Germany is building the world’s first wind turbines with built-in hydroelectric batteries

In the first large-scale example of two different technologies being integrated to supply reliable renewable energy, engineers in Germany are storing water for hydroelectricity inside four wind turbines, which allows the towers to act like batteries at times when there is no wind.

The turbines, which are each stood in huge basins of either fresh or saltwater, store energy from the spinning blades by pumping water up inside the turbines themselves. When the wind stops, water flows downhill to generate hydroelectric power, and a man-made lake in the valley below collects water until turbines pump the water back up again.

This project is ground-breaking because excess energy usually goes straight to the national grid, but this project creates a way to store excess energy in a natural reservoir, meaning the source of energy and the storage facility for it are one and the same entity.

Germany is currently in the midst of its attempt to virtually eliminate fossil fuels, and aims to draw 45% of its energy from renewables by 2030 and 100% by 2050.