The Clean Power Plan could be a historic step toward protecting America’s environment and combating climate change. However, the Environmental Protection Agency’s failure to fully consider the impacts of methane—a potent greenhouse gas—threatens to undermine this major federal effort to curb emissions.

The Clean Power Plan aims to reduce greenhouse gas emissions from the power sector to 32 percent below 2005 levels by 2030. One of its main strategies is switching power generation from coal to natural gas, along with improving coal plant efficiency and deploying renewable energy. The EPA recently calculated that nearly half of the total emission reduction target has already been achieved, due in large part to this shift from coal to natural gas. But according to a study by PSE Healthy Energy released in January, methane leakage from natural gas wells and pipelines could severely undermine the climate objectives of the Clean Power Plan.

The Environmental Protection Agency (EPA) estimates that the nation’s “upstream” methane leakage rate – the amount that escapes the natural gas system before it is used – is around 1.5 percent. But recent independent scientific studies put nationwide methane leakage between approximately 2 and 4 percent, with rates of 9 percent or higher measured in some places. The exact rate of methane leakage is difficult to calculate nationally, but any leakage has a powerful impact on the climate. 

Methane is roughly 34 times more potent than carbon dioxide over a 100-year time span, and 86 times more powerful over 20 years, meaning it has an outsized impact on near-term climate change.

As a result, the real climate benefit of natural gas is much lower than the EPA suggests. When the data is adjusted to accurately account for a higher level of methane leakage, the EPA’s projected 2030 energy mix will fall short of its 2030 goals. At 4 percent leakage, for example, only 28 to 29 percent of emission reductions are achieved by 2030 when considering the 100-year impact of methane, falling far short of the CPP’s 32 percent greenhouse gas emission reduction goal. When considering methane’s 20-year climate impact, only 22 to 23 percent of emission reductions are achieved by 2030. Methane leakage erodes the climate benefit of switching to natural gas in all scenarios, but this impact is largest in the near-term due to the shorter lifespan of methane than CO2. A 6 percent leakage rate erodes the greenhouse gas benefits of switching to gas even further. 

In January, the Bureau of Land Management proposed a new set of rules to cut methane emissions from venting, flaring and leaks from oil and gas production on public and tribal lands. These rules add to the EPA draft regulations introduced last fall to reduce methane emissions from new and modified oil and gas infrastructure. Unfortunately, real reductions in methane leakage rates will be limited, because the proposal does not cover existing oil and gas infrastructure. The EPA must take all methane leaks seriously if the CPP is to be a success.

The upshot of the CPP is that states have a huge amount of flexibility in their approach to compliance. Ramping up investment in wind and solar, for example, can help achieve CPP goals without increasing natural gas use. 

If states switch to renewable energy and adopt more energy efficiency measures, the national CPP emission reduction target will be achieved even with potentially high methane leakage rates. Even better, if beginning in 2020, states deploy renewables every year at the maximum rate seen historically, the US can easily surpass the CPP’s emission reduction goal – and take more effective action towards curbing climate change.   

If methane leakage is not curbed, it could severely undermine the EPA’s aim to slash greenhouse gas emissions from the power sector, especially if states shift from coal to natural gas, rather than to renewable energy. The dependable way for states to meet, or even exceed their commitments under CPP is to focus on renewables and energy efficiency, rather than a switch to natural gas.

Krieger, PhD, is director of the Renewable Energy Program at PSE Healthy Energy. Hausfather is a PhD candidate in the Energy & Resources Group at UC Berkeley.