Households face the prospect of higher energy bills unless the government accelerates a massive £70bn modernisation of the UK’s electricity grid. The National Audit Office (NAO) has issued a stark warning that failing to upgrade the ageing network of pylons, substations, and overhead lines will not only stifle economic growth but also drive up costs for the public.
The current programme aims to expand the grid’s capacity to transport clean energy from wind and solar farms to homes across Great Britain. However, the NAO reports that the project is currently off track. Of the 80 critical infrastructure projects identified as necessary to meet the 2030 decarbonisation targets, only 16 have been completed, with the majority still in their early development stages.
Gareth Davies, head of the NAO, cautioned that the scale of the required work will “test systems not designed for activity at this pace or scale.” He emphasized that the value of the investment is entirely dependent on successful delivery, noting that delays will inevitably hamper economic growth and inflate consumer expenses.
The financial risks are significant. When the grid lacks the capacity to move electricity from generation sites to demand centers, the system operator must pay wind farms to disconnect and gas plants to ramp up production. These “constraint costs” reached £1.9bn in the 2025-26 period. The NAO warns that without rapid infrastructure improvements, these costs could surge to £7.8bn annually by 2030.
To meet the necessary timeline, private transmission companies must drastically increase their annual investment, rising from £2.5bn in 2025-26 to more than £11bn by 2027-28. While the industry regulator, Ofgem, estimates that timely completion could save households roughly £30 per year by reducing curtailment, the NAO describes the current schedule as “very challenging.”
Concerns have also been raised regarding a lack of transparency. The NAO noted that the government, Ofgem, and the National Energy System Operator (Neso) do not publish sufficient data on project progress or costs. Geoffrey Clifton-Brown, chair of the public accounts committee, stressed that the grid is in “dire need of upgrading” to support clean energy and rising demand from new homes and data centers, calling for more rigorous reporting to ensure accountability.
In response, Ofgem welcomed the findings, stating that upgrades are essential to shield consumers from volatile international gas prices. A spokesperson confirmed that funding is released in stages, subject to strict scrutiny, with financial penalties in place for companies that fail to deliver. Energy minister Michael Shanks described the report as a reminder of the consequences of “years of historic underinvestment,” asserting that the government’s reforms are vital to reducing dependence on fossil fuels.
Neso also pledged to continue working with government and network companies to maintain security of supply while managing balancing costs. The NAO remains firm, however, that the gap between new energy generation and grid connectivity must be minimized to avoid project delays that would postpone the benefits of a clean energy transition. The report also notes that which are ultimately passed on to the public, could reach £7.8bn a year by 2030, the National Audit Office (NAO) said that without faster action the extra costs associated with managing the ageing power network. The report also notes that but the NAO said that if the planned upgrades did not happen fast enough then bills could rise instead, labour has said its plan to decarbonise the grid by 2030 will keep consumer bills lower than they would otherwise be. The report also notes that just 16 are finished and most are in their early stages, of the 80 projects it said were needed to meet the target. The report also notes that he added “Value for money now depends on delivery. The report also notes that meaning “some new generation” was likely to connect before necessary grid upgrades were completed, it said some of the projects were already forecast to run beyond 2030. The report also notes that “[The Department for Energy Security and Net Zero], Ofgem and Neso must deliver critical projects on time and provide transparent reporting so parliament and the public can hold them to account.”.
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