WASHINGTON — To stave off climate change, sources of electricity that do not emit carbon will have to replace the ones that do. But at the moment, two of those largest sources, nuclear and wind power, are trying to kill each other off.

In the electricity market, both are squeezed by pressure from natural gas, which provides some carbon reductions compared with coal but will not bring the country anywhere near its goal for reducing greenhouse gas emissions. Natural gas has a carbon footprint that is at least three times as large as that goal.

Energy companies announced this year that five nuclear reactors would be closing or not reopening, and the owners blamed competition from natural gas and wind. In the Pacific Northwest, wind and hydroelectricity — neither of which produce carbon — are sparring to push each other off the regional power grid.

Output from the two has sometimes forced the Columbia Generating Station in Washington State, the region’s only surviving nuclear reactor, to cut back its production. One recent study found that shutting down the reactor would save consumers $1.7 billion, partly because it cannot run full time, and partly because its costs are higher than some other technologies.