The climate stakes of nuclear plant retirements

New warning: The think tank Third Way just published an interesting look at the effect of planned and potential nuclear plant closures on carbon emissions in the U.S. power sector.

Why it matters: Even if just some early retirements come to pass, it will knock the country further from a target set under former President Obama to cut greenhouse emissions by 80% below 2005 levels by 2050.

Check out the chart above: The top black line shows how much zero-carbon power — from renewables and nuclear plants — is needed to support the economy-wide 2050 goal (based on analysis underlying a 2016 White House report).

The solid dark purple line shows how close we get if nuke plants don't close.

The dotted lines below show how much varying levels of retirements will cause the U.S. to fall even farther short of the goal of generating 2,750 million megawatt-hours of zero-carbon power annually by 2030.

One level deeper: Much of this generation will likely be replaced by gas, which means more emissions, and even if it's all replaced by renewables, that's still a setback.

"The only way we win is if we grow the amount of zero-carbon energy we’re producing. As nuclear plants get shut down, new renewables will have to pay-off that zero-carbon debt before they actually start increasing our totals again," writes Ryan Fitzpatrick, deputy director of the Third Way's clean energy program.

"Even if we limit the loss of nuclear generation between now and 2030 to just 20%, that’s a setback of 4.5 years’ worth of clean energy growth," he writes.

Click here for more in the Axios stream.