A Net Energy Parable Revisited

(**Note: This was my first main post on TOD. It was an anecdotal attempt at showing how scaling of lower energy gain renewables might have deleterious wide boundary impacts on society. The core principles behind this story remain intact and relevant).

Besides water, energy is the most important substance for life on the planet. For most organisms energy is embodied in the food they eat, be it bugs, nuts or gazelles. The excess of energy consumed to energy expended (net energy) has been integral in the evolution of the structure and form of present day organisms.

Net energy is measured as how much energy is left over after the calories used to find, harvest, refine and utilize the original energy are accounted for. It is a term linked to physical principles and departs in many cases from our current market mechanism of valuing things by price. The alternative energy debate seems to have two firmly entrenched camps - those that acknowledge the importance of energy gain to our society and those who focus on gross energy, energy quality and dollars. This post explores what net energy is, why its important and how its principles may impact the future organization of our society. For most living things, energy is calories. Over eons, natural selection has optimized the most efficient methods for energy capture, transformation, and consumption.( Lotka) Cheetahs that repeatedly expend more energy chasing a gazelle than they receive from eating it will not incrementally survive to produce offspring.

But humans, in a very brief evolutionary time span, have puzzled out how to unlock the hydrocarbon bonds in fossil fuels, freeing up vastly more energy that can be directly eaten. The vast majority of our per capita energy production is spent on non-nutritive exosomatic consumption. We have gradually, with rapidity at times, advanced modern human civilization to a global scale, with liquid fuel in jets, trucks, and automobiles providing the glue that links people and products together.


To harness and consume energy requires some type of energy investment. This investment is what comprises the difference between gross energy and net energy. There is various nomenclature that describes this concept. Energy profit ratio, surplus energy, energy gain, EROI, and ERoEI all represent virtually the same relationship of how much energy we receive, relative to an energy input(dollars do not factor in). The most referenced metric in the Peak Oil literature is EROI or ERoEI (Energy Returned on Energy Invested), which, in its simplest sense is the ratio:

Energy Output / Energy Input

There is disagreement (sometimes dramatic) in the energy literature not only as to what should be included as energy inputs and outputs (a boundary issue) but how variables are included (how to evaluate co-products, how to include other limiting inputs to an energy technology, etc) These nuances will be covered in a subsequent post.

Net energy is typically given as per unit of energy invested. Thus:

EROI = Net Energy + 1.

(For those of you who've played craps - some tables pay off the hard-ways FOR one and others TO one. EROI and net energy have a similar relationship. EROI is how much energy output FOR an energy input and net energy is the energy output TO the energy input.)

Net energy also can refer to a sum as well as a ratio. For an ethanol process that has an EROI of 1.2:1 -the net energy is just .2, but we can also calculate how much net energy is created for society in a given year or a life-of-resource total. At EROI of 1.2, the 3.9 billion gallons that the US produced in 2005 required 3.29 billion gallons of BTU energy input, resulting in a `net energy' of 610 million gallons. (This post will use net energy and EROI interchangeably - if a sentence uses EROI, just subtract one to get net energy, if I use net energy, just add one to get EROI)


Briefly, the above graph shows a theoretical depletable resource which follows the 'best first' concept of resource extraction. The vertical axis is quantity and the horizontal is time. The gross energy resource "X", is the entire area under the curve. ("X" = "A"+"B"+"C"+"D"). Direct energy costs are "D". Indirect energy costs (like tractors and highways and medical insurance and such) are "C". Environmental externalities (in energy terms) are "B". "A" represents the total net energy of the resource after costs have been subtracted. At any given point in time the EROI can be calculated by taking a ratio of the total area divided by the costs (depending on the boundaries). As can be seen, net energy peaks and goes to zero way before the total gross energy is depleted. (This graphic is from an upcoming paper on EROI by a colleague (Kenneth Mulder) and myself.)


Energy quality is also relevant. From an economic standpoint, the value of a heat equivalent of a fuel is set by its price, energy density, physical scarcity, cleanliness of the fuel, capacity to do useful work, flexibility, safety, conversion aspects, etc. (1)

(Source - Neal Elliot - ACEEE)

Electricity is currently the highest quality energy we have in our society, largely due to its ability to do work. Although crude oil is of lower energy `quality' than electricity, its use is ubiquitous in allowing other segments of society to transport goods, etc. and its `quality' as measured by price, has been increasing relative to electricity in recent years.

Cutler Cleveland et al. devised one method of `quality correcting' the net energy of oil and gas extraction using, The Divisia Index, which accounts for energy quality of both inputs and outputs(1 )Below is a graphic of the the thermal and quality corrected EROI of US oil and gas extraction.

"The Divisia EROI is consistently much lower than the thermal equivalent EROI. The principal reason for this is the difference in the fuel mix, and hence fuel quality, between the numerator and denominator of the EROI. The outputs are the crude, unprocessed forms of oil and natural gas. The inputs are electricity and refined fuels such as gasoline and other distillate fuels. The latter are higher quality than the former, and have higher prices. Refined fuels and electricity are, therefore, weighted more heavily in the Divisia formulation."(1)

In the 1930s, US oil was easy to discover. In many cases it was almost at the surface and had an EROI of discovery of 100:1.(2). It has since declined, depending how one measures it or who one talks to, in the range of 10-15:1. As it gets deeper, harder to find, more viscous, higher sulfur content, etc, the EROI will continue to decline. A typical refining efficiency is about 10:1, so the total refined EROI of our precious liquid fuel is still between 5-10:1. This may not seem so high (compared to 100!), but how many stocks have you owned that make 500-1000%? On each iteration? This is the type of energy subsidy world society has become accustomed to.(My paucity of references for this segment gives evidence to how little concern our leadership has for the issue of net energy. Charles Hall, (with data from John S Herold and Co.) and others are working on new updated oil and gas EROI numbers - but solid energy data is either proprietary or difficult to assimilate)


We all intuitively know the difference between net and gross - we use the concept everyday. If you make $100,000 per year in salary and the government takes 38%, your net is $62,000. If the government took 99%, it really wouldnt matter whether you made $100,000 or $1,000,000, your take home would be very small. The same concept applies to energy, and in particular, whatever energy source is most central to society. Basically, net energy matters because net energy is what we use.

"Energy gain, or EROI, varies with the quality (transformity) of a resource deposit and with the efficiency of the technology used to locate, extract, process, distribute and exploit the resource. As the ease of obtaining or using a resource declines, more energy must be devoted to these activities, causing energy gain to decline. Where an energy budget is substantially constant, allocating more resources to energy production reduces the amount of energy available for other activities. The potential impacts of such a situation on a human system include less leisure time, a lower standard of living, higher taxes, and an increase in childhood mortality. In an animal population, allocating greater effort to energy production may mean less winter fat, increased embryo resorption, lower birth weights, or the like.Tainter(3)

It is fundamentally impossible to maintain a constant level of net energy while the aggregate energy profit ratio drops. Only after the energy profit ratio and the need for new fuel related level off can net energy supplies return to the desired level (4).(This book, Beyond Oil, is 20 years old, but is probably the best book on the concepts of net energy, agriculture and society)

We are currently living in the highest energy gain era of any organism in the history of earth. Although the total amount of BTUs consumed in 2005 was higher than any year in history, world energy per capita peaked in 1979.(5)(One could argue that the plateau in net energy per capita has been maintained by a large wealth transfer from poor to rich, from future to present, and from abstract 'energy' (debt) to real consumption).

There are a finite amount of stored fossil fuels on the planet. Some of the largest, highest quality resources have already been exploited. The remaining resources are in many cases more energetically difficult to harvest, or have negative side effects (e.g climate change and coal).

"Environmental degradation is greater when the resource is of low quality and distributed but heavily used. Thus, a switch to renewable energy sources might bring, ironically, environmental damage comparable in scale to, or greater than, that caused by the use of fossil fuels." (Joseph Tainter)(2)

We already see evidence of this in some of the scaling of biofuel production in Asia


Net energy of corn ethanol examples and debates have been presented ad nauseum from both proponents and detractors. The redundancy is trivializing the concept. Though the ethanol debate is critically important in deciding how to deploy of our remaining fossil energy, what follows is a more benign example:

A civilization of 1000 sasquatches lives on a small distant Planet P. They require only food (energy) and water to live but also enjoy a vibrant culture with artisans, builders, and craftspeople. Sasquatches are vegetarians (as everyone knows) but do raise animals for labor help, namely Hephalumps. These animals help them harvest large hempy plants from the mountain near where they live and process them into Saspacks (the finest, sturdiest, durable backpacks in the universe). Each week (which is 10 days long, based on Planet P's sun), the sasquatch colony works very hard for five days and then has leisure time during for the next 5 days. Once a year, a ship from Planet X lands and trades luxury food items (non-caloric but tasty), medicine, comic books, and basic materials in exchange for an agreed upon cargo of Saspacks.

