FROMLINE: Lauren Quinn
Newswise – URBANA, Ill. – Despite the enthusiasm for electric vehicles and their potential to reduce the transportation sector’s carbon footprint, Predictions for 2023 suggest that electric vehicles will not displace gasoline-powered vehicles in the next few decades. Since conventional vehicles are likely to dominate the ground fleet for the foreseeable future, University of Illinois Urbana-Champaign Experts say cellulosic biofuels shouldn’t be overlooked.
Researcher in the College of Agricultural, Consumer and Environmental Sciences (ACES) and the Institute for Sustainability, Energy and Environment (iSEE) at the U. of I. find that support for cellulose has waned in part due to uncertainty over land availability, feedstock yield, costs and greenhouse gas (GHG) emissions savings. In one Recent studyThey quantified these uncertainties across multiple feedstocks and policy scenarios and concluded that cellulosic feedstocks outperform corn ethanol in almost all cases – but require significant policy support to grow and sustain the industry.
“Perennial feedstocks offer many benefits for decarbonizing transportation,” he said Madhu KhannaACES Distinguished Professor of Environmental Economics in the Department of Agricultural and Consumer EconomicsChairman of the Alvin H. Baum Family Fund and Director of iSEE and senior author of the U.S. Department of Energy-funded study led by the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI). “We need long-term policy commitments with assured demand for cellulosic biofuels, as well as short-term policy support such as tax credits that could be based on the carbon intensity of biofuels.”
The CABBI team developed a complex model that integrates economics, crop growth information, land availability, refining processes and carbon benefits to compare multiple biofuel feedstocks – corn, soybeans, corn stover, miscanthus, switchgrass and energy sorghum. The team predicted outcomes for 2016 to 2030 under different policy scenarios. These included a “no policy” or baseline scenario in which corn ethanol remained constant at 6 billion gallons per year; a 15 billion gallon corn ethanol mandate; and a corn + cellulosic ethanol mandate that calls for 16 billion gallons of cellulosic ethanol by 2030 (31 billion gallons total).
The model predicted everything from the impact of ethanol regulations on corn and commodity prices to where each commodity would be grown most productively, taking into account land use change, greenhouse gas emissions and societal costs. In the end, the cellulose mandate prevailed.
“Electrification has received a lot of attention and there is a lot of political support for it, but the transition of the vehicle fleet will be a slow process. “Liquid biofuels offer an almost immediate benefit with existing infrastructure,” Khanna said. “Cellulose biofuels are particularly promising because they offer a high yield per unit area and can be grown at least partially on marginal land, i.e. on areas with low productivity where crops can be grown without conversion, for example on fallow land. Therefore, their production is much less in conflict with food crops compared to the use of corn and soybeans for biofuels.”
The team was particularly interested in quantifying indirect land use change (ILUC). When biofuels are produced, Khanna explains, land prices rise, which drives up commodity prices. This creates incentives for the conversion of non-arable land (e.g. grassland or forest) to arable land, but the conversion releases stored carbon.
“This creates a ‘carbon debt’ that can take many years to repay. The more crop prices rise, the greater the ILUC effect and the smaller the overall carbon benefit,” Khanna said. “Even if we say that cellulosic biofuels are not inconsistent with food production and have lower carbon intensity, there is still a lot of uncertainty in this regard.”
According to Khanna, the amount of marginal land that could be used to grow cellulosic biofuel crops is a major source of uncertainty.
“Our analysis found that a relatively small amount of marginal land (1.5 million hectares or 3.7 million acres) is being converted to energy crops,” she said. “The corresponding estimate of the amount of marginal land likely to be converted to cropland under the corn-ethanol mandate scenario would be much larger and more uncertain at 2.2 million hectares.”
The model predicted that greenhouse gas emissions would gradually increase by a few percentage points over time in the baseline scenario, but the corn-ethanol and corn+cellulose regulations reduced emissions by 3% and 10.4%, respectively, by 2030.
Accordingly, the model estimated that the corn+cellulose policy would cost significantly less to reduce greenhouse gases than a corn-ethanol-only policy, about $150 and $233 per megagram of carbon dioxide, respectively.
These numbers feed into another focus of the analysis, a concept known as the economic welfare cost of any policy.
“If we force consumers to pay for more expensive products, their well-being decreases. For them it is a net cost. So if there’s a requirement that we use 16 billion gallons, that forces much more expensive biofuels onto the market and welfare goes down. But CO2 emissions are also falling,” said Khanna. “We examined the change in economic well-being caused by the introduction of stricter regulations and compared it to the reduction in greenhouse gas emissions. Then we can say what cost per ton of reduction occurred?”
The model predicted that although cellulosic ethanol far exceeds the cost of corn ethanol, the overall welfare cost of reducing greenhouse gas emissions with a cellulosic mandate would decrease due to additional carbon savings.
The study suggests that political support for cellulose would not only be good for the planet, but could also be good for society.
“Even if we achieve the current policy targets of a 50% share of electric vehicles in new sales, it will take decades for the share of electric vehicles to dominate the total fleet due to slow sales, particularly at a global level. A large proportion of cars will continue to require liquid fuel. It is better to power them with low-carbon biofuels than gasoline,” Khanna said. “They don’t have to be electric vehicles or Biofuels. We need to take a balanced approach and focus on multiple ways to reduce emissions in the transport sector.”
The study “Quantification of uncertainties in greenhouse gas savings and abatement costs with cellulosic biofuels” was published in European Review of Agricultural Economics [DOI:10.1093/erae/jbad036]. The research was supported by the US Department of Energy [award number: DE-SC0018420].