Thursday, January 24, 2008

BioFuel Tradeoffs and Costs

I recently had the opportunity to correspond with one my readers who is a news hound. After reading what I'd written in response to his questions and comments, I thought I'd share for the rest of you and expand my response a little bit.

I was waiting for this foot to drop. If you increase the arable acreage devoted to farming biofuel material, you must be taking it away from food production. If you take down trees and other scrub vegetation to increase your farming acreage, then you're removing a key partner in the oxygen-carbon dioxide cycle. So do you choose to grow crops for fuel and spend more on food OR do you keep the status quo and find a better biofuel source material and/or a more efficient production method? The idea of using the existing acres of fieldgrasses in the USA as a biofuel source appears as a compromise. No food production acreage is removed while a renewable (as in 'it regrows because it's a plant!') biofuel source is harvested. In an analogous vein, my initial thought is to look at hay production as animal feed. You mow the fields each year(once or twice), make your doodles or rows, collect it and store for later use. I guess you'd have to quantify the amount of hay needed for any one animal in one growing season then measure the resulting output (primarily edible products, but I can see an argument for measuring cow noochie as a fertilizer source. Stinky and renewable, not counting boot scrapings . Ah, country air!).

Can't say I've looked at the quantities/costs involved when it comes to producing biofuels so I'll chalk this up as an uninformed opinion. From what I understand, it still takes more energy and a lot of corn to make 1 gal of ethanol than you'd save by not using oil refined into gasoline. Now that I think about it, is the term 'biofuels' being substituted for 'ethanol'? ADM wouldn't permit a competing source material, would they? Come on! They feed America! They wouldn't do that! (HA!).
Biofuels is used to describe not just ethanol (corn, sugarcane, cellulosic) but also covers the so-called biodiesels, essentially pure soy or rapeseed (canola) oils. ADM, Monsanto and Cargill win no matter what...8) (Monsanto is already rumored to be looking at switchgrass genetic modifications)

Every human endeavor involves a trade off. Even a so-called renewable non-food crop used for fuel is going to have a detrimental impact on its soil over time. Soil is going to deplete and yields are going to be reduced over time, especially since harvesting the grass breaks the natural reuse cycle from decomposition of previous growth. That doesn't include any detrimental soil amendment such as heavy nitrogen fertilization that leach other nutrients from the soil and applied in a form that doesn't stabilize in the soil, but runs off to the Gulf and contributes to the dead zone. At least with "junk" plants the farming practices will hopefully not be as intensive allowing the life cycle energy analysis to be positive, though there is certainly a risk that land used for food will be switched to a more profitable fuel-crop. And even given all that, ethanol yields for cellulosic sources haven't been quantified so far as I've read, even with higher energy balance on the side of wood chips and switchgrass, it may not be enough to significantly reduce oil for fuel needs.

Another concern here is that "scrub" vegetation isn't the only thing being removed. Rain forests are being cut down in order to plant sugar cane and oil palms in order to produce fuels, thereby reducing 1) the amount of carbon locked in plant materials and 2) reducing the ability of natural systems to absorb CO2.

And lastly, a response to the "how much land do we need" question. From what I've seen, the best estimate is that the US can produce 2 billion barrels of ethanol if able to convert biomass to ethanol at around 45% efficiency. That's only about 40% of the amount needed today. Want to read a bit more about that topic? Check out a post on Grist that discusses the recent debate on GristMill between Vinod Khosla, an ethanol investor, and Joseph Romm a regular contributor to GristMill (I forget his background). Tom Konrad has an interesting side proposal that bypasses ethanol, but assumes widespread adoption of electricity as the primary power source of most vehicles.

Our technologies are such that we have to take something from the earth in order to provide power, clothes, shelter, and many other things for ourselves. The question is, what has the least long term total impact irrespective of initial financial cost? Unfortunately, we don't know everything, and in many cases, we don't even know what we don't know, so determining impacts is hard and determining a monetary value for them is even more difficult.