Energy Journal Roundup: September 2009

Feature Article

Ida Kubiszewski, Cutler J. Cleveland and Peter K. Endres, 2009, Meta-analysis of net energy return for wind power systems, Renewable Energy, Volume 35, Issue 1, January 2010, Pages 218-225

EROI for operational wind turbines below 1 MW as a function of power rating in kilowatts.

A side note: Over the past few months Rembrandt and I have been following roughly 10 or so academic journals related to energy. One of these journals, Renewable Energy, produces literature every month that I believe has particular relevance to the various issues discussed on The Oil Drum. This month's feature article is taken from Renewable Energy, and here is a link to the full table of contents with free download for this month's publication.

The Energy Journal Roundup is a monthly post listing citations and abstracts from some of the peer-reviewed literature published in various energy journals around the world.

Ida Kubiszewski, Cutler J. Cleveland and Peter K. Endres, 2009, Meta-analysis of net energy return for wind power systems, Renewable Energy, Volume 35, Issue 1, January 2010, Pages 218-225 Download free here.

This analysis reviews and synthesizes the literature on the net energy return for electric power generation by wind turbines. Energy return on investment (EROI) is the ratio of energy delivered to energy costs. We examine 119 wind turbines from 50 different analyses, ranging in publication date from 1977 to 2007. We extend on previous work by including additional and more recent analyses, distinguishing between important assumptions about system boundaries and methodological approaches, and viewing the EROI as function of power rating. Our survey shows an average EROI for all studies (operational and conceptual) of 25.2 (n = 114; std. dev = 22.3). The average EROI for just the operational studies is 19.8 (n = 60; std. dev = 13.7). This places wind in a favorable position relative to fossil fuels, nuclear, and solar power generation technologies in terms of EROI.

Eriksson, O., Finnveden, G., 2009, Plastic Waste as a fuel – CO2-neutral or not?, Energy & Environmental Science, Vol. 2, pp. 907-914

Municipal solid waste (MSW) is not only a societal problem addressed with environmental impact, it is also a resource that can be used for energy supply. In Northern Europe combustion of MSW (incineration with energy recovery) in combination with district heating systems is quite common. In Sweden, about 47% of the household waste is treated by incineration with energy recovery. Most incineration plants are CHP, summing up to 0.3% of the total electricity generation. MSW is to a high extent a renewable fuel, but plastic, rubber etc. can amount to 50% of the carbon content in the waste. Recycling of plastic is in general environmentally favourable in comparison to landfill disposal or incineration. However, some plastic types are not possible to recycle and some plastic is of such low quality that it is not suitable for recycling. This paper focuses on the non-renewable and non-recyclable plastic in MSW.

A CO2 assessment has been made for non-recyclable plastic where incineration with energy recovery has been compared to landfill disposal. In the assessment, consideration has been taken of alternative fuel in the incinerator, emissions from waste treatment and avoided emissions from heat and power supply. For landfill disposal of plastic the emissions of CO2 amounts to 253 g kg-1 plastic. For incineration, depending on different discrete choices, the results vary from -673 g kg-1 to 4605 g kg-1. Results indicate that for typical Swedish and European conditions, incineration of plastics has net emissions of greenhouse gases. These emissions are also in general higher for incineration than for landfill disposal. However in situations where plastics are incinerated with high efficiency and high electricity to heat ratios, and the heat and the electricity from incineration of plastics are replacing heat and electricity in non-combined heat and power plants based on fossil fuels, incineration of plastics can give a net negative contribution of greenhouse gases. The results suggest that efforts should be made to increase recycling of plastics, direct incineration of plastics in places where it can be combusted with high efficiency and high electricity-to-heat ratios where it is replacing fossil fuels, and reconsider the present policies of avoiding landfill disposal of plastics.

Wang, L., Gwilliam, J., Jones, P., 2009, Case Study of zero energy house design in UK, Energy and Buildings, Vol. 41, pp. 1215 – 1222

Possible solutions for zero energy building design in UK are discussed in this paper. Simulation software (EnergyPlus and TRNSYS 16) are employed in this study, where EnergyPlus simulations are applied to enable facade design studies considering buildingmaterials, window sizes and orientations and TRNSYS is used for the investigation of the feasibility of zero energy houses with renewable electricity, solar hot water system and energy efficient heating systems under Cardiff weather conditions. Various design methods are compared and optimal design strategies for typical homes and energy systems are provided

Faghih, A. K., Bahadori, M. N., 2009, Solar radiation of domed roofs, Energy and Buildings, Vol. 41, pp. 1238 – 1245

Solar radiation received and absorbed by four domed roofs was estimated and compared with that of a flat roof. The domed roofs all had the same base areas, and equal to that of the flat roof. One of the roofs considered was the dome of the St. Peter’s Church in Rome. Compared with the other roofs considered, this dome had a higher aspect ratio. It was found that all domed roofs received more solar radiation than the flat roof. Considering glazed tiles to cover a selected dome in Iran and the dome of the St. Peter’s Church, it was found that the solar radiation absorbed by these roofs is reduced appreciably. In the case of the dome of St. Peter’s Church, the amount of radiation absorbed was roughly equal to that absorbed by the comparable flat roof in the warm months. In the case of the glazed reference dome located in Yazd, Iran (a city with very high solar radiation), the radiation absorbed was less than that of flat roof at all times. In addition to aesthetics, this may be a reason for employing glazed tiles to cover the domes of all mosques, shrines, and other large buildings in Iran.

Jiří Jaromír Klemeš and Hon Loong Lam, 2009, Heat integration, energy efficiency, saving and security, Energy, Volume 34, Issue 10, October 2009, Pages 1669-1673

This editorial and overview of a Special Issue dedicated to the 11th Conference Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction – PRES 2008. Thirteen papers have been selected and after being peer-reviewed. Nine were accepted for publication covering important subjects of energy generation and usage. They are focusing on recent development of various features of heat integration which is an important methodology for increasing energy efficiency and saving. The complementary issues covered are emissions reduction and the security of energy supply. This issue of ENERGY is the fourth special journal issue dedicated to selected papers from PRES conferences.

Joni Valkila, 2009, Fair Trade organic coffee production in Nicaragua — Sustainable development or a poverty trap?, Ecological Economics, Volume 68, Issue 12, 15 October 2009, Pages 3018-3025

This article assesses the impact of Fair Trade organic coffee production on the well-being of small-scale farmers in Nicaragua. Studying the results of organic management is crucial for evaluating the advantages of Fair Trade because approximately half of all Fair Trade coffee is also organically certified. A wide range of farmers, representatives of cooperatives and export companies in Nicaragua were interviewed during seven months of field work between 2005 and 2008. Fair Trade organic production raises farmer income when low-intensity organic farming is an alternative to low-intensity conventional farming. However, low-intensity farming produces very little coffee in the case of the most marginalized farmers, keeping these farmers in poverty. With higher intensities of management, the economic advantages of Fair Trade organic production largely depend on prices in the mainstream market.

Perry Sadorsky, 2009, Renewable energy consumption and income in emerging economies, Energy Policy, Volume 37, Issue 10, October 2009, Pages 4021-4028

Increased economic growth and demand for energy in emerging economies is creating an opportunity for these countries to increase their usage of renewable energy. This paper presents and estimates two empirical models of renewable energy consumption and income for a panel of emerging economies. Panel cointegration estimates show that increases in real per capita income have a positive and statistically significant impact on per capita renewable energy consumption. In the long term, a 1% increase in real income per capita increases the consumption of renewable energy per capita in emerging economies by approximately 3.5%. Long-term renewable energy per capita consumption price elasticity estimates are approximately equal to −0.70.

Take a look at "Meta-analysis of net energy return for wind power systems" available for free download here.

Table 1 gives a list of the wind turbine results reviewed. The list shows 119 lines, according to my count. Of those, 72 are from reference [4], whose lead author is Manfred Lenzen, and 25 are from reference [25], whose lead author is also Manfred Lenzen. In total, 97 out of the 119 or 82% of the items analyzed are from papers whose lead author is Manfred Lenzen.

When one Googles Manfred Lenzen, one quickly gets to this page, which is selling life cycle assessments. This is part of what the site says:

The contact information is Prof. Manfred Lenzen . . .

