How do we solve this problem? 

In theory, there are lots of solutions to this problem, ranging from the conventional to the esoteric.

Currently, batteries are one of the simplest solutions. They can be used to store all forms of renewable energy and are already in use in homes around the world in conjunction with solar.  

But the lithium required to make them is a scarce resource in high demand and the mining of these minerals has significant environmental and social impacts, often in less economically developed countries. 

Pumped storage hydropower is another solution that is already widely used.

It works by pumping water uphill using renewable energy. Then, when the grid requires electricity, the water is released downhill, spinning a turbine to create energy. 

This solution is expensive and obviously doesn’t work in flat landscapes. However, it has fast become the world’s largest renewable energy storage solution by capacity. 

China leads the way on this front, and with the completion of the new Fengning Pumped Storage Hydropower Plant — which can store 3.6GW— global capacity for this solution has surpassed 200GW, or around eight times the UK’s average energy demand.

Scientists are developing other ideas too, including gravity energy storage, geomechanical pumped storage and superheated salt batteries, but these are still all a long way from a rollout.