Bio fuels versus fossil fuels (Paul Driessen, Howard Cork Hayden) USofA

This discussion took place in a series of e-mail exchanges

Bio-fuels versus drilling for fossil fuels Paul Driessen and Howard Cork Hayden March 2, 2018 Paul Driessen Senior Policy Advisor, Committee For A Constructive Tomorrow, CFACT Somehow responsible environmentalism has been perverted to mean it is better to plant millions of acres with monoculture crops (corn and canola, eg) that can be converted into energy, than to drill a few holes in the ground to produce oil and natural gas from multiple wells from a single drill pad.

Somehow it is better for the environment to pursue biofuel programs that also require immense quantities of water, fertilizer, tractor fuel and other energy inputs – to produce fuels that typically get less mileage per gallon than petroleum fuels. In fact, corn-based ethanol and biodiesel require much more water than does fracking, which at least can use brackish water that would destroy crops and soils.

And somehow it is environmentally acceptable to ignore the fact that biofuels also emit (dreaded but plant-fertilizing) carbon dioxide as petroleum-based fuels. In fact, on a life cycle basis biofuels emit just as much CO2 as gasoline does.

But try to get this discussion posted on Facebook or You Tube, and your attempted post will probably be rejected as “hate speech” or “intolerable non-consensus science.” (or maybe that’s not just humorous … but real).

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Howard Cork Hayden Emeritus Professor of Physics, University of Connecticutt On biofuels: There was an article a few years ago in C&E News (attached) about the yields of biofeedstocks. The best ones that could grow in most area would yield 10 tons of dry matter per acre per year. You’ll notice that the units are inherently solar --- energy per unit time per unit area. It is telling that nowhere in the article is there any mention of the energy content of the fuels, or the rate of conversion of sunlight into stored energy.

It’s all about energy, but don’t mention the word.

1 kg of dry matter yields 15 MJ. One year is 31.6 million seconds. One acre is 4047 m2.

One ton is 907 kg. P/A = 10*907*15E6/(4047*31.6E6) W/m2 = 1.06 W/m2.

Result: 1.06 W/m2 is the year-round average rate of conversion of sunlight into dry matter.

Untended hardwood forests yield about ½ cord per acre per year (sustainably, to use a favored word). One cord of white oak (one of the best for firewood), when burned, yields 3 ´ 1010 J, so firewood yields about 500 W/acre, or 0.12 W/m2.

The gross yield from ethanol from corn is about 900 W per well-tended, well-fertilized, well-watered acre of land. There are arguments about whether the net yield is energypositive of energy-negative. Suffice it to say that the most optimistic yield is in the range of 250 W/ acre, or 0.06 W/m2.

Take it from there.

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