Why Britain faces the growing risk of Spanish-style blackouts
In the rush for decarbonisation, operators fear the solar farm drive will cripple UK’s power grid.
The great British blackout was once a threat that hung over the country during the depths of winter, when generators struggled to meet demand or storms destroyed power lines.
But today, as the net zero revolution rolls on, the greatest threat to grid stability could land on a sunny Sunday afternoon.
According to the National Energy System Operator (Neso), the body responsible for keeping the lights on, the UK power grid is at increasing risk of being overwhelmed by surges in solar power.
Underpinning this threat is the fact that too many solar panels have been connected to the grid without any way of monitoring them or controlling their output.
As a result, a typically sunny day in summer can lead to nearly 19 gigawatts (GW) of power pouring into the UK’s networks, while only 12-15GW is being consumed.
That imbalance is a recipe for disaster because significant destabilisation of the grid can cause blackouts.
In practice, Neso is confident the UK will never see such a disaster. However, it admits the challenge is growing as ever more solar farms are built in Ed Miliband’s net zero drive.
“We are confident that we have the tools required to operate the system safely and reliably,” Neso said in its Summer Outlook report.
“But there may be periods when balancing supply, demand and system needs will require us to use our full range of operational tools, including system notices.”
However, independent experts are not so sure – and we may soon find out who is right. The crunch will probably come around the late May bank holiday, or on any sunny summer Sunday.
Last year, that date saw national demand for power plummet to a record low of 11GW, while sun and wind drove up power generation to nearly 19GW. And crucially, Neso could do little to stop it.
This sense of powerlessness is new. In the past, the grid operator’s response to an excess of power was simply to switch off some power stations.
But Neso’s problem is that it can no longer see what is happening on the UK’s power networks.
Unlike before, energy is being created naturally from wind and solar farms that Neso cannot control.
Underlying Britain’s energy grid are two main power networks.
At the top is the high-voltage transmission grid, which takes electricity from power stations to cities, towns and industry.
Everything on it is closely measured and monitored from Neso’s Electricity National Control Centre in Wokingham, Berkshire.
There, controllers use a giant wall-to-wall digital map of the transmission network to match supply to demand – switching power stations on or reducing output as needed.
Below that lies the distribution network, which takes electricity from the transmission grid, reduces its voltage, and pumps it into our homes and businesses.
It was designed to be a passive power carrier, meaning it lacks most of the switching or measuring systems found on the transmission grid. Ultimately, this makes it hard to monitor or control.
However, in the rush for decarbonisation, officials have been hooking the distribution system up to hundreds of new power sources, particularly solar farms.
Almost all of those solar generators are largely invisible to Neso’s operators, and they cannot see how much power is being generated or switch it off.
This now poses a problem, according to Simon Gallagher, the chief executive of UK Network Services, a leading consultancy.
“Traditionally, most power generators were connected to the transmission system and ‘dispatched’ centrally, so Neso can instruct them to turn on, turn off, ramp up and down to balance the grid in real time,” he says.
“Big power stations with large gas generators get tuned up and down as Neso monitors changes in demand.
“But solar is almost all connected to the distribution system and Neso has no control or even visibility of what it is doing. It means there is a risk of imbalances. On a sunny summer Sunday, demand will be very low, but solar will be generating at full capacity.”
Full story here.