The Office of the Gas and Electricity Markets, the U.K. government's energy watchdog, was called on to investigate energy security as depleted North Sea reserves and other factors pushed wholesale gas prices up as much as 40 percent for the winter heating season.
The Daily Telegraph newspaper reports from London there are concerns about whether the government can raise the $275 billion needed by the end of the decade to update its energy infrastructure.
"As our old coal and nuclear power stations shut down, gas can provide flexible and reliable backup electricity to complement the next generation of renewable and nuclear energy," Energy Secretary Chris Huhne said in a statement. "Our analysis shows that it is likely to remain significant beyond 2030."
OFGEM said Britain gets half of its natural gas from regional suppliers, though that could fall to 20 percent by 2020.