[NEWS] Is Jet Biofuel Feasible?
– by Brad Plumer, May 6, 2016, Vox
When I called Schäfer to chat about his paper, he pointed out that biofuels represent a big chunk of the reductions in the most optimistic decarbonization scenario. But, he cautioned, it’s still not certain that low-carbon biofuels will actually materialize in such large quantities.
Ideally, we’d want biofuels that produce far fewer greenhouse gas emissions than jet fuel does and don’t conflict with food supplies the way corn-based ethanol does. So companies like Boeing and Airbus are looking into making fuel from cellulosic biomass (i.e., grasses or the inedible parts of plants) or algae. They’ve even flown a few planes on experimental jet fuel made from these green sources.
But right now, these biofuels are still quite expensive. Marie Caujolle, a spokesperson for Airbus, told me that current estimates suggest aviation biofuels are about three to four times as expensive as jet fuel. The hope is that the cost will come down over time as production ramps up. But, points out Schäfer, “there is currently no commercial-scale plant operating” that produces synthetic jet fuel made from, say, cellulosic biomass. “These processes may work well in the laboratory, but scaling it up has proven challenging.” (See here for more on the challenges.)
There’s also the question of whether there will even be enough biomass available to supply vast quantities of jet biofuels. The United States and Europe already have laws and programs to ramp up cellulosic ethanol for cars and trucks. And some climate plans call for a massive ramp-up of “negative emissions” electricity involving cellulosic biomass. There’s only so much plant matter to go around for our energy needs — so who gets priority?