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Image Credit: Energy Networks Association

The electricity system has historically developed around a ‘centralised’ system, where a small number of large power stations provide the majority of electricity supply. However, the system is changing, driven by three long-term processes: decentralisation (power that is increasingly supplied by smaller power generation, situated closer to the consumer), decarbonisation (the move towards forms of generation that do not contribute to climate change) and digitisation (the increasing use of data, automated processes and ‘smart’ systems in the power sector).

Decentralised power can flow in more complex patterns across the network than in the conventional system. This, combined with a greater proportion of supply becoming weather-dependent and the increasing use of electricity for heat and transport, will place extra pressures on the network. To manage these challenges a more flexible electricity system is being developed. Flexibility is defined as the ability to rapidly change supply or demand in response to a signal (such as changing price) to help manage the electricity system. Current and developing technologies are increasingly providing flexibility to the system. The role of the electricity many of network operators is also increasingly changing to become more active.

Key points in the POSTnote include

  • Changes to power, heating and transport require a more ‘flexible’ electricity system, where sources of supply and demand can be rapidly adjusted to help balance the grid.
  • Flexibility may offer a more secure supply and consumer savings. Some users will benefit more than others, however, and flexibility may present cyber security issues.
  • Supply-side sources of flexibility include more flexible generation, electricity storage, and interconnection.
  • Demand-side flexibility provides incentives for consumers to increase, decrease or move the timing of their demand at key times.
  • Network operators’ roles are changing to facilitate flexibility. Some networks will need strengthening with new lines, but in places local flexibility solutions could offset this. 


POSTnotes are based on literature reviews and interviews with a range of stakeholders and are externally peer reviewed. POST would like to thank interviewees and peer reviewers for kindly giving up their time during the preparation of this briefing, including

  • Will Broad, Department of Business, Energy and Industrial Strategy (BEIS)*
  • Edward Nelson, BEIS*
  • Ben Eyre-White, BEIS*
  • Nick Brooks, BEIS*
  • Pamela Howie, BEIS*
  • Alice Fourier, BEIS*
  • John Christopher, BEIS*
  • Doerte Schneemann, BEIS*
  • Nicholas Gall, Solar Trade Association*
  • Alastair Martin, Flextricity*
  • Colm Murphy, National Grid*
  • Alice Etheridge, National Grid*
  • Eric Brown, Energy Systems Catapult*
  • Professor Keith Bell, University of Strathclyde *
  • Victoria Pelka, Citizens Advice*
  • Mark Thompson, Innovate UK*
  • Anthony Price, Energy Storage Network*
  • Roger Hey, Western Power Distribution*
  • Randolph Brazier, Energy Networks Association*
  • Dr Phil Grunewald, University of Oxford*
  • Andrew Roper, SSE*
  • Roger Kemp, Lancaster University*
  • Alastair Davies, EDF*
  • Dr Justin Andrews, Elexon*
  • Dr Rob Gross, Imperial College London*
  • Ed Rees, Smart Energy GB*
  • Patrick Smart, RES*
  • Hanae Chauvaud de Rochefort, ADE
  • Jack Abbott, Centrica
  • Charles Wood, Energy UK
  • POST Board Members*

* denotes people who acted as external reviewers of the briefing.

Documents to download

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