Study: RNG Has Better GHG Emission Reductions When Considering Complete Lifecycle Analysis

A recent study sponsored by the Argonne National Laboratory, the Joint Research Center, and the European Commission confirms that Battery Electric and Hydrogen technologies, other than hydrogen made from renewable natural gas (RNG), emit far more greenhouse gases (GHG) when evaluated through a “well-to-wheel” (WTW) analysis, verses just looking at what is happening at the tailpipe. The reason is that upstream emissions from the production of the energy is not as clean as what is being attributed solely at the tailpipe. This conclusion was made after the study performed a WTW analysis for all transportation fuels, applying both the U.S. and EU forms of WTW measurement.

Specifically, the study found that “in both the U.S. and EU markets, waste-streams-to-energy technologies, such as CNG production via anaerobic digestion of wet waste resources, offer the biggest opportunities to reduce WTW GHG emissions.” In comparison, RNG was said to have the best GHG emissions, including a negative carbon intensity (CI).  The study concluded that “timely, deep decarbonization of the transportation sector requires a mix of low-carbon, renewable energy and powertrain technologies that could scale up collectively,” and notes that Battery Electric and Hydrogen systems require RNG to meet carbon neutrality goals.

A WTW analysis considers the full lifecycle of the fuel, from production to use, and not just what happens during the end use, as noted in the diagram below. 

Source: Decarbonization potential of on-road fuels and powertrains in the European Union and the United States: a well-to-wheels assessment

This study highlights what the data and science continues to confirm – that RNG used as a transportation fuel performs better than electric when considering its full lifecycle impact, especially for near-term reductions.  The production of electricity can result in significant CO2 emissions, depending on the feedstock. 

By simply moving to a WTW analysis (the exact process used to evaluate the CI of fuels under CA’s Low Carbon Fuel Standard), it becomes apparent that there are more solutions to help California meet its carbon neutrality goals and we need them all if we are to succeed.