This societies only source of energy(calories) is Waybread, which is a highly energy dense cake made with Spice, water, and the meat from the Mongo nut, which grows in an enormous grove 25 miles from the sasquatch community. Once a Ten-Day, a troupe of the strongest 300 sasquatches traverses 25 miles to the Mongo nut groves, fills up their packs with nuts, and returns home with their energy bounty. It is a one day grueling journey across the Black Plains and through the Black Swamp but they make a ritual of it, telling stories and laughing most of the way until they arrive late at night. They spend a second day climbing trees and picking Mongo nuts, laughing at the colorful monkeys that play in the Mongo trees as well as picking some flowers to bring home to their wives and girlfriends. On the third day they leave at the crack of dawn and are home by nightfall. These same 300 sasquatches then spend two more days, cracking, pounding and combining ingredients together with the nuts to make Waybread; enough for the entire community for the next Ten-Day. All these sasquatches do no other work or leisure on the days they are procuring energy for the tribe. In return, they receive exalted status as the tribes energy providers, and a five day rest.

Since Sasquatches are freakin' huge, each member of their society consumes 4 m-cals a day. They really only require 3 m-cals to survive, but the extra makes them fat and hearty and also contributes to general gastronomic pleasure (sasquatches do not like to feel peckish). Hephalumps are even bigger and the 100 strong herd each requires 8 mcals per day of Waybread to survive and function. Although Waybread is highly nutritious, it is also highly perishable, and must be consumed within one Ten-Day, after which time it gets wormy, and gross.

During the five-day ritual of energy harvesting and preparation, 600 other tribal members are busy harvesting fiber from the mountain, and weaving and stitching it into Saspacks. The remaining 100 bigfoots, mostly youngsters, clean and maintain the village, manage the water supply from the river, and comb the hillsides for Spice. At the end of the fifth day, a feeling of joy emerges in the community as the tribe can look forward to relaxing, dancing and sleeping for five straight days, with plenty of Waybread for everyone. This routine has been going on for as long as any sasquatch can remember. None of them could imagine anything otherwise.

We can determine the energy gain (or net energy) of this society based on the above information. First let's look at the energy output:

Each of the 1000 sasquatches eats 4 mcals per day and there are 10 days per week on their planet. This equates to 40,000 mcals energy consumption per Ten-Day. Each of their herd of 100 Hephalumps requires 8 mcals per day (8,000 mcals per Ten-Day) Therefore the Mongo nut energy source provides them with a flow of energy of 48,000 mcals per Ten-Day. This is their energy output, which is entirely consumed.

How much energy does this society spend in order to get the 48,000 mcals? Well, 300 sasquatches work/travel for three days to acquire the Mongo nuts and then spend two days refining it into edible quality. They have to eat for nourishment during this time otherwise they would not have the strength to do work. Their caloric input (from the prior week's waybread) is 300 sasquatches times 5 days times 4mcals equals 6000mcals.

The energy gain for this society is 48,000 mcals less 6,000 mcals equals 42,000 mcals per ten-day.

The EROI is 48,000mcals/6,000mcals =8:1. The net energy is EROI-1 or 7:1. (Remember, EROI is FOR one and net energy is TO one.) For every unit of energy spent in energy harvesting/refining, 8 are produced. Since they used one unit to produce 8, 7 are left over for other areas of society. (Of the 48,000 mcals of energy available to their society, 6,000 is used for energy production, 12,000 is used to make Saspacks, 2,000 used for cleaning and water procurement, 8,000 to feed the Hephalumps and 20,000 to sustain the tribe during their 5 days of hedonistic leisure.) Sidenote -even though there is a 8:1 EROI, 30% of the tribes members contribute to energy procurement.

One day, the 300 energy procurers arrive at the Mongo grove and find many of the colorful monkeys lying dead on the ground. They were so disturbed that they carried 2 of the carcasses home to show the shaman. They also discovered that the Mongo nuts were no longer as easily reachable from the ground and they had to go either deeper into the forest, or climb higher up the trees to fill their packs with the largest ones. This ended up taking a whole extra day.

After returning home a day late, the community was in a panic. They would have to spend a day out of their Five-Day to finish the procurement of food! And the sight of the dead, dark colored monkeys made many sasquatches cry. It was decided to call an emergency Council, to determine what might be done about the turn of events. Many wise and respected sasquatches voiced their opinions. They were saddened by the dead monkeys, but they were more concerned about the lack of easy to find Mongo nuts - the implications being the 300 energy workers might have to work MORE than 5 days per Ten-Day. One of the senior males suggested "We could save a little time by not stopping to pick and bring home flowers which aren't really needed for our energy supply". A matriarchal sasquatch immediately stood up and chastised "Zeke-Stinky-foot, you come home without flowers and you'll see how much they are needed, Husband-mine!". There was a vote and it was decided to continue to pick and bring home flowers.

During much arguing and debating, the shaman entered the pavilion and everyone quieted down. He exclaimed "Colorful Monkey-friends die from Black poisoning" A sharp intake of breath from the Council-members. "Our energy providers feet put Black Desert and Black Swamp on Mongo trees while they pick nuts. Colorful-monkey friends get on paws then in mouth then die." The Council went into an uproar - Black poisoning! Because of our energy procuring! How awful! Yet what can we do? - We need the Mongo nuts to survive and have energy to work and sing! And if we go around the Black Desert and Black Swamp it will take an extra day in both directions!!" The sasquatches were very upset, and spent most of their Five-Day arguing and trying to make a new plan, where none had ever been needed before. It was decided by the Council to have the 300 workers spend an extra day at the groves to fill up their packs. The Shamans comment about the Black Desert being carried to the trees, and killing monkeys was only talked about by a few, and drowned out by the sasquatch leaders who really wanted at least 4 days of leisure and 4mcals per day. It was also decided to send 100 of the 600 saspack workers on exploratory missions, something that hadn't been done in generations, to see what was beyond a 25 mile radius of their community.

These plans worked out reasonably well and gradually the sasquatch colony adjusted. After all, they still had the same amount of food and energy, even though they had to work slightly harder for it, and produce a few less Saspacks. At the end of each Ten-Day the sasquatches were not quite as well rested, but were happy in their resolve to work a little harder to get energy for the tribe. (The Hephalumps did not notice any of this, and continued to chew their 8,000 mcal of Waybread per week.)

The phenomenon of `best-first' apparently applies to Mongo nuts as well as oil. We can now calculate an updated net energy for the sasquatch society. The energy production was the same, at 48,000 mcal per Ten-Day. But the 300 sasquatch energy team now worked 6 days per week requiring 4mcal per day or 7,200 mcal. Also, 100 workers spent 2 days per week (on average) exploring and looking for other Mongo nut sites. From a societal perspective, this `energy exploration' expenditure of 100*4*2=800 mcals should be included (somewhere) in any net energy calculations even though it didn't directly result (yet) in energy production.

The updated EROI formula is:
Energy output = 48,000 mcal/Energy input =8,000 mcal = EROI of 6:1 (net energy of 5:1)

Now of the 48,000 mcal of production, 8,000 is used for energy procuring, 11,200 is used for industry (Saspacks), 2000 for village maintenance, 8,000 for Hephalump food and 18,800 for leisure. Everyone in the sasquatch civilization still consumed the same amount of energy as before, but societies mix of labor allocation and free time had shifted.

***Sidebar of interest: We also now have information to calculate a more advanced (thorough) form of EROI, one that includes co-products and externalities. Flowers have value to sasquatch society and as such get a `co-product' credit in the EROI calculation. (much like dry distiller grains in the ethanol calculation) Since they are an additional output, we can reduce the amount of energy allocated to getting the Mongo nuts, as some of the sasquatch caloric expenditure is now considered necessary for getting flowers. How we allocate this is a debated but relevant question. We could take the market price of the two products (sasquatch society has none) or allocate by mass( the flowers have 50% of the mass of the Mongo nuts) or by volume (they are very light - only 10% the weight of nuts).

Allocating by mass would increase the EROI quite a bit:

Energy output = 48,000 mcal Energy input =4,000 mcal (4,000 allocated to flowers) = EROI of 12:1 (Net energy of 11:1)

Allocating by weight would increase the EROI slightly:
Energy output = 48,000 mcal /Energy input = 7,200 mcal (800 allocated to flowers) =EROI of 6.66:1 (Net energy of 5.66:1)

Our market system (in my opinion) underestimates the long term value of energy to society and net energy calculations that give so much `energy credit' to things like Dry Distiller Grains, thus overestimate the true energy gain (or underestimate the energy loss).

Regarding externalities, it is difficult to put an energy cost on dead monkeys. However, the poisoning was clearly a direct result of the sasquatches energy harvesting techniques and to exclude it from an energy analysis would not be holistic. Modern EROI analysis is just starting to value externalities as costs (see Patzek and Pimental regarding soil mining and Life Cycle analysis of GHG emissions) Ecological economics attempts to value things that humans need and value but are considered `free' in the market system. Quite possibly, the limiting factor of large scale ethanol production, even cellulosic, is the degradation of soil and assumption of continued ease and availability of irrigation.

