WASHINGTON Dec 17 Democratic lawmakers concerned about the growing U.S. reliance on natural gas for electricity on Tuesday called for a congressional hearing on emissions of methane - a potent greenhouse gas - from oil and gas production.
Henry Waxman, the top Democrat on the House of Representatives' energy and commerce panel, and Bobby Rush, chairman of the House energy and power subcommittee, asked for a hearing following two recent studies that found the U.S. Environmental Protection Agency underestimated methane emissions and the amount of methane leaks.
The pair said an investigation of the science behind methane emissions is essential as the United States continues to see massive growth in natural gas production.
"Sound science must inform our policymaking as the nation increases its production of natural gas, uses more natural gas to generate electricity, and even begins to export natural gas to new markets," they wrote in a letter to their Republican committee counterparts.
A report by Harvard University researchers published in November in the respected Proceedings of the National Academy of Sciences journal raised concern about the EPA's estimates of methane emissions.
The research found the agency may have underestimated the total by 50 percent in 2007 and 2008, and that discrepancies were greatest in oil and gas-producing south-central states, where total emissions are nearly five times greater than EPA measurements.
Another study that recently appeared in the same publication, by researchers at the University of Texas, examined gas production at 190 wells around the country.
The study found that leaks of methane from certain types of production equipment were much higher than previously thought.
Waxman and Rush attributed the country's recent success in lowering power plant carbon emissions to switching from coal to natural gas. But they expressed concern about the climate impact of the full lifecycle of the production, processing and distribution of gas.
Methane, like carbon dioxide, is a greenhouse gas but it is more potent, with a higher global warming potential.
EPA regulations targeting power plant pollution are expected to rely heavily on continued switching to natural gas from coal as a fuel source.
In a proposal released this fall, the EPA said that any new coal plant that can be built would have to have the same emissions rate as an average natural gas burning plant - a requirement backers of coal have said is unachievable. (Reporting by Valerie Volcovici; Editing by Dan Grebler)