The ‘great grid upgrade’ is off track, ministers should spell out the risks for bills | Nils Pratley

National Audit Office calls for greater transparency on £70bn programme that is running over budget and behind schedule

Speed up electricity grid upgrade or else face higher bills, warns UK watchdog

How far behind? How much more? It is impossible to get straight answers from the bodies overseeing the massive spending programme, which may continue at an even greater scale into the 2030s. The Department for Energy Security and Net Zero (Desnz), its in-house body, the National Energy System Operator (Neso), and Ofgem , the supposedly independent regulator, publish acres of information on narrow matters, but none provides a clear big-picture assessment: how is the grid upgrade really going?

Thank goodness, then, for Friday’s National Audit Office (NAO) report. The watchdog has unearthed a few hard statistics and demanded far greater official transparency. Prime minister Andy Burnham, in cost-of-living mode, should take note: trouble is brewing.

Of the 88 grid upgrade projects originally identified, 12 have already been completed (good news) and 12 have been subsumed into newer work (fair enough). But of the 56 deemed “essential” for meeting the government’s target of clean power by 2030, the NAO says 50 are “forecast to be delivered after their optimal date”. Of those, only 22 are forecast to be less than a year late; the rest are further behind schedule, with one put at between six and seven years behind.

The “optimal” date, in this context, is the date required not only to fulfil the 2030 clean power deadline but also to keep a lid on the maddening “constraint costs”, payments to Scottish windfarms to turn off when the grid can’t handle their output, plus payments to southern gas-fired generators or interconnecters to France to start supplying electricity.

On one windy day alone this week, such constraint payments reached £29m. The tally for the whole of 2026 is virtually guaranteed to top £2bn. The big worry is that the upper end of Neso’s forecast for 2030, a colossal £7.8bn, all going on bills, might be realised if the delays worsen.

Therein lies the reason why a grid upgrade is needed in the first place: the transmission network suffered from a lack of investment, even before the switch to renewables started. The transition makes the work more urgent. But what is also revealed is a state failure, going back decades, to expand the grid to keep pace with additional generating capacity. The suspicion now is that the same mistake is being repeated.

Many construction delays can be explained, it should be said. The NAO report cites standard stuff such as acquiring land rights, obtaining planning consents and legal challenges. But then there are procurement headaches caused by the need to wait for project‑specific signoff from Ofgem. There is also global competition for equipment as other countries expand their electricity networks. According to the report, the government estimates that some kit has risen up to five times in price from 2022 levels, with delivery times becoming extended. In short, the whole thing is taking longer and costing more.

But nailing down what it implies for that original £70bn figure, and thus bills, remains impossible. Nobody, it seems, is willing to put the numbers together. This passage from the NAO report is damning: “Publicly available information gives a partial and inconsistent view of progress towards upgrading the grid. Coverage is incomplete and key delivery risk metrics are missing. As a result, the available datasets cannot be reconciled with each other or the data we received from Ofgem, Neso and Desnz, and they do not give a clear view of overall portfolio delivery status.”

The watchdog calls for Ofgem and Neso “to deliver critical projects on time and provide transparent reporting so parliament and the public can hold them to account”.

On-time delivery may already be out of reach, but the demand for greater transparency is spot-on. Ofgem should publish medium-term forecasts for electricity bills, as this column has regularly argued , because the “network costs” element, what we’re talking about in this context, is capable of being forecast. Or it should take up the excellent idea from EDF , one of the big generators and retail suppliers, for “a live, publicly accessible tracker” to “radically increase transparency on cost and ongoing construction progress” and allow a strategic review.

The political danger for the government is that, sometime around 2028, the delays and cost inflation will become impossible to ignore. Even some pro-renewables enthusiasts, who fully back the government’s stance that the upgrade is the only way to bring down electricity bills eventually, warn of a backlash if £70bn becomes a much larger number. Ministers should do themselves a favour: be open.