SerpApi.Org
The UK grid operator has been forced to scramble for extra power supplies after delays to many of the UK’s most crucial net zero schemes.
The National Energy System Operator (Neso), a quango which runs the UK power system, has had to buy in at least two gigawatts (GW) of extra gas-fired generation capacity to ensure it can keep the lights on for the next five years.
The revelation comes in a report from experts appointed to assess Neso’s plans as it tries to hit the Government’s target of decarbonising the grid by 2030.
The report, published by the Department for Energy Security and Net Zero, warned that many planned low-carbon generation projects were being delayed or cancelled, so the UK would need extra gas-fired backup.
It said: “There is an upward trend in non-delivery ... which has averaged 1.8 GW over the last five years and 2.1 GW over the last three years.”
The lost capacity equates to several of the UK’s nuclear power plants, of which five remain, each with a capacity of just more than one gigawatt. Four are due to close by 2028.
The report warned that paying for extra generation capacity now was important to ensure the UK’s lights could stay on.
It said: “It is prudent to account for more non-delivery at the T-4 stage [four years in advance], as Neso has proposed this year ... This buffer would allow decarbonisation with less risk to security of supply.”
The UK has more than 30 gas-fired power plants with an increasing proportion supplying the capacity market, switching on when low-carbon sources such as nuclear, wind and solar cannot meet demand.
In theory, they can supply a total of 38 GW of capacity – but about half of the plants are more than 25 years old and so increasingly unreliable without expensive upgrades.
Delayed new low-carbon generation projects include the Hinkley Point C Nuclear Power Station, under construction in Somerset.
Originally expected to come online in 2025 at an estimated cost of £18bn, the completion date has slipped to after 2030 with overall costs escalated to more than £50bn.
Soaring inflation in the offshore wind sector has also caused key projects to be cancelled altogether, including the massive 2.4 GW Hornsea 4 offshore wind farm.
Danish developer Ørsted warned that supply chain costs had made the scheme unviable.
The report warned that more cancellations were probable: “It is widely recognised that the costs of most new-build power stations have increased significantly in the last few years, as evidenced in the reasons for the cancellation of a number of new projects.”
Separately, a 2025 analysis by Onward, a think tank, found that delays in constructing vital high-voltage grid transmission lines linking new offshore wind farms in East Anglia and the South East to demand centres had led to bottlenecks of clean power.
Connection problems have plagued gas-fired power station projects too, as recently happened with some open-cycle gas-turbine plants commissioned by Drax. They should have been running since autumn 2024 but delays in grid connections mean the first – in Hirwaun, Wales – has only just been commissioned.
Kathryn Porter, from Watt-Logic, an energy consultancy, said: “The current four year construction timeframe does not take account of real world delivery schedules and supply chain constraints.”
The Department for Energy Security and Net Zero said the procurement of extra generating capacity was aimed at maintaining the security of the UK’s electricity supplies and showed the capacity market was working as intended.
A spokesman said: “Our capacity market ensures security of supply while providing value for money for consumers. We’ve cut VAT on electricity to give families breathing space and our focus is working to bring bills down for good.”
Neso was approached for comment.