I don't know about you, but I would feel a whole lot better about the study if I didn't think the vast majority of the analyses came from a single individual, who seems to making a significant part of his living selling these reports. I am sure the organizations buying these reports very much want a high EROI results to justify their investing in wind turbines. I have a hard time believing the results are unbiased--especially when it is difficult to tell in advance what the actual capacity factors will turn out to be. Maybe I am cynical.

I wrote to one of the authors (Ida Kubiszewski) with some of my concerns several months ago, but never got a reply.

In total, 97 out of the 119 or 82% of the items analyzed are from papers whose lead author is Manfred Lenzen.

Well, knowing nothing else, that fact you point out is suggestive of systemic risk, which folks should be a bit more familiar with these days. The good news is that one would hope the boundaries are commensurate on the ones he performed.

I'd like to see, if possible, an integrated net energy meta-analysis on the energy return of wind not at the turbine site, but after transmission, storage and indirect exogneous energy costs necessary when wind blows too much or not enough. When we have one fuel, like gasoline, it is relatively straightforward to both calculate and compare energy gain, but EROI falls far short as comparison tool when it becomes a 'portfolio EROI' which also includes different timing of energy flows.

I agree very much. Taking one little piece of the system, and attempting to estimate it, often before the wind turbine is even built, invites exaggeration.

I think if one is actually thinking of building electric cars with the system, the calculation needs to take the additional energy requirement of building electric cars to replace gasoline cars into account as well, especially if these cars are more energy-intensive to make.

well there we disagree. The energy return should just be the energy input as denominator, and the wide boundary energy costs as numerator. What we DO with the energy once it is produced is not an EROI question, but one of allocations and efficiency. Matching the assets and liabilities is what ultimately needs to be done - if we conflate the two it will be nigh impossible to compare.

Maybe additional investment and energy requirements for electric autos needs to be a separate calculation. With limited investment dollars, it is not at all clear we will have funds available to make electric cars, even if wind is beneficial on an EROI basis.

In many ways, I think sufficiently high EROI is a necessary but not sufficient reason for adopting a method of energy generation. There are a lot of other issues as well: water requirements; investment requirements; CO2 issues; ability to keep up long enough term to make EROI calculations valid; land requirements; spent fuel issues (for nuclear and coal). You can probably think of others as well.

I see the whole $79.95 book Biofuels, Solar And Wind As Renewable Energy Systems: Benefits And Risks is available for free download (with registration). You are one of the authors of Chapter 12. Robert Rapier is the author of Chapter 7 - Renewable Diesel. Several chapters are by the editor, David Pimentel.

I disagree. Making electric autos is not part of the equation. How would you even factor that into wind production eroei?

This is, to me, the equivelant of saying... we must factor in the energy required to build 2010 model cars, since they are replacing the old clunkers. It doesn't work that way. We are replacing them anyway. Why would we scrap all of the old cars? Why do we have to have as many cars at all?

These are the kinds of problems you get in when you start overthinking EROEI and confusing it with what you do with the enregy product once it is produced. In the end, no matter what, the EROEI of our global civilization, if you take all of these nth-order things into the equation, is ALWAYS 1:1. We produce energy with the intent to use it. Nate's right, we can have more gains from better efficiency, but there's no need to include it in EROEI.

Now if those cars were trucking oil... it'd be a different story.

I've said it before, I'll say it again: the post production & distribution "n-th order" eroei factors aren't drains on the system/economy, they are the economy.

I don't think it's impossible to compare complex networks, sometimes quite easy, but you have to be careful to frame the questions so they're the kind you can answer with confidence.

For example, you could frame the correct whole system question, as Gail was suggesting (and as my model formulas do). You can be confident that you're at least asking the right question. Then you might throw up your hands and just list the major imponderables as thoroughly as your time allows, to explain why you only found a small piece of the model possible to calculate. The calculation then is still useful for competing businesses in the same industry, to compare their parts, as well as giving the best available information to the investors on all sides to see the imponderables that have to be solved too to give the calculation meaning.

I disagree. Framing the whole system is NOT the way to address this - at least not wind/electric cars. We need to offset fossil fuel decline by either less population, less consumption, change in type of consumption, or increase in energy production. To perform an energy analysis on wind and then add to it how much energy and non-energy inputs electric cars will require will completely obfuscate the benefit or lack thereof of wind itself for basic energy needs that might not include more cars.

Yes we need entire system analysis, but not in this case.

FWIW, if you include electric cars the system cost will fall sharply.

There's a marvelous synergy between EVs and wind power: EV charging can by scheduled dynamically for those times when wind power is strongest, and charging can discontinue when wind power is weakest. These benefits are essentially free to the utility, and without cost to the EV user. Dynamic pricing is very likely to allow the utility to, in effect, pay the EV owner for the benefits provided to the utility.

In the long-run, V2G is likely double the benefits, as EVs will be able to supplement the grid when renewables are weakest.

May I just inject that there might be a question in future of what kinds of road surfaces these electric cars will be driving upon? Something other than asphalt, I presume?

Yes, I imagine they'll be driving on concrete.

Perhaps something low CO2, like this:

Well Nick, I wonder about that. Cement roads are very costly compared with asphalt, and we seem to be moving into a world where communities and states, someday perhaps even the feds, have less to spend on maintaining roads, etc. Also, your linked article mentions that the CO2-absorbing magnesium silicate-based cement may have structural limitations compared with limestone-based portland cement, as well as requiring heat to make, although less than that necessary for portland cement. Then there's magnesium silicate availability, although common, not nearly so much as your friendly limestone mountain just outside of town.

OTOH, cement roads are rather permanent, so perhaps we do indeed need to make more of them before society can no longer afford to build and maintain them. Maybe they can be our pyramids. Every once-great civilization needs iconic structures to be remembered by, how much moron fitting for ours than our vast network of concrete freeways, overpasses and boulevards?

Cement roads are very costly compared with asphalt

Their upfront costs are higher, but they last longer and have lower maintenance, so their lifecycle costs are the same.

Highway engineers like them just fine.

Concrete is a major source of CO2 emissions (3% ? from memory).

Highway engineers like them just fine.

Actually not. Fine for first construction, in some places, but a bitch to repair and needs asphalt for an overlay.

In areas with unstable ground, concrete is a poor choice as it tilts and breaks.

I prefer cobblestones (such as Felicity Street two blocks from me). Longer lasting, no CO2 emissions, easier to maintain.


A bit bumpy, though, and labor intensive to install (though this could be a plus as millions fill the ranks of the unemployed).

Don't we really think that most roads will revert to gravel and dirt (=mud in the wet seasons)?


Your comment brings up an interesting question-will it be cheaper -even though perhaps exteremely expensive -to maintain paved roads than to pay the price of conducting business -particularly essential business -on dirt and gravel roads?

Native gravel (stone suitable for roadway use with only minor processing) is not very common and while manufactured gravel-crushed stone- is still pretty cheap the future price is anybodys guess The mining,and hauling are highly ff dependent.Sfaik,nearly all the crushing is now done electrically,at least in places with an adequate grid.

My guess is that heavily traveled existing paved roads can be maintained for much less than the extra costs of trying to run vehicles of any kind on unpaved roads.A heavily traveled unpaved road
quickly becomes impasssable in most cases if there is a lot of rain and every vehicle on it will use substantially more fuel per mile traveled or ton hauled,wet or dry.Tire wear and other vehicle maintainence and repair expenses also go up sharply.

Areas with little essential traffic can probably get by with stone and gravel roads.

Lightly traveled roads will almost certainly revert to dirt with a little gravel applied occasionally.

Farm "roads"(really just vehicle pathways on private property) are commonly "maintained" by dumping whatever is handy in the worst ruts and mudholes-usually stones removed from fields and pastures in my nieghborhood,but also broken brick and block from demolition work if available.

People living on residential streets will find themselves doing the same thing eventually.

I do think that lots of Toto's superlight railroads will be built unless things go downhill too fast.

I'm not saying that it is necessarily the most rational thing, but short term expense is going to be the dominant concern, IMO. Many localities will find asphalt prices too high for anything but repair of the most crucial routes.

Deteriorating roads may actually be another way to discourage car use. As fewer and fewer people drive, there will be more and more pressure for car and truck drivers to bear the full cost of road and bridge building and repair. This could hasten the demise of well maintained roadways.

I would love to see a movement toward active de-pavement--tearing up much existing asphalt and concrete infrastructure and turning them into gardens and parks. I live a couple blocks away from a two-block stretch of city street where they did just that--tore up the street and planted trees, gardens, and lawns. It is a showpiece for the city, but oddly has not been replicated yet in many other neighborhoods.

