Climate Benefits From Natural Gas Seen Hinging on Plugging Leaks
Leaks in the production and delivery of natural gas threaten to undermine the benefits to the climate from expanded use of the fuel in manufacturing, transportation and appliances such as heaters, according to a report.
Advanced drilling techniques that are unlocking reserves, promising to supply the U.S. with enough gas for almost 100 years, also trigger stray emissions that must be plugged to achieve national goals, according to a report released today by the Center for Climate and Energy Solutions, a nonprofit group advocating policies for tougher rules to limit the gases.
Emissions tied to global warming are falling as utilities switch to gas, which produces half the carbon dioxide as burning coal to generate electricity, according to the report. Further savings are possible by using gas for home water heaters and heavy trucks.
“If you substitute gas for coal there’s big savings,” said Eileen Claussen, president of the Arlington, Virginia-based group, known as C2ES.
The report also stresses that long-term cuts in global-warming gases will require broader use of carbon-free energy sources such as wind, solar and nuclear power.
Carbon-dioxide emissions have retreated to mid-1990’s levels as abundant and cheap gas produced by hydraulic fracturing has replaced coal in power plants, according to the report. Gas generated 29 percent of U.S. power in 2012.
Higher production may also increase leaks of methane, a main component of natural gas that has about 21 times the heat-trapping potential of carbon dioxide, according to the report. Environmental groups say stray emissions from drilling can offset any benefit from burning gas over other fossil fuels.
Leaks occur in production and transmission and “represent a significant source of global-warming pollution,” according to the World Resources Institute, a Washington-based environmental group. Methane leaks are about 3 percent of all greenhouse-gas pollution in the U.S.
The Environmental Protection Agency in 2012 issued the first rules to combat air pollution from gas drilling. The agency gave gas drillers until 2015 to meet the most stringent requirements.
Based on greenhouse gas data reported by companies, the EPA reduced the assumed leakage rate for natural gas systems from 2.27 percent in 2012 to 1.54 percent in 2013, according to the report. Independent studies estimate leak rates ranging from 0.71 percent to 7.9 percent.
Leaks must be less than 1 percent of total production to ensure that the climate impacts of natural gas are lower than coal or diesel fuel, according to the World Resources Institute.
Issues with production include “everything from traffic in a local community and the capacity of institutions in a local community to deal with all the expanded activity, to water issues to chemical disclosure issues,” Claussen said. “We looked at one slice of this.”
The potential for expanding the use of natural gas to reduce greenhouse-gas emissions is significant, she said. On average, about two-thirds of the energy created from fossil fuels is spent before a home appliance is switched on compared with 8 percent when gas is used to power an appliance.
As a result, gas-powered water heaters are more than twice as efficient as electric models, according to the report.
Manufacturers that replace older, less-efficient boilers with new models can reduce carbon-dioxide emissions and save as much as 20 percent a year on fuel costs, depending on the price of natural gas.
Increasing the use of natural gas in heavy trucks and buses can benefit the climate by displacing carbon-intensive petroleum-based fuels. Government policies should provide information on the efficiencies of using natural gas in buildings and for transportation, according to the report.
“There are infrastructure issues to make sure people can actually have access to gas, but there are huge educational issues here,” Claussen said in an interview. “If consumers were better informed they would make some better choices.”
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