Study: Ethanol decreases greenhouse gas emissions

Source: By Marc Heller, E&E News reporter • Posted: Wednesday, January 27, 2021

Ethanol backers are cheering a new industry-funded study that suggests the corn-based fuel is better for tackling climate change than its critics contend, just as the Biden administration considers how aggressively to pursue biofuels.

Researchers at two Boston-area universities and Environmental Health & Engineering Inc. said corn-based ethanol can reduce greenhouse gas emissions by 46% compared with gasoline and even as much as 61% in some situations. And the research casts doubt on complaints that biofuel mandates spur conversion of environmentally sensitive land to corn.

The paper was published yesterday in Environmental Research Letters.

The study’s lead author, David MacIntosh of Environmental Health & Engineering, told E&E News the new work is the first comprehensive life cycle analysis of ethanol’s greenhouse gas impact in the past decade, taking in 28 years’ worth of data. Researchers from the firm, as well as Harvard and Tufts universities, reviewed ethanol from the corn-planting stage to production and consumption, drawing on a wide range of research papers sometimes published in bulletins and other obscure places, he said.

Overall, the study said, corn ethanol’s greenhouse gas intensity has fallen by about half over the prior 30 years.

While the study could give the industry new talking points in discussions with the Biden administration and Congress, the contours of the debate haven’t changed. Environmental groups such as the National Wildlife Federation maintain that conventional ethanol isn’t the beneficial fuel alternative they’d hoped for when the renewable fuel standard was adopted in the mid-2000s and is doing more harm than good.

The conflict among biofuel groups, environmental organizations and the petroleum industry will weigh on the Biden administration as it reviews pending regulations under the renewable fuel standard. Proposed regulations on minimum biofuel volumes for this year are behind schedule, and EPA has withdrawn regulations on the RFS and other policies that were under review at the end of the Trump administration.

Among other findings, the researchers said new technology and better farming practices have reduced ethanol’s carbon footprint. Farmers use less fertilizer per acre than they did years ago, yielding greenhouse gas benefits, MacIntosh said.

Another benefit comes from farmers who feed distillers’ grains — a byproduct of ethanol production — to their livestock, MacIntosh said. That reduces farmers’ need to plant additional acreage for feed grains.

Ethanol producers, too, have made improvements like consuming less energy in making the end product, MacIntosh said. Plants reduced their energy use by 50% in 2010 compared with 10 years earlier, the researchers said.

There’s room for improvement in the ethanol industry too, MacIntosh said. Some refineries are still powered by coal, which has about double the carbon impact of natural gas, he said. And plants that recapture carbon dioxide would take a bigger step toward climate benefits.

Biofuel groups hailed the study, which was commissioned by the ethanol company Poet LLC.

“The evidence proves time and time again that ethanol should play a key role in our nation’s climate goals of decarbonizing the transportation sector and reducing greenhouse gas emissions,” said Emily Skor, CEO of the industry group Growth Energy.

Traditional corn ethanol is especially under fire from critics of the RFS. It remains the top biofuel in the U.S. and is the driving force behind a 15 billion-gallon minimum conventional biofuel mandate set in law. However, the RFS hasn’t delivered the flood of next-generation fuels like cellulosic ethanol that promoters predicted years ago.

The National Wildlife Federation cited a study in 2019 that found the biofuel mandate is accelerating climate change, draining Western aquifers and harming pollinator habitat. More than 10 million acres of land was converted to crop production from 2008 to 2016, driven in part by the RFS and the higher crop prices it spurred, the study said (E&E News PM, March 7, 2019).

The NWF’s climate and biofuels specialist, David DeGennaro, told E&E News through a spokesman that the latest study draws on computer-generated models of land-use change that aren’t universally accepted.

“But looking at what has actually happened on the ground, in addition to using plain common sense, we know that increasing demand for corn leads to more land in corn production, vast releases of soil carbon from land conversion, and destruction of wildlife habitat,” DeGennaro said. “Rather than continuing to squabble over the emissions associated with ethanol, we need to hasten the shift to zero-emission vehicles.”

Alternatives like renewable biodiesel — which saw production gains last year, even with the pandemic — and cellulosic ethanol could receive stronger support from the new administration, fuel industry groups say. President Biden’s choice of Gina McCarthy, the former EPA administrator under President Obama, to a top climate policy role could help, said Brooke Coleman, executive director of the Advanced Biofuels Business Council.

Coleman said that McCarthy put the RFS on a better track after the Obama administration let regulatory deadlines for volume announcements slide and that she appeared to support a diversified transportation fuel mix.

“The RFS is still underutilized to help with climate change,” Coleman said.

Although biofuel volume requirements top the agenda for the industry, Coleman said McCarthy could give those businesses a jolt by approving applications for various advanced biofuels, such as crop residue, that have been sitting at EPA for months or years. “There’s still lots of unused horsepower in that program,” Coleman said.

In the longer term, groups are discussing how the government could create a low-carbon fuel standard, which could maintain demand for biofuel as a carbon-friendly alternative, although officials would have to decide whether to keep the RFS as is. Biofuel groups and the NWF wrote to Biden in December, asking him to pursue the idea.