I lived in Georgia for a while, and many older people there can clearly remember the first paved road that was made in their county. Somehow people lived for centuries in these counties without any paved roads for centuries. I'm not saying it was easy. But many of the same people also note some of the negatives that came with the network of paved roads--it was easier to get to the small towns, but also easier to leave them or drive through or around them, so most towns suffered economically and in other ways.

Many localities will find asphalt prices too high for anything but repair of the most crucial routes.

It's highly unlikely that asphalt prices will go that high. Oil prices are unlikely to ever stay above $200 in a sustained fashion: there are too many substitutes, and it would put too heavy a burden on the economies of oil importers.

Don't forget, asphalt currently only uses 400,000 barrels per day in the US - that's only 2 % of overall oil consumption. Given that even 100 years from now oil production will be 10-20M B/day (if there's the demand for it), asphalt paving can continue for a long time.

If there develops a consensus that paving maintenance costs are excessive, the obvious solution is to charge those costs to the long-haul trucks (especially over-weight trucks) that cause 90% of the damage. This will move freight to trains, where it belongs, and make roads last much longer.

In the short-term road maintenance will out-bid other uses for asphalt, and in the long-term gradually move to alternatives, chiefly concrete.

As we are discovering, nominal cost in US dollars is not as important as ability to pay. States and municipalities are out of money. Cut backs in every direction are now underway. Long-haul trucks should have been paying the lion's share of repair on roads on which they travel. But they haven't, by and large, and they probably won't.

Yeah, but cobblestones really suck if you are on a bicycle. Besides being hard to ride on in good conditions, they are treacherous in the rain.

The tires chosen have a significant impact.

And bicycle only "streets"/paths should last almost forever if well built.


And bicycle only "streets"/paths should last almost forever if well built.

Amen. If some virsus caused all humans to become violently ill in the presence of ICE vehicles and if we then used Human Powered Vehicles (HPV) for local, personal transport - we could save oil for building and maintaining asphalt bike paths.

On the other hand, cobble stone and washboard gravel roads significantly reduce the efficiency of HPVs. I remember when most of Norther Minnesota had gravel roads - washboard roads - what a pain they were.

cobblestone is not so bad for bicycles. Lower speed for more comfort & control (8 to 10 mph say) but quite bikeable..

Best Hopes,


Fine for first construction, in some places, but a bitch to repair and needs asphalt for an overlay.

Literature says that concrete life cycle cost is comparable to asphalt, and highway engineers tell me that asphalt isn't needed for repair. If you have sources/links for further info I'd be pleased to look at them.

Concrete highways are more cost effective. Repair: They last a long time. One can repair them with concrete. It costs more to do. But then the repairs last a long time too.

Nate -

Aha, I see we are once again mired in the EROEI question regarding wind turbines! Gail doesn't seem to quit in her quest to discredit the very idea of wind turbines.

As I have stated over and over, it is not essential to account for every single BTU of energy input, but rather all one needs to do is to prove that the energy input cannot EXCEED some threshold number for the real EROEI to be acceptable. This is a deliberately simplistic engineering approach, but it is all that is needed to make the point.

Ergo, I will hereby attempt to prove once and for all that even under the most unfavorable, onerous, and biased assumptions that one could reasonably envision, the EROEI of a wind turbine is still OK. By OK, I mean the energy return makes building it worthwhile.

Now, here's my underlying assumption, which I think is irrefutable: The total installed cost of a wind turbine system cannot be LESS than the cost of the energy incurred directly and indirectly in its manufacture and installation. For how can it be? To reduce the argument to absurdity, let us say that 100% of the cost of a wind turbine system is energy input. No other costs. Then, unless the builder of the wind turbine system wants to build it at a loss, he has to charge an amount at least equal to the cost of the energy that went into it.

A wind turbine with a 2.5 MW nameplate capacity costs several $million to build and install, depending on location and a bunch of other factors.

Let us now assume the following:

i) A 30% capacity factor.

ii) An operating life of 30 years.

iii) $1 million of the total installed cost represents the cost of energy either directly or indirectly expended in its construction and installation. This represents between one half and one third of the total installed cost. (I think it can easily be shown to be far less than this, but to prove a point, I will stick with the $1million figure as a very worst possible case.)

iv) The value of the energy expended and produced by the wind turbine will be on the basis of equivalent barrels of oil @ $50/bbl.

OK, so here goes.

$1million worth of oil @ $50/bbl is 20,000 bbl. Assuming 5.25 x 10^6 BTU/bbl, the total amount of energy input into the building and installation of the wind turbine is roughly 1.05 x 10^11 BTU

At a 30% capacity factor, our 2.5 MW wind turbine generates 750 KW on average. Over it's 30-year operating life, this amounts to 1.97 x 10^8 KWh, which is equivalent to 6.7 x 10^11 BTU

Dividing 6.7 by 1.05, one gets as an absolutely conceivable worst case EROEI of about 6.4. Not too shabby for a super worst case, eh?


Looking at it another way, how can anything even approaching 20,000 bbl of oil (weighing over 3,300 tons) possibly be expended in the manufacture and installation of something that probably weighs no more than 400 or 500 tons? We're largely making and fabricating large steel components here, not producing high-tech computer chips.

So, having gone through the above exercise, I tend to believe that, based on more realistic and reasonable assumptions, an actual EROEI of over 20 is indeed quite credible. I think the key point here is that the energy input to manufactured and installed heavy equipment, such as a wind turbine system, is typically not a really large fraction of the total cost of that system.

Now that I've finally put this whole wind turbine EROERI question to rest, let us all go on to something more fruitful.

I agree with most of this but don't have time to get into it yet again. Two parts you left out off top of head (one in favor one opposed):

1)A good part of the cost of wind is financing which doesnt have an energy cost. People wanting future certainty of energy flows will make different decisions towards wind than the market (discounted present value with positively sloped yield curve) will make. It is a fundamental disconnect between energy and the markets, and is why state owned energy companies in Europe have gone ahead and built out wind farms in face of credit crisis.

2) From the 19:1 in meta-analysis, we need to subtract: a)transmission of energy from wind sites to where it is needed, (roughly 20% drop in EROI), b)buildout of shadow capacity/problem of intermittency (either for storage capacity generation or unused electricity) - could be another 20% drop, c)storage (another 10% + drop). Finally, as we know wind is not liquid fuels - so if we have surplus of electricity capacity but not so with liquid fuels, the EROI has a quality mismatch. So Joule, I agree with you, from an energy perspective, wind passes your threshold test, but it isn't without problems.

And I agree, there are decreasing returns to complexity discussing these issues ad nauseum.

Nate -

You are quite right about the cost of financing. It adds costs that are totally unrelated to the making of physical things and further reduces the fraction of the total cost associated with energy expenditure.

As far as transmission losses and their negative effect on EROEI goes, unless one is dealing with totally decentralized power systems, such as home PV installations, I think this factor tends to be a wash, as all centralized power stations, be it coal, gas, or nuclear, also incur such losses. But it is probably a bit worse for wind power, as the windiest places tend to be thinly populated. Then again, some of these huge 'mine mouth' power stations are not near heavily populated areas either.

I would be the first to agree that wind is not without its problems, some of which are quite serious, but the point I was making is that low EROEI is NOT one of them.

Transmission losses take a step down when moving from HV AC to HV DC.


buildout of shadow capacity/problem of intermittency (either for storage capacity generation or unused electricity)

Besides that interconnected windfarms provide baseload, your shadow capacity already exists:

Natural gas (US): 449 GW
Hydro (US): 78 GW
Hydro (Canada): 99 GW
Pumped storage (US): 20 GW
Biomass (US): 5 GW
Wood (US): 7.5 GW

Wind will mostly save natural gas and reduce drop of hydro reservoir levels.

In addition if fossil heaters were replaced by heat pumps, excess wind electricity can easily be stored in heat energy (water tank for heating and hot water). Or why waste oil in oil heating system and oil based hot water heaters?

transmission of energy from wind sites to where it is needed

In the USA it is estimated that to upgrade the transmission system to take in planned or potential renewables would cost at least $60 billion. Total annual US power consumption in 2006 was 4 thousand billion kWh. Over an asset life of 40 years and low cost utility investment grade funding, the cost of $60 billion investment would be about 5% p.a. (i.e. $3 billion p.a.) Dividing by total power used gives an increased unit cost of around $3,000,000,000 × 100 / 4,000 × 1 exp9 = 0.075 cent/kWh.

