Sunday, June 19, 2016

ERoEI is unimportant and is being used incorrectly

In this article I will show that ERoEI is almost totally unimportant by itself. It does not matter if ERoEI is increasing or decreasing. ERoEI provides no guidance about which sources of energy we should pursue, nor does it offer any guidance about how much net energy will be available to us in the future. By itself, ERoEI is a useless figure. Although different sources of energy (such as coal or solar PV) have different ERoEI ratios, this means nothing important.

What is important to civilization (and to us) is the amount of net energy obtained from a source of energy. It is an amount of net energy (not a high ERoEI) which allows us to drive cars, fly airplanes, and so on. If we obtain 1 GWh of NET energy, then it does not matter if it came from a high-ERoEI source, or from a low one. What matters is the amount of net energy.

In turn, the amount of net energy depends upon two things: ERoEI AND the amount of gross energy. BOTH of those figures are required to determine the amount of net energy obtained. ERoEI by itself tells us almost nothing.

Let me provide an example, to demonstrate this point. Suppose you have a solar PV panel with an ERoEI of 2, which returns 1KW on average continuously for 30 years. In that case, the net energy provided by that solar panel is 131.4 MWh ((1*24*365*30)/2) over its lifetime. If, however you have 10 such solar panels, then the net energy returned is 1314 MWh—ten times the amount of net energy returned, despite no change in ERoEI.

For the most part, the amount of NET energy we can obtain is determined by the amount of GROSS energy we can obtain, not by ERoEI. Usually, ERoEI is only a minor factor. This is because the difference in the amount of gross energy between sources of energy is so large that is completely overshadows any minor influence that ERoEI would have. For example, suppose we had single 1KW solar panel, and the panel had a very low ERoEI of 4. Even if you increased the ERoEI from the very low value of 4, all the way up to to infinity, so that no energy was required to replace that solar panel, it would make practically no difference--it would increase the amount of NET energy obtained by only 25%. On the other hand, if you could build 3 such solar panels, instead of 1, then you would triple the net energy obtained. In this case, building two more solar panels had 12x greater effect than increasing the ERoEI to infinity. In general, it is the NUMBER of solar panels, not their ERoEI, which determines how much net energy could be obtained.

Generally speaking, the amount of net energy goes up as ERoEI declines, although it’s a weak correlation. This is because the amount of gross energy is vastly higher at lower ERoEI ratios, and the greater amount of gross energy more than compensates for any decline in ERoEI. For example, it’s commonly claimed that crude oil had an ERoEI of 100 in 1930, but only has an ERoEI of 15 now. I seriously doubt that, but I’ll assume it’s true for the moment. From those figures, we can show that a decline in ERoEI led to a gigantic increase in net energy. If oil had an ERoEI of 100 in 1930, and 5 million bbls per day were extracted back then (source: ), then the total amount of net energy per day from oil in 1930 was 4.95 million bbls of oil. On the other hand, if oil has an ERoEI of only 15 now, and we extract 90 million bbs per day, the total net energy from oil per day is now 83.99 million barrels. The amount of net energy from oil is 17 times higher today than in 1930 despite an 85% decline in ERoEI. This is because the greater AMOUNT of oil at the lower ERoEI completely overshadows the effect of lower ERoEI. This is frequently the case; more NET energy is frequently available at lower ERoEI ratios, because the amount is so much greater that ERoEI makes little difference.

For the most part, the net energy obtained from solar power (or windmills, or whatever else) would be determined by the number of solar panels built, not by their ERoEI. In turn, the number of solar panels which can be built, is determined by non-energy factors like capital and labor, because those are the scarce factors which prevent the construction of more solar panels. Energy for investment is not scarce, because this planet is bombarded with 23,000 terawatt-years/year of solar radiation, which is vastly more than we will ever use. It is the scarce factors which determine how many solar panels we can build, and therefore, for the most part, how much net energy we will obtain. This point is complicated and requires further elaboration, so I will discuss it in a subsequent article. Suffice it to say, that the net energy of solar power is determined by non-energy factors such as capital and labor, and has almost no relation to ERoEI, because capital and labor (not energy) are the scarce factors which prevent the construction of more solar panels.

The equation for determining net energy would be as follows, given ERoEI and an energy investment:

energy_net = (1-1/ERoEI) * energy_investment

You will notice that it’s IMPOSSIBLE to solve this equation without knowing what the energy investment is. As a result, it’s impossible to calculate net energy returned from any type of energy (for example, coal) by knowing its ERoEI alone. As a result, ERoEI is a useless figure by itself and cannot be used to determine the amount of net energy which could be obtained from any type of energy.

In general, renewable sources of power could provide vastly greater amounts of net energy, even if they had much lower ERoEI. This is because they are available in far greater amounts, by a degree which totally erases the importance of ERoEI.

For example, let's calculate the maximum net energy we could obtain from solar power. The Earth is bombarded by 23,000 terawatt-years/year of solar radiation. Let’s assume that only 1% of this could ever be captured by solar PV panels. Also assume the panels have an extremely low ERoEI of 4, which is certainly an underestimate. In that case, the amount of NET energy which is available from solar PV is 172.5 terawatt-years/year, which is more than 10x worldwide energy consumption at present (more than 30x if you apply an energy quality correction). As a result, the amount of net energy possible is vastly greater from solar power than from fossil fuels, EVEN IF the ERoEI of solar were very low. The reason we don’t obtain that much net energy from solar panels is because we don’t have enough NON-energy resources such as labor and capital to build that many solar panels. It has nothing to do with ERoEI.

Again: net energy available is a function of BOTH EROEI AND AMOUNT. Either one of them by itself cannot be used to calculate net energy. If we wish to use a “rule of thumb”, then we should assume that MORE net energy is available at lower ERoEI ratios, but the correlation is so weak that it can’t be relied upon. In any case, ERoEI is not generally an important factor.

Unfortunately, ERoEI theorists do not realize any of this. Over and over again, they wrongly assume that ERoEI is somehow proportional to net energy. They assume that a higher ERoEI somehow implies more net energy obtained. This is a severe mathematical error, but it’s repeated endlessly throughout the ERoEI literature.

