President Joe Biden is trying to promote solar development in the US using the same Cold War-era law Donald Trump invoked to prop up money-losing coal plants: the Defense Production Act.

The presidents’ shared strategy of leveraging reliability concerns to meet their very different energy ambitions underscores how American leaders are grappling with an electric system that’s rapidly being reshaped by the fight against climate change amid cheap renewable power and geopolitical tensions.

One of Biden’s emergency declarations Monday was rooted in an assertion that disruptions to energy markets, droughts and electric supply shortages are threatening the reliability of the nation’s power systems. An “acute shortage” of solar modules and components has jeopardized new electric generation capacity, he said.