Khosla and Searchinger on bioenergy GHG accounting

Today in the Boston Globe, two of the biggest, but very different, names in biofuels have coauthored an op-ed on the importance of getting the GHG accounting right for bioenergy. I’ve written and done a video on this critically important topic, so after reading the op-ed check those blogs out if you have more questions.

If you don’t know, Vinod Khosla is one of the most aggressive VC investors in a whole array of low-carbon and other environmental technologies. Some have criticized Vinod as too much of a biofuel booster, but Vinod has made a lot of money and he's not shy about putting it where his mouth is. He talks eloquently about the challenge of finding climate solutions that will scale not just in rich countries, but in developing countries.

Tim Searchinger, in contrast is known for taking a hard look at the challenges to getting biofuels right. The lead author of the seminal study of GHG emissions from indirect land-use in 2008 and more recently an essential analysis of the the accounting for GHG emissions from bioenergy in the climate bill.

The op-ed strikes a nice balance in stating the problem with assuming that all biomass is carbon neutral clearly but also pointing out the very really opportunity to reduce GHG emissions that bioenergy provides if we do it right.

Here are a few choice quotes:

Although bioenergy does not significantly change the carbon dioxide released by tailpipes and smokestacks, bioenergy can offset these releases by stimulating higher rates of plant growth, which absorb carbon dioxide from the atmosphere in a recycling effect. The use of fast-growing plants on abandoned and degraded farmland provides a great opportunity because they can not only generate additional biomass for energy but simultaneously restore carbon to the soils. Such areas could produce most of the world’s biofuels.

Yet the earth’s plants and soils store three times as much carbon as the atmosphere holds today, and if bioenergy uses or displaces this carbon it too adds carbon to the air. Some ways of thinning forests may stimulate faster tree growth that rapidly replaces the lost wood (and lost carbon), but broader clear cuts to make wood chips for electricity will generally reduce forest carbon stocks for decades, which reduces or eliminates the benefits of displacing coal.…

[Here I would just add that some amount of forest residues are also needed to provide critical nutrient and wildlife habitat values and that I think it's an open question as to whether thinning increases carbon sequestration rather than just speeding it up.]

Because of these very different consequences, treaties and laws that place limits on carbon dioxide need to distinguish bioenergy by its source and production process.

If the error continues globally, it gives oil firms or electric utilities that must reduce their greenhouse gas emissions a false incentive to switch to those forms of bioenergy that result from clearing forests.

Hats off to these guys for coming together on a thoughtful and helpful piece.