Let me provide some examples which I read just a few days ago:

“Look [at a] Cheetah… That beautiful and ultra efficient machine, needs an EROI of about 3:1 (sped three times less energy running for the prey, that the energy contained in the prey it is going to eat). That’s a metabolic minimum EROI for mammals.Being the minimum EROI for any live being (mammals in particular) 2-3:1 in average, to be kept alive as species and for the couple to successfully breed their offspring (minimum of 2-3 per couple), probably Charles Hall is very right to state that a minimum EROI of 5:1 is required to have a minimum (very primitive and elemental) of civilization, beyond us living as naked apes.”
No, because that wrongly assumes that greater amounts of net energy are obtained at higher ERoEI. Dr Hall observes that civilization requires more net energy than just the metabolism of its inhabitants require. Then he wrongly concludes that a higher ERoEI means more net energy. That is a basic mathematical error. Frequently, using a lower ERoEI source of energy will obtain more net energy than a higher ERoEI one.

The Cheetah example is also mistaken in other ways. The Cheetah doesn’t just have a low ERoEI; it also has TOO FEW prey which it can catch. If the Cheetah could eat prey every 5 minutes, then it would have a vast excess of energy even at an ERoEI of 1.5. The problem is that many animals eat only once per day and some animals (such as crocodiles) eat only once per week or so. The problem is amount, not ERoEI. If they eat only 10,000 kilocalories per week, then increasing the ERoEI wouldn’t matter much (even increasing ERoEI to infinity in this case would only gain the animal another 3,300 kilocalories). What would help is to catch MORE prey.

We can take our ERoEI 20 FF and invest them in ERoEI 50 sources and make a huge energy profit. Or we can invest them in <5 and make a loss. Our policy makers have lost their heads electing to promote loss making activities.”

No, because that is confusing ERoEI with an AMOUNT of net energy. If an ERoEI were an amount, then spending fossil fuels with ERoEI 20 on solar panels with ERoEI 5, would imply a loss of 15. However, you cannot subtract the ERoEIs of different sources of energy, because they are not AMOUNTS which can subtracted. The correct mathematical operation is to multiply those two numbers, not subtract them.

If you take ERoEI 20 fossil fuels, and invest them in ERoEI 5 solar PV, then the aggregate ERoEI is 100 (invest 1 unit of fossil fuels initially, obtain 20 units of fossil fuels with ERoEI of 20 thereby, invest each of those 20 units in solar panels with ERoEI 5, then obtain 100 units at the end of it for an initial investment of 1).

IMO, the only thing that could delay the bad impacts of declining high ERoEI FF is to introduce to the global energy mix an energy source that has higher ERoEI than the fuels they have to replace. Introducing low ERoEI energy sources simply makes things worse.”

No, because (again) that is confusing ERoEI with an AMOUNT of net energy. The “bad impacts” are caused by TOO LITTLE net energy, not a low ERoEI. Adding any source of energy with an ERoEI higher than 1 increases the total amount of net energy available. Only an ERoEI lower than 1 would make things worse. If the source of energy is cheaper per unit of net energy (as solar power actually is) then it is easier to obtain more net energy that way, regardless of its ERoEI.

…All three of the above quotations are taken from leading figures in the ERoEI literature. Granted, the ERoEI movement is a tiny fringe movement, but these people are among the leading figures of it. Over and over again, they wrongly assume that ERoEI and net energy are somehow proportional, and that higher ERoEI implies more net energy. That is a basic mathematical error. Frequently, the opposite is the case.

What matters is the AMOUNT of NET energy available to civilization, and that amount is far higher for renewables than for any other source, regardless of ERoEI.

* NOTE: In this article, I am using the term "ERoEI" to by synonymous with "EROI" and other spellings. I am referring to the amount of energy obtained for an investment of energy. There are rare circumstances where ERoEI would actually be important, for example, if it were less than 1, and were therefore an energy sink. This is not the case with any common source of renewable energy. This could easily be determined by unsubsidized price; if an energy source has an ERoEI less than 1, then it must be much more expensive than the energy source used to construct it. Since this is not the case with renewables, their ERoEI is unimportant.

I revised this article on June 21, two days after its initial publication, to improve the flow of the text.

Wednesday, June 17, 2015

There are many alternatives to oil

One of the main ideas of the peak oil doom movement is that there are no possible alternatives to oil. Oil is apparently some magical irreplaceable substance with no known alternatives, and no way to find alternatives. For example, here is a recent post from a prominent peak oiler on

...It is highly unlikely we will discover a viable alternative to oil... We can't invent a new energy source to oil since that would violate the laws of thermodynamics. You can't make something out of thin air just by imagining it.

As usual, that idea is factually totally wrong.

There have always been many alternatives to oil, since the beginning of the oil age. For example, cars can use electricity from batteries (most major car companies have released, or are releasing, battery-electric cars). Trains and buses can use electricity from overhead wires; more than half of rail traffic worldwide now uses this. Ships can use steam turbines which can use anything that will burn as fuel, such as coal, peat, wood chips, oil shale, torrefied biomass, etc. Internal combustion engines can use natural gas--even gas from fracking or methane hydrates. For the few uses which really require a liquid combustible fuel, there are many synthetic liquid fuels such as anhydrous ammonia, dimethyl ether, and many others. Those synthetic liquid fuels can be manufactured using electricity from renewable sources and abundant elements. All of the aforementioned alternatives have been available for many decades, and everyone in the relevant industries knows about them.

The only reason we don't use those alternatives already is price. For example, battery-electric cars and synthetic fuels are only competitive when oil costs $120/bbl or so.

When oil production enters its gradual terminal decline, the price of oil will shoot up and stay there. The economy will then gradually transition to now-cheaper alternatives. There is vastly more time than is required for the economy to transition to those alternatives (we have at least a century), and the economy has already begun transitioning to them, far earlier than required (car companies started designing plug-in vehicles at least a decade before any declines in oil production).

