The NAO said: “The Department of Energy Security and Net Zero has allowed renewable electricity generation to expand faster than the grid, which has led to increased constraint costs.
“Successive governments’ ‘connect and manage’ approach has allowed new generation projects to connect before the network was ready.”
This failure means wind operators can claim compensation when they are ordered to switch off. Costs are then increased further as the Government must pay gas power stations to fire up to provide lost power.
Under the UK’s Clean Power 2030 programme, there are £70bn of projects in the pipeline to upgrade the high-voltage transmission grid.
This includes 80 key projects, of which only 12 have been completed.
The NAO criticised the overall management of the scheme, claiming that no department has taken responsibility.
“While accountability for individual projects rests with the Transmission Owners, no single person is accountable for delivery of the portfolio as a whole,” it said.
Missed opportunities
It also criticised energy regulator Ofgem for taking too long to start upgrading the grid – meaning that when projects finally began, they faced delays and cost overruns.
“Opportunities to upgrade the grid earlier were missed,” it said.
“Ofgem did not approve some proposed grid upgrades when they were first proposed. Some are now being approved at higher cost, at a time of intense global competition for labour and equipment.”
Gareth Davies, the head of the NAO, said: “The planned upgrades of the electricity grid will test systems not designed for activity at this pace or scale.
“Failure to implement these necessary grid upgrades will hamper economic growth as well as increase consumer bills.”
The NAO report echoes similar warnings made elsewhere.
John Constable of the Renewable Energy Foundation said it was ridiculous to give renewable energy operators subsidies and compensation payments for building wind farms in areas without transmission lines.
“The obvious question is whether constrained wind farms should be compensated at all,” he said.
“Transmission grid constraints in Scotland are a foreseeable and well-documented, commercial risk that operators could have taken into account when choosing their sites.”