Since sasquatches are a peaceful and conscientious race, lets arbitrarily allocate a high energy cost to the biodiversity loss to their culture of 8,000 mcals. The EROI would then be:
Energy output = 40,000 mcal (8,000 were subtracted) / 8,000 mcal energy input
=EROI of 5:1 (net energy of 4:1)

Continuing with our story:

The sasquatches situation, largely beyond their control, deteriorated further. The Mongo nut supply, while still enormous, was becoming more thinly distributed. Also, the nuts, which once averaged 3 lbs were now mostly 1-2 lbs. It took the sasquatches much more time and effort to pick and organize them. It also took more time to process them into Waybread, as the shell to nut ratio had increased substantially. All in all, it took an additional 100 sasquatches (400 total) a total of 7 days to harvest and process the Waybread. They were not beginning to get restive.

One day, while the stressed sasquatch community was hard at work on what was normally their 7th day (2nd of leisure), a troupe of youngsters came running full out into the village "We are saved! We are saved! - We found a new Mongo nut grove with huge nuts and plenty of them!! We'll soon be able to go back to our old routine of dancing and reading comic books! For a Five-Day! These nuts are huge!"

A Council was hastily convened where the youths were eagerly bombarded with questions: "How big was the grove? Were there colorful monkeys? Would you like some water? Have you met my daughter Fern-Blossom?" An old silver-back sasquatch, one of the tribal leaders, stood up and quietly asked "Sons, how far is this grove?" One of the scouts replied "Sir, its 120 miles on the other side of the mountain, but an easy walk, with no Black Swamp or Desert". The leader nodded: "That is 5 days in each direction. If we send our energy workers that far, there will not be enough time for them to process the Waybread upon their return." He paused, "However, our Mongo nuts close to the village are getting smaller. I think we should go harvest this new, bigger energy source you have discovered. We will have to take more of our Saspack workers and our village cleaners too. But you are right, you have saved us."

When everything was sorted out, the sasquatches had to organize 2 energy procurement teams of 375 sasquatches each. One team brought water from the village and met the other team halfway and then returned with the large Mongo nuts to process them. These teams traded off in their duties but worked 8 days total out of every Ten-Day. This left 200 sasquatches to work on the saspacks, and it was decided, to be fair and because they were behind contract, that they also work an eight-day. There were only 50 of the tribe left to work on cleaning, and basic village maintenance. The community was amazed that so much! of their time was spent making Waybread, just to spend it on making more Waybread - very little singing and relaxation time anymore. After a few months, the tribal leader, at a somber Council meeting, announced that everyone would have to cut back, and strict rationing of daily consumption to 3 mcals per sasquatch would be enforced.

Because of the reduction in Saspack labor time, the Hephalumps weren't all needed and some started to roam the village. A large controversy erupted when one of the energy workers, strained from a long ten-day on the road, hit a hephalump on the head and killed it. He wanted to eat it but didn't know how.

The energy gain of this society continued to decrease. The energy output of 48,000 mcal (before the rationing), had an energy input of 750 sasquatches times 4 mcal times 8 days = 24,000 mcals.

The EROI was 48,000 / 24,000 =2:1 (Net energy of 1).
A large portion (50%) of this societies efforts were now allocated to energy procurement. Of the total 48,000 mcals procured, 24,000 was from energy procurement, 8,000 was for their livestock, only (200*8*4mcal) =4,800 mcal devoted to Saspack production, and 1,200 to maintain the village and procure water and 10,000 mcals for leisure and art.

A further problem, (for which I dont plan to attempt the math) was that WATER, not energy was now a limiting factor in the energy harvesting process. Water was much heavier to carry than Waybread so a cache had to be set up midway between the water source and the Mongo nut source. The Energy Return on Energy Invested stood steady at 2:1, but the Energy Return on WATER Invested, was declining dramatically.

After the tribal decision to ration consumption, the energy gain of society upticked. Since each sasquatch only consumed 3 mcals, (and many noticed new clarity of thinking and vitality after initial grumbling), the energy production requirements tapered off a bit:

The tribe still procured the same amount of Waybread (the extra was allocated to the following weeks Mongo picking team). The energy input was now only 750 *3mcal *8days = 18,000 Mcals. Because of their belt tightening (or efficiency) the societal EROI increased to 48,000/18,000 = 2.66 (net energy 1.66).Note: the EROI of energy procuring didnt change, but the societal energy gain, from a Tainter-like perspective, did increase.

At year end, the spaceship landed from Planet X. (There were 14 female sasquatches, and one male, waiting at the landing port, hoping to be rescued.) The alien trader strode down the ships conveyor and frowned when he saw the somewhat disheveled sasquatch community. There were Hephalumps everywhere (a delicacy on his planet), huts and sidewalks were in disrepair, and the tribe looked thin.

He was greeted by the tribal leader who sheepishly stated "Noble trader, our energy supplies have dwindled and we had to spend extra time harvesting a new energy source so only had time to make 3,200 Saspacks, not the 6,000 per our agreement."

The alien snorted, "Silly sasquatches - your world, though small, is FULL of energy - what you call the Black Swamp is also known as crude oil and what you call Black Desert is called coal-both of these substances have way way more energy than your precious Mongo nuts. Since you are good customers, I will give you your materials and ½ the medicine but withhold the tasty treats and comic books until you can make more Saspacks. If you like, I will bring machinery to your planet and help you to harness your Black Swamp, in return for great riches" The community was saddened and confused. How could the Black Desert be strong energy? It was poison. They held an immediate Council and concluded that they could do without the comic books, materials and candy. The local shaman could find his own medicine, and they would continue harvesting Mongo nuts, but would further divide the labor among the tribe and produce Saspacks no more. They also didn't need the Hephalumps anymore and would lead them to the Mongo groves and leave them free next Ten-Day. They waved goodbye to the galactic trader for the last time.

The sasquatches were transitioning from a high to a low gain energy system. By removing the Hephalumps and the Saspack industry, which brought them niceties that they didn't really need, they now only had to procure 30,000 mcals per ten-day. The energy input was still 750 *3mcal*8days = 18,000 Mcals.

The final EROI in our example is 30,000 / 18,000 = 1.66:1 (Net energy of .66). While lower, the community now had reorganized in such a way that 18,000 mcal went to energy procurement and 12,000 were left for leisure and dancing and singing (40% of all energy).


Sasquatch civilization underwent a decline in net energy. The results were less industry and less free time, as a larger effort had to be made to procure essential food. Eventually, they partially offset this loss in energy gain, by jettisoning certain aspects of their culture that were energy intensive yet did not really provide the satisfaction that it cost. The situation of the Sasquatches is not that different from our own. Our assets are human ingenuity, 1.2 trillion barrels of oil, 179.8 trillion cubic meters of natural gas, and 909,064 million tones of coal (of various qualities)(source BP), and the various renewable flows generated from the planet. Our liabilities are a large population, the seemingly unquenchable human desire for more, a growing realization that we have in fact tapped the 'best-first' energy reserves, and ecosystems that are nearing the limits of their resilience to human extraction and waste absorption.

Our civilization is organized around high energy gain infrastructure - low gain sources, possibly even as low as 5:1 may not have the energy density required to power our liquid fuel intensive society. As can be seen by the below graphic, shopping centers and skyscrapers are part of a high energy infrastructure. Renewable flows, at least thus far do not match up in energy gain. Large scale wind has a higher EROI than oil, but cannot (as of yet), power our planes, trains and automobiles.

(Graphic from Cutler Clevelands EROI powerpoint.)

The corn ethanol and even the cellulosic ethanol debates typically miss a larger point. Much mental effort is spent debating whether the energy balance is slightly positive or slightly negative while society runs on an energy gain significantly higher than any liquid fuel alternative. When we hit $150 oil, there won’t be too many parents buying their kids a new GI Joe with the Kung Fu grip toy. At the same time, energy companies will need more and more employees to man wildcats and oil rigs and install solar panels. Though we might not be thinking in these terms at the time, the lack of energy gain (or lower net energy) will be manifesting itself in resources taken away from marginal areas of society (toy companies, hot tubs, hemorrhoid cream, Snausages, poker chips, etc) into energy producing and distributing sectors.


1) Net energy is more important from a relative basis than absolute. A 3:1 EROI doesn't tell us much unless we know how that compares to what an organism/society has been built on/used to. A 2:1 EROI would have made stone age villagers incredibly rich. A 5:1 EROI may not be enough to power our society. (e.g. as fossil fuels get more expensive they will collapse the economy and no real recovery will ever happen as the high energy gain outputs are already gone)

2) Energy reserves are not as important as energy flow rates. We could have a billion mongo nut trees, but all that matters is the maximum flow that society is able to harvest in real time. (This obviously applies to oil as well)

3) Energy quality depends on the context. High BTU substances, like oil or coal, are clearly very useful to our society, but may not be to others. (the sasquatch colony valued and used Waybread, not oil)

4) Liebigs law of the minimum applies to an energy portfolio. Wind has a high EROI, but our system infrastructure relies on liquid fuels. The net energy of the weakest link matters more than the overall net energy of society. (Adding high EROI wind capacity while net energy of oil dwindles does not solve the problem, unless the energy mix changes from liquid fuels to electricity)

5) Using different boundaries in net energy analysis will lead to different conclusions. A society running at 5:1 EROI would be happy to develop a scalable technology with an 8:1 EROI, however, after environmental externalities are included, it might only be a 3:1 technology. (Coal-to-liquids and climate change comes to mind) The difficulties lie in making meaningful comparisons and valuing important life functions not priced in the market system.