Wind will mostly save natural gas

That's a social choice. If we put a price on carbon, wind should take a big bit out of coal.

I have a few concerns with this argument, though I only partially disagree with your conclusion:

1. I don't think $1 million for a 2.5MW turbine is a realistic installed cost. This article suggests that wind turbines in this size-range cost between $1.2 million and $2.6 million per megawatt of installed capacity, concluding that a 2MW turbine costs about $3.5 million installed. If that's the case, your "worst case" EROEI comes to about 1.9.

2. As Nate pointed out, this measure doesn't include transmission, storage, grid-upgrade, etc. When factored in, this could cut that number in half (e.g. possibly below 1).

3. I also disagree that we can discount any of the cost of the turbine as an energy input--at least not without careful analysis (which, to my knowledge, has not been performed). I think it's entirely plausible, to use your words, for something "even approaching 20,000 bbl of oil (weighing over 3,300 tons) possibly be expended in the manufacture and installation of something that probably weighs no more than 400 or 500 tons." That makes me think that these low EROEI numbers are not entirely unlikely--even quite likely.

All that said, I tend to agree that Wind is one of the better renewables investments available, and that it makes great sense in many (though not all) applications.

Where I'm worried is when we start to talk about wind as the foundation of a massive transition from fossil fuels to renewables. Even if the EROEI is as high as 6.7, there would be massive impacts from any rapid transition program (such as one that attempted to replace oil at the rate its production declines--see my article on the topic. I don't think it's necessarily knowable whether or not these problems would be insurmoutnable at an EROEI of 6.7, but they very likely are at an EROEI much lower than that (as I argue is actually fairly likely). My conclusion here is that wind is likely not a suitable vehicle for civilizational transition from fossil fuels to renewables.

However, I still think that wind makes a lot of sense, and that we should continue to pursue it. It is the renewable that seems close enough to the EROEI threshold that we may be able to cross it with more innovation (and, perhaps through subsidies at some point, focusing developement and design on EROEI maximization rather than profit maximization). Additionally, it's long enough lasting that it will be of value well into the future regardless of its current EROEI. Even if the true EROEI was 0.8, it might still make sense because investing that energy in wind now will ensure that 20 years from now we have electricity generation, as opposed to extra rusting autos or burned-out flat screen TVs... I just don't think we should get our hopes up that it will facilitate any sort of continuation of BAU via a massive transition program.


I think you probably misunderstood my basis: I said that a 2.5 MW wind turbine would cost SEVERAL million dollars, not one million dollars. The $1 million figure is what I more or less arbitrarily chose as an upper bound of the value of the total energy input in the construction and installation of the wind turbine system. As such it would represent between one third and one half of the total installed cost, a deliberately extreme number.

Regarding your third point, I would invite you to show me how one can conceivable expend anything close to the equivalent of 10 tons of oil to produce, manufacture, and install one ton of fabricated heavy equipment. As I said, maybe such a number might be true for something like silicon chips, but we are talking here largely about dumb old heavy machinery and structural steel. I very much doubt that it is even a 1 to 1 ratio. Check it out. See how much energy is expended in the manufacture of a ton of steel, concrete, and fiber-reinforced resin. That double, triple, or sextuple that to account for manufacture, shipping, installation, etc. , and you will see that it doesn't even come close.

As I said, this is why I think that an EROEI on the order of 20 for wind power is quite a credible number.

Now, as to the other problems with wind power, I don't at all dispute their seriousness. Which is why I don't think wind power will ever constitute more than a relatively small fraction of our (US) total electrical generating capacity. But to my way of thinking, that is no reason not to pursue wind power in those areas where there is plenty of wind. It won't solve our energy problem in and of itself, but it will make a positive contribution, and we're going to need all the help we can get wherever we can get it.


Appologies, I misunderstood your argument. While it sounds like we're largely in agreement on the big picture, I still disagree on the (important) details here. First, I think that the entire installed cost is ultimately composed of energy, not just 1/3 to 1/2. This is because of my (admittedly extreme) view that, when addressing issues of societal transition, we need to completely open the boundary and include ALL inputs. I'll illustrate this by addressing the second point (how one 10 tons of oil can be used to produce a 1-ton manufuactured good): Let's look specifically at a wind turbine. I'll admit that I don't have the time to put together a well-sourced study, but I think it can be anecdotally established. Take the neodynium in the generator, for example (something that has been much discussed recently as a rare earth coming primarily from China). I don't know what the energy costs are to mine the ore, process the ore, cast and finish the final pieces, build and operate the machines, plants, control systems, HR systems, etc. to do this, transport the goods back and forth around the world, feed all the people involved, etc., but my *guess* is that it's much more than 10 times the weight in oil of the final product. This will become increasingly true as we expand wind production and need to exploit increasingly low-grade rare earths ore in this process. While this is only part of the process, I think it's an example of the very high embodied energy that will compensate for some of the admittedly lower embodied energy parts.

This is already getting too long-winded, but my ultimate argument that energy inputs are much higher than accounted for in most EROEI studies is that the industrial and societal support pyramid needed to produce any complex product is very large, and requires (VERY roughtly) converting the entire price of the end product into energy...

jeff -

As to your point regarding the neodynium magnets in the generator of a wind turbine, I very seriously doubt that 10 tons of oil fuel equivalents are needed to produce one ton of neodynium. I'm not sure about neodynium, but many of these so-called rare-earth metals are produced as a co-product associated with the extraction of less exotic materials. Anyway, it would be relatively easy to look into.

And even if it were true for neodynium, the weight of the magnets in the wind turbine's generator is but a few tons, and therefore a small fraction of the total weight of the installed turbine system.

Also, one other point needs to be made: while neodynium is a highly desirable material to use in generator magnets, it is not an absolutely vital material. For many decades electrical generators were made with magnets of plain old iron and various mixture of iron and cobalt. The benefit of using neodynium is that it allows you to reduce the weight of the generator/motor and to also improve its efficiency. This is is particularly an advantage in electric vehicles, but less so in stationary applications. In fact, a generator doesn't even need permanent magnets in the first place. Electromagnets can be used to create the magnetic field, but those require power and incur associated power losses. So, in a pinch we could do without neodynium.

All energy production systems have a host of difficult-to-quantify energy inputs, but the trick is in knowing which ones are significant and which ones are of less importance. And that is what I have attempted to do in my little exercise.

Hi Jeff and Joule,

Just a note of appreciation for your informative discussion. I have a grandson that I've encouraged to become a engineer or technican in the wind power industry. I'm always looking for useful information to pass onto him. The quality (and civility) of you discussion is the kind of thing that keeps me tuned into TOD. Thanks.

I'll illustrate this by addressing the second point (how one 10 tons of oil can be used to produce a 1-ton manufuactured good): Let's look specifically at a wind turbine. I'll admit that I don't have the time to put together a well-sourced study, but I think it can be anecdotally established.

At least the latent heat of melting for 1 ton of steel (e.g. melting 3 to 4 Hummers or 1/7 of an Abrams tank) is only about 70 kWh.

Now 10 tons of oil contain roughly 100,000 kWh. (Or the latent heat of melting of 1430 tons of steel).

I believe you are way off.

Take the neodynium in the generator, for example (something that has been much discussed recently as a rare earth coming primarily from China).

At least until recently most large wind turbines had synchronous generators and they usually do not contain neodymium (and even if some do - they will definitely run without it).

So 'rare'-neodymium won't kill wind turbines and not even EVs for that matter (e.g. the Teslaroadster has an asynchronous motor without neodymium).


Low EROEI is only a problem when you deliberately constrain the EROEI to use barrels of oil. If we do that, there is a huge problem because oil is about to start (by 2015 or thereabouts) declining at possibly a 6% net annual depletion rate globally.
In the case of the hypothetical wind turbine fabrication plant I'm not so worried.
The reason is that for the energy inputs required to build the factory, most are supplied by electricity.

In a worst case (crash) scenario the plant could be built near the ocean or railroad line so transportation energy costs are limited. Energy inputs could be by big hydro (i.e. the plant should be built in an area where most electricity is hydro). Then, you would get greater bang for the buck by siting the windfarm off shore to capitalize on the high efficiency of ocean freight vs land freight.

