Energy Return on Energy Invested (ERoEI) is a useful concept if interpreted correctly!
An Essay by S. Tom Bond, Retired Chemistry Professor and Resident Farmer, Lewis County
There are two very important unfamiliar quantities connected with depletion of resources: “energy return on energy invested” and “net energy”.
In simple mathematical form one measures or calculates the amount of output energy of a process, then adds all the input energies and divides output energy by input energy, deriving a ratio. The larger this ratio is, the better the process. If it falls below 1:1, the process takes more input energy than it produces and reduces the energy available. Thus 1:1 is an upper limit on viable input energy. In fact, the useful limit is not a fixed number, but a limit. In practice a useful minimum ERoEI is reached long before 1:1.
To get ERoEI, one must consider all the energy used to produce the energy required for a particular purpose. This is not a trivial exercise. It is full of pitfalls, from setting improper boundaries to the problem to carful attempts to mislead the reader. It is not the purpose of this article to calculate EROEI’s but to help the reader appreciate the difficulty of such calculations, and why such a variety of values appears in the literature.
Let’s consider two cases. First, the energy for fracking gas to make electrical energy used in the home and elsewhere. The energy to find the gas, the surveys, including the energy used by support personnel, their transportation and food, the energy to make the equipment and use it and to get the data into usable form, including the office staff and publication. Next the drilling and fracking, personnel, all the equipment, transportation of fluids and dispose some of it, to process liquids co-produced, (their value must be considered a plus), enrgy for manufacture of chemicals used, steel, including miles of pipe, and the energy to run all that.
Then all the energy to make the pipe to transport the gas to market, to compress it, the energy to support many kinds of workers involved. The energy to store it for later use, and energy to get it to the electrical generating plant. A lot of gas is lost along the way, including the compressors , ect,. so enough must be produced to cover that loss along the way.
Then there is the energy used to run the plant to generate the electricity. Some 60% or more is lost if the gas is used to heat water which turns a turbine. In a “combined cycle” generating plant the gas is used to fire a turbine and the waste heat from the turbine heats water the theoretical loss is as little as 40%, but I read in practice it is nearer to 50%. Then there is the transmission to the customer.
The energy going into the copper and aluminum power lines must be counted. Both are rare elements requiring a lot of energy. When I took my first college chemistry course there was section in the book explaining how they obtained copper from less than 1% ore, 60 years ago. Aluminum must be made by electrolysis at high temperature, in nations where electricity is cheap, from bauxite ore that usually has to be transported to the refining plant. These are hugely expensive in terms of energy. Also, steel towers for the high tension lines and specially grown and treated wooden poles add to the energy costs. Then it can be used in homes, public places and factories.
Compare this with photovoltaic solar. It costs a lot of energy to produce the special glass used in solar panels. Rare elements frequently are called for, and these are expensive to find, mine and manufacture. The panels are expensive, but can be shipped like any other merchandise. They can be placed by local people with little more than usual electrical training. If energy is to be stored for night or cloudy days, some battery must be provided.
A present, this is the weak link, but Tesla is building a “gigafactory” in Nevada, $5 billion dollars worth, to build lithium ion batteries to power its electrical automobiles. It is expected these can be used to store electrical energy from photovoltaic, too. Last week’s Science, journal of the American Association for the Advancement of Science, one of the two most prestigious places for scientists to publish, had a cover article on a lithium-air battery development which overcomes all disadvantages of previous lithium-air batteries. It appears to set the way for 10 times more dense electrical storage. Again, rare elements mined far away are needed.
Wire for conducting the electrical current is minimal if no supply from a remote source is required, as in home and small business installation. How do you think ERoEI compares between these? A caveat applies here. Home and small business photovoltaic must be higher ERoEI than for a city, because there is only one or two stories involved and land is cheap. For cities, remote land must be involved if many stories are involved, and sunlight is a premium. Some can go on roofs, but you cannot block the canyons between buildings, because they are needed for light and air. This, along with conductors for the current, decreases EROEI.
