Driving Growth in Driving Green
Driving vehicles that run on natural gas reduces emissions and allows us to breathe cleaner air. But what many don’t realize is that this is rapidly becoming truer through the increasing use of renewable natural gas in North America’s natural gas vehicle (NGV) infrastructure.
Renewable natural gas (RNG) is derived from the methane that emits from organic waste as it decomposes. This methane is captured at agricultural facilities, landfills, wastewater treatment plants, and separated municipal solid waste digesters, and then cleaned in a treatment process to produce a product indistinguishable from natural gas. The resulting biomethane, or RNG, is then either injected into natural gas pipelines, compressed or liquefied to be used as transportation fuel in the form of renewable compressed natural gas (CNG) or renewable liquefied natural gas (LNG).
As CNG and LNG from renewable feedstocks are blended together with natural gas transportation fuel from geologic sources, our nation’s transportation system becomes drastically cleaner. Switching vehicles to run on geologic-sourced CNG and LNG already reduces emissions. Natural gas provides 90 percent lower NOx emissions with new Near-Zero engines, and a 99 percent SOxreduction, compared to diesel.
Blending in RNG reduces fuel emissions even further. Driving a vehicle with 100 percent RNG can reduce greenhouse gas emissions (GHG) by more than 80 percent. RNG from some sources are carbon negative, meaning that they sequester GHG during the fuel life cycle.
Figures released in April by the California Air Resources Board show that, as of the end of 2015, half of the natural gas being used to fuel vehicles in the state is RNG. Only three years ago, in 2013, RNG’s share of California NGV fuel was just 10 percent.
RNG’s growth in California evidences the effectiveness of California’s Low Carbon Fuel Standard in driving growth in emission-reducing, clean fuels.
The extent of RNG used nationally to fuel NGVs is less certain than in California. U.S EIA sources indicate that between 15 and 35 percent of natural gas transportation fuel consumed in the U.S. is RNG. However, evidence shows that use of RNG as a cellulosic transportation fuel is growing at an unprecedented rate, thanks in part to the renewable fuel standard (RFS).
In 2013, prior to the RFS pathway approval of renewable CNG and LNG as eligible cellulosic biofuels, the RNG industry produced just 25.9 million estimated gallon equivalents (EGE) of transportation fuel. By the end of 2015, that volume had grown five-fold to nearly 140 million gallons, making up 98 percent of the cellulosic biofuel produced under the program.
Current and future production rates look even stronger. RNG producers are on track to reach 230 million EGE in 2016, and surpass the U.S. EPA’s draft rule renewable volume obligation (RVO) of 312 million EGE for 2017. The Coalition for Renewable Natural Gas, which advocates for the North American RNG industry, forecasts production of over 350 million gallons of RNG in 2017 and over 450 million gallons in 2018.
RNG adoption is naturally linked with the increasing deployment of NGVs, many of which are high horsepower vehicles. Over 25 percent of transit buses in the U.S. today operate on natural gas, including those serving nearly 40 major airports. Over 60 percent of new refuse truck orders are NVGs.
Fleet conversion costs to RNG stack up favorably with other renewable engine technologies. A report produced for LA Metro by M.J Bradley & Associates and Ramboll and Environ in early July determined that bus fleet costs are more affordable with a new low-NOx engine plus RNG fuel combination (1 percent annual cost increase) than either an all-electric (8 to 14 percent increase) or fuel cell (9 to 13 percent) bus fleet.
Together, RNG and natural gas vehicles are an affordable and proven long-term solution to reducing air pollution and carbon emissions. It is critical that companies, states, municipalities, and citizens across North America collectively continue to embrace ultra-clean, domestically produced and available fuels like RNG. If we do, the air we breathe will be cleaner. Public health will improve. We’ll combat climate change, stabilize fuel price volatility, reduce dependence on foreign oil, and curb unsustainable waste practices. Sustainability is the future of fuels. When NGVs are fueled on RNG, we ensure that waste isn’t wasted, but instead is used as resource that moves us down the road toward a sustainable future.