6) Rather than pursuing the highest and most promising energy technologies, it might be prudent to pursue ones that are certain, and meet the net energy decline half-way by reducing energy footprints. As we decline in aggregate societal energy surplus, a great deal of remaining energy is going to be wasted, ostensibly going after 'more oil and gas', which will likely be unprofitable both monetarily and from energy perspective.

7) Since evolution has favored organisms that have the highest energy output energy input ratios, it will be a cognitive challenge for us (as organisms) to willingly reduce the numerator.

8) Consumption, in the sasquatch example, continued very high until late in the game, and was subsidized from borrowing from other aspects of society. Lack of energy gain was a phantom concept until the situation was much deteriorated. The difference between their society and ours is that they got 'paid' directly in energy while we have an intermediate step - an abstraction in the form of digital money. So unlike the sasquatches who had immediate negative feedback to declining net energy, we might temporarily 'paper over' this decline by printing money or relaxing financial requirements - these measures will not be based on anything biophysical and make an eventual reckoning much more severe. In the end, it's not about how much energy we have but how much societies can afford via real inputs and how resilient their institutions are to a change in the the prior trend.

Our collective task will be to improve our net (total cost) energy from renewables while changing the infrastructure of society to best match what our long term sustainable energy gain can be.

-thelastsasquatch (a.k.a. nate hagens)

(1) Net Energy from the Extraction of Oil and Gas in the United States. Cutler Cleveland, Boston University

(2)Hydrocarbons and the Evolution of Human Culture, Hall et al. Nature Novermber 20, 2003

(3)Resource Transitions and Energy Gain, Tainter et al. Conservation Ecology 2003

(4) Beyond Oil: The Threat to Food and Fuel in the Coming Decades, Gever et al, 1986 Ballinger Publishing

(5) The Olduvai Theory: Energy, Population and Civilization, Richard C Duncan, The Social Contract Winter 2005-2006

Excellent post Nate. When evaluating "renewable" energy for ERoEI generally the direct energy inputs are all that are considered and the energy supplied by humans is totally excluded. In the case of Brazilian Ethanol from cane the energy of humans harvesting the cane is not counted even though each human is required to harvest as much as 8 or more tons a day. http://redgreenandblue.org/2008/07/28/brazilian-ethanol-is-it-more-effic... While the energy to fuel these human machines is minimal due to long hours and low pay it is substantial in terms of the total input to the production of cane ethanol. In the US since we use inorganic machines we count the energy at least to run those machines (and hopefully to manufacture them) so the ERoEI is higher.

In the end the ERoEI of the society as a whole is what counts. It is easy to see in your Sasquatch illustration how that is true, especially since there is basically one energy source and one type of energy obtaining machine (the Sasquatchs). It is probably impossible to calculate for a society as complex as ours with multiple energy sources, multiple ways of using that energy, multiple ways of obtaining that energy. And yet that is what in the end matters, not the ERoEI of windmills or solar panels, but the ERoEI of the whole structure for building, maintaining, and using that energy accounting for military to help us get whatever raw materials aren't on our soil, roads, changes to delivery infrastructure, etc along with the energy needs of the human machines. While we are currently shrinking how much energy those humans get, another consideration is at what point in that energy use shrinkage do those humans stop working and start rioting.

Your piece is the best I have seen at trying to tease out ALL the factors that relate to the energy a society uses to maintain status quo or in the end to continue to even exist.

"In the case of Brazilian Ethanol from cane the energy of humans harvesting the cane is not counted even though each human is required to harvest as much as 8 or more tons a day. http://redgreenandblue.org/2008/07/28/brazilian-ethanol-is-it-more-effic... While the energy to fuel these human machines is minimal due to long hours and low pay it is substantial in terms of the total input to the production of cane ethanol. In the US since we use inorganic machines we count the energy at least to run those machines (and hopefully to manufacture them) so the ERoEI is higher."

The referenced article suggests that sugarcane in Brazil is mostly grown close to the Equator: not true at all.
But you contradict yourself when you say "While the energy to fuel these human machines is minimal" and "it is substantial in terms of the total input to the production of cane ethanol". I don't know whether you have done a comparison between those human machines and the inorganic machines, but it seems to me that the human machine is incredibly efficient. Both in terms of "building" them and in terms of their "utilization". Unless you have some data to support your statement, I am not worried about it.
The social issues of cane cutters are another thing altogether. What would they do if there was no cane to be cut? Will you feed them? And ethanol in Brazil is really mostly a by-product: cane will be cut for sugar anyways.

Human muscles are about 16% - 20% efficient, according to Vaclav Smil, Energy in Nature and Society (2008), Chapter 5. So, nearly comparable to gasoline engines, or a bit less efficient than diesels.

Of course, with non-working time, and the energy inputs into growing and transporting the workers' food, the final net efficiency would be lower. And if the workers are eating meat, lower still.

William when I said the energy of using humnan Brazilian is minimal I mean that in the sense that the energy "paid" to these workers is pretty much just the minimum needed to keep them alive (briefly) and working. Basically enough energy for food and a tad of shelter. The energy US humans require for their work is vastly larger. They require energy for food shipped from all over the world with a heavy meat component, energy for building and driving a car, building and heating/cooling a large house etc. In Brazil since you can get away with paying humans the minimum energy credits to survive for a few decades using humans is more cost effective than using machines. In the US even using illegal aliens many farm tasks are more cost effective using machines. Money in the end is energy credits and roughly corresponds to energy inputs.

I wasn't addressing the social issues, just how do you count ERoEI. If you don't count at least the energy necessary to keep humans alive to do whatever work they do in the process you haven't counted all the energy. My main point was that if in the case of Brazil you don't count at least the energy needed to feed the humans while in the US you count the energy needed to harvest the corn by mechanical machine then you don't have a genuine comparison.

Supposing you think of it this way, if in a US solar panel factory they were using their own solar panels to power the factory and instead of using money they used more solar panels to pay their workers with electricity, that extra electricity they had to generate would be part of the energy input for making more solar panels. But because they give them a paycheck the energy credits embodied in that paycheck are not counted.

This will become more clear to everyone as cheap energy runs out. Regardless of how efficient we are compared to mechanical machines we are machines that require fuel and if you don't count that energy you haven't counted all the energy inputs.

While the energy to fuel these human machines is minimal due to long hours and low pay it is substantial in terms of the total input to the production of cane ethanol.

Caloric needs of workers represent less than 1% of the energy contained in the ethanol they produce.

Pitt can you substantiate that statement. What are the caloric needs of a human cutting 8 tons of cane a day. You also have to count the calories to feed the family just as a hunter gather has to kill enough prey to feed his family. Housing and transportation are energy needs of that human too, as well as medical care. In a complete system you also have to count the calories needed to raise that child from an infant...some figure apportioned out over the years of their life.

You said that one person in Brazil can harvest 8 tons cane per day. Let's assume that this hard worker consumes 5000 cal/day and let's put 250 cal per BTU. That amounts to 2.5 BTU/ton harvested. This seems very low.
Because in the US we use about 8.4 gallons of diesel to mechanically harvest an acre. Let's say that acres is 35 tons of cane and a gallon diesel is 139000 BTU. Then the amount of BTUs required is 33000BTU/ton.

The gusher photo shown is of the Spindletop discovery well “Lucas 1” in 1901. This photo was quickly transmitted around the world and caused the USA to be immediately regarded as a world super power. The 100,000 BPD gusher flowed more oil than all of the other wells in the US combined.


Energy is an abstraction. It does not exist outside its concrete forms. I do not care how it is measured whether in calories, joules, megawatts or whatever. There must be a concrete form of it to be measured.

The same is true of another abstraction: grain. It does not exist outside its concrete forms. It doesn't matter how it is measured in bushels, kilos or pounds. There must be a concrete form of grain to measure it. Grain can not be measured except in its concrete forms.

It is also true with metal. Metal is an abstraction like energy and grain. It does not exist except in its forms. It can be measured in tons, ounces, kilograms whatever, but a concrete form of metal has to exist in order to measure it.

Now lets examine net grain. Are we going to choose whether it is better to produce corn or soybeans based on net grain? Clearly corn would be the choice since for every seed planted about 450 seeds are produced on the ear while soybeans have about 50 pods of 3 each from each soybean seed or 150. GROGI for corn is 3 times GROGI for soybeans. Using that logic no soybeans should be produced. It is absurd.

The case is similar for metal. The yield of a gold mine is very small compared to the iron needed for shaft supports and such. The MRORI is very low for gold therefore no gold should be mined using logic similar to EROEI. It is nonsense.

The EROEI/net energy logic is further complicated in that energy is unique it that it is relatively easy to change one form into another. Whereas forms of grain are difficult to change from one to another and forms of metals almost impossible except in nuclear reactions. Furthermore energy is not finite like metal or grain. A new supply arrives from the sun everyday. Why should we care about net energy except in the case of fossil fuels which deplete and are finite?

