In many of the states with the nation’s most aggressive climate goals, officials are investing millions of dollars to save the power source that was long the No. 1 target of many environmental activists: nuclear plants. Despite longstanding safety concerns, many state leaders and some environmental groups say climate change poses a greater risk than reactors, and that preserving nuclear power will prevent an expansion of fossil fuel-powered plants. Nuclear plants provide about 19% of the nation’s electricity, far more than wind and solar combined. Some activists counter that state investments in nuclear plants are coming at the expense of renewable projects, slowing the clean energy transition. In Connecticut, officials made a deal in 2019 to procure power from the state’s Millstone nuclear plant for 10 years, part of a suite of projects for carbon-free electricity. According to state Sen. Norm Needleman, a Democrat who chairs the Energy and Technology Committee, the agreement provided a fixed price for the plant’s operator, Dominion Energy, allowing enough certainty to leave Millstone online.