Since then Plevin’s position has changed completely. “My conclusion at the end of all this is it’s misguided,” he says. The problem, Plevin argues, is that it’s impossible to accurately estimate the overall emissions that result from using biofuels. The effects of biofuel mandates can ripple out in unpredictable ways. If biofuel displaces gasoline in one country, then this could suppress the price of gasoline elsewhere in the world and lead to people increasing their fuel use. Add in a war, or trade embargoes, and the whole dynamic can flip again. “You can assume 10 different scenarios about the way things are going to unfold and you’ll get 10 different answers, and they might all be equivalently realistic. How do you build a policy around that?”
For Plevin this leaves us with an obvious choice: reducing our dependence on liquid fuels altogether. “If I were king for a day, I would be putting all my effort into electrification right now,” he says. Hill agrees. “It’s no longer corn ethanol versus gasoline. They have the same interest, and they’re both feeling pressure from electrification, which is their common enemy,” he says.
There are other impacts of bioethanol too. Global food prices jumped by a record 13 percent last month. Diverting some US corn away from bioethanol and toward food would help keep prices lower and replace lost exports from Ukraine and Russia. “There is all this competition for the land,” says Annie Levasseur, a professor at L’École de Technologie Supérieure, an engineering faculty based in Montreal. “If we want to look at the impact of increasing biofuel, then we will need cropland, and there will be this displacement.”
Levasseur and Hill are both part of a committee put together by the National Academies of Science, Engineering, and Medicine (NASEM) to assess current methods for analyzing the impact of low-carbon transportation fuels. The committee’s report, which will be published in the third quarter of 2022, “contains information that the EPA may wish to take into consideration if it decides to develop a new RFS or a low-carbon fuel standard,” says Camilla Yandoc Ables, a senior program officer at NASEM.
In Lavasseur’s opinion, bioethanol production is already high and shouldn’t be increased. Instead, the US government should be looking at other ways to reduce transportation emissions. “We cannot keep increasing demand for energy and then transform everything to biofuel,” she says. “We really need to decrease the demand.”
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