The idea that EROEI/net energy which are abstractions can be used as a determinate for which concrete form to produce is absurd. It is even more absurd that this intellectual miscarriage should be used to decide which grains should be produced or not. The same applies for metals.

EROEI/net energy has only limited application to comparable forms of energy produced in comparable ways and with comparable characteristics. Otherwise it is nonsense.

You say

Energy is an abstraction. It does not exist outside its concrete forms.

and go on to make your points about grain and metals.

But then you reverse and say

The EROEI/net energy logic is further complicated in that energy is unique it that it is relatively easy to change one form into another.

That's not a complication -- that's the essence of the matter -- energy is NOT just an abstraction.

EROEI/net energy has only limited application to comparable forms of energy produced in comparable ways and with comparable characteristics. Otherwise it is nonsense.

Precisely wrong! Energy can be converted, (although there is always a tax) and this is precisely what the cornucopians rely upon in wishing us a merry future (or whatever). If only we could get fusion working, if only breeder reactors could made safe, if only we could unlock methane hydrates.

Furthermore energy is not finite like metal or grain. A new supply arrives from the sun everyday. Why should we care about net energy except in the case of fossil fuels which deplete and are finite?

You don't need to go to the sun to prove that energy is not finite. E=mc^2. Mass is energy. One mountain totally converted to energy would take care of all our needs for a very long time. Of course energy is infinite! What's NOT infinite is ACCESSIBLE energy -- energy we can get at! That's the problem. Nature has not supplied us an infinite amount of accessible energy. Luckily. We would do ourselves in more certainly than any cokehead with an unlimited supply.

"You don't need to go to the sun to prove that energy is not finite. E=mc^2. Mass is energy. One mountain totally converted to energy would take care of all our needs for a very long time. Of course energy is infinite! What's NOT infinite is ACCESSIBLE energy -- energy we can get at! That's the problem. Nature has not supplied us an infinite amount of accessible energy. Luckily. We would do ourselves in more certainly than any cokehead with an unlimited supply."

In a debate between fossil fuel usage and alternative energy usage it as boneheaded to say that "we're running out, because we can't come up with any good alternatives" as "there is no problem if we run out, because we can come up a good alternative".

1. The "running out" part is debatable for one: we don't know what we don't know: there is no gauge on Earth's crude oil tank. (Exxon thinks there is still plenty out there). Although, it seems safe to assume that we're running out so as to have us make an effort to find alternatives before we're completely on empty.
2. To say that we can't or can come up with good alternatives, is showing magical insights into what is not yet known and therefore not reliable enough. How do you know we can (or cannot) get fusion to work some day? Until then, it seems justified to keep looking for good alternatives.

How do you know we can (or cannot) get fusion to work some day?

I don't. But the best and the brightest have been working on it for over 50 years. Even the extreme optimists say its 20 years off. So there's a hint in there someplace.

BUT, if if we were to find a miraculous source of energy, it would at best delay our problems. Metals and minerals are depleting, albeit more slowly than energy. Their extraction therefore takes escalating amounts of energy, water and land, and metals and minerals themselves. Plus, there is an escalating toll on the atmosphere, the soil, the water, etc. If one takes a somewhat holistic view, it becomes evident that we are facing systemic limits, not just energy limits.

Ahh good your typical skeptic lets skip the BS and analyze the powerful logic form they use to debate peak oil and the crisis we face.

Understand that one of the main results of my own work is that your probably right when attacks on your position do not use powerful logic with excellent data. And of course this ensures we will certainly have problems post peak.

1. The "running out" part is debatable for one: we don't know what we don't know: there is no gauge on Earth's crude oil tank. (Exxon thinks there is still plenty out there). Although, it seems safe to assume that we're running out so as to have us make an effort to find alternatives before we're completely on empty.

Here we find the typical name drop attack in this case its "Exxon" certainly someone who is in the energy industry is far more knowledgeable then a bunch of people on the internet. No mention of course of Exxons position on global warming or other positions Exxon takes. Nor to mention that most publicly traded companies are not exactly going to be announcing from the rooftops that the resource that forms the core of their business is declining. And even with all this no mention of other industry experts that don't share Exxons views.


Mr de Margerie, however, said while forecasts could always change, “100m barrels [per day] . . . is now in my view an optimistic case”.

He added: “It is not my view: it is the industry view, or the view of those who like to speak clearly, honestly, and not . . . just try to please people.”

This suggests that the CEO of Total feels compelled to disagree with the view points of some of the other large players given the situation this calls into question Exxons position.

You can read the rest of the article and I happen to feel that even his claims are probably not correct the reserves are not only hard to get out they are not real reserves we will never extract them. Modern reserves have increasingly become and estimate of OIP with very optimistic assumptions about its extractability.

Regardless if you wish to argue the situation using real logic at the minimum include a statement that suggests the opinions are not unified on the subject. Exxon believes we have plenty of oil while Total does not question the reserves but our ability to extract them at high production rates. Overall the energy industry seems to believe that future production will be a lot more expensive than in the past.

This is I think a balanced consensus of the energy industry all have suggested that the era of cheap oil is probably over. I don't think this is debatable and its a balanced viewpoint.

The lack of cheap oil however tends to fit quite well with concerns about EROEI so its not near as good as the name dropping cheap shot approach.

Although, it seems safe to assume that we're running out so as to have us make an effort to find alternatives before we're completely on empty.

Why ? Obviously if we are eventually running out production will decline well before we hit "empty". This sort of backhanded well your wrong but I'm going to make a statement that makes no sense to support my position.
I'd suggest that maybe we should wait until production has obviously peaked we have every indication that we have plenty of oil but it will be expensive and we may not be able to grow our production rate. Lets wait until we are sure that alternatives are warranted and viable in a more open market. Certainly we should support research into alternatives now. Even if we find ourselves on a undulating plateau as CERA claims we need to expand our energy supply to grow our economy.
Plenty of sound reasons to continue to pursue alternative energy.

2. To say that we can't or can come up with good alternatives, is showing magical insights into what is not yet known and therefore not reliable enough. How do you know we can (or cannot) get fusion to work some day? Until then, it seems justified to keep looking for good alternatives.

Not magical or at least no more magical than Moores Law. Most of the concerns are about our ability to make the transition. If there is any magic its in the assumption that some magical breakthrough will save us. If it happens great but realistically we have to plan to go renewable with technology thats off the shelf and that does not look all that promising.

Robert Rapier did some brilliant analysis of corn ethanol and found it was not a viable alternative fuel. Using arguments quite similar to what Nate is using. He was widely criticized by many people most using variants of faulty logic short of facts.
Now we are finding that his work is becoming the mainstream view point.

And last but not least no one is really attacking alternative energy on the oildrum its just that many of us believe that its a much much harder problem than proponents suggest. And its not clear that it will allow us to seamlessly move off of oil.

My own position is fairly simple our biggest problem is not energy its population the first problem we have to solve is our breeding problem and it will be solved regardless of what we do. Doing nothing ensures the worst possible outcome.
The energy problem is a result of two things rapid population growth and consuming large amounts of non-renewable energy. We have to develop a society willing to be happy with much lower population numbers and much lower total and net energy usage.
We need to decrease our own impact on the earth to the point it does not hinder natures biodiversity. Obviously renewable energy resources are critical to accomplishing this but its a much deeper position and it suggests that far more important is that we focus on becoming wise stewards of the earth limiting ourselves on purpose. And thats really the key position its not a renewable vs non-renewable energy debate but one of if we choose to self limit or not. We simply don't do certain things regardless of if we can or cannot. If we choose the self limiting route then it makes sense to limit ourselves to this biodiversity impact level why set the limit higher ?

So not only is it questionable that we can transition to renewables and continue to grow its questionable that growth makes sense at all regardless of how its accomplished.

If your talking about a population limited to under 1 billion people or even less then its obvious that we have plenty of renewable resources we simply don't need to consumer more than we produce and indeed the earth will be primarily a natural planet.
So by actually addressing the actual opinion which is really a question about growth with concerns about renewables as being viable as a secondary issue I think the battle lines are clear.

My position and that of many on the board is that we need to focus on reforming ourselves to a society of 1 billion or less people.

We have six billion people on the planet running out of oil how do we get to the target number with the least amount of pain ?

Underlying this desire is ever mounting evidence that we may well not have a choice in the matter. This alone should convince you that verbal games are probably not worthwhile lets move the debate to the crux of the problem and talk population. I'm sure there are plenty of people that believe we can allow the earths population to increase a lot more without harm but lets debate changing and considering a real alternative living in harmony with our planet.

So if your serious:
What are your views on population ?
What are your views on the disparity between incomes on this planet ?
How can we really improve the life of the global average person ?
Where does alternative energy and the decline of fossil fuels fit into the equation ?

Memmel has it right --population is it. I happen to have the luck to live on a huge bit of well-watered land covered with trees, deer, and turkeys, and my wife likes to grow food. A couple of days a year and we have all the meat we can eat- and we don't use any fossil fuel or NPK on the garden. I don't but I could easily get all my energy from wood using quite primitive technology we all know about.

