You couldn't make it up...

Jun 24, 2026 Last reply: 3 weeks ago 27 Replies

From the DT.,..


"Gas-powered plants across the UK have been ordered to fire up production as soaring temperatures trigger a slump in solar energy.



The National Energy System Operator (Neso) issued a rare summer power supply warning overnight as the country braces for temperatures near 40C on Wednesday and Thursday.



Gas plants have been urged to ramp up output to deal with high levels of demand expected on Wednesday night as homes and offices turn up the air conditioning to endure the heatwave.



The notice comes as soaring temperatures make Britain’s solar farms less efficient, putting further strain on the power grid. Solar panel efficiency typically drops by 0.3pc to 0.5pc for every degree that a panel’s temperature rises above 25C.



Noemie Baud, from energy consultancy Montel, said: “Higher demand for air conditioning and cooling systems is contributing to the increase [in power demand], while lower outputs from solar and gas generation means more conventional generation is required to meet demand, pushing up prices.”



Data from the UK’s grid network showed gas generation jumped from around eight gigawatts at 12pm on Tuesday, to more than 17 gigawatts overnight.



More than half of Britain’s power needs were being supplied by gas on Wednesday morning, with wind generating around 12pc and solar less than



10pc.
“Our forecasts are showing tight margins on the electricity system for tomorrow evening,” Neso said on Tuesday night. “This is due to the impact of extremely high temperatures affecting Great Britain and the Continent and low wind.” Energy shortfall

Britain was facing a 1.9 gigawatt shortfall in its “margin” for Wednesday night – the buffer between available power generation and total consumer demand – according to an alert at 9pm on Tuesday from Elexon, the company that manages the electricity trades that keep Britain’s lights on.



The alert signals to Britain’s gas power plants and other suppliers to start generating more energy to meet the expected demand and is not a sign that blackouts are imminent.



A spokesman for Neso said: “We are asking market participants to make any additional generation capacity they may have available.



“The Electricity Margin Notice does not mean electricity supply is at risk.”

Such warnings are usually issued during winter when demand for energy is at its highest. However, households and businesses are expected to ramp up power usage for air conditioning and other means of keeping cool, after the Met Office issued a red weather warning.



Britain’s energy shortage has been compounded by relatively low wind generation across the country and continental Europe.



Meanwhile, imports of French energy have fallen by 48pc since Sunday. France has been forced to switch off a nuclear power station as high river temperatures mean the water is too warm to safely cool reactors.



In a worrying sign for consumers, energy market intelligence firm Montel said the decline in renewable efficiency had pushed up wholesale power prices.



Prices climbed to £248.39 per megawatt hour at the evening peak on Tuesday, an increase of more than 75pc compared with the same time a week earlier."



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Regardless your site is showing the solar (however that is measured) is the highest producer of power at the time of writing (34%)

Of course it is. And that's the danger. Unlike gas or nuclear, it has no ability to respond to overload without tripping out.

<snip>

I assume we deploy different solar panels to hotter climes? Much as we use different road surfacing mixes which start to melt around

30C. I didn't realise that solar panels had an optimum temperature range.

Every day a school day.

Cheers

Dave R

I think people just design for reduced efficiency.

Well they dont work when molten, for sure.

All semiconductor devices have temperature affected parameters. "Solar panels are tested under Standard Test Conditions (STC) at 25°C (77°F). When the sun is beating down on a panel, its internal temperature can easily reach 65°C to 75°C (150°F to 165°F). "As semiconductors get hotter, the increased internal heat causes electrons to move more chaotically, increasing resistance and significantly reducing the voltage produced. " The "Sweet Spot": Panels hit their peak efficiency during cold, crisp, sunny days (e.g., around 5°C to 15°C).

Ive finally decided to shut the Aga down for summer.

A solar panel is effectively a current source shunted with a diode.The forward voltage of the diode limits the output voltage and this reduces as the panel heats up. More of the incoming solar radiation is now dissipated as heat in the panel, further increasing the temperature. John

And how does the actual power output change as the temperture increases ?

I found some data online that shows up to 15% lost at say 60°C which is not unusual in this sort of sun.

Its very googleable - Googles AI comes up with decent facts pretty quickly

15% of what is lost? How does 'this sort of sun' compare with standard?

Oh FFS read it for yourself. 15% of the normally available current (at

25°C) isn't available at the same voltage so 15% of the normally available power is gone.

This sort of sun is where ambient is over 30°C and open sun temperatures of materials designed to absorb light may well peak at 85°C or more.

But you'ld rather put your fingers in your ears and say 'you're making it up'

AIUI the %age for solar and wind is just the metered ? There is addition generation which goes to reducing the overall demand before metering ?

I'm thankful that the annual boiler service is being carried out tomorrow. It's really struggling in these conditions, so much so that it hasn't kicked in all week :)

When I relayed the main part of this thread to a green friend the sole reaction was:

"My brain immediately converts the "too much sun" part to "if we had solar and wind energy, the planet wouldn't be frying in the first place".

Indeed, though the article seemed to suggest that solar output was very low, 10% which it may have been at the time. 34% is quite a respectable figure, just needs to keep that up for 7/24/365.

Umm,

I think 24/7/52 is the correct metric :-)

(Hrs/day - days/week - weeks/yr) ???

Avpx

'normally available', but now we have exceptional sun.

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"Irradiation is the primary driver of Production. However, the effect of Temperature is critical only in the maximum production regime (High Irradiation). The unexpected result is that Low Temperature is suboptimal when Irradiation is highest, suggesting that conditions associated with slightly higher ambient temperatures (Medium or High) are more conducive to overall performance in the peak sun regime."

No. Wind is what is metered but it comprises the bast majority of windpower. Solar is a guess, from Sheffield University who I think use a sampling technique to create it.

BM reports dioesn't have a 'solar' section AFAIK

I switched off my Aga yesterday

Boiler only doing hot water now as well

The cognitive dissonance is huge. The plany isn't frying. Not even England and France

Without fossil fuel the greens would not exist to moan

I fired up my boiler for central heating yesterday:) Only for a few minutes to circulate some water after reinstalling radiators I had taken off to paper behind them :)

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