Caution to the reader, you will see all kinds of figures given for each kind of energy production. One to beware of for solar energy, is that people who want to find an unfavorable value for it will want to count the energy input from the sun as a part of energy invested. No, no, no! Energy from the sun is not depleted; it is there day after day, year after year. It doesn’t take away from the future supply from the sun. It is true that energy conversion is in the range of 15 to 20%, but sunlight is not an economic input. It is free.
One to beware of with gas stops the analysis with the energy content of the gas itself, say at the wellhead, i.e. energy content of the gas over energy to get gas out of the ground. Not enough! What you really want is to compare electrical power to the customer when comparing gas production with other processes. You must go all the way to the final consumer. Boundaries of the analysis must be correctly chosen!
Net energy is the difference between the total energy put into a process and the energy recovered from the process, a subtractive operation, rather than a division. It determines how much energy is available for society to use. Generally speaking, a society needs a certain amount of energy to function at the current level. If the ERoEI is high, it is relatively easy to meet the societies’ needs. The lower the ERoEI, the less energy there is to meet needs other than getting more energy.
Unfortunately, it is possible to make money on such schemes with low ERoEI and that will be covered in the next article which is on “rate of return”.
Point Your RSS Reader to FrackCheckWV.net/feed/
{ 9 comments… read them below or add one }
I’ve long suspected that the glorious ERoEI claimed for coal vs solar (by coal-backed think tanks) was a case of comparing apples to orangutans – i.e., dividing the energy output of a coal plant by only the energy required to mine the coal, while considering every last erg required to mine/transport ore/manufacture/ship/install/maintain a solar panel. If solar EROEI were calculated by the same criteria as coal it would be infinite (since the cost of mining the fuel source for solar is 0).
Once you include the cost of coal power plants, trucks, ash disposal, etc. ERoEI for coal is not nearly as high (even without considering the enormous externalities).
Thanks for posting a reality-based ERoEI comparison chart!
Don Alexander
WOW!!
This is so important, both getting this critical concept out there, and the fact that this chart differs drastically from others I’ve seen. In particular, I’ve seen coal rated at 70-to-one, higher than anything except oil seventy years ago.
So I figured the common assumption that “coal’s not coming back” was wishful — but I never could get answers to the question of what the number was based on. But your chart also shows the solar energy choices as considerably higher than other charts I’ve seen.
THANK YOU, Mary Wildfire, Roane County
I’d like to see evidence of what is included in each analysis. It ought to be possible to come up with one agreed-upon, accurate chart (especially since each ERoEI is shown as a range).
One of the points I wanted to make was the extreme variations you can find ERoEI for any process. I’ve even seen 2 for solar cells!
As for one agreed-on value, I don’t think it is likely without violation of our concept of freedom of speech! The basic idea (and algebra) is so simple any one can understand it, though.
It is similar to efficiency in that it measures how important a process is for society.
Best wishes, Tom Bond, Lewis County
I mean, I realize there could be a lot of disagreement of what to count.
The energy to grow the ingredients in the lunch eaten by the guy who drove the truck to haul the windmill blades to the final site? But it doesn’t really matter as long as you use the same criteria for all energy sources.
Thanks, Mary Wildfire, Roane County
Tom, great article. None of our local and state leaders seem to consider ERoEI, at least I’ve never heard them mention it. I’d like to make a couple of points.
1. It seems to me that to compare these energy sources based on ERoEI we can forget about what happens after the resource gets to the power plant. Getting electricity to the consumer should be common for all fuels. That should reduce the complexity considerably.
2. Where did you get the values for your chart? Shale fuels and Tar Sand are the highest I’ve seen.
3. I published an article on the relationship between energy independence and fracking–there was none. In doing so I ran across an article you may enjoy.
“Michael L. Aucott and Jacqueline M. Melillo; A preliminary Energy Return on Investment Analysis of Natural Gas from the Marcellus Shale; Journal of Industrial Ecology-Yale University 2013;”.
In it they discuss two methods for calculating ERoEI – NER and NEER. Doing using the NEER gives a value of 85:1. Using the NER gives a value of 8:1. The difference in the two methods is not including the value of the energy used for operations. What I could never understand is the following comment.
