How Will The UK Keep The Lights On?
Independent energy consultant Kathryn Porter has posted up the transcript of her speech this week to the Institute of Power Engineers
She said:
In the past 25 years we’ve been racing to build more renewables. We now have 32 GW of wind (Gridwatch shows 20gw of wind capacity not 32 – Ed) and almost 20 GW of solar.
This is backed up by 32 GW of gas generation, and another 12 GW of nuclear and biomass, just under five GW of hydro and pumped storage, and just under seven GW of batteries.
Current interconnector capacity is 8.8 GW, but imports can’t be relied on if continental systems face the same weather pattern, causing corresponding stress events….with the exception of France and Norway our connected markets both share similar weather to us and are following a similar wind-led energy strategy.
France relies on an aging nuclear fleet and has a more temperature sensitive grid than us – during cold spells, we often export to France rather than import from it.
And Norway is going off the idea of exporting electricity altogether since it has seen increases in power prices and power price volatility. Some in the Norwegian parliament want to cancel the interconnectors it has with Britain and Germany.
So we have roughly 64 GW of dependable firm capacity against 48 GW of peak winter demand.
Of course, no form of generation is 100 percent available so even if a technology is firm and dispatchable, it will still have maintenance outages and the occasional unplanned trip.
This is accounted for through de-rating factors, and after applying these adjustments the current amount of available firm capacity is 50.5 GW, which gives a spare margin of just 2.5 GW based on firm power.
In reality there is generally some contribution from wind, but this can be very low – on several occasions this year, the actual output of the installed 32 GW was below one GW and at times as low as 200 MW (which, amusingly is Grok’s estimate of the amount we could generate if everyone in the UK blew very hard into all the wind turbines!)
Despite higher amounts of wind on the system, in 2025 wind output is down, not just in Britain, but across Europe. Solar of course contributes nothing to the winter peaks which are always at night. After the sun sets. A depressing number of people still need this explaining to them!
NESO, Ofgem, DESNZ and just about anyone with an opinion on this says we need to hang on to all of that 32 GW of gas to keep the lights on, on those cold still winter days when demand is higher and renewable output low to non-existent.
So it’s pretty unfortunate that a third of the fleet was built in the 1990s and is getting a bit long in the tooth. My analysis shows that it’s not in fact 10 GW of gas capacity that’s nearing retirement, but 12 GW.
We may gain a couple of GW of smaller units, particularly open cycle turbines, and 3.2 GW of new nuclear at Hinkley Point is expected to open in the early 2030s, but by then almost 5 GW of AGRs will have closed. The net retirement risk is therefore about 12 GW of firm, dispatchable capacity in the late 2020s and early 2030s.
Let me repeat that – firm power equivalent to over a quarter of current winter peak demand could be off the grid in the next few years. And there is no concrete plan to replace it.
Not only are we sleep walking into a capacity crisis, we’re trying to make it worse. The Government wants to decarbonise everything, and as it’s now widely accepted that hydrogen will play a minimal role, and many, including the Climate Change Committee are sceptical about the role carbon capture will play.
This means electrification is seen as the primary route to decarbonising heating, transport and whatever industry we have left. Indeed de-industrialisation, in power grid terms, is something of a blessing in disguise, taking some pressure off tight margins.
The Government also wants to AI data centres to be built in Britain, having designated them as critical national infrastructure – that could add another six GW of demand by 2030 according to recent Government analysis.
So in this presentation, I will go through the scale of the CCGT-retirement challenge; why the winter risk and demand control issues escalate; how this plays out in different demand-scenarios (status quo, electrification only, AI only, electrification + AI) to 2030; and finally to offer commentary on why technological solutions such as hydrogen or CCS are unlikely to scale in time, and why grid and equipment lead-times are a serious obstacle.
Read the full speech here.
As Kathryn points out, we are already close to the bone, where firm capacity is concerned:
Gas Power – 32 GW
Nuclear/Biomass – 12 GW
Hydro/Pumped – 5 GW
Batteries – 7 GW
A total of 56 GW, facing peak winter demand of 48 GW. That capacity cannot be guaranteed 24/7, so 50 GW is more realistic. Moreover that seven GW of batteries, plus 2.7 GW of pumped storage can only supply for an hour or so – enough to meet peak demand, but worthless for longer periods.
As a result, we are already totally dependent on imported power, at the times when wind power cannot meet demand.
But the real value of Kathryn’s analysis is that she has identified how much gas power capacity we could potentially lose in the next few years. Not only is 12 GW at risk of closure by 2030, but another six GW could go by 2035.
As she notes, much of our CCGT fleet was built in the “dash for gas” in the 1990s. Older plants are naturally more at risk from outages, higher maintenance downtime and reduced flexibility to ramp up and down.
The Peterhead CCGT built in 2000, she says, had unplanned downtime in the last 12 months of 2800 hours – that is equivalent to 116 days!
One particular issue concerns the stress on turbine of continual ramping up and down. Not only do these problems reduce the reliability of CCGT plants to step up when needed, the increasing maintenance costs will eventually make older plants unviable.
Replacing these older plants is not a simple matter, even if the political will was there, which it plainly is not. There are eight-year lead times for gas turbines in the world market, whilst grid connections here can take a decade.
Worse still, who is going to invest in a CCGT, when the government intends to slap punitive ‘carbon’ taxes on it and ultimately ban it completely?
Kathryn notes:
New CCGT investment is subject to market risk – if investors believe policy is moving away from gas because of net-zero trajectories, they may be reluctant to commit – indeed, Langage and South Humber have 15 year refurbishment contracts under the capacity market for 2028-29 onwards but appear not to have taken the final investment decision – delivery seems unlikely.
Langage and South Humber have capacity market contracts for 905 MW and 700 MW respectively. As these are refurbishments, they are not “new” capacity and will leave a big hole if not executed.
We are rapidly running out of time.
See more here notalotofpeopleknowthat
Header image: The Sun
Bold emphasis added