There’s an interesting op-ed by Robert Blohm in the Wall Street Journal analyzing the issues with an all-renewables electric grid. The biggest problem is that it’s impossible or, at best, can’t accomplish the objectives of an electrical grid:
An electric power grid involves second-by-second balancing between generated supply and consumer demand. In the case of a sudden imbalance—such as from the loss of a generator’s output—all the remaining generators on the grid instantaneously pool together. Each one pitches in a small part of the required power to make up for the lost generator fast enough to keep supply and demand balanced.
This doesn’t work for wind and solar because you can’t spontaneously increase wind or sunshine. Hydro power is limited and unevenly distributed around the country. And for safety reasons, nuclear power—even if the Green New Dealers accepted it—can’t be cranked up to neutralize imbalances. Nor can consumer demand be suddenly reduced enough.
If you genuinely want to reduce carbon emissions, you should embrace things that will work first and avoid those that won’t. An all-renewables grid won’t work.