Large-scale electricity storage

This policy briefing explores the need for energy storage to underpin renewable energy generation in Great Britain. It assesses various energy storage technologies

Wind and solar energy will provide a large fraction of Great Britain’s future electricity. To match wind and solar supplies, which are volatile, with demand, which is variable, they must be complemented by using wind and solar generated electricity that has been stored when there is an excess or adding flexible sources. This report (PDF) examines a range of options that can provide electricity when wind and solar are unable to meet demand.

Why is electricity storage needed? 

Meeting the UK’s commitment to reach net zero by 2050 will require a large increase in electricity generation as fossil fuels are phased out. Much will come from wind and solar, which are the cheapest form of low-carbon supply, but vary over a wide range of timescales. No matter how much generating capacity is installed, there will be times when wind and solar cannot meet all demand, and large-scale storage will be needed. Historical weather records indicate that it will be necessary to store large amounts of energy (some 1000 times that provided by pumped hydro) for many years.

What electricity storage will be needed, and what are the alternatives?

Electricity can be stored in a variety of ways, including in batteries, by compressing air, by making hydrogen using electrolysers, or as heat. Storing hydrogen in solution-mined salt caverns will be the best way to meet the long-term storage need as it has the lowest cost per unit of energy storage capacity. Great Britain has ample geological salt deposits that could accommodate the large number of salt caverns that will be needed. There will also be a role for other, more efficient, types of storage. Nuclear power, and burning biomass (and perhaps some natural gas) and capturing the carbon-dioxide, may also play a role; however, these forms of generation are not well to suited to providing all of the flexibility that will be needed to complement wind and solar power. 

What is the future of electricity storage in Great Britain (GB)? 

In order to meet GB’s needs in 2050, construction of large hydrogen stores must begin in the near future. There is also a need for large-scale demonstrations of other storage technologies. If the incentives that will be required to catalyse the necessary investments are not in place soon, GB will not have the storage that will be required when it is needed.

The Royal Society has produced a report (PDF) that addresses the issues and a briefing document (PDF) summarising the findings. Supplementary information (PDF) for the report is also available.