In the renewable energy community, Ethanol has a bad rap, due to some often-quoted, seldom checked studies on energy payback.
It’s received wisdom that ethanol from corn has an energy return on energy invested (EROEI) of somewhere between 0.8 and 1.0; i.e. you get less out than you put in. The persistence of this idea is possibly due to some great cartoons. I’m probably going to undermine my whole argument here, by including this one…
Then again, I expect that my audience is highly intelligent, and not easily distracted. If you weren’t, you probably wouldn’t still be reading my extremely dense and often-tortured prose. You deserve a good cartoon every now and then…
Back in the world of ethanol, times have changed.
Even though cellulosic ethanol is still very much in its technological infancy, a lot of companies and people are doing a lot of interesting things with corn ethanol to make the process more efficient, and, get those energy inputs in the form of “free” waste heat from some other process, or from renewable sources such as cow manure or landfill gas.
I’ve been educating myself a lot about this reading C. Scott Miller’s Bioconversion blog. I admit I’m having to do a lot of catch up on this, because I was one of those people who believed ethanol was a total government subsidized boondoggle until recently.
All that said, even at an EROEI of 1.25 to 1.8, ethanol is not much of an energy “source.” Sure, we’re getting a little energy out of the process, but one way to think about EROEI is how much effort it takes to get our energy.
As a rough illustration, at an EREOI of 2, there has to be one person working to get energy for every person doing something else. So if civilization were to exist one out of every 2 people would have to be employed in the energy sector… the other 50% would then have the energy they needed to do other useful things, like be doctors, politicians, soldiers, engineers, builders, investment advisers, bloggers, artists, manufacturers, scientists, psychologists, food farmers (as opposed to energy farmers), talk show hosts, etc.
You might argue that some of those professions aren’t very useful (investment advisors and politicians perhaps), but even if we eliminate all those “useless” professions, I think the more useful professions like talk show hosts and artists might start finding themselves a little squeezed.
There is a reason that the human race was 95%+ farmers or hunter gatherers for most of of our history: the energy sources we were using were not powerful enough, with too low EROEI to sustain higher forms of civilization, such as talk show hosts.
If you don’t believe me, read this great article on “Peak Wood,” the cause of the iron age.
Back to ethanol: it’s not going to solve our world energy problem. It’s a useful way to turn non-liquid fuels (manure, biogas, or coal) into something you can put in your car, but if we in the U.S. are looking for a domestic source of energy that will wean us off the Middle Eastern oil teat, we can do it, only if we want to be a nation of farmers, witha much smaller population and lower standard of living than we have now.
Ethanol is big business these days, and it will make a tiny dent in our oil addiction, so all the investment is probably doing some good. I predict that the biggest beneficiaries will be the farmers, and considering how hard farming is, that’s not a bad thing. It’s probably better than out-and-out farming subsidies.
Basically, I’m no longer worked up about ethanol subsidies and mandates. There are a ton of better ways we could be spending the money, but it’s hardly the stupidest thing our government does with our money. I’d even be happy about it if they’d simply replace the money spent on all farm subsidies with subsidies for farm based energy.
I just don’t want it to distract from the important work we have to do to deal with the twin probems of peak oil and global warming:
- Improve energy efficiency (especially of our vehicle fleet.)
- Develop high ERoEI energy technologies: Wind, Solar concentrating, Geothermal. PV will probably make it on this list as the technology improves.
- Displace some of that oil in transport with renewable electricity, via plug-in hybrids. (Economic fuel cells are still too far away to make hydrogen a viable transportation fuel in the next 20 years)