There are promising alternatives to battery storage that address the problem of intermittency.
Nuclear currently provides 20% of power in the U.S. vs. 60% from fossil fuels, so (back of the envelope) we’d need to construct about 200 nuclear reactors (there are currently 94) of equivalent capacity. However, we also need to factor in the age of the current nuclear fleet:
The average age of American power plants, which are licensed to run for 40 years, is 39; in the last decade, at least five have been retired early, largely because maintenance costs and cheaper sources of power made them too expensive to operate.
The most recent closure came just last week, on April 30, when the second of two reactors was shut down at the Indian Point power plant, on the Hudson River north of New York City. Until a few years ago, those reactors had supplied a quarter of the city’s power. Nationwide, the EIA predicts that nuclear power generation will decline 17 percent between 2018 and 2025.
While environmental opposition may have been the primary force hindering nuclear development in the 1980s and 90s, now the biggest challenge may be costs. Few nuclear plants have been built in the U.S. recently because they are very expensive to build here, which makes the price of their energy high.
One hopes that this is an outlier, but recent experience does not inspire confidence: