The UK government has set an explicit target to achieve a decarbonised electricity system by 2035. But what does this mean, and what might that look like on a day-to-day basis? In particular, how might this decarbonised electricity system operate during the more challenging periods of the year?

Project duration: December 2021 – October 2022


To address the challenge of how a decarbonised power system could operate during challenging periods of the year, Regen worked alongside National Grid ESO’s Bridging the Gap programme to produce ‘A day in the life of 2035’. The project asks: How will a very low carbon electricity system, with a very high proportion of variable renewable energy, significant new demand from EVs and heat pumps, and much greater levels of flexibility, remain flexible enough to deal with the diverse conditions that the British weather and energy system will throw at it?

We looked at the specific pieces of the puzzle needed to achieve a decarbonised electricity system by 2035, including:

  • How much offshore wind will be located in the various seas around the UK coast
  • What technologies and fuels will provide low carbon flexibility and dispatchable generation
  • The role of overseas interconnection
  • How domestic and non-domestic consumers engage in an increasingly digitalised and data-driven energy system.

In early 2022 we published the first report illustrating how a 2035 decarbonised electricity system may operate on a challenging day in winter with high demand and low availability of renewables.

We have now published the second edition, which adds a summer’s day with significant excess renewable energy. This means finding ways of keeping the system secure and stable when demand is low and the availability of wind and solar is high. Traditionally much of the system’s stability services and its ability to respond to unexpected faults has been provided by fossil fuel generation – by 2035 we need those services, as well as our energy, to come from zero carbon sources.

The report

Click below to view the final report

Screenshot 2022 10 13 085305

This analysis was published 13 October 2022.

First edition

This publication was launched in March 2022 alongside National Grid ESO’s Bridging the Gap programme.. The analysis has been integrated into the second edition released in October 2022. With particularly high levels of interest in the project, we hosted a Q+A session to discuss some of the assumptions and uncertainties. A recording of the session can be found here.

View the first edition of the report here

  • If you are interested in finding out more about this project or our future energy systems work, please contact Jonty Haynes.
  • To stay up to date with the launch of Regen’s publications and other market insight, sign up to our mailing list here. 


People on this project

Johnny Gowdy
Johnny is a director of Regen and leads the development of our advisory projects,…
Jonty Haynes
Principal Analyst
Jonty is a Principal Analyst at Regen delivering a range of technical support services,…
Prina Sumaria
Net Zero Project Manager
Prina specialises in local energy and just transition issues. She leads Regen's work supporting…
Sophie Whinney
Senior Energy Analyst
Sophie has a masters in Engineering Design from the University of Bristol, where she…

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