Authors: Joshua Lait and Alan Walker

A recent UKERC funded Parliamentary Office of Science and Technology (POST) Fellowship focused on longer duration energy storage, below you can read the overview from the POSTnote developed and download a copy in full.


Low–carbon, longer duration energy storage (LDES) currently plays a relatively minor role on the UK energy system. However, as the electricity system decarbonises, the amount of LDES needed is likely to increase significantly to replace the storage traditionally provided by fossil fuels. The Government is currently supporting the demonstration and commercialisation of new LDES technologies. Examples include flow batteries, mechanical and thermal storage, and hydrogen.

As the proportion of wind and solar generation on the electricity system grows, flexible types of generation (such as LDES), which can be scheduled to meet demand under low wind and dark conditions, will become increasingly important. Storage can also contribute to security of supply by meeting prolonged supply shortfalls, such as wind droughts, low annual wind speeds and power generator failures. In addition, LDES can provide a source of demand for the growing number of renewable plants, preventing costly constraints when the electricity networks are congested.

Storage will need to be deployed throughout the UK, with certain technologies needing to be located in particular geographic areas that have suitable conditions, such as salt caverns and mountains. Many of these technologies are not well known to the public, with positive and negative perceptions of their safety starting to emerge.

Current market arrangements do not adequately reward energy storage over longer timeframes, particularly over seasons and years. The Government are reviewing electricity market arrangements for the GB power system, which will impact the potential business cases of LDES assets.

Key messages

  • There is a range of different energy storage technologies in development, which includes flow batteries, mechanical devices (such as pumped hydro, liquid air and compressed air), thermal storage, and hydrogen.
  • Longer duration storage can support a future energy system with high proportions of renewable energy by providing flexible energy supply and demand, and increasing the resilience of energy networks.
  • Increasing amounts of energy storage will be needed, but to deploy the technologies at scale will likely require further innovation, demonstration, better business cases, investment and Government support. Deployment will also depend on ongoing developments in energy markets and a better understanding and communication of the risks.
  • The Government will implement a policy on longer duration energy storage by 2024.

Download the POSTnote here


  • Joshua Lait, POST Fellow, University of Exeter.
  • Alan Walker, Parliamentary Office of Science and Technology