New England now gets more than half its power from natural gas. Compare that to 10 years ago, when about 20 percent of the region's energy needs came from natural gas, and you get some idea of the huge paradigm shift that's occured due to the discovery of shale gas reserves in the U.S. Natural gas is cleaner, cheaper and more plentiful than sources like coal and oil. But with this increasing reliance on natural gas comes with some concerns: concerns that were expressed to Congress this week by Gordon van Welie. He's president and CEO of ISO New England, which operates the region's power grid, and gave testimony in Washington D.C. on Tuesday before a House subcommittee on energy. Van Welie explains the basis for his concerns in an interview with Maine Things Considered host Tom Porter.

Maine Things Considered host Tom Porter talks with Gordon van Welie, the president and CEO of ISO New England, which operates the region's power grid. Van Welie testified Tuesday before a congressional subcommittee on energy.