“Brandt and Dale note the NER is a more comprehensive measure of the total energy return from a production pathway and can be expected to correlate closely with environmental impacts, such as GHG emissions, of a pathway. Conversely, the NEER is a more useful measure of the contribution of an energy source to the energy supply of society because it counts only the inputs that must be produced and delivered externally through the existing energy supply system.” Maybe you can explain it to me.
4. Another thing that astounded me is that neither of the methods include the gas that is flared. In 2013, frackers in the Bakken flared about 9 Trillion CF of gas. That’s about 1/3 of what this country burns in a year.
5. What do the red arrows in your chart mean?
6. All of our presidential candidates advocate the same approach to our energy climate problems. They want to produce more. Amory Lovins has been promoting energy efficiency for 40 years. No one talks about it but it has more going for it including jobs than any other approach. Amory claims that it takes 10 units of energy tp get one unit of energy to the end user. I claim that’s an ERoEI of 10. Probably not but close. So if some fuel resource doesn’t have an ERoEI of at least 10 it shouldn’t be considered. By insulating and reducing infiltration you could easily get that up to 20. Our blower door test showed that we had the equivalent of abut 1 SF opening in our home. The contractor said that was the best he’d seen up here. I’m guessing most old homes have the equivalent of an open door. Lots of energy to save.
Thanks again for a great article.
Jim Guy
To: Jim Guy and anyone interested:
1. I don’t think we can forget about transmission, because photovoltaic and other local generation saves big on transmission costs. Copper ore is rare and expensive to reduce to the metal, as is Aluminum, which is produced from ore that has to be transported from where it is found to an area where electricity is cheap (like Iceland), then reduced by high temperature electrolysis. Also “Transmission and distribution losses in the USA were estimated at 6.6% in 1997 and 6.5% in 2007.” The only cost I can find is from California, see here, Page 4.
http://www.caiso.com/2360/23609c2864470.pdf
2. Reference for ERoEI graphic is as follows:
http://8020vision.com/2011/10/17/energy-return-on-investment-eroi-for-u-s-oil-and-gas-discovery-and-production/#disqus_thread
Jim Kimball, “Energy return on investment EROEI for US oil and gas discovery and production, http://www.8020vision.com, October 17, 2011.
My intention was to show how a comparison could be made, not to claim that I have correct values.
3. I didn’t see the article by Michael L. Aucott and Jacqueline M. Melillo. My guess is the NER exclude externalized costs, or some of them, such things as environmental damage, cost of sickness and injury, property loss of value, damage to other industries, including small conventional gas, farmers, forests, recreation and retirement, etc. They also say “EROI is also sensitive to the energy used or embedded in gathering and transmission pipelines and associated infrastructure and energy used for their construction, energy consumed in well drilling and well completion, and energy used for wastewater treatment.”
Incidentally, researching the answer to your question I found a table of ERoEI of wind power which has a value of 44.5 from Germany and one which has 2.3 from Japan!
4. Yes, gas flared would be an important externalized cost. If they only calculate gas delivered to some point, not gas taken out of the ground, production of it could be considered a cost of production.
5. I take that to mean most of the estimates run to that end of the bar. The author has collected values, since he does not give one which would represent his best effort.
6. “I claim that’s an ERoEI of 10.” I agree. I agree also that conservation is the most obvious route to go for an informed public. I heard Amory Lovins speak about 40 years ago. He was far ahead of the times then.
Honestly I expected a chemistry professor to be more cautious in dealing with such an important topic, instead this analysis is very superficial, as it fits with someone probably oriented toward promoting renewables.
Let’s have a look at some points that have not been cover:
1) there is a long description of all the energies involved for fracking, but there is a very short and incomplete description of the energies involved in the production of PV panels up to the selling. What should be said is that the fracking process is not limited to the production of gas, every plant dealing with the fracking process has minor processes and products that are useful for sale and provide a good income, thus the total energy should be distributed in percentages among all the collateral minor processes. Eventually the energy involved in the sole production of gas, is about 70-75% of total.
