In 2009, when I handled climate issues in the US Senate, we studied how to treat the burning of biomass in great detail (“Can burning trees ever be green?”, the Big Read, July 2).
We ended with a key question: which is more valuable, a ton of green coal or a ton of green gasoline (or other liquid fuel)?
Burning wood to make electricity turned out to be grossly wasteful, but great technologies have been proven to convert scrub wood especially into mixed alcohols, the best fuel for combustion engine cars.
It is easy and cheap to require new cars which can burn gasoline to also use such fuels. This analysis is worth reviving.
Retired Official, National Science Foundation, Arlington, VA, US