to .. (sing along with Joan Baez) "ra-aize, raze the coal plants, to the ground". As long as they're operating, we'll need to do something about the CO2 they emit. And once they're gone, it will be easy enough to switch to atmospheric CO2 -- either directly, via Klaus Lackner's "artificial trees", or (more likely, IMO) indirectly via biomass.
In fact, a likely transition strategy for coal phase-out would keep any newer plants equipped for CCS operating, but modify them to burn bio-mass instead of coal. So any pipelines set up to transport their CO2 would remain usable.
One obvious objection to using CO2 from coal-fired plants for fuel synthesis is that it doesn't actually sequester the CO2. Just holds it, temporarily, until the fuel is burned in a vehicle. That's true, but if the synthetic fuel replaces petroleum fuel on a gallon-per-gallon basis, the effect on atmospheric carbon balance is the same as if the coal plant CO2 were permanently sequestered, and the vehicles powered by the synthesized fuel were instead powered by fossil petroleum.
You wouldn't want to use synthetic fuel as a "solution" to peak oil that would allow us to continue our current current oil-based transportation paradigm unmodified, but I see zero likelyhood of that anyway. I think the electrification of most land transport is inevitable. My hope for synthetic fuels is that they can cap the cost of fuel for applications that can't be electrified at a level that will put an end to heroic efforts to extract remaining (expensive) oil reserves.
But any infrastructure built to use it will. Sunk costs are as strong an influence as technology.
I'm of the opinion that we will need to shift to energy systems which are carbon-negative, and fairly quickly. If we build fully-sequestered coal plants pumping to carbon sinks, we can add biomass to their fuel stream and remove carbon from the atmosphere. It's going to be very hard to do that if large-scale systems are built on the continued need to do the opposite.
Actually, this factor is probably much higher than 30.
A 3 MW wind-turbine may require a ground patch of approx. 80m2. With a capacity factor of 25% it'll produce 6.6 GWh or 82,000 kWh / m2 per year.
In comparison 10,000 m2 of Miscanthus produces about 80,000 kWh of CH4. That's 80 kWh / m2 per year.
http://www.miscanthus.at/sites/site_landw_allg.php
In this case wind produces approximately 1000 more energy (granted it is electric energy and not biomass) per ground area (and this is what matters) than biomass does.
Nah, you can't count it that way in this context. That's just the foundation pad and tower service area. That would be the right figure if you were just counting land area not available for other purposes. But for wind capacity over an extended area, you have to figure with the distance that the turbines must be spaced apart. Don't have that figure handy, but IIRC, it does work out to what Doty states: a range of 4 to 30 times the productivity of any biomass that might be grown on the same area.
Of course, the presence of wind turbines doesn't preclude growing biomass on the 99.9% of the land area that isn't occupied by the foundation pads.
But for wind capacity over an extended area, you have to figure with the distance that the turbines must be spaced apart.
So? This is completely irrelevant in this context as you mention correctly:
Of course, the presence of wind turbines doesn't preclude growing biomass on the 99.9% of the land area that isn't occupied by the foundation pads.
So the land surface area is still mostly usable for other purposes, such as biomass or:
http://www.scientificamerican.com/article.cfm?id=wind-and-solar-in-sicily
Besides off-shore wind-turbines do not even require land area (in that case the factor is even higher).
It may only be relevant if the available wind resource and area available was very limited and would not even remotely be sufficient to power the world, but this is obviously not the case.
http://en.wikipedia.org/wiki/Wind_power
And this is not even considering the fact, that the average power demand would drop, if the world was much more electrified (e.g. heat pumps, electrified transportation etc.)
If flash pyrolysis is better suited to production of solid biocarbon fuels - a more likely plant that can be put into a container and hauled around from place to place by truck or train, co-generating electricity or making some other use of the hot exhaust gas - then wouldn't the biocoal produced make a suitable fuel for gasification?
I will note that the 20% threshold ought to be more properly for the suite of liquid biofuels rather than for the individual elements in the suite, as putting electric rail on a level playing field with diesel road freight and gasoline road passenger transport would mean that we can reduce our liquid fuel needs substantially, while more fuel efficient transport would further reduce demand - for the US, 20% of current liquid fuel consumption from biofuels combined with 33% transfer of tasks to electrified transport and 33% reduction in fuel consumption to perform the remaining tasks would bring conventional fossil fuels down near current domestic production levels, so that scaling demand for conventional liquid fuels in line with ongoing declines in domestic production could be pursued by ongoing mode shifts and efficiency gains.