This just in:
Biofuels produced from switchgrass and post-harvest corn waste could significantly reduce the emissions that contribute to climate change, according to an analysis by EWG and University of California biofuels experts.
EWG’s analysis found that the life cycle carbon intensity of cellulosic ethanol from switchgrass was 47 percent lower than that of gasoline. Ethanol made from corn stover – the leaves and stalks that remain in the field after the grain is harvested – has a life-cycle carbon intensity 96 percent lower than gasoline’s.
By contrast, studies have found that the life cycle carbon intensity of corn ethanol is greater than that of gasoline (Mullins et al. 2010, EPA, 2010a). Yet current federal policies strongly favor the production of conventional biofuels such as corn ethanol at the expense of lower-carbon alternatives.
Congress should reform the federal Renewable Fuel Standard to eliminate the mandate to add corn ethanol to gasoline and should further reform the standard to accelerate development of biofuels from lower-carbon feedstocks. At the same time, Congress should adopt new protections to ensure that fuels from grasses and crop waste also meet soil and water quality goals.
If Congress fails to act, EPA should employ the “reset” provisions of the Renewable Fuel Standard to gradually reduce the mandate for corn ethanol and encourage development of lower-carbon second-generation fuels.
Further, they should forbid the use of ethanol and promote the development of using switchgrass, et al, to produce bio-butanol, which has significant advantages as a liquid fuel over ethanol (including a higher EROEI).
A technology meriting more investigation and investment is the use of biochar from the pyrolysis of biomass to both produce energy AND sequester carbon as a stable soil amendment. Carbon soil sequestration can be used to produce highly fertile amended soil known as terra preta. Improving soil fertility and sequestering carbon and generating non-fossil fuel energy definitely looks like a multiple win strategy. Soil nutrients are returned to the soil, and toxic minerals are not concentrated and made mobile to the extent that they are in ashing processes.
"Installment 9 of Creating a Sustainable Food Future shows that any dedicated use of land for growing bioenergy inherently comes at the cost of not using that land for growing food or animal feed, or for storing carbon.
It recommends several policy changes to phase out forms of bioenergy that use crops or that otherwise make dedicated use of land."
"The study finds that biofuels can be instrumental in bringing an agricultural renaissance that revitalises land use and livelihoods in rural areas. Price signals to small-scale farmers could significantly increase both yields and incomes, securing real, long-term poverty reduction in countries that have a high dependence on agricultural commodities. Large-scale biofuels cultivation could also provide benefits in the form of employment, skills development and secondary industry.
However, these possibilities depend on security of land tenure. Where competing resource claims exist among local resource users, governments and incoming biofuel producers, and where appropriate conditions are not in place, the rapid spread of commercial biofuel production may result - and is resulting - in poorer groups losing access to the land on which they depend. In these contexts, the spread of commercial biofuel crop cultivation can have major negative effects on local food security and on the economic, social and cultural dimensions of land use."
These might also be of interest:
My own conclusion is that we shouldn't let our our enthusiasm for alternatives to fossil fuels blind us to their possible negative effects. This concern seems to be especially valid for biofuels.