This kind of transition is something the economy does all the time. Companies are always evaluating alternatives and switching between them. Take ships as an example: the shipbuilding industry started off using sail, then switched to reciprocating steam engines burning coal, then switched to steam turbines burning coal, then switch to steam turbines burning oil, then switched to diesel engines burning oil. There have already been four major transitions in ship propulsion. There are many, many alternatives for the fifth transition. As another example, electricity production switched from hydroelectric, to oil, to coal, to nuclear and back, and now is switching from coal to gas in the US, because gas is now cheaper.

This notion that "there are no alternatives to oil" is just factually totally wrong.

It is also possible to use oil far more efficiently. When oil begins its very gradual decline and prices shoot up, people can buy cars such as Priuses which get twice the mileage. Shipping companies are already ordering ships that are more than twice as fuel-efficient. Cargo traffic can be switched from truck to rail which is 4x more efficient. Those things by themselves would compensate for declines in oil production for many decades.

Don't expect anything exciting or dramatic to happen to transportation networks. Granted, the price of oil may swing around wildly (because of inelasticity of demand), and there are recessions caused by many things. However, the actual supply of oil changes gradually over decades. Oil production won't enter a sustained decline for at least another decade, and the decline will be very gradual thereafter. There is a lot of time, and there are many alternatives.

Thursday, May 21, 2015

Energy decline theory is pseudoscience

Here is a response I wrote on a forum:
I'm sorry, but there's just no science happening here. It's not sufficient to say the word "science" and to use scientific-sounding terms like "biophysical". Those kinds of things are also common within pseudoscience.

What is required are specific, falsifiable, risky predictions of things which weren't happening anyway. Then those predictions must be confirmed by subsequent evidence. That is the first step toward actual science, and it has never happened and is not happening within this group.

This group has all the hallmarks of pseudoscience. It has never produced any risky, falsifiable predictions which were confirmed by subsequent evidence, not even once. There have been massive failures of prediction, over and over again, but the theories remain totally unchanged, and the failures of prediction are not even addressed. Failures of prediction are handled by making the theory less and less falsifiable ("there is now a long descent which is difficult to see", see John Greer). Members do not respond to criticism, and leave errors uncorrected when they are pointed out. Notably, this group is ignored by legitimate researchers. There is almost no interconnection between this group and actual legitimate fields of study, and this material is rarely cited outside this group. Notably, it appears that this group settles its conclusions in advance ("civilization is about to collapse"), then generates theory after theory which all lead to that conclusion, but then the predictions all fail.

If you guys want to start doing science, then you need to respond to criticism without badly misreading it, modify your theories in light of failed predictions, and make falsifiable, risky predictions which are confirmed by subsequent evidence. Those things would be the first steps toward actual science, but those things are just not happening here.

Here is another post from the same thread:
George, you said:
"I'm talking about net free energy per capita, not raw energy produced... The numbers you quote do not take into account the amount of that energy it took to obtain that amount...So with slowing net energy increase and increasing total population the amount of usable energy for the economy per individual is in decline."

No, that's clearly wrong. Let's do the math. According to the EIA's numbers, world energy consumption has increased from 480x10^15 to 524x10^15 btu, between 2009 and 2013 (inclusive). At the same time, world population increased from 6.83x10^9 to 7.08x10^9 people ( That means that per-capita energy consumption has increased from 70.27x10^6 btu/capita to 74.01x10^6 btu/capita in that time. In other words, per capita energy consumption increased by 5.3% in 4 years, which is a compound growth rate of ~1.3% per year.

Now let's look at the prior 29 year period, from 1980-2009 (inclusive), using the same sources of data. Per capita energy consumption increased from 63.63x10^6 btu/capita to 70.27x10^6 btu/capita over 29 years, which is an increase of 10.4% over 29 years or only ~0.35% per year.

In other words, per capita energy consumption is not only increasing, but the rate of increase accelerated. The growth in per capita energy consumption was much faster during the period of 2009-2013 than during the prior 29 years.

Those figures are not EROI adjusted. It's impossible to find reliable statistics on worldwide average EROI.

However, it's totally implausible that average EROI worldwide has dropped by an amount sufficient to erase that acceleration in energy consumption. Even if EROI had been stable and had not declined at all over 29 years, and then suddenly dropped from 30 to 15 (a decline by half, which is totally implausible) in only the 4 year subsequent period, the EROI-adjusted per capita energy consumption still increased faster (0.5% vs 0.35%) during the period from 2009-2013 than during the prior 29 years.

The straightforward conclusion from this, is that per capita energy consumption is increasing, and the rate of increase has sped up, no matter what you think happened to EROI (within reason).

I don't know how you arrived at the conclusion that "usable energy ... per individual is in decline". Your statement is not compatible with the data which hitssquad just presented.

This is exactly the opposite of what energy doomers had predicted. They had confidently predicted a sudden collapse of civilization in the late late 2000s and rapid declines in energy consumption. What happened was the opposite of what they had predicted, yet again.
The consistent and severe failure of prediction from these theories implies that there is something seriously wrong with them. It's long overdue to start asking what is wrong.


Here is another post from the same thread:

Hi Harry,

I just read through the comments again, and came across yours. You said:

"Could you be very kind and point me to some of those suggestions? I am about to radically decouple!"

Harry, are you going to radically decouple because you expect civilization to collapse soon? If so, you're about to throw your life away. Civilization is not collapsing for these reasons. The most recent collapse predictions from this group are no more scientific, and no better founded, than any of their other collapse predictions over the prior decades.

This material is just totally wrong. It's littered with severe errors that invalidate its conclusions, it's ignored by almost all relevant experts, it does not meet the minimal criteria of a valid scientific theory, and it's characterized by massive, repeated failures of prediction without any corresponding correction of the underlying theories.

There have already been many people who moved out into the wilderness circa 2005 in expectation of a drastic collapse of civilization, for these reasons. They wasted ten years of their lives on a fringe doomsday theory. Do you really want to join them? Of course, you can do whatever you want, but you should clearly envision what you will feel like when five or more years have passed and civilization hasn't collapsed and not that much has happened other than you living in the middle of nowhere.

The original conversation is here.

