Wind Power and UK Energy Use

[HSTEd]

As of todays 1700 settlement period virtually no gas was scheduled to dispatch due to high wind and solar output but because of the grid constraints in Scotland NESO has had dispatch multiple gas plants onto the system. Its paying c£30/MWhr to windfarms to shut down and £140/MWh to £215/MWh to CCGTs to ramp up. Yes price of gas is elevated due to Hormuz debacle but there is also a lot in the price to cover ramping up as CCGTs are only highly efficient when running stably at full load and they only get dispatched for 30mins. Of course reality is they will be redispatched every 30mins so are really taking advantage but thats market design.

Then the other nonsense we get is all but the French i/c's are in export mode currently as energy traders know that wholesale price would be depressed with forecast high renewable output so they bid to take that power and sell it in Europe. Thing is they dont have to pay the actual system costs for doing so. The battery operators equally benefit from low wholesale prices.

The CEGB would have run the system for least cost the current market design doesnt deliver that for consumers.

The CEGB would also not run a grid so dysfunctionally that there were enormous constraints for transfer of power across the grid (and yes I know the CEGB didn't run the grid in Scotland, but I doubt NSHB or SSEB would have done so either!). This is another side effect of decoupling generation from transmission I think.

But this is the Thatcher-approved model that we are now stuck with for want of political drivers to eliminate it.

 

[Bald Rick]

I almost wonder if there isn't a need for some sort of, probably state owned (even if at an arms length like Network Rail), organisation whose role is to provide that standby generation capacity as cheaply and efficiently as possible but isn't intended to be a profit making exercise so won't need to "walk away" if somewhere like Pembroke B can't be kept on profitably but would still be very useful from a grid point of view. A reasonable amount of generation can probably be run on a commercial basis (it certainly does elsewhere!) but it feels like there's bit that we really need where it it just going to be cheaper and more efficient to have non-profit seeking body do it. You could perhaps call it the Central Electricity Generating Board Authority

Perhaps Great British Energy?

Oh.

 

[brad465]

Is there a particular reason most days the reported solar power generated dips mid-morning? Is it just a reporting error or is it the case demand isn't rising fast enough for solar supply. Here's today's example, which is notably more extreme than previous days:

National Grid: Live

Shows the live status of Great Britain’s electric power transmission network

grid.iamkate.com

(Graph of energy generation in last 24 hours)

 

[Nottingham59]

My guess is it's spurious. https://gridwatch.co.uk/Solar shows a smooth curve for today

 

[The Ham]

My guess is it's spurious. https://gridwatch.co.uk/Solar shows a smooth curve for today

Looking at the daily average graphs at the bottom, and bearing in mind we are yet to have the longest day, the daily average for this year so far is 2.238GW vs 2.038 for the whole year (roughly +10%).

 

[Ted633]

Price per MwH has absolutely skyrocketed this afternoon, not sure I've ever seen it that high (£343)
Interestingly as well, we are also exporting 1.5 GW. All very unusual (in what I've seen), issues on the continent?

 

[Lloyds siding]

France, and probably other countries, have reduced their nuclear output, so that they can still cool the plants in this heatwave.

 

[HSTEd]

French nuclear output is indeed much lower than might be expected according to gridwatch France.
Most likely they have had to reduce output to avoid cooking the rivers, if this continues expect to see a dispensation as during the last great European heat wave.

 

[Class 317]

Request from France to allow them to lower nuclear output for cooling reasons but still cope with rising demand.

 

[Krokodil]

Interesting to note the contrast between France's nuclear power stations - which use rivers for cooling; and Britains - which (other than Trawsfynydd) use the sea. Is one more effective than the other?

 

[AndrewE]

Interesting to note the contrast between France's nuclear power stations - which use rivers for cooling; and Britains - which (other than Trawsfynydd) use the sea. Is one more effective than the other?

There is a lot more sea for ours to disperse the heat into, hence the comments about French nuclear power stations being turned down so that they don't overheat the rivers, driving off the oxygen, boiling the fish and wiping out the wildlife!

