Utah, we have a problem. That's the conclusion of a report from the publication Nature saying that methane leaks from US natural gas fields may be anywhere from two to three times as large as previously estimated.

As much as four percent of the natural gas production at a field near Denver is escaping into the atmosphere via methane leaks, Nature says, citing researchers at the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado in Boulder. Meanwhile, a Utah field may be leaking as much as nine percent of its natural-gas production.

These numbers are too high to be good for the environment, and the production leaks could indicate that expanded production of natural gas may outweigh the other environmental benefit of both reduced oil consumption and fewer coal-fired electricity plants. Natural gas fields had previously been though to leak about 2.4 percent of their production, while Princeton University researchers said last year that anything less than a 3.2 percent leakage rate would indicate that natural gas production is environmentally beneficial.

Thus we can see a problem for increasing the number of natural gas vehicles. With lower leakage rates, more natural gas production could be considered beneficial in both the energy and transportation industries because natural gas's abundance in North America could cut America's dirty foreign-oil dependency. Honda, for example, makes a natural-gas powered Civic (now called the Civic Natural Gas, formerly the Civic GX), while General Motors is among the automakers producing natural-gas powered trucks. There are about 1,150 compressed natural gas (CNG) refueling stations in the US, almost a quarter of which are in California, according to the US Department of Energy. If the natural gas production is dirty, then using more of it isn't the solution.