Monday, May 11, 2015

Six Errors in ERoEI calculations

The ERoEI ratio refers to the amount of energy which we must expend in order to obtain more energy. For example, if we must use one barrel of oil in order to drill for another three barrels of oil, then the ERoEI ratio of the oil we obtained thereby is 3:1, or just 3. As another example, it may take one bushel of coal worth of energy in order to mine 10 more bushels of coal, in which case the ERoEI of the coal we obtained is 10:1, or just 10.

Different sources of energy have different ERoEI ratios. Some sources of energy (such as coal) have high ERoEI ratios, typically more than 20:1, which indicates that coal requires very little energy expenditure to obtain it. Other sources of energy, such as oil, have much lower ERoEI ratios. Some sources of energy, such as corn ethanol, take as much energy to obtain as they will yield. They provide no leftover energy to society, and have an ERoEI of 1.

The ERoEI of various energy sources has been calculated throughout various papers on that topic. There are at least 30 papers calculating the ERoEI ratio for various sources of energy such as nuclear, coal, solar PV, and others.

Unfortunately, the reported ERoEI ratios for any given energy source are often widely divergent from one paper to the next. For example, Weissbach et al[1] report an ERoEI of 75 for nuclear power, whereas another study[2] reports an ERoEI of less than 1 for the same energy source. As another example, the ERoEI of solar PV is reported as 2.3 in Weissbach et al's paper[1], and the high 30s in another paper[3]. Those kinds of discrepancies are common throughout the ERoEI literature.

Much of those discrepancies are caused by errors in the calculation of ERoEI which I will detail here. Once these errors are corrected in the offending papers, the resultant ERoEI ratios for different sources of energy become much closer together.

The errors are as follows:

Error #1: Energy consumption is repeatedly treated as energy investment

It's crucial not to count energy consumption as energy investment, because they are different things. It would be incorrect to include energy consumption in a ratio of energy investment. That would be like counting the number of cars on a street and then including pedestrians. It would yield the wrong result.

As an example, the paper[4] from C Hall (What is the Minimum EROI that a Sustainable Society Must Have?) calculates the EROI of oil. However, it includes  the energy cost of freeways, automobiles, and so on. That is a mistake, because those things are energy consumption, not energy investments to obtain energy.

If you include all energy consumption as energy investment, then the EROI of every energy source is 1. This is an application of the first law of thermodynamics. It would be highly surprising if we got more energy out of an energy source than was present within it. As a result, it is not surprising that the EROI of any energy source will converge to 1, as consumption factors are included. However, that does not yield any useful information, because it does not tell us how much energy is left over after obtaining the energy to provide for consumption. That is just a roundabout way of testing the first law of thermodynamics--something which has already has been tested and which could be tested far more directly. If we wish to find how much energy is left over for consumption, then we must exclude consumption from the ERoEI ratio.

Many of the conversions of money to energy, which are found throughout the EROI literature, are implicitly committing this mistake. For example, in Hall's papers such as Spain's Photovoltaic Revolution[5] and the accompanying presentation[6]. On pp 12 of that presentation, there is a conversion of money into energy units, in order to find the energy cost of things like accountants employed by solar companies, etc. The formula presented is "At 1 Toe = 42 GJ, this represents 5.12MJ/Euro" which is derived from dividing the GDP with all energy usage in the entire country (Spain). That is a mistake, because most energy usage in the country is energy consumption, not energy investment. To correct this mistake, Hall et al should take the total energy consumption for the country as a whole and divide it by the ERoEI which prevails for the country as a whole.

Performing this correction (assuming an average EROI of 10 for the country), by will increase the reported ERoEI of solar PV for that paper from 2.79, to 5.22. The figure of 5.22 is much closer to other reported ERoEI calculations for solar PV. This correction was performed by dividing all values by 10 which were the result of a money conversion as found in the chart on pp 12 in the above presentation[6].

Error #2: Lifetime estimates are incorrect

Many papers wrongly assume that the lifetime of an energy source is identical to its warranty period. For example, Hall et al's book[5] indicated above, and Weissbach et al's paper[1], both assume that the lifespan of a solar PV module is 25 years because that is the warranty period.

It would be highly surprising if solar PV cells failed on exactly the day their warranty expired. For example, I bought a car with a 50,000 mile warranty, but it didn't cease working at 50,000 miles.

The reason manufacturers are offering a 25 year warranty on solar cells is because they expect the vast majority of cells to last longer than that.

This error has a large effect on calculated EROI. In Weissbach et al's paper[1], the EROI of nuclear is calculated as 75 but the EROI of solar PV is calculated as 3.8, partly because nuclear plants are assumed to last twice as long as their original rated lifespan based upon observations, but solar cells are assumed to fail the exact day their warranty expires.

Even worse, many EROI papers contain incorrect aggregations of lifespan estimates. For example, C Hall's book[5] includes energy costs for things such as access roads to the solar plant, metal fence posts around the solar plant, concrete in the foundation, steel frames for the solar cells, etc. These things are grouped together with the solar cells themselves and are therefore wrongly assumed to have the same lifespan as the cells themselves. Even if the solar cells spontaneously stop working the very day their warranty expires, the rest of the plant (access roads, fences, steel frames, canals, and so on), will certainly last much longer, and would be re-used.

Error #3: Not counting embedded energy which is recovered

Papers about EROI frequently include the "embedded energy" cost of components for an energy source. For example, calculations of the EROI for solar PV often include the "embedded energy" in the aluminum frames which support the solar panels in the field.

If embedded energy is counted on the way in, then it must also be counted on the way out. These papers uniformly fail to account for the energy which is recovered when the aluminum is recycled when the frames are dismantled. The recovered energy should be counted because the aluminum will be recycled. Almost all major corporations recycle structural materials such as aluminum because they save money by doing so.

This factor alone has a large effect on the reported EROI of solar PV. Much of the energy for solar PV is actually devoted to the aluminum frames which support the panels. About 75% of the energy for manufacturing those panels would be recovered when the panels are decommissioned.

