Backup power could also be provided by linking wind farms with a solar cell, with conventional or pumped-storage hydropower, or with efficient natural-gas-burning turbines.

将风力发电厂与太阳能电池、常规或抽水蓄能的水电或高效的天然气涡轮机连接起来，也可以提供备用电力。

youdao

In the 1970s, some pumped hydropower storage was built at existing dam reservoirs to store nuclear power that otherwise went largely wasted at night.

FORBES: Energy Storage Critical to Solar Industry

And of course we can do that already: pumped hydropower, we know how to make batteries and fuel cells running on hydrogen can also be seen as a sort of battery.

FORBES: Two New Lithium Discoveries Make The Renewable Energy Economy Just That Much Closer