They will not be the last. Yet more upgrades will be needed by the eight regional distribution companies whose lower voltage cables carry power to its final users.
SSE runs two of these, Scottish Power runs two more and National Grid runs a fifth. The North East is covered by Northern Powergrid and the North West by Electricity North West.
The largest is UK Power Networks, serving 8.3 million homes and businesses across London, the South East and East of England. Collectively those companies manage another 500,000 miles of power cables, seven million pylons and an estimated 800,000 transformers and substations.
Those networks were designed to do one thing: carry power from the transmission grid to customers.
Miliband wants them to do much more – serving as connection points for the hundreds of new solar, wind and other low-carbon generators. It is a significant engineering project, set to cost £30bn by 2028 and similar amounts more in the years following.
It is yet another cost which will be dumped on to our bills. Zoe Yujnovich, National Grid’s chief executive, confirmed last week that it would double the charges it adds to electricity bills to pay for hundreds of miles of new electricity transmission lines.
It will mean households would be paying £43 a year on average by 2031 to the National Grid for running the UK’s high-voltage transmission network.
In her view, expansion of the grid is essential if only to reach wind farms already built.
“We’ve gone from having what was a traditional north-south power grid into one where we’re having to build out eastwards so that we can connect offshore wind,” she says.
However, she says she understands there is a growing debate. “We are big advocates of flexibility and big advocates of getting the most out of the existing systems.”
Lawrence Slade, chief executive of the Energy Networks Association, said companies “consider every option to squeeze more capacity and capability out of existing grid infrastructure” before drawing up investment plans, and pointed out that Ofgem, the regulator, approves all of them.
For others, such as Octopus Energy’s Fletcher, there is really only one way to ward off the looming threat of higher energy bill charges.
Smart grid technologies, she says, offer a solution – although they are currently “playing second fiddle to grid build-out”.
It means Britain is at risk of permanently higher electricity prices, Fletcher says.
“If Ofgem, the system operator and the networks don’t prioritise these digital, flexible solutions over expensive physical build-out, we are actively choosing to make Britain’s electricity some of the most expensive in the industrialised world.”