 

[HSTEd]

Interesting to note the contrast between France's nuclear power stations - which use rivers for cooling; and Britains - which (other than Trawsfynydd) use the sea. Is one more effective than the other?

Chapelcross, Calder Hall and the SGHWR at Winfrith also did not use the sea, which is why they had cooling towers. However, yes, once through sea based cooling is almost universally considered to be suprior.

The inland stations in France are, to some degree, a result of constraints of geography - there is a lot more of the country a long way from the sea. However, I think the French have come to the conclusion that longer transmission distances are preferable to inland siting for new reactors.

 

[Bald Rick]

Request from France to allow them to lower nuclear output for cooling reasons but still cope with rising demand.

Also presumably with massive solar output today, the French chose to constrain Nuclear rather than solar?

I saw that Germany was generating 40GW of solar at lunchtime.

 

[HSTEd]

Also presumably with massive solar output today, the French chose to constrain Nuclear rather than solar?

I saw that Germany was generating 40GW of solar at lunchtime.

I would be somewhat surprised if they did. EDF have concluded that turning plants off for short periods of time costs more than operating them.

 

[brad465]

IIRC during the 2022 heatwave the National Grid had to buy some electricity from Belgium at a 4-figure sum to prevent a London blackout.

 

[AndrewE]

IIRC during the 2022 heatwave the National Grid had to buy some electricity from Belgium at a 4-figure sum to prevent a London blackout.

Guardian article today: https://www.theguardian.com/busines...mp-in-europe-as-demands-soars-in-the-heatwave

Europe’s heatwave drives electricity prices to new highs as demand soars​

Great Britain has paid at least six times the normal price for imported power as millions turn on air conditioning and windfarm output sags
The heatwave has prompted a sharp rise in electricity prices across European markets as millions turn to air conditioners and electric fans to battle record high temperatures, which have also caused a string of power plant outages across the continent.

Great Britain imported electricity from Europe at more than six times the normal price on Tuesday as the high-pressure heat dome has slowed wind speeds, hitting renewable energy generation, and led to outages at multiple gas plants across the country.


The heatwave has caused windfarms on the continent to slow, and led to lower output at some nuclear plants in France, where high river water temperatures are making it more difficult to cool the reactors.

The combination of rising electricity demand and falling generation across Europe has caused market prices to climb to multi-year highs.

Great Britain’s energy system operator has resorted to paying about £470 per megawatt-hour to secure electricity imports from the continent between 5pm and 7pm on Tuesday to help meet the country’s peak electricity demand.

etc. Worth reading the whole thing.

 

[Krokodil]

Price per MwH has absolutely skyrocketed this afternoon

Looking at Agile Octopus, it may be even worse tomorrow.

== Doublepost prevention - post automatically merged: 23 Jun 2026 ==

not sure I've ever seen it that high (£343)

I've just checked and it's currently at £410

 

[jon0844]

Looking at Agile Octopus, it may be even worse tomorrow.

== Doublepost prevention - post automatically merged: 23 Jun 2026 ==


I've just checked and it's currently at £410

Axle Energy will pay me £1 per kWh export tomorrow (plus 12p per kWh from Octopus), but sadly only for one hour so I can't supply more than 5.5kWh! I'm generating about 40kWh a day, plus 13kWh stored in a battery charged up overnight, so I would be quite happy to export for longer and help the grid and earn some money!

While Agile is bad for import, Agile Export is paying out 36-38p per kWh from around 1800 to 2200.

 

[HSTEd]

Axle Energy will pay me £1 per kWh export tomorrow (plus 12p per kWh from Octopus), but sadly only for one hour so I can't supply more than 5.5kWh! I'm generating about 40kWh a day, plus 13kWh stored in a battery charged up overnight, so I would be quite happy to export for longer and help the grid and earn some money!

While Agile is bad for import, Agile Export is paying out 36-38p per kWh from around 1800 to 2200.

