A no-deal Brexit could cost the UK £2.2bn every year as the network connecting the nation’s electricity supply with its European neighbours would no longer function effectively.
Environmental think tank Green Alliance issued the warning as Britain’s future clean power supply looked uncertain following a string of failed nuclear power projects.
With Japanese firm Hitachi pulling out of the planned Wylfa plant in Wales, the UK now faces a “nuclear gap” of about 15 per cent in its future electricity supply.
Environmental groups say the gap can be plugged with renewable energy, and business secretary Greg Clark acknowledged the tumbling price of wind powerwas making it a more desirable option than nuclear.
However, concerns still remain around how variable power supplies, such as wind and solar, can provide the grid with reliable power.
One way around this problem would be to invest in networks that span multiple countries, meaning when the wind is not blowing in Britain energy can be provided from somewhere else.
Such a network would also provide a market for the country’s renewable electricity at times of surplus. In 2017, energy trading across borders brought £700m into UK markets.
Despite these benefits, and projects in the pipeline to link the UK up with Belgium and Norway, Britain remains one of the least connected countries in Europe.