@hi Large parts of Europe trade energy on Nordpool.

There's different sectors, e.g. Denmark is divided into two different sectors.

This setup partially solves this "storage" problem. When the sun is shining (daylight, summer) and wind is blowing (spring/autumn) in Denmark we produce and export power to especially Norway and Sweden, where we have the largest links.

As a result of this, they can turn off their hydro-electric plants and store the energy (as water).

At night-time and during winter, the Swedes and Norwegians let the water flow and generates hydroelectric power, that is then sent to Denmark lacking solar and wind power.

At the Danish Energinet website you can (scroll down a bit) see the actual flow of power in real-time: https://en.energinet.dk/

More local solutions for the problem exists as well under the term https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity.

Not easily done on ones own property, though 😃