A recent Purdue University study found that estimates of how much methane escape from natural gas power plants and refineries may be off by a wide margin, but concluded that overall natural gas plants are still better than coal for the environment.

As natural gas has become relatively inexpensive, it’s replaced coal as a fuel for electric power plants. It’s also less damaging to the environment if it doesn’t leak. There’s no doubt that burning natural gas is much cleaner than coal; however, methane is an even more potent greenhouse gas than carbon dioxide. The breaking point for burning natural gas to be better for the environment than burning coal is about three percent leakage.

Although the recent study conducted by Purdue University found methane emissions were significantly higher than rates reported by the Environmental Protection Agency and the EPA’s Greenhouse Gas Inventory of Emissions and Sinks, which diminished emissions to negligible, they were less than the break-even point. The study found emissions to be around 0.3 percent on average.

Learn more: Purdue University > Estimates of emissions from natural gas-fueled plants much too low, study finds