Building wind turbines is not likely to be the problem from an EROEI perspective. It's finding places and energy to build hydro storage to solve intermittency that's the challenge.

Intermittency isn't that difficult to solve.

You just need geographic diversity and a moderate amount of long-distance transmission; Demand Side Management, especially of EVs; and backup by idled FF plants and eventually biomass plants (for perhaps 5% of KWHs).

Consider: the US has all the peak generating capacity it needs, for quite some time (current peaks can be shaven by time-of-day pricing). So, wind doesn't really need to provide firm capacity, even though it does provide more of that than people realize.

So, all that's left is managing a diverse set of generators in such a way that variance from renewables doesn't destabilize the system, and that's where DSM will be invaluable.

Eventually EV V2G will be be valuable, as well, but that's not needed in the medium-term.

Here's a longer discussion:

And here's a discussion of whether storage is needed:

Don't forget about waste incineration for DSM, that's a good five percent of our electricity use. There would be trade-offs in designing peaker plants instead of baseload plants, but there's still plenty of potential sources to smooth out a mostly renewable grid.

waste incineration for DSM, that's a good five percent of our electricity use

Have you seen a good source of statistics for that?

This is a good overview IMO.
And the numbers certainly seem to pan out.

With ~200+ billion kg of municipal waste per year in this country, at the equivalent of ~50+ billion kg of fuel oil, we could see ~200 billion kWh of electricity given power plant efficiency of ~35+%.


Any idea how much intensive recycling would reduce this? It might make more sense to recycle plastics than to burn them, for instance.

My conclusion here is that wind is likely not a suitable vehicle for civilizational transition from fossil fuels to renewables

With a broad brush, conceive of

1) significant efforts for conservation & efficiency
2) Widespread electrification of transportation (rail first wave, EVs second wave)
3) A North American Grid with the following characteristics

a) HV DC transmission capable of shifting 1/8th of peak consumption from region to region
b) Pumped Storage & Storage Hydro = to 25% of peak demand and capable of storing 10 hours total consumption in PS (note: 40 GW more hydro from Canada, more turbines on existing dams, controlling spring fall of Great Lakes (like Lake Winnipeg today)
c) Fuel sources (annual MWh)

Wind - 47%
Nuke - 28%
Geothermal - 4% (all West of MS River)
Solar Thermal - 4% (SW USA only)
Solar PV - 11% (mostly below 43 degrees lat).
Fossil Fuels - 8% (back-up when things don't balance with renewables, fairly often with 8% of total MWh, but just "topping off")
Pumped Storage Losses (+8% out & -10% in = Net -2%)

Please consider,



I think this is a theoretically possible program IF the EROEI of renewables and nuclear energy is high enough (I'm very skeptical on this point, but I recognize that it's a possibility and so I'll leave that debate to another time). However, just how practicable such a transition would be is a function of just how high the EROEI of these energy sources actually is. For example, if Wind is as low an EROEI figure as I fear it may be (~4, declining as it scales due to grid issues), then 1) 25% of that wind energy will need to be diverted to produce the next generation turbines, 2) it won't be possible to bootstrap current wind generation to provide the initial outlay of energy for the massive build-up necessary to hit that 47% number on any kind of acceptable timeline, and 3) therefore the amount of fossil fuels that we'll need to divert to ramping up wind generation will create serious supply/demand issues when we're already experiencing them from primary decline, making the whole endeavor politically/economically extremely challenging. If the EROEI is actually 20, then these problems are diminished, but definitely not eliminated--I'm just guessing at where the critical threshold would lie.

These issues are further exacerbated by the additional energy that must be initially diverted from fossil fuel supply to provide for electrification of transportation, improvements in transmission, pumped storage, etc.

If the EROEI of wind, when accounting for ALL inputs, is actually 4 or less, then I think this program is unworkable, unless "serious conservation" is extreme (maybe 80%). If the actual EROEI is 20 then I think this program is possible, but I don't see it as being politically practicable. Not because it isn't a good idea--maybe even the best idea, who knows--but because it will require exactly the kind of proactive sacrifice for future reward that (as Nate has often and convincingly pointed out) we have a very poor track record of selecting. In the end, I fear that there will always be a well-oiled (no pun intended) politician offering the promise of BAU and saying that those who call for such "extreme" measures are self-interested or self-important radicals that can safely be ignored. Even those offering wind as a super-high-EROEI "solution" in the absence of the need for dramatic conservation and sacrifice might well fit into this camp.

All of which leaves me to wonder: is it best to push for a solution that, even if workable, is unlikely ever to be implemented? Are there any viable alternatives? While I don't think that society at large will choose to invest in the infrastructure necessary to support localized self-sufficiency, I do think that individuals and communities can and will do so to varying extents, and that this might be a better use of our limited and dwindling supply of surplus energy than the pursuit of massive and centralized renewable energy programs that may (will?) ultimately fail...

making the whole endeavor politically/economically extremely challenging

I will eMail something to you tomorrow. Low probability of success, but I seem to have found one possible way.

Best Hopes !!


"If the EROEI of wind, when accounting for ALL inputs, is actually 4 or less, then I think this program is unworkable, unless "serious conservation" is extreme (maybe 80%)."

It strikes me more and more that something like this is going to be necessary in any remotely realistic scenario. Yet we (and almost everyone else) spend much more time talking about sources of energy than about the best ways to cut our profligate energy use.

IMO, the first through 30th things we need to do is conserve and curtail (and legislate the same, ideally at a global level, to avoid the Jeavons Paradox types of effects). But we are spending most of our time discussing the 31st...things on the list of priorities.

On the one hand, conservation and curtailment are not sexy and often involve sacrifice or what appears to be sacrifice. On the other hand, these are generally far the least expensive approaches.

So the central question to me is: How little can we consume and still have a life that includes things we most value.

This approach, of course, brings us up against the very issues of what we value as a society that we have tried to evade by pretending to supply enough energy so that people (with means) can do whatever they want with it.

Unfortunately, the strongest values Americans seem to be expressing recently are the desire to feel protected (both militarily and financially--on which trillions have recently been spent) and the desire to be entertained (the only tax passed by our "no new taxes" governor--in spite of the fact that schools, libraries, hospitals...are all in crisis--has been to fund a new baseball stadium).

No need to point out that all of these expenditures further funnel vanishing resources into the pockets of those who already have the most. This is the most likely future direction of most expenditures, despite whatever more rational schemes for resource allocation we hatch here.

Hi dohboi,

Unfortunately, the strongest values Americans seem to be expressing recently are the desire to feel protected (both militarily and financially--on which trillions have recently been spent) and the desire to be entertained (the only tax passed by our "no new taxes" governor--in spite of the fact that schools, libraries, hospitals...are all in crisis--has been to fund a new baseball stadium).

Unfortunately, I think you are right. As I have posted many times - the average US citizen simply does not believe there is a looming problem with fuel supply - at least not anything that we cannot work around with new technologies.

So, the big question is: why is the problem of PO (and peak other stuff) not recognized and understood by the average person? I submit that the average US citizen is severely deficent in critial thinking skills and is simply unable to deal with numbers like 85 mbd, 4 mbd spare capacity, 7 % decline rate versus reserves and futue discoveries of a lessor value, 6.8B humans growing to 9 or 10B versus far less planetary carring capacity, 30% species extincition rate, over 2 degree C GW, aquifer declines, 80% fishery depletions, etc, etc. This combined with relentless disinformation via popular media to prompt people to consume more and more. And, underlying all this mental deficiency is the fact that 80 some percent of US Citizens have "faith" in nonsensical myths about afterlife, prayer, etc. - belief systems that render them nearly incapable of discerning truth from fiction. And, of course, we have basic human traits of greed, laziness, and selfishness that encourage most people to resist any kinds of conservation measures that involve more work or inconvenience.

I think that it would be entirely possible to combine conservation, efficiency, family planning, and alternative energy to transition to a very nice life style for generations to come. Then I see a NASCAR race on TV.....

"relentless disinformation"

Yep, on top of all the other points you make, this really nails the coffin. If people think they have reason for reasonable doubt, they will default to whatever view confirms their own lifestyle an prejudices. Those pedaling this disinfo know this--they don't have to completely convince most people of their view, just plant enough doubt that people stay confused, uncertain, and default to BAU.

But, hey, these grim facts needn't keep us from fantasizing about how things could be managed if people suddenly came to their (or our? ;-}) senses.