In J Lundin's paper[7], there was some confusion expressed over how much recycled material should be assumed within incoming aluminum used to build solar frames. In my opinion, the incoming aluminum should be counted as 100% virgin, and the outgoing aluminum must also be counted, and should be counted as 100% recycled minus the energy costs of recycling. This is the only correct way. If recycled aluminum is used when a power plant is constructed, then the recycled portion is displacing the usage of that recycled aluminum elsewhere, which would require precisely that amount of aluminum to be made from raw materials for something else. Thus, 100% of the aluminum used for construction of the plant should be counted as virgin. However, 100% of the aluminum which is recovered should be subtracted from energy investments (not including the energy used to recycle the aluminum) because that is displacing aluminum which would have been made from virgin material elsewhere.

Error #4: Waste heat losses are counted as energy returns

This is a recurring problem throughout the ERoEI literature. Waste heat should not be counted as energy returns because it is not usable as energy to society. The only exception is when the waste heat is actually used for something (such as combined heat and power plants), but this is rare.

This factor is parcticularly important when computing the ERoEI of oil. Oil is refined and then used as transportation fuel within vehicles. Those vehicles have engines which convert the chemical energy in fuel to kinetic energy (movement). However, the engines lose about 70% of the energy in the fuel during the conversion. This must be counted as an energy loss. As a result, the EROI of oil is overstated almost everywhere by at least a factor of 3.

In fact, it might be useful to abandon the ratio "EROI" in these cases, and adopt the ratio "thermodynamic work over energy investment" or TWoEI. It is work which we want in the economy, not waste heat.

This factor is especially important when considering the oft-repeated figure that "oil had an EROI of 100 back in 1930". This comment is frequently repeated by the doomsday prepper sect. In fact, that EROI of oil back in 1930, does not include refinery losses, nor does it count losses in internal combustion engines which were even less efficient back then. If I perform a back-of-the-envelope calculation which takes into account those two factors (100*0.7*0.15), I obtain a corrected EROI of 10.5 for oil in 1930, not 100.

Error #5: Outdated figures are used

Frequently there are large discrepancies in the EROI calculations because different technologies are assumed when calculating energy inputs. For example, there are large discrepancies of the reported EROI of nuclear power. That is partly because some papers[1] calculate the EROI using gas diffusion enrichment of uranium, while other papers calculate the EROI using centrifruge enrichment[8]. Those different assumptions will yield very different EROIs for nuclear power, because centrifuge enrichment is so much more efficient. This factor is a large part of the energy investment for nuclear power, and so has a big effect on the resultant EROI.

When calculating the EROI of an energy source, we should use the most modern technology when calculating energy inputs. We wish to know the EROI of an energy source going forward, not the EROI of an energy source if we had built it years ago.

As an example, the paper by Weissbach et al[1], in its calculations of the EROI of solar PV, assumes the Siemens process is used to generate solar PV grade silicon. However, that process has been supplanted by processes which use only 40% of the energy[9]This factor by itself increases the EROI of solar PV in Weissbach's paper from 3.8 to 6.6.

Error #6: Invalid Comparisons Are Made

The are actually different types of EROI depending upon where the boundaries are drawn for calculations. When calculating the EROI of oil, do you include refinery losses? Energy losses for the transport of oil? Waste heat losses from the car? And so on. Each one of those calculations represents a different type of EROI. Some EROI calculations attempt to include only energy inputs used for extraction at the mine mouth, whereas other EROI calculations attempt to include every energy investment in the entire economy, such as the energy investment for building rail lines to transport the coal. Those are different types of EROI.

EROI figures should not be compared if they draw the boundaries very differently. For example, there was a very famous graph from Charles Hall which makes such comparisons[9] (found here). That graph spread like wildfire throughout the peak oil community. However, that graph is repeatedly comparing different types of EROI figures which are not comparable.

For example, the comparison of the EROI of coal (about 70) to nuclear (about 10), taken from that graph. There is a big difference in the kinds of EROI for those two sources. The figure for coal is before waste heat losses are subtracted for generating electricity, whereas the figure for nuclear is after waste heat losses are subtracted. When a correction is made for that, coal has an EROI of about 24.5, compared to nuclear of 10. The discrepancy has been reduced considerably.

As another example from the same graph, oil from 1930 is reported to have an EROI of 100, whereas hydroelectric is reported to have an EROI of 30. However, the EROI of oil from does not include refinery losses and waste heat losses from interal combustion engines in 1930. Correcting these factors yields an EROI of 10.5 for oil in 1930, not 100. Of course, hydroelectric also suffers from electrical resistance losses which reduces its EROI to perhaps 25. However, the adjusted EROI ratio for oil has gone from much higher to much lower when an adjustment is made so the figures are comparable.


The six errors described above are widespread throughout the ERoEI literature. They are partly responsible for the wide discrepancy between reported ERoEI findings.

For example, Charles Hall et al's book[5]Spain's Photovoltaic Revolution, is committing errors #1, #2, #3, and #5. When I correct those errors and re-calculate, I obtain an EROI of 6.27 for solar PVnot 2.79 as reported.

Weissbach's paper[1] calculates an EROI of solar PV at 3.8. However, that paper is committing errors #2, #3, and #5. When I correct those errors, I obtain an EROI of 12.96, and not the 3.8 which that paper reported. Incidentally, that paper also calculates the EROI for solar in a cloudy site in Germany, and then generalizes that to the EROI of "solar PV" altogether. If I correct that factor also, and use the average insolation for the inhabited northern hemisphere, then I obtain an EROI figure of 22 for solar PVwhich is much higher than the reported figure of 3.8.

Finally, even the concept of EROI has problems. Perhaps net energy should be expressed or reported differently, using a different ratio. This is because EROI gives an exaggerated impression of the difference between energy sources. For example, assume a hypothetical energy source with an EROI of 10,000, and compare it to an energy source with an EROI of 10. The source with an EROI of 10,000 would require 0.0001% of its output (1/10000) to build another like it, whereas the source with an EROI of 10 would require only 10% of its output (1/10) to build another like it. In other words, a reduction in EROI of 99.99% led to a reduction of net energy output of only 10%. This is because EROI is less and less important as it becomes higher. Instead of using EROI, we should calculate net energy as 1-(EI/ER), and then express that as a percentage. For example, if natural gas has an EROI of 15 (everything included such as infrastructure), and solar PV has an EROI of 6.27 (everything included), then their inverted ratios are 93% and 84% respectively. This means that 7 percent of the energy from the gas plant is necessary to build another gas plant, whereas 16 percent of the energy from the solar plant is necessary to build another solar plant. The net energy available to society has declined by only 9% despite EROI falling by more than half. Thus, EROI figures give an incorrect impression, and should be calculated and reported differently.

