More than 60 percent of electricity in the USA is still generated with fossil fuels, especially coal-fired and gas-fired power plants that have the ability to quickly ramp up or ramp down power to follow loads on the electric grid. Most experts agree that even with a radical advancement in energy storage technology, relying exclusively on wind and solar to replace fossil fuels won’t be enough to maintain a stable electric grid and avoid the major impacts of climate change. To complete the transition to a carbon-free energy future, one key piece of the puzzle remains: nuclear power.

See https://www.ans.org/news/article-2763/road-to-advanced-nuclear-how-doe-and-industry-collaborations-are-paving-the-way-for-advanced-nuclear-reactors/