"I think that it would be entirely possible to combine conservation, efficiency, family planning, and alternative energy to transition to a very nice life style for generations to come."

So what specifically would you implement if you were king of the forest?

When I get elected to be god and supreme commander I will start with a few modest changes:

There will be no more than 2B humans by the end of the century - whatever it takes.

GHG will be returned to 300 ppm - whatever means necessary

Extinction of other species must return to historical levels for the last 10K years

Humans will no longer be allowed to damage the ecosphere (mining, fishing, drilling, etc) simply to enjoy an extravagant lifestyle. Everything taken from the planet needs a sustainable counterpart. Personal transportation will no longer be centered on a car culture. Asphalt will be used primarily for bike paths.

There will be no such thing as perpetual growth and endless consumption - Republicans will be required to wear an arm band so that we can monitor their natural tendencies for selfish behaviour.

All churches will be turned into community centers and science education facilities (religions, of course, will be treated with the same status as Greek and Roman mythology - maybe Santa Claus and the Easter Bunny will be tolerated for comic relief)

There will be no such thing as a Federal Reserve operated by private banks. Governments will issue whatever money is needed to facilitate legitimate exchange of value for productive activities. Government will provide for universal health care and education. Defense will only be for real defense.

I will then rest for a day and decide what else needs to be done. On my rest day everyone will get all the free fine wine and cheese they want. Republicans will be lucky to get a beer and a hotdog.

You get my vote.

Now that I've finally put this whole wind turbine EROERI question to rest …

not so fast Joule. I think you have to adopt the new reality concerning WT’s - it’s taking place offshore with added costs, at least i Europe.Here are fresh as of today numbers/costs for the world’s largest WT-offshore park, Horns Rev 2/Denmark inaugurated today.

Horns Rev 2: Installed capacity 209 MW, 91 turbines, inst.cost $694 million ....
Costs per 2,3 MW-unit : $7.6 million.

Offshore Norway :Statoil-Hywind has a floating WT-pilot just comming onstream. Costs till date $67 million and a 2,3 MW-unit on top.... mass production cost ? Don't ask me, but I can guestimate if you like me to ;-)

On another note , regarding Horns Rev 2
The article also claims that this Offshore-park will propel 200 000 Danish households … now let’s see ..
Back of my envelope –

=>> 209 MW * 8760 hours per year * 30% efficiency at sea = 549252 MWh or 549 252 000 KWh (per year)

=>>549 252 000 KWh / 200 000 households = 2746 KWh per household/year = 7,5 KWh/ day.

Is it likely that an average Danish houshold only uses 2746 KWh per household/year ?

Thumb of rule in Norway say 20 000 KWh per household/year - (and -yeah true- we use alot of electrical resistant heating during winter ...)

paal -

Well, I hope you realize that the whole point of my little exercise was not to analyze the installed cost of wind turbines per se, but rather to prove that the cost of the total energy input can not be a large fraction of the total installed cost.

My analysis said no more than that the installed cost of a 2.5 MW turbine was several million dollars. By that I meant something on the order of $2 to $3 million. So you come up with a number of $7.6 million. This shows that we are still in the same range. Of course wind turbines installed in the hostile environment of the North Sea are going to be more expensive than those installed in north Texas.

However, this doesn't have much to do with my main point: even under the most extreme and unrealistic worst-case assumptions, the EROEI of a wind turbine is quite favorable. Wind power has many drawbacks and is quite lacking as a sole energy source, as you've illustrated, but it doesn't HAVE to be a sole energy source, just a supplement.

you may absolutely be correct joule - and your approach with regards to eMergy-evaluations - may be the best way so far. But my fresh offshore example just Trippled eMergy for a 2.3 MW WT - just like that. Interesting no ? Thus at this point in time my EROEI-jury is out discussing.

If you stretch your way of thinking 'all the way' - you may end up concluding that 'Everything that is made possible till date' will also apply in 1000 years.

And using wind-generated electricity for heating seems a particularly poor approach.

Super insulation in northern areas seems to me to be one of the first priorities. Electricity may need to be used for heat exchangers, energy pumps, etc, but it shouldn't be a direct major source for heating.

Regarding Danish household consumption, It seems reasonable to me. When I was living in Germany, we used about 2200 KWH/year (3 people in 120 m^2 apartment).

Danish average electricity consumption for flats is 1800 KWh/yr and for Single family homes ca 4000 kWh.
Our Norwegian friends use electricity for heating- which is rare in Denmark. That accounts for the difference.

Gail doesn't seem to quit in her quest to discredit the very idea of wind turbines.

Maybe if this bloke Lenzen gave her a paid trip to (say) Denmark to stay in a nice hotel and look at some wind turbines she'd feel differently.

But probably he has less money to splash around than certain oil companies.

To reduce the systemic risk you are worrying about, take all the papers that he did NOT co-author, sum them up and make them 70% to 80% of the total. Then take all of his papers. sum them up, and make them 20% to 30% of the total.

Still enough studies to convince me that wind is a very good energy investment.

However, the much larger systemic risk is overlooked.

Large wind turbines, with even higher EROEI, were specifically excluded.

Hardly ANY <1 MW wind turbines are being erected today. 1, 2 and 2.5 MW dominate the AWEA list. So there is a strong systemic bias in this study to under report EROEI.

Just pick the state of your choice and look at installed and under development wind projects to see my point.


I haven't checked to see how many of the other authors are in the business of selling their reports. This might be interesting to find out as well.

At some point, one gets an "expectation" of how one does published wind EROI reports, based on what other ones are out there. How many new entrants into the field are going to break the mold, and, for example, look at wind turbines in actual operation, with a little wider boundary on energy requirements?

The summary noted both "conceptual" and operational studies.

Our survey shows an average EROI for all studies (operational and conceptual) of 25.2 (n = 114; std. dev = 22.3). The average EROI for just the operational studies is 19.8 (n = 60; std. dev = 13.7)

There was an article/post of TOD a couple of years ago on "where to draw the boundaries". It asked if Iraq should be included for oil (no one alleges that we invaded Iraq to get their wind resources, or we use the US Navy to protect our wind imports).

Any sort of apple vs. apple comparison needs to have comparable boundaries. However, the numbers are *SO* high for large wind turbines (1 MW and larger) that any rational expansion of boundaries will give a high enough EROEI to give a strong YES !! to "Is building wind is worth doing ?"


I have no doubt that building out wind is a very good thing-It seems to me that the actual savings in fuel costs alone will eventually make any wind farms built now future gold mines.

As far as the intermittent nature of wind is concerned,I also believe that we will very easily find it damned convenient to make good use of every kwh a few years down the road.So far as I can see no new technology whatsover(just new features added with existing tried and true tech) is needed to build a refrigerator that has an ice reservoir adequate to keep it cold for three or four days for instance,and it would cost very little to install a super insulated 100 gallon or larger electric water heater in many houses set at 200 degrees(with tempering valves of course!) when an old heater goes bad.Such a water heater once heated would last a small family a week easily.

Insulated slabs could be used to store large amounts of heat captured with heat pumps
on cold windy windy days and also as prechilled heat sinks in hot weather.

Washers and dryers can be loaded and left either until the wind blows or for a set period of time until running the load any way.

Excess wind when avalable can be utilized to run irrigation pumps a day or two ahead of the normal schedule.

Some industrial processing such as grinding wood scraps (as left over during the manufacture of furniture) can be shifted to a considerable extent by increasing storage capacity until wind is blowing. The ground wood is used to manufacture particle board,etc.

If they could buy cheap wind power as available I have no doubt that many small manufacturing businesses and some big ones would find ways to take advantage of the cost savings.

Once the public is faced with paying for transmission lines for wind and intermittent air conditioning or no air conditioning at all due to a coal or ng crunch the money will be found to build the transmission lines.

Some will object that a solar water heater is a better energy deal but they need to consider that the water heater I propose can be installed in the existing spot with no additional plumbing,and no external construction,eliminating nearly all of the hassle and a huge up front expense.

I believe this aspect of the renewables business -low hassle low visibility integration into the life of Joe Sixpack needs more consideration.

An insulated slab would only work in new construction of course but installing the heating or cooling coils in something that is going to be built any way is a FAR DIFFERENT, cheaper and easier sell to the new home buyer than adding collectors to a roof for instance.

Of course the smart grid and off peak pricing will be needed but these are already well tested.

These things and all others that may contribute to a faster build out of wind need all the emphasis possible.