When all the problems above are corrected, it's unclear if there is any significant difference in net energy between different methods of generating electricity. The highest EROI source (hydroelectric) requires 1.3% of its output to build another hydroelectric dam, whereas the lowest source (solar PV) requires 16%. This implies only that we would need to build slightly more solar cells (~15% more) to obtain the same net energy. Any EROI more than 5 or so makes little difference (20% at most). All common methods of generating electricity seem to exceed that threshold.

Certainly, we should investigate further into this matter. If any method of generating electricity has a disastrously low EROI (lower than 4 or so, everything included) then it would be very helpful for us to know about it. Hall's work is very useful in this regard, insofar as he attempts to include all energy investments, which will give us better approximations of relative EROIs. However, we must avoid the above mentioned errors in performing our calculations.

p.s. This paper should be seen as a draft. I will update it if any relevant objections are made.

Sunday, April 26, 2015

Civilization would rapidly rebound after a catastrophe

Here is a comment I wrote in response to an article. The article was asking whether industrial civilization could be reconstituted from scratch after a worldwide collapse. The author argues that it would be more difficult to rebuild, now that the best fossil fuels are depleted. I argue that it would be easier to industrialize the second time around. As follows:

I think that industrial civilization would be reconstituted fairly quickly, like within two centuries.
In my opinion, It would be FAR easier to industrialize the second time, despite fewer and worse fuels. Any reborn civilization would progress through the industrial revolution far faster, and far easier, than we did originally. That is because they would start with our technical knowledge, which would more than compensate for any degradation of fuel quality.
For the first 80 years, up until about 1790, steam engines had an efficiency of just 1%. Early steam engines lost 99% of their coal energy as waste heat. This was because nobody had invented the Watt engine, the Corliss engine, the Wilkonson boring machine, the compound engine, and the Parsons engine. Those basic inventions in steam technology increased the efficiency of steam engines from 1% to 15%. In other words, that basic technical knowledge allowed steam engines to obtain 15x as much power per unit of fuel. A triple expansion steam engine from 1890 is not much harder to manufacture than a Newcomen engine from 1790, but it provides 15x the work per unit of fuel. Simply understanding the basics of thermodynamics and how to build a more efficient steam engine, results in a 15x advantage.
Any reborn civilization would start with that knowledge. They would start with engines which produce 15x the power, per unit of fuel. That advantage would more than compensate for any degradation of fuel quality. Does coal really have 15x as much energy as charcoal? The answer is no.
If industrial civilization was able to advance with 1% efficient engines, then it would be able to advance with 15% efficient engines. That advantage would far outweigh any degradation of fuel quality.
As long as a few textbooks survive and those textbooks describe how to build such engines, then industrial civilization would bounce back fairly quickly. Any new industrial revolution would be far faster than the original one.
After that, if we retained even 15 textbooks about basic physics, chemistry, thermodynamics, electricity, inventions, and so on, it would be enough to bring us well into the 20th century fairly quickly.
(The original article, to which this was a response, is here.)

Sunday, February 8, 2015

Do not grow your own food

One of the major tenets of the peak oil collapse movement was that civilization will collapse and then revert to a medieval state. There will be no more electricity, gasoline, diesel, machinery, or any other conveniences of modern civilization. Instead, life will soon resemble what it was like in the 16th century. People will need to grow their own food, make tools by hand, and so on. These ideas are found throughout the works of Richard Heinberg, James Kunstler, and many, many others.

To that end, many peak oil doomers relocated to very rural areas and began growing their own food on small plots of land. Some of them also engaged in "re-skilling" which meant learning medieval crafts such as making shoes, weaving, sewing, blacksmithing, and so on. They believed (and some of them still believe) that doing so was preparation for the new medieval era which would happen after civilization collapsed from peak oil.

Some peak oilers are still doing this. Some of them are still trying to grow their own food or are considering moving to rural locations so they can grow their own food. Let me give an example from a comment I read today on

I plan on buying a house in the middle of nowhere and starting to grow food there... The best way to prepare for peak oil is to grow your own food and help others grow their own food.

...and the same sentiments have been echoed thousands of times on peak oil forums. 

Unfortunately, the author of the above quotation is sadly mistaken. Growing your own food is a waste of time and is the worst way to prepare for collapse. Even if civilization were really collapsing, it would still be a waste of time to grow your own food.

Food is a about 50x cheaper now, relative to the average income, than it will be when the tractors stop running. For example, it takes a subsistence farmer about 100% of his labor to grow enough basic foodstuffs to survive, whereas it takes a modern American about 2% of his income to do the same. As a result, the rational strategy to prepare for collapse is to make as much money as possible now, and to stockpile food while it's easily obtained. You could stockpile far more food by purchasing it than you could by growing it. Furthermore, you could stockpile far more food now than you could ever hope to grow after the collapse. As a result, the best strategy is to stockpile food while it's still plentiful, not to grow it, which would be a waste of time even if civilization were collapsing.

I think the best thing to do would be to stockpile canisters of granulated sugar in some hidden remote location. Do not relocate to the hidden remote location, because that would interfere with your income and therefore with your ability to stockpile food. I would stockpile granulated sugar because it has an indefinite shelf life, is extremely cheap, is calorically dense, and could be bartered after the collapse for whatever other foods you would need. Granulated sugar would be like gold after the collapse and could be bartered for other goods.

