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beberly37 comments on No Safe Defense, Not Even Science - Less Wrong

14 Post author: Eliezer_Yudkowsky 18 May 2008 05:19AM

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Comment author: beberly37 27 September 2015 02:24:10AM 1 point [-]

I obviously haven't logged into LessWrong in a long time. Do you still want the answer?

Comment author: Good_Burning_Plastic 27 September 2015 09:19:41AM 1 point [-]

Dunno about MarkusRamikin, but I'd sure be interested in hearing why you "think it is quite insane that we don't make more ethanol from corn".

Comment author: MarkusRamikin 27 September 2015 10:02:50AM *  0 points [-]

Yep, me too.

Comment author: beberly37 28 September 2015 04:28:10PM *  0 points [-]

disclaimer This defense of corn ethanol is by no means “publish ready”, it is simply a gathering of data and concepts obtain during my work that has been sufficient enough to change my mind on the merits of a seemingly insane practice. It could use more work, however I don’t really care enough either way to put much more effort into this particular topic.

The primary data driven argument against corn ethanol is that it takes more energy to make than the fuel contains. A statement that is generally true, which I don’t really care about. The whole point of getting away from fossil fuels is to reduce the emissions of greenhouse gases (GHG) and slow/stop/reverse climate change. My grizzled, old, super-conservative thermo professor in undergrad often complained about hippies wanting to conserve energy. “Energy is always conserve” ,he would suggest , “what we need to conserve is exergy”. Likewise, I (and I believe the collective “we” should feel the same) don’t care about energy balance, I care about carbon balance.

To find the “best” data on carbon balance of fuels, I turn to the California Air Resources Board, which limits carbon intensities (CI) for fuel sold in California, they have lists of every producer of fuel sold in the state and list the CI’s of the fuels. The unit they use is gCO2e/MJ (grams of CO2 equivalent per megajoule). Which can be found here. They also have published pathways for CI, which are documents describing how they arrived at the CI numbers. The one for corn ethanol is here. Reading through the pathway for corn ethanol, the biggest take away is that there is wide variation in production practices that have major impact on the CI of ethanol, for example, the highest CI for corn ethanol listed as of 5/20/15 is 120 (1) gCO2eq/MJ while the lowest is 63(1) gCO2eq/MJ. That’s nearly a factor of 2. For comparison, the CI of standard CA gasoline is 95(1). The difference between the high ethanol CI and the low is primarily the production energy (ie heat for boilers) for the former is coal and the latter is natural gas with some landfill gas and waste wood.
If you look at the breakdown for “average” corn ethanol there are three major sources of carbon emissions, ag chemical production, ethanol production and land use, each being approximately 30 g/MJ. The total number listed for “average” dry mill is 97 (1) gCO2/MJ. I should note that there is a -11g/MJ credit for “co-products”, which is the left-over solids that is used as animal feed call dried distillers grains.

So here is my general belief, making corn ethanol is not inherently bad (insane), however the way we do it is slightly insane. We get a marginally lower CI fuel, which gets blended into gasoline and reduces non-GHG emissions (at least that’s why it’s mandated in CA). However, by shifting the process (which I might outline sometime if folks are interested, but would turn this comment into more of a TLDNR) to one that is more sustainable, and more cost effective, corn ethanol production become perfectly sane.

So why does this mean we should have more corn ethanol? Well more corn ethanol means more corn ethanol plants (building out the infrastructure is costly and time consuming and a large barrier to expansion). Eventually, there will be a revenue incentive to ethanol plants for caring about the CI of their fuel (since in the US, as a whole, it’s only mandated as being non-fossil caring little about GHG’s). California is a good example of this. Gasoline blenders have to buy ethanol because gas in CA has to be 10% ethanol. There is also a limit to the CI of the gas/ethanol blend, which right now is higher than the CI of most ethanol. However, this “low carbon fuel standard” CI drops every year until 2020, where is stays at 89 (1) gCOe/MJ. This means that if the ethanol a company is trying to sell in CA has a CI above 89, the customer would have to purchase carbon credits as well. So companies would then have an incentive to change their production practices to lower their CI, because they could sell their ethanol for higher prices. If/when a US carbon tax (or something akin to the CA Low Carbon Fuel Standard) is adopted, having an existing ethanol infrastructure will make the scale-up and spread of low carbon liquid fuels able to happen much faster.

There are a few other sides to the corn ethanol argument; growing crops for fuel instead of food for example. An argument I find full of holes, since the increase in the corn crop has not been on the same scale as the increase in ethanol production (2) . This is due to the aforementioned animal feed co-product and the fact that before wide spread ethanol production most of the corn grown in the US was used as animal feed (2) . So making ethanol doesn’t displace another crop, only the starch portion of cattle feed. If you have a moral problem with growing a fuel while people in third world countries starve, you should have the same moral problem with growing a crop to raise meat while people starve. Also, if you have a moral problem with displacing food from American mouths, we have an obesity problem, which means we produce and consume too many calories per capita already, we don’t need more corn in our diet. There is also the notion the ethanol is bad for engines, while I believe that the higher anti-knock characteristics of ethanol combined with the higher heat of vaporization means ethanol-only vehicles could have diesel-like compression ratios with otto cycle performance, resulting in a higher efficiency, lower non-GHG emissions vehicle. There are a few other minor facets, but I think they are immaterial, though I did not want to give the impression that I did not consider them.

1) I’ve truncated these numbers as they are reported to the hundredths place.
2) I really need to dig up some good reference for these, because they are based on me looking at old ag reports, which is less than ideal

As for nuclear power, we know that it is a near 100% probability that burning fossil fuels is bad for the planet (and us too) and that can't really be mitigated with existing technology. However, catastrophe from nuclear power has a probability less than 1 and there is technology that can decrease that probability.

edited to fix hyperlinks and to fix unintended text formatting.

Comment author: Good_Burning_Plastic 29 September 2015 07:16:22AM 1 point [-]

Who the heck downvotes comments for answering a question?

Comment author: entirelyuseless 29 September 2015 01:29:21PM *  1 point [-]

I wasn't the one who downvoted, but the comment is not a very good defense of the claim that "it is quite insane that we don't make more ethanol from corn." At most it defends the claim that it would not be unreasonable to make more.