It will not matter very much if the eroei figures are favorable if the industry is not big enough to shoulder the load at the crisis point that is sure to come-if there is not enough wind and other energy available to adequately support both new renewables manufacture and other demand, renewables manufacture will be shortchanged in favor of more immediate needs and desires,but with much worse consequences.

Hi Mac,

If they could buy cheap wind power as available I have no doubt that many small manufacturing businesses and some big ones would find ways to take advantage of the cost savings.

You posted some excellent ideas - how do you see people being convinced to take these actions? Do you feel that we can do these things in a "Muddle Through" scenario or must there be a national awaking to the underlying problems before we are hit with the issues "like a ton of bricks"?

"Hardly ANY <1 MW wind turbines are being erected today. 1, 2 and 2.5 MW dominate the AWEA list."

This point struck me as well, Alan. Can anyone point to a comparable study of these larger turbines (or at least one that includes these). There have been a number of posts here that suggests that small wind is probably not a great way to go as far as EROEI or even financial return on investment goes. What, I wonder, is the cut off point for good return on either kind of investment?

Presumably the study above covers a lot of pretty tiny turbines. If one just looked at turbines at right around 1 MW (let alone those with much larger capacities), I would assume the EROEI picture would look much better.

Based on watching the wind industry develop for a couple of decades, there were some good designs at 225 & 250 kW. Not much smaller than that except some super rugged 100 kW WTs (for Antarctica, etc.).

I would draw the line around 225 kW.


"...except some super rugged 100 kW WTs (for Antarctica, etc.)."

Alan, would you be referring to the NorthWind 100 turbine from Norther Power?
I spent 2 years at Northern, building the NW100 version 'A' (direct drive, excited field) turbines.

The current version 'B' is a much better turbine (Direct drive, permanent magnet), and is pretty cost effective.

The NW100 was not designed for the arctic/antarctic, but it was designed so it could be used at cold weather sites. Northern is selling them all over the world now.

I think the size issue is governed by economies of scale - you can build (and install) a larger, more efficient turbine for less money per output unit.

Yes, plus one other (vague memory). A good unit ! Good choice for islands that depend upon oil.

I do wonder what the EROEI is for the that WT ?

Best Hopes for Good Technology,



Do you have any figures or estimates on the residual value of wind farms?

It seems that it would be much cheaper to overhaul an existing wind farm than to build a new one,and total costs must be the name of the end game.

Nobody would buy a house with a thirty year mortgage unless he thiught the house would be worth quite a bity at the end of the thirty years.

Maybe by the tome the first turbine /generator units need replacement there will be much better ones available.Maybe it will be poractical to add another fifty feet to a tower and use a smaller turbine generator unit.

Engineering estimates (all that is available ATM) are that the towers will last through 2 generations of WTs and then be Grade 1 scrap. The electrical transmission & transformers will go at least two generations as well with some component replacement (see annual maintenance expense).

All analysis (EROEI, economic) is based on payback in one generation.

Note that a comparable WT has to go back on that tower to reuse it all, and future economics may drive, for a prime windy spot, replacing 1 MW WTs with, say, 4 MW WTs despite the infrastructure & tower savings with like for like replacement.

Hope that Helps,


Higher towers are almost always economic *IF* you can get a big enough crane out there (see next to railroad ROWS :-)

One “rule of thumb” from NREL is that doubling tower height will increase overall costs by 10% while increasing generation by 45% (1/7th power rule). In addition, maintenance decreases with height and life expectancy increases (less delta in wind speeds from top of blade arc to the bottom of the arc).


Other excellent small turbines :

the Windflow 500 kw (

the Vergnet 250 kw and 1 Mw

Both companies make two-blade designs : a great deal lighter and more robust; able to be installed in remote locations without the sort of roads and cranes that the big boys require. The Vergnet machines are specially designed for cyclonic conditions : can be immobilised in an hour and will survive the worst hurricane : all three-blade designs fall to pieces quickly in such conditions.

I don't have EROI numbers. That would be an interesting thing to calculate, but it's important to realise that they are "niche" players, often bringing electrification to places that wouldn't otherwise have it, or diesel generator only. On the other hand, that's a pretty big damn niche!

In fact Vergnet just signed a contract (in typically picaresque Nigerian conditions) for a 10 Mw wind park in Nigeria, which will be operated as an island, not connected to the national grid :

(full disclosure : I hold shares in both...)

Hello all
I have seen Life Cycle Assessments for Wind Generators up to 3 MW size
One peer reviewed study studied 3 MW in onshore- and offshore configuration(North sea). EROEI for Wind generator and infrastructure was in the order of 25-30,a little better onshore than offshore.
The energy payback was 9 months offshore and 6.8 months onshore.
So the durability 20,25,30,35 years of the system will eventually decide the EROEI.
study here:

By the way.
Today Denmark officially opened the Horns Reef a large offshore windfarm,in the North sea , producing electricity for 200.000 Danish homes.

/regards And1

I think a proper statistical approach for meta-analysis review in case of assumed publication bias would be a 'trim and fill' analysis.

The whole notion of EROI paybacks as a way to choose energy alternatives needs to be questioned.

One issue is that of utility(value). Some people think clean, renewable energy is more valuable than fossil fuel. EROI folks
contend that they know how to add in the value of these but frankly it's ridiculous, for example a 'eco-extremist' might
put an extremely high value on clean energy while a business owner would put a low one.

Another issue is that the approach pretends that choice is a simple 'either-or' option when we know that renewable energy
is a highly local resource.

If the object is simply to increase the amount of energy per amount of energy input wind fails IMO to measure up as it is highly variable and distant from points of use.

To be fair,
you would have to add in the cost of transmission lines and cost of energy storage. The cost of running trains full of coal or pipelines full of oil is less transmission lines that run full sometimes and empty other times.

I support (very) massive wind (+1 TW) because the resource is large, clean and sustainable. It will last well beyond fossil fuel exhaustion. It's efficiency is low IMO but adequate for our basic needs. A lifeboat has very marginal utility but is still a necessity.

Well, if EROEI were bellow one, I doubt you'd support it. EROEI is simply a useful metric, there are a few of them, and each one must ponder them acordingly to personal wishes and relative cost of the several economical factors to make an informed decision.

And, yes, I agree that we should factor in the costs of transmission and storage, too bad I'm not in the business of making EROEI estimatives, and consequently, don't really have a say on this.


I think your argument - while otherwise worthy - misses a point.

Scientifically and let's say 'ideally perfect EROEI' method is not the only nor necessarily the best method of selecting energy production method.

However, it can pinpoint a HARD physical limit (1) and softer structural-economical-sustainability limit (i.e. what EROEI does it take to continue running complex/advanced civilizations such as know - even if with added efficiency. Some estimate this at 8-10 to 1).

As such, EROEI acts as a filter to weed out all the useless stuff that never have a possibility of breaking even. Then it weighs the ones that offer us more or less of net energy.

That's all it does.

It doesn't and cannot directly account for social costs, mining environmental destruction, pollution, CO2 emissions, aesthetic concerns and many other issues.

Consider it like a pre-selection in competition. It doesn't determine the winner, but it does select who even gets to compete.

And considering how many proverbial untrained whackos claiming to be able to run marathon under 50 minutes there are out there, I think it would of everybody's interest if we limited the amount of big-mouth whackos that can enter the competition, the winner of which we will lay our civilization hopes on.

As such, EROEI acts as a filter to weed out all the useless stuff that never have a possibility of breaking even. Then it weighs the ones that offer us more or less of net energy.

Sorry, no sale.
As a measuring stick, EROI leaves a lot to be desired. It reminds me of measuring with an elastic ruler--imprecise and (unfortunately) misleading. Thermodynamic net energy makes more sense but that's not what EROI seems to be according to the EROI experts.

Then again, using the profile as information about the system he is part of, it seems likely that his methods are very mainstream for the LCA community, an very large body of professionals following international government supported standards and employed by virtually every manufacture ring business on earth.

You then also can know that none of the energy costs of the commerce involved in delivering any of the technology products will be counted. The ISO 14000 neatly solve the major uncertainty problem with calculating the impacts of purchasing products by completely ignoring the question of what people will use the money you give them for, and consider only the necessary energy uses implied by the associated technologies...

I think treating the untraceable energy costs of giving people money as "about average" is a better estimate than zero.