Peripheral to the topic, is Axle actually on top of your existing export tariffs, also are you credited for all power exported during the event or merely battery export?

 

[jon0844]

Peripheral to the topic, is Axle actually on top of your existing export tariffs, also are you credited for all power exported during the event or merely battery export?

It's on top. Axle takes control of my home battery and sets the export when they have an event. The company has stopped allowing new users to give up total control of the battery, and currently only do (it seems) a couple of events per month like this. They always top up to a minimum of £10 regardless of how much you export.

Octopus is going to do similar soon and pay a minimum of £12 per month. Others will likely enter the market and maybe we'll get enough competition to see higher rates per kWh exported. I believe Axle gets paid around £3 and give me £1. To me that's easy money (I do nothing) but it's also perhaps unfairly tilted in their favour a bit too much.

As it's not linked to my tariff, I still get paid by Octopus for the export recorded on my smart meter. Axle doesn't actually take over the meter in any way... My inverter and DNO approval limits me to an export of no more than about 6kW, so if I'm generating solar at the same time I guess it doesn't know the difference as the inverter and battery are both from the same company and managed via the same app that Axle has access to.

 

[Bald Rick]

I would be somewhat surprised if they did. EDF have concluded that turning plants off for short periods of time costs more than operating them.

That’s kind of what i meant, ie turn them down in high summer for a coulle of months while solar and pumped hydro can pick up the slack. But i suspect aircon demand in early evening (when solar is low) is what is driving the evenign prices.Grid scale battery owners will be making a killing.

 

[quantinghome]

The inland stations in France are, to some degree, a result of constraints of geography - there is a lot more of the country a long way from the sea. However, I think the French have come to the conclusion that longer transmission distances are preferable to inland siting for new reactors.

They also have bigger rivers. Very few rivers in England and Wales could support the Nuclear power stations in use in France. And the newer generation reactors now being built are generally larger so not suitable even for the larger French rivers.

 

[brad465]

So far evening demand pricing has got to just under £250/MWh, which while markedly higher than the daytime, is not as bad as yesterday so far. Tomorrow will hopefully be better as it's set to be windier, plus London & the SE are forecast to be cooler than today.

 

[Bryson]

A bright breezy day today and generation is at 114% of the demand. A lot of energy is been exported and the storage is getting topped up.

 

[brad465]

View attachment 207055

A bright breezy day today and generation is at 114% of the demand. A lot of energy is been exported and the storage is getting topped up.

90% renewable energy generation has to be a record (or is at least close to it).

 

[zwk500]

90% renewable energy generation has to be a record (or is at least close to it).

GB has run on 100% renewable energy for periods last year: https://www.carbonbrief.org/analysi...ean-power-for-record-87-hours-in-2025-so-far/

(Northern Ireland is on the separate All-Ireland Grid)

 

[Bryson]

90% renewable energy generation has to be a record (or is at least close to it).

Today's peak was 93% renewable as a percentage of the demand.

 

[Krokodil]

£203.89 per MWh at 06:30 this morning. Prices remain high all day. I've turned the water heater timer off, the tank will be good for a couple of days until Agile prices return to sensible levels.

 

[AndrewE]

£203.89 per MWh at 06:30 this morning. Prices remain high all day. I've turned the water heater timer off, the tank will be good for a couple of days until Agile prices return to sensible levels.

That will be why Octopus have a "Power down" session this evening then...

Get ready for a Saving Session later today! Use less electricity than normal to avoid fossil fuels and earn Octopoints.

Power down 6-7pm, Mon 17th August (today!)
During the hour, you'll get 101 Octopoints for every unit of electricity you save compared to normal.

i.e. get a token reward!

 

[brad465]

Gas prices have been elevated the last two months, presumably because the Strait is still not open and the Northern Hemisphere is buying supplies for the winter now. As our prices are still pegged to gas most of the time, this is why they have been more expensive of late. This is also not normally a windy time of the year; solar of course has been doing really well, but until battery storage ramps up further, this only has a material price impact in the middle of the day.