RNG to Provide Future RFS Environmental Benefits

This summer, the U.S. EPA issued its second triennial review of the Renewable Fuel Standard. Critics of the RFS program were quick to laud certain summary findings of the report.
By Marcus Gillette | September 06, 2018

This summer, the U.S. EPA issued its second triennial review of the Renewable Fuel Standard.
Critics of the RFS program were quick to laud certain summary findings of the report, primarily the argument that the RFS has cumulatively had as much, or more, negative overall environmental impact compared to the benefits it has achieved in reducing greenhouse gas (GHG) emissions through increasing nationwide use of biofuels. Some critics even called for full repeal of the program. 
A deeper dive into the report, however, reveals that far less concern is warranted than the initial headlines might suggest. 

Reason 1: EPA’s report doesn’t assess life cycle GHGs. Although rogue GHGs present the world’s largest environmental challenge, EPA acknowledges that the report didn’t consider life cycle GHG emission impacts of biofuel.  EPA states that it determined not to expand the scope of the assessment beyond the explicitly enumerated requirements in the law, which does not require GHG life cycle analysis.

Excluding GHG life cycle analysis when analyzing environmental impact is incongruous, especially considering that advanced and cellulosic biofuels, by definition, must have lifecycle GHG emissions that are at least 50 or 60 percent less, respectively, than the baseline life cycle GHGs.

In reality, the fastest-growing segment of the RFS is cellulosic biofuel, including renewable natural gas (RNG). RNG facilities easily meet the law’s 60 percent GHG emission savings threshold. According to RNG project analysis using the GHGs, Regulated Emissions, and Energy Use in Transportation (GREET) Model by Argonne National Labs, RNG facilities regularly capture, destroy and displace GHG emissions to realize 70 to 300 percent lifecycle GHG emissions savings.

As such, a life cycle assessment of the RFS would result in findings that show substantially greater environmental benefit.

Reason 2: Land use impacts from crop-based biofuels are largely sunk costs. EPA’s report attributes a significant amount of the program’s undesirable environmental impacts to land-use changes related to crop-based biofuels. Critics using the report to add fuel to their argument for RFS repeal focus attention on conventional, crop-based fuels that have historically provided growth to the program. However, they neglect the law’s requirement that program growth beyond 2014 must come from advanced and cellulosic biofuel.

From 2005 to 2014, the RFS spurred the rise of the modern corn ethanol industry. Historic analysis may provide an intellectual exercise that properly informs future policy decisions, but regret over sunk costs should not color an environmental analysis of how the program is performing today. A cost-benefit environmental analysis of the RFS moving forward is far more helpful. EPA should ask what fuels are growing at the highest rate, and what impact do they have on the environment?

While a majority of biofuels used in the RFS have thus far been in the conventional category (i.e. corn ethanol), trends show that the annual growth rate of cellulosic biofuels is now outpacing other fuels categories by more than double, and corn ethanol by nearly 20 times. Cellulosic biofuel’s 30 percent growth rate continues with the 2018 volume standard of 288 million gallons and EPA’s proposed 2019 standard of 381 million gallons.

The RNG industry provides over 95 percent of the cellulosic biofuel used in the RFS program.
With more than 50 RNG production facilities under construction or having reached stages of substantial development, the RNG industry is primed to meet EPA’s projected growth.

Reason 3: Continued future growth of RNG will yield increased overall environmental benefit from the RFS. RNG facilities capture methane emissions that would otherwise be flared or escape into the atmosphere from waste streams at landfills, wastewater treatment facilities and anaerobic digesters. They convert methane into a fuel that is interchangeable with conventional natural gas, and can fuel natural gas vehicles including passenger buses, 18-wheelers and refuse trucks.

EPA’s life cycle analysis distinguishes RNG transportation fuel as among the biofuels with the most environmental benefit. As discussed above, by definition, in being eligible for the cellulosic biofuel category of the RFS, RNG derived from the organic content in wastewater, MSW in our landfills, and from dairy and farm waste results in life cycle GHG benefits of 60 percent or more, compared to the diesel fuel baseline.

Utilization of RNG as a transportation fuel not only helps mitigate methane emissions, it helps sequester carbon from certain sources. Under California’s Low Carbon Fuel Standard, the California Air Resources Board finds the reduction in carbon emissions from using RNG transportation fuel derived from organic waste in landfills and wastewater to be comparable to the carbon intensity of electric vehicles. RNG from dairy waste results in a carbon intensity score around negative 200, by far making it the lowest-carbon fuel available.

RNG is already accepted in the marketplace, and is a win-win for both a clean environment and clean economy today. Its increasing use as a renewable fuel will result in future environmental benefit from the RFS, and for our planet.

Author: Marcus Gillette
Director of Public Affairs, Coalition for Renewable Natural Gas