Made from organic waste, renewable natural gas is rapidly gaining ground as an alternative fuel source with the potential to significantly reduce greenhouse gas (GHG) emissions. Public and private interest in this low-carbon fuel has grown dramatically in recent years, said Marianne Mintz, principal transportation systems analyst at the U.S. Department of Energy’s Argonne National Laboratory.
Argonne maintains a database that provides a comprehensive list of projects, currently in operation or under construction, which upgrade biogas for pipeline injection or on-site dispensing as vehicle fuel. Along with the nonprofit Energy Vision, Argonne has tracked these projects for the past five years, recording sustained, rapid growth. Data shows that between 2019 and 2021, the number of projects that are operational, under construction or planned for transportation increased from 219 to 402 total projects, which is an 85% increase.
Biomethane aids the environment in two ways. Along with cutting GHG emissions from methane that would otherwise have been emitted, it can be used to fuel trucks that would normally burn fossil fuels. Vehicles are the largest source of the GHG emissions that trap heat in the atmosphere and warm the planet.
“Renewable natural gas is a very attractive option for decarbonizing heavy-duty transportation, which is very difficult to do,” Mintz said. “It is a ‘drop-in fuel,’ meaning any natural gas engine can use it in the same way as fossil-natural gas. Renewable natural gas uses existing technology and infrastructure, and no engine modifications are needed. It can be transported in any pipeline network. Using it in larger vehicles like heavy-duty trucks and buses reduces the damaging effects of diesel emissions on air quality and health.”
Argonne data shows that in 2021, the 230 operational biomethane facilities alone produced over 59 million MMBtus, the equivalent of over 459 million gallons of diesel, which is enough to fuel 50,000 refuse trucks. That growth represents a 30% increase in production capacity since 2020.
Growth in production and use of renewable natural gas is closely tied to federal and state incentives, which are expanding. For example, California awards credits through its Low Carbon Fuel Standard (LCFS), which focuses on reducing the carbon content of fuels used within the state. “Other states are moving in the same direction as California,” Mintz said. “Oregon and Washington have adopted clean fuel standards and several other states are considering adopting similar legislation.”
The Argonne database tracks biomethane projects by feedstock: food waste, landfills, livestock/agriculture and municipal wastewater. Most projects involve landfills, but all feedstock categories are growing. The potential for domestic production is estimated to be 10 to 20 times greater than current production.
Renewable natural gas is just one piece of the overall decarbonization strategy — not the entire solution. “Near-zero emission technologies are needed until zero-emission technologies and infrastructure are available and affordable,” Mintz added. “Renewable natural gas is part of a portfolio of solutions. We have a lot of arrows in our quiver, but many solutions are going to take time. Renewable natural gas is here now.”
Currently, renewable natural gas is primarily used as a substitute for conventional natural gas which itself is a substitute for diesel in heavy-duty vehicles. While electric cars are now a viable, clean-energy solution, heavy-duty trucks will take longer to successfully electrify, making biomethane a good fuel for near-term decarbonization in large vehicles.
Source: Argonne National Laboratory