I don't know how large the LCA/ ISO 14000 community is but apparently this certification amounts to corporate brownie points
(like the ISO 9000 quality standards)for manufacturing companies(polluters)and below is an online list of US companies is from 2006.

It looks like a venue for selling books, courses and 'certification'.
What is the EROI of these?

Gail, you could perform a trim and fill analysis to give your argument a little bit of additional backing. If there is crude publication bias, it'll probably show in the analysis. Granted, you'll still have a possibility that trim and fill suggests bias, even when there truly is not. But at least if trim and fill shows no bias, there likely isn't any.

Plastic Waste as a fuel – CO2-neutral or not?, it is available for free download as well. I haven't checked the others.

I ran across a vaguely related article that has been featured on slashdot.

New Envion Facility Turns Plastic Waste into $10/Barrel Fuel.

Envion makes its plastic-to-oil conversion by heating up plastic to a pre-set temperature using infra-red energy. The process removes hydrocarbons without the use of a catalyst, resulting in a net gain of captured energy–82% of all material that goes in is transformed into fuel. In the past, attempts to turn plastic into fuel have resulted in a net loss of energy.

Each Envion machine can process up to 10,000 tons of plastic waste each year (including bottle caps) and produce three to five barrels of fuel per ton with a total electricity cost of 7 to 12 cents per gallon.

It is hard to see how this will produce very much oil replacement, but it seems like it could give a little.

Since almost all plastic comes from fossil sources and most of it currently ends up in landfill or other environmental discards, where the carbon remains out of the atmosphere probably for centuries, it is hard to see plastic to oil for burning as CO2 neutral. It is a fossil fuel pure and simple.

The range in the article certainly looks that way.

For incineration, depending on different discrete choices, the results vary from -673 g kg-1 to 4605 g kg-1. Results indicate that for typical Swedish and European conditions, incineration of plastics has net emissions of greenhouse gases.

It seems like plastics are a way of locking up carbon. Plastics don't biodegrade well. It seems like burning them gets the CO2 back into the atmosphere. Is that too simple a way of looking at it?

I prefer to recycle used plastics into something useful, like composite railroad ties (better than concrete ties under some conditions).

Best Hopes,


Yes, but there's another interesting side, that algae-to-plastic technology that people are working on then becomes a meaningful means of CO2 sequestration.

Just wait until someone gets the idea to go out in fishing trawlers and harvest the great garbage patch.

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The rub, of course, is the missing paradigm shift, that improving technology will foster any direction of development that the liberated resources get used for, i.e. for either growing uses of the earth or for completing and perfecting our uses of the earth.

Ever growing uses of the earth is what efficiency gains actually foster today. We don't yet have even a public concept of using them for completing and perfecting our systems for using the earth. We only think of them as solutions for multiply solutions, using every crafty savings in one place to relieve bottlenecks and provide resources for building ever greater systems of consumption in others.

It's that difference, between using efficiencies to assist in starting more things or finishing them, switching from multiplying systems to completing and perfecting them, that turns up in every single kind and scale of "job well done". We just don't seem to "get" how it also applies to creating a comfortable home on earth for mankind... i.e. a new kind of business. It was a good formula at one time when mankind was small, maybe, but now we're big, and the the effect of hat alters the meaning of virtually all our values and we still seem to not be getting up to speed on the change at all. We won't be able to steer our investments according to a new purpose till we have one...

As to technical matters, I have a new even more simplified whole system EROI model (below) as a lead-in to the general "Simple Whole System EROI model". Questions or tips regarding either would be very welcome. A couple lines don't seem to be labeled, but the main question is whether the concept reads clearly at least?

The main feature of is treating the resource system as a whole and the user system as a whole, as serving each other, and doing that by accounting for both the very real energy costs of the technology and of the commerce. So, that means including the 6000btu/$ for the land use fee for wind and all the other business costs. It most certainly decreases the "real delivered" EROI and would surely alter the relative EROI for different technologies. I think not doing it that way makes it very easy to miscalculate the value of the parts to the whole system they are parts of.

Quick comment: what is the notation you are using for your diagrams? It's not familiar to me.

I'd consider simplifying and improving consistency:

1) identify stocks (resources) - label as nouns
2) identify processes (consume/transform resource, produce other output as resource)
3) identify transfers (exchange of resources between processes) - label as verbs
4) indicate directionality - arrows
5) indicate amount (relative) - weighting on lines, etc.
6) indicate feedback (growth in X leads to growth in Y via transfer Z) - +/- etc

(all with their distinctive symbols/glyph types to visually separate them quickly)

It could be it's already there all of it, but I can't yet read it properly. Still, keep up the modeling work - I'll try to look at this more later.

The UK has a serious rapidly approaching predicament - by 2020 domestic coal, oil, natural gas and nuclear will all be massively depleted requiring imports we can't afford or some adequate non-FF alternative, the UK Government's proposal is 25GW nameplate of windmills in the North Sea - IMO there are a number of problems with this.

compounded by the need to import all of them because our only windmill manufacturer has just closed it's factory:

The windmills required are 10,000 of the biggest that currently exist in the world and we need to install six per day in the summer months to meet the required average 2 per day target.

Sadly these six 5MW units

took 2 years to instal in realtively shallow water.

To maintain BAU we need to replace the energy in the fossil fuel gradually, we can't just suddenly switch over in 2020, the windmills are required to replace the fossil and nuclear fuel used to make electricty.

Most of the energy embedded in the windmills is fossil fuel and is invested during the manufacture and installation - it takes around six months to get this invetment back, so:

invest FF in one windmill, 12 months later you have recovered the FF energy and have enough to build a second windmill (but no excess to send to the grid.)
at 18 months you have enough net energy to build 2 more (but no excess to send to the grid.)
at 24 months you have enough net energy to build 4 more (but no excess to send to the grid.)
and on exponentially until around year 8 you finally can start sending energy to the grid, (if you can install 5000 windmills or so in 4 months!)

Do you think the UK Government understand the situation?

Do you think the UK Government understand the situation?



BTW, the North Sea was chosen because of all the onshore NIMBYs in Great Britain. For quick power to supplement low natural gas supplies, on-shore WTs are the way to go, with nukes and HV DC undersea cables after that.

When it gets very hot or very cold in the UK it is often because of what is called a 'Blocking High' - we get a high pressure zone of almost still air that sometimes lasts for days, windmills stop producing power right at the time of maximum need for heating or cooling.

IMO windmills are an 'as well as' method of producing electricity not an 'instead of' - for anything like BAU they have to have expensive backup.

IMO, eventually, nearly all our primary energy will be electricity which is a massive task for windmills, wave or tidal, and for us solar PV is no good as we have no sun when we need heat in the winter.

IMO we are all going to be in the same situation soon so nuclear is likely to be inadquate for the world - uranium, like oil, can only be produced at a limited rate if it is to stay affordable.

I suspect powerdown is the only option, so BAU it ain't. Make the most of your SUVs while you still can.

Save some NG, and trade back for hydro with some wind you shipped to Norway, when that blocking high hits.

If one burns NG just 25% of the hours of the year, a relative trickle of NG will do.

Wind plus pumped storage, plus extra imports of French nuke power in the spring and fall (nukes otherwise down for lack of demand), will do it.


Norway and Sweden have approximately 43GW of Hydro capacity producing around 200TWH annually. Retrofit these dams with pumps storage and you have a huge 'battery' that could back up massive wind developments in the Baltic and North Seas.

In addition Austria, Switzerland and france have significant hydro capacity which could be retrofitted with pump storage capability..

Have you analyzed hydro 'stock' against wind seasonality vs aggregate demand?

Usually around the seasons when it rains, it also winds and vice versa.

This could indicate that hydro installations might be capacity constrained to store wind input.

Haven't done the analysis, though.

Hydro in higher latitudes and altitudes suffers from the solid water problem in the winter. And wind (except sea breeze driven) tends to max in the winter.


Thanks Alan, good to know.

And for us adquate hydro needs lots of rain all year round (not snow) with valleys suitable for flooding - mostly already used in the UK.

Fortunately, 'solid water' typically forms at the top of the water column, and creates an insulating blanket preventing the rest of the water freezing. As long as the intake pipes are underwater, no problem.

Solid water does not flow into the reservoir.

Halslon in the Icelandic Highlands drops over 30 m each "solid water season" (> half the year there). This reduces head and limits the total power generated when needed most.

Then there is a flood of liquid water in the phase change season.