A community group that took over a leisure centre was shocked its energy bill was more than £15,000 for a month.
The Friends of Wadebridge Leisure Centre (FOWLC) saved the facility after previous operator GLL said it could no longer afford to run it.
Previously, the centre's annual energy costs were £85,000 but they are now expected to be £250,000.
The government said a bill relief scheme had been introduced for places like leisure centres.
But Amanda Pennington, from FOWLC, told BBC Radio Cornwall the bill was "absolutely staggering".
"When we did our forecasting, we forecast that the bills could cost £135,000 a year and when we did that we expected that to be way higher than it actually would be – but thought it was sensible to go high.
"The reality is far worse, it is likely to be £250,000 a year for gas, electricity and water."
The group is calling for government support for leisure centres, with energy prices set to rise again in April, according to the Local Democracy Reporting Service (LDRS).
Ms Pennington, who is also Mayor of Wadebridge, said: "Across the UK, 85% of community leisure centres are saying if they are not in trouble now they will be and will be under serious threat of closure by April next year.
"The government needs to do something. There are huge public benefits of swimming and having leisure centres, but they seem to be sticking their heads in the sand."
The Wadebridge centre is reducing its energy use where possible and there are plans to install solar panels and other renewable energy sources.
Since FOWLC took over, membership has risen from about 780 members to 1,100 and the centre is now employing more staff, increasing employees from seven to 15.
It is also open longer and provides more classes for users.
The group is reluctant to raise prices for users as keeping it accessible to as many people as possible "was a key reason why we took over the centre", Ms Pennington said.
A government spokesperson said: "We know many swimming pools are contending with major increases in running costs. That is why we have introduced the Energy Bill Relief Scheme, which means some pay less than half the predicted wholesale cost of energy this winter.
"We provided an unprecedented £1bn to ensure the survival of the grassroots, professional sport and leisure sectors throughout the pandemic – including the £100m National Leisure Centre Recovery Fund, which secured the survival and reopening of more than 1,100 swimming pools across the country."
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