Cleantech
Busting Myths About Biodiesel’s Environmental Impact

As carbon-neutral policies around the country begin to take hold, there’s a growing interest in the total environmental impact of alternative sources of energy — also known as life cycle analysis (LCA).

The California Air Resources Board, Argonne National Laboratory and other scientists have separately conducted LCAs of biodiesel and found that it reduces greenhouse gas emissions by 50 to 86 percent, compared to petroleum.

Still, debate about whether biodiesel, ethanol and other biofuels are environmentally friendly goes on — especially around land use. At issue is whether the current amount of land available for agricultural production can support the growing global population’s demand for both food and fuel.

One of the biggest myths about biodiesel is that the renewable fuel increases greenhouse gases because it causes land to be cleared. New cropland is not needed to make biodiesel in the United States, because it is produced from co-products and byproducts of crops already grown for food and other materials. In fact, from 2008 to 2016, the US tripled biodiesel use and doubled exports of whole soybeans to China, while farmland decreased by 18 million acres.

“In the US, we have lots of unused land available to farmers who can convert it to corn or soybeans. There has been no need to cut forests here,” said Farzad Taheripour, a research associate professor in agricultural economics at Purdue University. “In addition, crop productivity has increased significantly over time, providing more yield on the same amount of land. Because of those, the expected deforestation or conversion of natural land has not had to largely happen to account for US biofuel production.”

The current research about biodiesel weakens the criticism stemming from a well-known 2008 study by scientists at Princeton University published in Science magazine. They argued that increased biofuel crop production will result in land-use changes — such as deforestation — that end up releasing a great deal of carbon dioxide into the atmosphere. The land-use changes thus undermine the benefits of cleaner-burning biofuels.

However, in response to the 2008 study, Argonne National Laboratory found that the Princeton researchers did not properly consider increasing crop yields per acre, which reduces the need to produce replacement food on other acreage.

Now, new research by Taheripour also should quell concerns about the effects of US biofuels production on deforestation in other parts of world. His analysis showed that less 1 percent of the land cleared in Indonesia and Malaysia can be tied to US biofuel production.

Taheripour and the late Wallace Tyner, who also contributed to this study, have been modeling environmental impacts of energy policy for over a decade. Together, with various collaborators and researchers, they developed the GTAP-BIO model for the California Air Resources Board to quantify the market-mediated impacts of the California Low-Carbon Fuel Standard and the national Renewable Fuel Standard. Those polices hold biofuels accountable for increased agricultural production predicted to occur all around the world.

The National Biodiesel Foundation supported a portion of Purdue’s research. Significant funding also came from the Federal Aviation Administration — which is working with airlines to identify fuels that have total carbon benefits, including indirect impacts on global forests and land use change.