Natural gas infrastructure may be releasing vast quantities of methane into the atmosphere, adding to problems of global warming. Part of the solution may lie with old technology.
Methane is one of the gases which contributes to global warming, and in some cases, using it may be worse than diesel fuel. Much of gas is not accounted for by the U.S. government, or by industry regulators. Federal reporting may be missing up to 15.4 million tons of climate-changing gases each year. This is the conclusion of a new metastudy by researchers from Stanford University. Authors of the study believe most of these missing emissions are in the form of methane.
This chemical is the main component of natural gas, and is given off during combustion. Methane also pours into the atmosphere from cattle farms, oil wells, and several natural sources, such as wetlands and swamps. Of all the methane produced in the United States each year, roughly 1.5 percent leaks out into the atmosphere, according to the Environmental Protection Agency (EPA). This has the same greenhouse effect on the atmosphere as 1.3 million tons of carbon dioxide.
Some environmentalists are looking at natural gas to serve as a transition fuel, as the nation moves from oil to renewable energy sources. Natural gas burns cleaner than gasoline, but it still plays a role in global warming. Including leaked methane, the gas may play an even greater role in global climate change than once believed.
Despite this, the authors believe natural gas could, sometimes, be a viable alternative to burning petroleum products. For example, the authors point out passenger cars burning natural gas produce fewer greenhouse gases than a similar car running on gasoline. For diesel buses and trucks, however, the situation is reversed. These larger vehicles emit less harmful emission than the same vehicles operating on natural gas. In part, this is due to the highly-efficient nature of diesel engines. They found the process of fracking did not contribute significant amounts of methane to the environment.
Industry sources were quick to refute the study, saying the amount of methane accidentally leaked into the atmosphere each year is far less than the research claimed.
Measuring atmospheric methane can be tricky. Methods of measurement can have a large influence on the results. For instance, "top-down" recordings of the gas from airplanes show 50 more gas than calculations made from the "bottom-up."
These bottom-up studies calculate emissions based on the release of gas from wells, storage facilities, and cattle. It does not include abandoned wells, or natural sources, such as swamps.
"People who go out and actually measure methane pretty consistently find more emissions than we expect. Atmospheric tests covering the entire country indicate emissions around 50 percent more than EPA estimates, and that's a moderate estimate," Adam Brandt, of Stanford University who headed the study, said.
Natural gas may provide some environmental benefits over petroleum, but too much is lost to the atmosphere, according to the research paper.
The research was published in the journal Science.