And of course anybody could do the same with the same amount of land per person that I have.

So how do we get to that paradise? First create the vision by way of new stories, then let the thousands of ways to work down the population do it.

And, by the way, we have gobs of energy just waiting for our brains to go get it. Think, for example, of big wind kites pulling on a windlass. And so on.

And don't tell me I have to rewind that windlass. You rewind the furled kite with the one that's pulling at the high angle of attack.

If we are to fully embrace our new role within technological society, indentured to a corporate taskmaster, ruled by the clock and surrounded by the concrete, steel and mechanisms, then we should hand over our reproductive rights so that our lives become theirs entirely and we exist only for them. We will be trained for their use in the schools and we will enjoy the mind-numbing and body destroying fruits of mass production. When we are no longer useful and efficiency demands, we will be terminated. It (the society) will decide when and how we are to live and how many children we shall have and how they shall be raised.

For a while we could all kid ourselves that we were evolving towards greater freedom where all would be enlightened and freed from the drudgery of life and even freed from death itself. Now where do we stand? Realizing that if we move backwards we will have to abandon our dreams of technological utopia? And realizing that if we move forward we will become more and more controlled and our freedoms given up to the imperatives of the mass-consuming monster this society has become. We will become permanently trapped within the machine.Technological utopia is a myth as we shall become enthralled by the machines that we create. (I can't remember but maybe Lewis Mumford wrote about this in "The Myth of the Machine".)

The technological experiment will fail as the monkey becomes alienated and disillusioned with the destructive and controlling forces unleashed by technology.

Man is an ape, a freedom loving ape. Machines lack the desire to live and procreate without man. Either technology will shape man for a more perfect fit or man will destroy technology and perhaps himself in the process. (Or, then again, maybe we'll just run out of energy. : )

Memmel, keep the great thoughts coming. It's nice to have an alternative to the fodder served to the obedient in the MSM trough. I'll opt for some occasional fine dining on TOD.

It's a little hard to read all these ramblings. So, I address 3 points:

1. Exxon (and other oil producers). You seem to acknowledge that these guys have "deep" insights about the oil reserves, but then you say that you think even they are NOT correct. Based on what?
If there is plenty of oil out there, then of course it's a matter of how do we get it. And that is a matter of price and feasibility. That's why the EROEI method doesn't give you much guidance as to how to proceed. Because higher priced oil, would justify lower EROEI exploitations. In other words: EROEI is elastic and you can stretch it to whatever you want.

2. The same applies for the alternatives or oil substitutes. What is their affordability and feasibility? And I am not sure why Mr. Rapier's assessment would be so brilliant. I think many have argued against corn ethanol independently from him. But of course every belief system has their own saints...

3. How would you get rid of the population surplus? What would be your target number and why? What quality of life do you have in mind for the global average person? It seems to me that your "solution" is easier said then done than all the others....

3. How would you get rid of the population surplus? What would be your target number and why? What quality of life do you have in mind for the global average person? It seems to me that your "solution" is easier said then done than all the others....

Well we can do nothing and all I argue is that doing nothing will probably result in one of the most painful outcomes. Before you can even get anywhere you have to consider if any other solution besides nothing is possible. I'd argue probably not.

However whats important is to have a decent basic model of population and energy a simple yet powerful one is easily constructed.

Consider the net energy curve as a sort of parabolic or bowl shaped curve at the bottom the net energy is high as you go away from the center its lower. For now we need not worry about the exact shape just that the overall system is bowl shaped.

Next consider population modeled as a ring of spheres like a pearl necklace periodically the number of spheres double but in doing so they move up the net energy curve to lower net energy. There is a doubling rate and a rate at which the population ring moves towards lower net energy. This can easily be seen by dropping various sized rings into a a concave bowl they will stick at different heights.

Now the key doomer hypothesis is that at some point the net energy falls below a level that allows doubling to proceed. In fact the system has a sharp inflection point.

When the system hits this inflection point the population can no longer double but has to decline to access lower net energy resources. Now instead of a ring moving up a net energy curve with expanding population the system undergoes a complete phase transition and you have a shrinking ring moving down a declining net energy curve eventually to some very small but stable level at the bottom.

If this concept is correct the the population need not do any constructive action to deal with the situation it well naturally happen.


So first and foremost thats the basic doomer model before you can eve discuss anything else you need to decide if you believe this basic model. If you don't then its fruitless to go forward.

Assuming you agree with the basic model then its a matter of determining the exact shape of the system etc. Once you get past the basic population issue then and only then can you discuss how to prevent the simple outcome I presented from happening.

Now as far as oil goes if you make it far enough even past this first stage we can happily discuss how steep the walls of this net energy bowl are. I believe that are quite steep and have so far found nothing to invalidate this conclusion. But these are small details realistically. At best they have some effect on our own lives and maybe with a lot of optimism even a few generations but if the basic model holds then this is really not all the relevant. It really boils down to if we will be alive or dead when or own detailed view of the model is proven right or wrong. My own model results in it being proven or not within months or years at most well within my natural lifespan. I have noticed that most of the alternative models have a interesting property in that they tend to be proven wrong after the promoter has either retired or died. I find that linkage interesting indeed. In general all the serious problems mankind faces of the invariant property that if they are not dismissed completely they tend to be 30 years out in the future if they exist at all. The current generation seems to always not be facing any serious problems.

Hopefully you can at least see why I argue we must start with population only once the population/ net energy problem is recognized can you even begin to asses the true situation.

1. I honestly have a hard time picturing your model. You suppose a cause and effect relationship between population growth and net energy. Why? (the OP defines net energy as the result of ER - EI) How is that more people would reduce the effectiveness of oil exploitation? Maybe the thinking is that more people will consume more oil (of which there is less available) and therefore even less would be available as EI for exploration/exploitation. But if E is scarce, the price will go up: therefore less will be consumed, and exploitation of lower net energy sources becomes feasible. Then more oilfields will come into production, etc. etc..

2. Doomer model. That population growth could be determined by lack of energy supply (not to be confused with "net energy") supposing that people cannot grow enough food in their vicinity nor can get it transported to them from elsewhere and starvation would result is a possibility (rather extreme though). We don't need complicated models to state the issue.

3. Prophet's death. If you're right you will be dead too, no? So, what's the point in arguing that "alternative models have a interesting property in that they tend to be proven wrong after the promoter has either retired or died."?

Sorry Willem you failed the test.

I gave you several chances and you missed every opportunity to enlighten yourself.

Its your problem not mine.

I'm sorry but I must reply to myself.

There are now six billion people on the planet you personal views converted to chemistry are measured in parts per billion. Which is often th limit of detection. Ive give you far more food for thought then most people get. Take or leave it I have a lot more to be concerned about and your personal views are barely worth consideration.

I simply don't have the time to wast for skeptics if if can execute what I feel I'm forced to do I could save millions the opinion of one of the billions is no longer important.

Let's say the teacher failed...

Willem I did not fail you don't think there will be a big problem.

Thats fine your certainly entitled to your opinion.

However at some point your in a triage type situation you have to decide.

We talk a lot about wasting resources on the oildrum but I think its now reached the point if you look at the overall US social/financial/energy situation that we are either going to manage to pull off a transition without dramatic change most importantly in the social situation or we are going to crash and burn.

If its really crash and burn then unfortunately its time to start triage you have no choice but to write off some people until they are forced to face reality.
My own father who is close to retirement devastated by the financial crash even though I warned him to get out of stocks last summer. He still believes he is going to get his pension. I can't get him to even consider that his pension may be worthless.
He still believes in the system and I suspect he will right to the bitter end.
On the plus side he has a large farm its paid off and he will get buy.

So either the doomers are completely wrong or they are right if they are right then its reached the point that if people are undecided then they have made a decision.

I'm not suggesting anyone take and action they would not be happy with if by some miracle we pull out of this White Swans are as possible as Black Swans. But I think its no longer productive to try and change a significant portion of the population thats not interested in changing. Nothing personal I've been forced to come to the same conclusion with my own parents. And I assure you thats a lot harder then some random person on the internet. Its not pleasant realizing that my parents who worked hard their whole lives and believed in the system and played by the rules and lived frugally are probably going to be mostly wiped out in the end.

If I'm wrong then feel free to laugh but if I'm right then I hope you realize that you had a chance, maybe you will get lucky and make it out either way no telling if so be thankful but I do hope you at least look at your own personal situation and think about how you would fare. Just the financial news alone should compel you to take stock of you life and how you can minimize the effects of problems.

Good Luck.

Do you have any evidence that people were generally wealthier when there were only 2 billion people on this planet? If so, please show us. Till then, I don't believe that massive population kill will get anyone out of the woods....


