Increased natural gas use can help reduce U.S. greenhouse gas emissions in the shorter term, but deeper long-term reductions will require broader deployment of other low-carbon energy sources as well, according to a new report by the Center for Climate and Energy Solutions (C2ES).
The report, “Leveraging Natural Gas to Reduce Greenhouse Gas Emissions,” examines the climate challenges and opportunities posed by the current natural gas boom. U.S. carbon emissions have fallen back to where they were in the mid-1990s, in part because power generators are using more natural gas, which emits half as much CO2 as coal.
The report identifies various opportunities to reduce greenhouse gas emissions by substituting natural gas for coal and oil in the transportation, manufacturing and building sectors.
But the report emphasizes that the climate benefits of increased natural gas use can be maximized only if further steps are taken throughout the natural gas system to reduce leaks of methane, the principal component of natural gas and itself a potent greenhouse gas. It also underscores the need for zero-carbon energy sources such as wind, solar and nuclear, and for carbon capture-and-storage technologies, to achieve the deeper emission cuts needed over the longer term.
“The natural gas boom can help grow the economy while shrinking our carbon footprint, and there’s much greater potential on both fronts,” said C2ES President Eileen Claussen. “But we need a diverse energy supply. Natural gas is not carbon-free and we can’t let it crowd out nuclear and renewables. It’s also critical that we do a better job of measuring and minimizing methane releases.”
The report was funded in part by grants from the American Gas Association and the Clean Skies Foundation.
C2ES is an independent, nonprofit, nonpartisan organization promoting strong policy and action to address the twin challenges of energy and climate change. Launched in November 2011, C2ES is the successor to the Pew Center on Global Climate Change.
The report draws the following conclusions:
- The expanded use of natural gas—as a replacement for coal and petroleum—can help efforts to reduce greenhouse gas emissions in the near- to mid-term, even as the economy grows. In 2013, energy sector emissions are at the lowest levels since 1994, in part because of the substitution of natural gas for other fossil fuels, particularly coal. Total U.S. emissions are not expected to reach 2005 levels again until sometime after 2040.
- Substitution of natural gas for other fossil fuels cannot be the sole basis for long-term U.S. efforts to address climate change because natural gas is a fossil fuel and its combustion emits greenhouse gases. Greater CO2 reductions will be necessary than natural gas alone can provide. Ensuring that low-carbon investment dramatically expands must be a priority. Zero-emission sources of energy, such as wind, nuclear and solar, are critical, as are the use of carbon capture-and-storage technologies at fossil fuel plants and continued improvements in energy efficiency.
- Along with substituting natural gas for other fossil fuels, direct releases of methane into the atmosphere must be minimized. It is important to better understand and more accurately measure the greenhouse gas emissions from natural gas production and use in order to achieve emissions reductions along the entire natural gas value chain.
Report advocates for the setting of a carbon price
In the long term, market pressures could result in the retirement of a significant portion of the existing nuclear fleet, all of which could be replaced by natural gas generation. Market pressures also could deter renewable energy deployment, carbon capture and storage, and efficiency measures. Without a carbon price, the negative externalities associated with fossil fuels are not priced by society, and therefore there will be less than optimal investment and expansion of zero-carbon energy sources, the report said.
Instead of being thought of as competitors, natural gas and renewable energy sources such as wind and solar can be complementary components of the power sector. Natural gas-fired plants can quickly scale up or down their electricity production and so can act as an effective hedge against the intermittency of renewables. The fixed fuel price (at zero) of renewables can likewise act a hedge against potential natural gas price volatility.
As coal’s share of generation continues to diminish, the implications for climate in the near and medium term are reduced CO2 emissions from the power sector. Further reductions in CO2 emissions are possible if natural gas replaces coal or petroleum in other economic sectors. Also, wider use of distributed generation technologies in the manufacturing, commercial, and residential sectors, namely natural gas-fueled combined heat and power (CHP) systems, has great potential to significantly reduce U.S. CO2 emissions.