Let's say I wanted to stockpile enough granulated sugar to provide calories for the remainder of my life. I have about 15,000 days left to live, which means I will consume (15,000*2500) 37,500,000 food calories in the remainder of my life. Since there are 4 food calories per gram of sugar, I would require 9,375,000 grams of sugar, or 9,375 kilograms, to provide enough calories for the remainder of my life. That's about 20,000 pounds of sugar, for those of us in the United States. I checked out the price of sugar at my local Sam's Club and found that it costs about $5 for a 10-pound bag. As a result, I could stockpile the 20,000 pounds of sugar I would need for approximately $10,000.

Let me repeat that fact:

I can stockpile enough food calories for the remainder of my life for $10,000.

That's about 2 months of my wages. Stockpiling food now is vastly easier than a lifetime of horrendous toil after the collapse.

Obviously, I can't live on sugar alone, but I could barter sugar for whatever other foods I would need. After the collapse, it will be calories that are in short supply. Sugar will be like gold. I could barter some of my sugar for other foods that provide the micronutrients I need. Let other people do the farming and back-breaking labor. Or, if I preferred, I could also stockpile some canned vegetables since vegetables are far cheaper now (relative to my income) than they will be after the collapse.

There is another advantage of stockpiling food rather than growing it. If the collapse prophecies fail, yet again, for the 50th time, then I've lost almost nothing. I spent $10,000 on sugar, and maybe also some money on canned vegetables, but it's still a fairly minor financial loss. By stockpiling food, I can continue living in a normal area and won't waste years or decades of my life preparing for a collapse that doesn't occur.

In short, growing your own food is the worst way of preparing for collapse, for two reasons. First, food is about 50x cheaper now (relative to the average income) than it will be after the collapse, so it makes sense to earn money and buy food now, while it's cheap. Second, if the collapse prophecies fail yet again, then I won't have wasted my life.

Growing your own food simply doesn't make sense. It doesn't make sense even if civilization were collapsing. Even if you want to prepare for collapse, the best approach would be to stockpile food and get on with your life in the mean time.

-Tom S

Sunday, November 16, 2014

The argument from big numbers

Energy decline adherents often claim it would be impossible for our civilization to transition to renewable energy. They have various arguments for that, all of which are wrong.

One of the more common arguments is what I like to call the “big numbers argument”. The argument consists of throwing out huge-sounding numbers, and thereby making the task of transitioning to renewables sound daunting. Some examples are as follows:

If we wanted to convert the entire world electricity system to wind turbines, it would take 333 gazillion TONNES of steel to make all those wind turbines. That’s FIVE TONNES of steel every SECOND, for the next 30 years. Therefore, it just can’t be done.

If we wanted to convert the entire world electricity system to nuclear reactors, we would need to build a nuclear reactor EVERY SINGLE MONTH for the next 40 years. Therefore, it just can’t be done.

The diesel trucks which are used to carry wind turbines, burn a gallon of gasoline every HOUR. Therefore, we can’t install very many wind turbines.

Usually, the units are CAPITALIZED in this argument to make them sound formidable. The point is that the number sounds so big that it sounds implausible to do anything about it.

The problem is, those huge numbers thrown around by energy decline adherents are usually relative to the entire world economy. Although those numbers are huge, the world economy is also huge. The question is: which is bigger? It may take gazillions of tons of steel to build all those windmills, but we may be capable of producing far more steel than that.

It’s meaningless just to throw around some huge number by itself, because any number by itself (no matter how huge) provides no basis for comparison. In order to compare the scale of some task with the scale of our solutions, we need TWO numbers, not just one.

If we wish to find out if some number is bigger than another number, we need to know both numbers, not just one of them. This is an elementary principle of mathematics. You cannot just say “five billion must be bigger than some other number I don’t know, because five billion is just so big”. The other number might be bigger still.

We’re talking about the entire world economy here. The scale of our problems may be huge, but the scale of our solutions is also huge. The question is: which is bigger? That question is never answered by the doomer authors.

An example

Let’s look at a prominent example of the “big numbers” argument. Let’s take an example from the sunweb website. That website is written by someone who subscribes to energy decline theories and who uses the “big number” argument repeatedly throughout his website.

What follows is an argument from that website. It details the difficulty of transitioning to a renewable energy system:

[Some people] proposed that starting in 2012, 50% of the worlds needs could be supplied by 3,800,000 five megawatt wind capturing devices to be installed by 2030.  Here are the numbers:
3,800,000  5 megawatts each supply 
211,111.11 Machines a year 
578.39 Machines a day for 18 years
24.10 Machines each hour each day for 18 years

[To build each wind turbine would require:]
For the Concrete 
478.8 Barrels of oil in 630 yards of concrete. 
409.5 Tons of CO2 released for 630 yards of concrete.

For the Rebar 
Taking a conservative 3 barrels of oil per ton the rebar would require 135 barrels of oil for the base of the 2.5 MW Turbine.89 tons of C02  released for 45 tons of steel for the base.

All Together 
The concrete and steel together for one base use 613 barrels of oil for each base alone. Each base release 498 tons of CO2(A barrel of oil is 42 gallons)

[To build all the wind turbines would require:]
Each hour we would need 14,773 Barrels of oil for these smaller [wind turbines]. And each hour we would release 12,000 tons of CO2.

Yikes! Just to build all those wind turbines would take 14,773 barrels of oil PER HOUR!! That’s a lot. That's a scary big number.

At the end of the article, the author concludes by saying “YOU DO THE MATH” (capitalization in original).

Okay, let’s do the math. It would take 14,773 barrels of oil per hour to replace 50% of the worldwide electricity grid with renewables. The question is, how big is 14,773 per hour, relative to the world economy?  After all, the world economy is also huge. Which one is bigger?

In fact, the figure of 14,773 barrels of oil per hour is trivial compared to the world economy. At present, the world burns 32 billion barrels of oil per year, which is 3.6 million barrels of oil per hour. Therefore, in order to replace 50% of our worldwide electricity system with wind turbines would require (14773/3652968), or approximately 0.4% of worldwide oil supply. In fact, even this number is exaggerated, because the wind turbines would be built in 15 years but would last for at least 40 years, so no construction would be happening most of the time. If we wish to measure how much oil is required to replace the entire world electricity system with renewables and keep replacing it as we go every 40 years, we’d find that it would take 0.3% of our current global oil supply.