Your "net grain" concept is one of the most pathetic straw man arguments I have ever seen. Even you, in your own post, admit that it has nothing to do with EROEI/net energy, because "energy is unique" in that is can be changed from one form to another. In admitting that, you are admitting that what you have been arguing for however long its been (months? years?) is wrong. Unlike you've been saying, EROEI and net/energy do compare concreta, and thus have very practical applications to a very broad set of concrete concerns. The only difficulties are in consistently measuring the concreta consistently. But science has become quite adept at measuring concreta in the last two hundred or so years, and there is very little about comparing different forms of energy that is actually difficult nowadays, for those who are trained.

Give this up, x.


Energy is an abstraction. It does not exist outside its concrete forms.

This is nonsense. An abstraction is something which does not have a 'concrete form'.


4. The result of abstracting: the idea of something which has no independent existence; a thing which exists only in idea; something visionary.

Oxford English Dictionary

Furthermore energy is not finite like metal or grain. A new supply arrives from the sun everyday. Why should we care about net energy except in the case of fossil fuels which deplete and are finite?

We should care because we cannot simply passively receive usuable energy from on high, like manna descending on the Israelites. Energy must always be expended in order to harvest more energy. Solar panels must be manufactured and maintained. Energy must be expended to plant cultivate and harvest crops which must then be processed into a useable form. If the final amount of energy 'harvested' is not significantly greater than that expended in the harvesting process the whole process is a waste of time and resources, including energy! Moreover, it would also be unsustainable (without an energy subsidy from some other energy procuring activity which did have a significant energy return).

If EROEI were unimportant it wouldn't matter how much effort it took to procure energy and how many intermediate stages it took to manufacture a fuel. We could then disregard thermodynamics and use fuel like this to power all our agricultural machinery.


Fascinating! Net energy, although in a narrower form, has been on my mind for the last few weeks.

Here's a graph, not to be taken too literally:


I assume that

Ei/Er = Q

Q is cumulative production, Q=1 max
Ei=energy invested,
Er=total energy returned.
Then net energy

Enet= Er - Ei

The assumption that Ei/Er = Q is correct at the extremes, i.e. early on when Q is low, certainly Ei is low relative to Er, and later when Q nears max (1) Ei/Er climbs close to 1. How accurate it is in between is debatable. Anyway, this is in line with your graphs, and says what you say, net energy will peak (has peaked) and will decline much more rapidly than the undiscounted energy supply.

I've also been exploring another reason the bell will be skewed (adversely) and will send all to you soon.

P.S. Don't know how to embed graphics yet. Will work on it.

Edit: Ok, I got it.

Thanks. I was just about to ask for that chart.

In fact, everyone might consider the fact that the usual oil production charts are unconsciously misleading, because they *look* like we have about half the total (oil) energy left.

People might think about various good ways to visualize this, like the example above. Maybe a series of replicated charts (a la Tufte) where the variables are net energy and efficiency?


I don't know how to incorporate this into your chart, but here is another issue - ERoEI involves an EI. All energy inputs have their own ERoEI. As the ERoEI of the EI goes down so does the final ERoEI. At very low ERoEI this can bring a positive down to a negative.

For instance if you are using net 8 to 1 oil to make solar panels for every 8 barrels used you are actually using 9 barrels. If your net on oil becomes 4 to 1 you are acutally using 10 barrels for each 8 that you use.

Making solar panels using solar panels is a whole different ball of wax than making solar panels using oil due to the low ERoEI of the EI as well as the fact that some things that we use oil for are going to be difficult to do with electricity.\

As the ERoEI of the EI goes down so does the final ERoEI. At very low ERoEI this can bring a positive down to a negative.

Try to be more precise with your terms.

Only a negative net energy (ERoEI below 1) of a component input can turn an overall positive net energy into a negative one. ERoEI can't be negative, since ER is by definition not below zero.

For instance if you are using net 8 to 1 oil to make solar panels for every 8 barrels used you are actually using 9 barrels. If your net on oil becomes 4 to 1 you are acutally using 10 barrels for each 8 that you use.

It's difficult to see how the utility of turning oil into solar panels is negatively affected by this. Turning oil into solar panels itself still has the same energy economy as when oil was cheaper. As long as we don't lose more energy (by using electricity from solar panels instead of oil) than we gain (by converting oil into solar panels), then we come out ahead. If we can do that, then it would make sense to turn every barrel of oil we can into a solar panel, regardless of the oil's own ERoEI. If we can't, then it doesn't make sense, regardless. (I think solar comes out ahead, but that's not the point here.)

It looks to me as though your chart indicates that we now have roughly half of the original net oil, we only have about a fifth of the original net energy. Is that about right?

The net energy curve peaks in the '90's, and that is also about when we saw very low oil prices begin their exponential growth that reach $147 last year. Is this correspondence a coincidence, or did the price in some way indicate the arrival of peak net energy?

(When I grow up I'll model all this stuff ...)

All the processing feedbacks are incremental and cumulative. Every additional step adds incremental costs so the energy balance sheet would reflect increases in the number of steps in any process - each step requiring energy of some kind. Yes Virginia, there is a relationship between greatest available net energy and the price curve .

The feedbacks increase with the expansion of the marketplace which requires more energy costly infrastucture and more complex processing. Depletion of cheaper deposits is also anticipated in the market. Small percentage increases here and there accumulate, so that relatively cheap energy inputs taken together sum up to substantially higher overall energy costs.

That's why $50 dollar oil isn't cheap. Percentage increases multiply like rabbits throughout supply chains eating into profits. No profits equals no businesses. This is a reason for China's and India's current economic success, they can compensate for higher cost energy with cheap labor. Cheaper labor in developed countries cuts into end use (consumption) which is also winds up becoming self reinforcing.

Dave's chart is very important. Peak of any material isn't so much geological so much as it is economic. The chart also illustrates the lag between the actual supply peak and the net (exergy or dollar) peak.

In a roundabout way, the overall level of costs reflects net energy or declining exergy. Only Santa Claus gives energy away and then only once a year and only if you are bad.


Excellent post.

Basically the system has no choice but to start winding down. It can't expand past a certain EROEI wall. This fits well with my intuitive dismissal of reserve expansion in the 1990's to today. We probably will never extract that oil. Our economy ran on cheap oil.

One can reconsider what the HL plots mean given this economic model.


If you look at the early part of the graph you can see and obvious early linearization to about 800 GB then and obvious change in the slope of the curve.

This 800 GB matches well with the resources on land.


Then we see a change in slope this can readily be assigned to move to exploit offshore reserves in the late 70's forward.

Now you have to really consider what to do next if you look at the slope change it moved from point towards about 800GB of total URR and initially kicked out to about 1200 GB this fits very well with reserve estimates up to about 1995.

But something else was happening the move offshore was also a major technical achievement the oil industry was itself transformed. As we continue forward the curve continues to kick out pointing towards 2000 plus barrels.

We practically doubled the reserve base from about 1990 to the present. The problem is this was done without finding any new large fields. It was not done by discovering new Ghawars it was done using technology advances to search known basins better and via reserve additions most based on production history yet our ability to extract oil increased dramatically over the same period.

Given this I suggest that these large additions are for the most part and artifact of our technical expansion. If so then one would expect expansion of reserves based on misunderstanding of the technical situation to stop fairly abruptly. They had no physical basis to begin with.

My opinion is our real URR never changed much from about 1250-1400GB thats all we have really had and its all we will ever extract. The part of the curve used most often for HL is simply and artifact of the technical explosion. Given its still well within the OOIP estimates of 2000-3000GB and our technology generally sees OIP and determining URR is and art not a science I suspect the data supports this amount of oil but we are in a sense extracting like we are going to get 50-80% recovery. Where the real recover factor actually never moved about 30-35%.

This suggest that future oil production will follow a interesting pattern. Sometime shortly after its peak production we would have drained the 1250GB or so of easily accessible oil that can be produced at a high production rate. The production rate should then plummet leaving final extraction of iffy marginal reserves from badly depleted fields at a very low production rate and very high cost. I doubt the economy will actually hold together long enough to support much extraction of these remaining reserves we may never find out how much of it was actually extractable.

Whats interesting is in my opinion this view of oil fits almost perfectly with how the economic situation has evolved they are actually one and the same processes tightly intertwined. Or economic system is obviously heading for a wall and this is actually a result of the underlying situation with oil. If all this oil was real I'd argue that given the amount of money we have created and the pressure on oil production esp the last decade we would have seen oil production actually be asymmetric with a much higher peak production its simply being forced to hard. I'd guess we would have gone to 100-120mbd with peak production as much as a decade away. Low quality sources such as the tar sands would have been brought online and deepwater sources which are a final third phase would have also come online kicking the HL plots out to 3000GB.
Still not real and still following my thesis bout you can see that the final collapse would have been from a much higher overall production level with some large but slow to produce unconventional sources probably serving to cushion the blow.

And it would not have been cheap oil call it medium expensive oil in the say 60-120 a barrel range.

We are in my opinion not going to get that last kick out.

Whats really interesting is this is probably a result of the two decades of fairly cheap oil we took all the easy oil and did not start exploiting the really hard stuff soon enough now we face this huge gulf that we cannot cross.

This is pretty much in line with the conclusion "shortonoil" at peakoil.com came to when modelling Available Energy.

Interesting net energy chart.

