If you read the Searchinger paper, then why do you write, “Biofuels that are part of the solution include cellulosic ethanol,…and made from agricultural plant waste or dedicated crops such as switchgrass…”? Waste is OK, but your call for switchgrass is misguided. The Searchinger Science articles said, “This analysis has implications for other biofuels. Cellulosic ethanol could use wastes that do not trigger land use change. But if American corn fields of average yield were converted to switchgrass for ethanol, replacing that corn would still trigger emissions from land use change that would take 52 years to pay back and increase emissions over 30 years by 50%.” Pretty much the only biofuels that meet your call for “low lifecycle greenhouse gas emissions” are those made from waste products, Tilman’s LIHD, and perhaps algae biodiesel.

But would even “low lifecycle greenhouse gas emissions” biofuels be a good idea. Not if they are a “moment of convenience, a lifetime of regret.” In fact, biofuels are a dead-end detour. They cannot get us where we need to go, but they can slow us down getting there. It would take 710,000 mi^2 to grow enough switchgrass to make cellulosic ethanol for E85 to handle U.S. 2050 Vehicle Miles (based on the January PNAS switchgrass yield article). This is a quarter of the non-Alaska U.S. (Alaska probably won’t be growing switchgrass for a few more years.) This is not realistic. Even if the factor of 3 hoped for form genetically engineering switchgrass pans out, this is too much habitat. We are only deluding ourselves by pursuing short-term cellulosic ethanol infrastructure that we will have to discard when we run into its limitations.

In contrast, it would take less than 5,000 mi^2 of desert land to power 2050 Vehicle Miles with concentrated solar power. 5,000 or 710,000 mi^2: the answer is trivial.