Obviously, it would be possible to produce that additional 0.3% of energy from renewables.

A few side points…

The author of the above-mentioned article also points out, that building windmills requires dump trucks, mining machinery, and so on. Those machines run on OIL, not electricity, but renewables only produce electricity. How would we power those dump trucks and mining machines, if we wanted to transition the entire economy to renewables?

Fortunately, it’s entirely possible to manufacture liquid combustible fuels using renewable electricity. For example, we can manufacture anhydrous ammonia, using air, water, and renewable electricity. Anhydrous ammonia is a liquid, combustible fuel, which will burn inside diesel engines. The technology to make such fuel from renewables is not complicated, and has existed for at least 100 years. And there are dozens of other alternatives for liquid fuels which do not require oil.

Granted, alternative liquid fuels like anhydrous ammonia are much more expensive than diesel fuel at present—approximately twice as expensive. However, we’re talking about 0.3% of present worldwide oil supplies needed to replace the entire electricity system with renewables. Even if we have to pay twice as much for that 0.3%, the result is—0.6%.

Another example

The same article referenced above, contains all kinds of scary-sounding big numbers. It uses the “big number” argument over and over again. For example, it points out that a typical iron mine has front end loaders, which consume:

“19,400,000 Btu/hour”

Yikes! 19,400,000 Btu per HOUR!

Is that a lot? Is that more than ever could be provided by renewable sources of energy? The author provides no clue.

It’s worth pointing out here that he’s using a unit of energy (BTU) which is actually very small. That’s like measuring distance in millimeters. That’s like saying “I could never make it to the supermarket, because it’s FOUR MILLION millimeters away! (which is actually just four kilometers)"

In fact, all mining equipment put together consumes only a very small fraction of worldwide energy production. Now that I mention it, all mining equipment and manufacturing equipment and agricultural equipment and transport of goods put together, still consumes only a small fraction of worldwide oil production. Most oil is used in just driving around on discretionary trips.

The vast majority of the worldwide transportation infrastructure could be electrified. The vast majority of transportation is performed using cars, trucks, and trains. Cars can use batteries, and trains and trucks could use overhead wires. There are isolated pieces of machinery (such as mining equipment, tractors, trucks in very rural areas, and so on) which could not be electrified. Those applications added together consume only a few percent of worldwide oil production. I’m using a percentage here because a percentage is relative to the global economy and is not just some isolated figure. That few percent of worldwide oil production could be provided by the alternative liquid fuels I listed above.

But the current fossil fuel system of energy is MIND-NUMBINGLY COMPLEX

Another related argument which crops up, is to point out how complex the current fossil fuel based economy is. This argument is raised repeatedly in energy decline circles. Usually the argument consists of showing how many steps are required to manufacture a given piece of equipment. Or, showing how complicated are supply chains worldwide. Or, showing how complicated are the many interactions between various industries. Presumably, the point is that it would be impossible to transition a system which is so complex as the world economy.

Once again, the argument provides no context for comparison. It’s meaningless just to say “a renewable energy system for the whole world would be very complex”. The question is: HOW complex? Is a renewable energy system more complex than the global economy could manage? Is it more complex than the current fossil fuel based economy? The doomer authors provide no answer.

Although it’s a very complex task to replace the entire energy system, we are capable of very complex things. The economy consists of millions of economic decision makers who communicate via prices and who can collectively handle complicated procedures. That is how we built the incredibly complex economy we have now, which doomer authors are describing. That is how we got to this point, and how we could build a different economy.

A renewable energy system would be no more complex than our current fossil fuel one. Most complicated devices operate using electricity and would  be the same whether the electricity came from fossil fuels or solar power. Most manufacturing procedures would have the same number of steps whether the source of heat were renewables or fossil fuels. Windmills are not drastically more complicated than combined cycle natural gas turbines.

Apparently it was possible for us to build a global energy system as complex as the current one, because we’ve already done it.  If we are capable of building something as complex as this, isn’t it possible for us to build something else as complex?

For that matter, we replace the entire industrial civilization every 40 years anyway, because machines wear out. If we have already undertaken the very complex procedure of replacing the entire economy, and do so every 40 years, couldn’t we do it again?

The renewable economy is no more complex than the current one. If we can handle this economy, we can handle that one also.


A recurring argument in energy decline circles is just to throw out some huge number (“windmills for the whole world would require BILLION OF TONS of steel”) and then just assume it must be impossible. Or, just to say “it’s VERY complex” and then assume it must be impossible.

Those arguments are totally wrong because they provide no context for comparison. In fact, those arguments are not even really arguments. They are just an attempt to sound scary by throwing around big-sounding numbers without context.

All those HUGE numbers which are thrown around by the energy decline movement, are actually small numbers when compared to the world economy. There is enough energy, materials, and money to transition to a renewable energy system.

We know this because renewable sources of energy are so much more abundant than fossil fuels ever were. Just using solar panels in deserts could deliver more than 10x more energy than the entire world uses at present. Furthermore, solar power can produce liquid fuels, and heat for industrial purposes. What's more, solar power is not dramatically more expensive than fossil sources of energy. Finally, solar panels are made out of SILICON which is approximately 10,000x more abundant than all fossil fuels in the Earth's crust ever were, and silicon is not being "burned" when we use the solar panels. As a result, we can conclude that solar power is vastly more abundant than fossil fuels ever were and could substitute for all the uses of fossil fuels. Even though fossil fuels deliver HUGE AMOUNTS of energy, solar power could deliver many times more.

There is also more than enough time to convert the entire world economy to renewables before fossil fuels are exhausted. Fossil fuels won't be totally gone for centuries, which is a lot of time to transition. The entire industrial economy is replaced approximately every 40 years anyway as machinery wears out, and industrialism is younger than 40 years old in many countries (such as China). If we could build or replace such an energy system in less than 40 years, then we could transition our energy system to renewables over centuries.

Granted, a renewable energy system would be more expensive than a fossil fuel one. That is why we haven’t done it already. However, it’s definitely possible to transition to renewables while retaining an advanced industrial civilization.