Britain’s state-owned grid operator should be made liable for damages over delayed upgrades to the country’s electricity network, the owner of the UK’s biggest power station has said.

Will Gardiner, the chief executive of Drax, said the National Energy System Operator (Neso) and the other companies behind Britain’s power networks should be made liable for failures that hold up vital new connections needed to keep the lights on.

The UK’s power grid has been under strain this summer as heatwaves forced Neso to scramble to import more electricity supplies in June.

The grid operator has also been grappling with a significant backlog of power projects – including many speculative or unviable schemes – that have been asking to connect to the UK’s electricity networks.

Mr Gardiner called on Miatta Fahnbulleh, the Energy Secretary, to change the law to allow power plant developers “to get paid damages when connections are not made on a date for which there is contractual certainty”.

“It needs a significant fundamental system change,” he said. “Because right now, the system operator and the transmission and distribution companies have no liability for missing the connection dates that they’re giving us.”

Mr Gardiner said Drax, which operates a four-gigawatt plant in Yorkshire, had been promised connection dates for a series of new gas facilities but these timelines had been repeatedly pushed back.

Mr Gardiner said Drax had completed three gas-fired power plants three years ago but only one has been connected to the wider UK network so far, leaving the other two sitting idle even as extreme temperatures left Neso racing to secure extra electricity on June 23.

The Drax boss said these projects could have helped Britain weather a power supply crunch that threatened the UK’s “system security”.

“We were originally told that the new gas power stations would be connected in 2024,” Mr Gardiner said. “Now it’s 2026 and one of them is connected but the other two are not.

“They send letters offering a connection date and then six months later, they send another letter with a later date. There’s no contractual certainty in either one of those letters and so there is no recourse for the costs we incur.”

Neso has been attempting to reform the UK’s queuing system for linking new power plants to the grid. This previously worked on a first-come, first-served basis but subsidies on offer to renewable generators saw dozens of new and untested operators demand connections for wind and solar farms.

By 2024, there were enough proposals to supply the UK eight times over, creating a bottleneck that is taking years to resolve.

Drax operates Britain’s most controversial power station, the wood-burning Drax plant in Yorkshire, which burns six million to seven million trees and emits 12 million tonnes of CO2 a year.

Its power is deemed green by Neso, which classifies forests as a “renewable” resource.

The company has been diversifying into new forms of generation including wind, solar and battery storage, as well as building three new gas power stations that can be switched on when wind output is low.

Neso has said its offers of connection dates depend on whether upgrades to the wider UK power grid are completed on time by transmission operators.

“Connections reform is designed to prioritise projects that are ready to progress and strategically needed for Great Britain’s future energy needs,” Neso said.

A spokesman for the Energy Networks Association, which represents the UK’s operators including National Grid and UK Power Networks, said: “Neso and the networks are continuing to issue offers to transmission and distribution projects under the agreed joint industry plan.”

Ofgem, the energy regulator, said it was aware of the concerns over delays and was considering financial penalties against network companies.

“We have also introduced tough new incentives to hold network companies to account, including financial penalties where they fail to deliver timely connections,” a spokesman said.