Britain is making plans for organised blackouts for industry and households over winter when cold weather may coincide with gas shortages, according to Bloomberg News.
Electricity capacity shortfall could total about a sixth of peak demand, according to the UK government's latest "reasonable worst-case scenario".
This is even after emergency coal plants have been put to use, Bloomberg reported, citing people familiar with the UK government's planning.
Under that outlook, coupled with below-average temperatures and reduced electricity imports from Norway and France, Britain could be exposed to four days in January when it may need to trigger emergency measures to conserve gas, the report said.
The Department for Business, Energy and Industrial Strategy did not immediately respond to a Reuters request for comment.
The Bloomberg report comes after the Bank of England warned last week that Britain was on course for a long recession as unprecedented energy prices push inflation towards 13%, but any political response has been hampered by the race to select a new prime minister on September 5.
European governments are seeking to conserve gas usage and increase storage following Russia's invasion of Ukraine.
But Britain's government has split into warring camps led by foreign minister Liz Truss and former finance minister Rishi Sunak who, competing to be the next prime minister, have clashed over how to respond.
Charities, business groups and politicians have called on Truss and Sunak to set out how they would help Britons cope with a forecast 82% rise in energy prices in October.