[opo]

Trying to rely only on intermittent power sources has huge storage requirements due to weather along with daily/seasonal variation. If grid energy storage was a simple problem it would have been done decades ago.

For example, one estimate is that for Germany to rely on solar and wind would require about 6,000 pumped storage plants which is 183 times their current capacity:

>...Based on German hourly feed-in and consumption data for electric power, this paper studies the storage and buffering needs resulting from the volatility of wind and solar energy. It shows that joint buffers for wind and solar energy require less storage capacity than would be necessary to buffer wind or solar energy alone. The storage requirement of over 6,000 pumped storage plants, which is 183 times Germany’s current capacity, would nevertheless be huge.

https://www.econstor.eu/bitstream/10419/144985/1/cesifo1_wp5...