2) what is missing in the section about PV panels is that the total energy involved in the production should take into account also the dismantling and the destruction of the panels when they are no longer efficient. This involves the handling and disposing of toxic materials, special machinery, and dedicated facilities. Moreover, the author mentioned mining of rare elements, but did not mention the metal work and the furnace energy involved to produce the supporting structures. And in case you are thinking that the steel structure for the PV domestic plants is very small, you shall moltiply it by the total number of domestic plants produced. This means also involving the personnel in the furnaces plants, their food, etc etc. You must then count the energy involved in the trasportation from the production facilities (absent in the case of gas, because it travels into pipes).
3) the concept of ERoEI and that of Net Energy are a sort of ‘anti-ERoI’ creation, but while the ERoI makes sense, because we compare the energy gain based on the total money investment, the ERoEI compares energy input to energy output, and does not take into account the availability nor the ability to produce energy on demand. Gas can allow a prodution of constant energy on demand, PV panels can not. This is why ERoEI is not a valid parameter when we have to evaluate the conveniency of an energy production method.
In case you are asking, I am a chemist too, an UE certified technician for the management of waters and environmental resources, I have worked in a chemical plant for 7 years, and since 2005 I’ve been working for a world-leading company in the Oil & Gas field; but we don’t only engineer oil & gas plants, we also engineer and build renewables, biofuel, and all kinds of energetic plants except nuclear.
REPLY TO ALESSANDRO:
All the way from Italy! Rome, no less. I’m impressed someone so far away would be interested in our problem here in Appalachia and the U. S. And I’ll forgive the not so gentle slam in the first paragraph from someone with such diverse interests. I’m interested in archeology, and other the things, too.
This letter is mostly gibberish, almost all natural gas is used for fuel. Of course, some is lost in leaks and flaring, publications say as little as three percent, others say as much as one-third, so some natural gas goes directly into the atmosphere, which is a very serious problem, because it has much greater greenhouse gas effect than carbon dioxide.
PV panels have long life, and since I was constrained to a limited number of words directed to a lay audience, it didn’t seem necessary to cover the relatively low energy cost.
Your claim PV panels require special handling for disposal seems questionable. They are ceramic, not given to crumbling, nor permeable to give off toxins to the air or hands on them. In the rest of the world they are classified as general waste (no special handling), but in the EU they are classified as e-waste in the Waste Electrical and Electronic Equipment (WEEE) Directive. They are recyclable, see here:
https://www.greenmatch.co.uk/blog/2017/10/the-opportunities-of-solar-panel-recycling
Certainly the steel involved is small compared to what is required for fracking.
Your confusion about ERoEI and Net Energy are not unusual. The ERoEI compares energy input to energy output, and does not take into account the availability nor the ability to produce energy on demand. Gas can allow a prodution of constant energy on demand, PV panels cannot.
Tom Bond, Lewis County, WV
We should all understand the ultimate energy solution is fusion nuclear power (contrast future use of fusion and the present use of fission). Fusion has many pitfalls, political, and for some possible paths, blocks by the military, a knowledgeable friend tells me. The question is will our high level of civilization with science survive until fusion takes a hold.
A little philosophical speculation now. In a sense you could say all energy is fusion based. The sun runs on fusion of hydrogen nuclei. This produces the light. Scientists estimate that Earth receives only about two billionths of it.
Of that amount, about a third is reflected back into space by clouds and snow. A little over 40% warms Earth, while about 25% is used by the water cycle. Winds and ocean currents absorb about 1%, while all the plants on Earth use only about 0.023% for photosynthesis!
Fossil fuels formed from plants over millions of years and are the primary fuels we have used for our climb up to our present culture, a tiny fraction of what plants absorbed in those millions of years. Food was obtained and houses were built in George Washington’s time much as it was in the Roman Empire. Progress had been slow.
The primary use of fossil fuels must soon end. The effects of global warming and climate change have already grown large. Will we humans be able to get enough cooperation together to make it through our present impasse? No one knows.
Tom Bond, Lewis County, WV