Q3 2019: How much energy storage will we need?

by Dr Iain Staffell – Imperial College London 

A big open question is how flexible will Britain’s power system need to be as it transitions to more renewable energy, and how much of this flexibility should come from energy storage? 

Getting to over 80% wind and solar power, as is suggested for reaching net-zero, might require a ten-fold expansion from 3 GW of storage today to over 30 GW in the coming decades.

It is clear that new technologies will be needed to balance out the variability of wind and solar farms, but how big might the market for storage be? This is a question that many academic and industry studies have tried to tackle. There is no one answer, as it depends strongly on how the rest of the energy system evolves – ranging from how much electricity comes from nuclear, renewables and flexible fossil fuels, to how many people buy electric cars and heat pumps. It also depends on how various studies model the workings of the power system, and the technical and economic assumptions they use.

National Grid provides four possible visions in their Future Energy Scenarios. They see Britain installing anything from 3 to 13 GW of new storage capacity over the next fifteen years, depending on whether we continue relying heavily on natural gas or move towards more renewables for our electricity. Other studies cover an even wider range, but one trend is clear. More storage is needed as more electricity comes from wind and solar power, and the requirement grows more quickly at higher levels of renewables penetration.

Of course, storage is just one form of flexibility that can help to integrate low-carbon power sources. Interconnection with neighbouring countries, demand-side response (such as smart appliances and hot water cylinders, etc.) and peaking power stations all have a role to play, and are similarly all expected to grow in the coming years.

Results from 28 studies of the future electricity system, comparing the amount of storage that gets built in the coming decades against the amount of energy from variable renewables. These studies cover four regions, indicated by their colours. Installed storage capacities are divided by the peak demand for electricity in each region to account for the relative size of countries.¹

1: Data from multiple sources as cited in the legend, in part compiled by Zerrahn et al., 2018. On the economics of electrical storage for variable renewable energy sources. 

Lead author: Oliver Schmidt