I think that as we slide down the net energy hill, society will be forced to adapt by modifying behaviour such that exergy per capita is maximized. Infrastructure will have to be created to support this. There exists a huge potential for this already.

I bought my first motorcycle about 5 years ago after hearing about peak oil - specifically for a 50km/day commute. Motorcycles are ideal urban vehicles:

- cheap to buy (my brand new GN250 was $3000NZ approx $1800US)
- easy to maintain (one can easily learn to do it oneself as they are far simpler than cars)
- reduce travel time considerably at peak traffic (takes half the time for my commute at peak)
- free parking
- And last but not least, I get 28km/l which is about 70mpg.

This gives me all the freedom and flexbility of personal transport without a lot of the hassle. Sure, it's a bit of an adaption riding on those cold wet winter mornings, but then you get used to it and I heard that electric clothing is now out. The big weekly to fortnightly shop is now smaller amounts more frequently (typically weekly - always fitted in with other things)

Electric motorcycles offer even a far far greater potential. (in terms of exergy per capita).


(Adding high EROI wind capacity while net energy of oil dwindles does not solve the problem, unless the energy mix changes from liquid fuels to electricity)

I totally agree with this and the answer I think for a large part of urban transport in the future will be provided by electric motorcycles.

- Far cheaper than cars in all aspects (purchase, maintenance, running costs) so converting to motorcycles will still be possible in a declining economy and money supply
- Less cars means a smaller need for roads, parking buildings and their maintenance
- Greater range of commutes are possible
- Provide be a market for wind energy at night when recharging would happen.

The energy mix will change from being dominated by liquid fuels to electricity. Building the infrastructure in a declining economy requires maximizing exergy per capita in order to hold our society together and wind energy and electric motorcycles I see as being a larger part of the solution.

An obvious way to disprove the phoney 'EROEI evaluations' is to compare like to like.

Ethanol is a direct substitute for gasoline. Ethanol has an EROEI of 1.33 or IOW 56000 BTUs of energy investment gets 75700 BTUs of energy out(1 gallon of ethanol).

Take a barrel of oil, which has 5600000 BTUs of energy in it. That's the amount of energy required to make 100 gallons of ethanol which is equivalent to 66 gallons of gasoline.

15% of the energy of barrel of oil sent to the refinery is used up( distillation, hydrogenation,etc.) leaving 4760000 BTUs. A gallon of gasoline equals 113000 BTUs, so dividing we get
4760000/113000= 42 gallons of gasoline.

So if we used oil to as the sole fossil input to making ethanol instead of cheaper natural gas or dirt cheap coal we'd still be 24 gallons of gasoline eqivalent to the (net)positive!

The argument they may be making is that the 'embodied energy'---cost of an oil refinery at $15000 per daily barrel is less than an ethanol plant at $30000 per daily barrel(boe) as an additional form of energy invested, ei.

This can be shown as the following equation;

-$15000+365*x=-$30000 + [66/42]*365*x and solving it you get a one year payback at $72 per barrel of gasoline or a two year payback at $36 per barrel, etc. 66/42 = EROEI(1.33)/ efficency of oil refining~85%.

The same applies to tar sands at $40000 per daily barrel with an EROEI of 1.5(?):

-$15000 +365*x=$-40000+ 1.5(has to go to the refinery like drilled oil so no 85%)*365*x getting a one year payback of $136 a barrel, 2 year of $68 a barrel, 4 year payback of $34, etc.

There is also the additional flat premium costs per barrel for things like deepwater or arctic operation (at $25 per barrel) which can just price certain reserves out of affordability.

And the assertion that energy reserves aren't important can't be correct at least in the short run as marginal reserves grow or shrink based on the price of oil.
If the price of extraction is too high, reserves will not be developed, i.e. what is contracting the world oil market currently.

But if you take away implied 'embodied energy' , net postive energy will always beat net negative energy.

Cutler Clevelands EROI Powerpoint link is not working.

Nate's found an ancient document about the Anasazi, in the last years having to travel 70 miles to get timbers, but he's mistranslated a few of the words.

The link to Cutler Clevand's EROEI for wind power shows that all turbines above 300KW have an EREI of 20-40. Wind turbines are now 1.5-3MW so this graph is dated. EROEI appears to be 50-200:1 for larger turbines.

I don't understand the diagram of power density from V Smil, are we saying wind farms can only cover 1km^2 area but oil fields 1000km^2 or is it that wind turbines are 1000 times smaller than oil wells??
Surely this power density/area is completely irrelevant, what is critical is the potential power available and how long it will last.
One oil well may deliver 10-1000 barrels/day(4MWh-400MWh) for 5-10years. One wind turbine can deliver 10-40MWh/day for 20-30 years. An oil field will last 10-60 years, a wind farm can last millions of years.

V Smil is making the mistake of considering average density of wind energy but not of an oil field, oil wells concentrate oil dispensed over a wide area or in many strata into one narrow pipe, wind turbines concentrate wind energy across 5000 m^2 into an electric wire, but only harvest 3% of the wind energy passing over just the first 140 meters of air mass in a region. If we go down 1-2Km for oil, why not consider the energy in 1-2km height air column?

This energy density theme is not relevant if we can store enough electric energy to provide useful work, clearly sea, rail and road transport can use electricity stored as chemical energy, so the original source density of the power is not relevant, any in any case wind and solar are fairly dense when compared to oil or coal energy content in first 1-2km of oil or coal bearing rocks.

From a global perspective, even if the EROEI is or will become low/negative for some some energy sources, there are still huge long term "energy subsidies" potentially available from renewable sources to help make up for some of this EROEI shortfall. The sun and the earth offer huge potential using such technologies as CSP and Geothermal, even after paying for the capital (and energy) costs of recovery. These will likely be net positives to the system in the long run, notwithstanding their distributed nature and development challenges.

Your post would make a little more sense if you used the term 'net energy' instead of ERoEI.

Renewables will almost certainly be "net positives", but that really isn't the big question. The big question is whether these renewables can be developed at a rate and maintained to a quantity sufficient to substitute for the world's current extravagant fossil fuel use.

The answer to your question is probably no given the high energy density, utility and depletion rate of oil. But, I am not sure that is necessary either. We will just have to learn to live with less consumption and that is where the world is headed.

Energy gain, or EROI, varies with the quality (transformity) of a resource deposit and with the efficiency of the technology used to locate, extract, process, distribute and exploit the resource. As the ease of obtaining or using a resource declines, more energy must be devoted to these activities, causing energy gain to decline. Where an energy budget is substantially constant, allocating more resources to energy production reduces the amount of energy available for other activities. The potential impacts of such a situation on a human system include less leisure time, a lower standard of living, higher taxes, and an increase in childhood mortality. In an animal population, allocating greater effort to energy production may mean less winter fat, increased embryo resorption, lower birth weights, or the like. Tainter

The use of the expression "where an energy budget is substantially constant" reveals confused thinking about the energy production process. China's energy budget is not "substantially constant". They are building coal fired power plants like crazy. Nevertheless net energy still plays a signifcant role in understanding the economic value of coal based energy. When a large energy source is being exploited and peak flow rates have not been reached, then the idea that there is an opportunity cost associated with the energy consumed during the energy production process is incorrect. If you could wave your magic wand once per second over a batch of energy have it disappear and then be replaced by an new batch of energy which was 10% larger (EROI=1.1) then you could increase your energy supply by a factor 10E+149 in one hour and the only cost would be the lost hour of labor.

When an energy source is still capable of a large expansion in total flow rate the opportunity costs associated with increased extraction (I am ignoring negative externalities) come from finite non-energy production resources such as labor, fresh water etc. These opportunity costs, of course are affected by the energy consumed during the energy production process. As I have pointed out on many previous occasions if the resource cost (e.g. hours of labor, liters of water, etc) of producing one unit of gross output energy is r then the resource cost of procing one unit of net output energy is given by r/µ where µ is the fraction of the output energy which is left over after the input energy has been subtracted out.

Hall et al. 2009 show there is a Minimum Energy Return on Investment of about 3:1
Gasoline/Diesel have about 4.14
Bio Ethanol about 0.5
Fossil fuels must be used to subsidize the ethanol to be viable.

Review What is the Minimum EROI that a Sustainable Society Must Have?
Charles A. S. Hall *, Stephen Balogh and David J. R. Murphy
Energies 2009, 2, 25-47; doi:10.3390/en20100025 energies ISSN 1996-1073 www.mdpi.com/journal/energies

Nate - Would enjoy seeing a book review from you on "How We Decide" by Jonah Lehrer. I think TOD'ers would find its contents and perhaps related works, to be valuable.

Nate, well done again on this post. You wrote:

"Our collective task will be to improve our net (total cost) energy from renewables while changing the infrastructure of society to best match what our long term sustainable energy gain can be."

The energy transition requires investment, that, in the current economic paradigm, equates to debt. Unless there is:

1. A complete overhaul of our financial system; and, even more miraculously

2 financial injection of hard cash by philanthropic billionaires out there, I can't see this happening.

Perhaps Sir Richard Branson could impart his Midas touch onto our be energy conundrum.