In Germany, due to cheap afternoon solar power, pumped hydro
operators have been running on two cycles a day, not just the
normal one at night. Essentially, this means that you’re
doubling the potential of existing pumped hydro infrastructure.
Here’s a little more info on this from KMB48: Solar has driven
down the afternoon wholesale price of electricity to
approximately the same level as midnight when pumped hydro
normally charge up their reservoirs. Pumped solar relies on
price differentials of daily electric markets. At night, when
old fashioned coal and nuclear power is abundant and not in
demand, power prices are cheap. Pumped hydro operators buy the
cheap nighttime power to run pumps to move water to high ground.
During daytime peaks, electricity prices are higher, so the
pumped storage operator let’s the water run down through
turbines to generate instant-on electricity to meet peak demand.
What’s new is that there is now a new low price trough in the
afternoon in Germany since so much solar power has