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NESO, FOI, whistleblowing, frequency response etc

33 comments started 2026-07-08 last 2026-07-27
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#2 Vestas

I'd believe it more if she wasn't a right-wing climate change denier....

#3 hoggy

We did have to kill our planned exports that day for us to pull the frequency up as it was getting a bit grim.
Margin was not great either.

Can't comment on the whistle blowing as don't know the context.

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#4 Vestas

hoggy Indeed but "our electricity grid is becoming increasingly unstable" tells you all you need to know - vacant self-serving culture "warriors" (aka fuckwits).

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#5 Roberto

Grid instability is not a surprise-Look at what happened to Spain year before last ? They too have reduced their reliance on traditional large inertia rotating machines to deliver grid stability. The UK has done the same. Our grid, like most was designed with large synchronous machines ( PS 500MW and 660MW) turbogenerators. Yet noew we are relying on PV and wind that is delivered largely by inverters.

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#6 Vestas

Roberto No we haven't. We're nowhere near the level of renewables Spain has. We have balancing mechanisms and more are planned - some more sane than others*.

*there's a scheme proposed for Loch Ness which would result in a rise/fall of 1 metre in water level. As a reminder, Loch Ness contains more fresh water than all of England and Wales put together. Having said that there's been a drought for the last few years so 1m drop in water levels would render the southern end of the loch/canal unnavigable.

#7 Maxwell

Vestas Oh no. What’s Nessie going to do ?

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#8 SteveCook

Maxwell
Nessie is about as real as as worthwhile GivEnergy warranty

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#9 mrand31

SteveCook Nessie is about as real as as worthwhile GivEnergy warranty

Wash your mouth out with Whisky 😮

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#10 T-M

Vestas There's a large chunk of spinning metal in Rassau just north of Ebbw Vale that was installed back in 2022 for just this purpose.

#11 Maxwell

The NESO bloke on the radio this morning didn’t really answer the question about the whistle blower claims.

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#13 wrefordj

hoggy It's good to know that there must still be some electrical engineers involved who know what they are doing, unlike Spain...

#14 hoggy

wrefordj well nothings a given, there's only so much you can plan for either generation or loss wise. If we were a 100% confident we wouldn't run black start trials.
They do solve a problem though and other than initial cost there's not a lot on them to go wrong/maintain.

I suspect like anything market efficiency based it's trying to find the right balance on what is the minimum you can get away with in reserve without paying over the odds the rest of the time when your just paying it to sit there.
Really difficult line to tread and I honestly don't know what the answer is to that.

#15 Maxwell

The whistleblower letter says nothing about how long the alleged frequency dip lasted. And i',m not sure whether this just comes down to a difference of technical judgement between folks in the ops space. We are not privy to whatever other data the ops folks had visibility of at the time of the alleged incident.

But looking at the different frequency registers, (Grid_Frequency, Inverter_Output_Frequency and Frequency) there is no real evidence of any sustained dip below the 49.8 value quoted in the letter.

Grid Frequency

Inverter Output Frequency

And Frequency

The orange dotted line is just the 49.8Hz value

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#16 mrand31

If a single, significant, generator trips, there is a noticeable frequency perturbation. That can't be helped and won't cause any issues that the public can see. Overall the 24hour average frequency is pretty much exactly 50Hz, because all power stations monitor grid time (synchronous clock) against actual time (originally Hipp clocks, now quartz and GPS, but all checked with the NPL time signal).

When we built our new computer room at work in 2001, we installed a standby 150kW generator with a super-synchronous flywheel and 20mS repsonse. For the next 15 years I was at work, that would power up about once a week due to grid frequency excursions. I think there were only about four times that we actually had to run off it for more than a few seconds.

Sorry, just reminiscing. 🙂

#17 Maxwell

So i looked at the frequency data on hoggy Terravolt page and you can see a dip below the fabled 49.8

And i can see a similar dip in my grid and inverter frequency for the same day at the same times

#18 hoggy

Maxwell yes it will be visible to most on their inverters as it will have been nationally felt. The return to "normal" aligns with when the flows to Netherlands and France were restricted.
You can see they tried to get a grip around half 7 but whatever they tried to do failed and then the frequency fell even more before they cut exports.

We had pretty much the entire fleet of OCGT & Peaker plants in at the time so they wouldn't have had much room to manoeuvre.

After the 2019 blackout however there has been a monumental effort to bolster RoCoF on plants so they don't trip so early on frequency swings and make everything worse. (It's one of the main differences between the old G83/G59 and the now G98/G99 compliance)

#19 Maxwell

hoggy Thanks for the explanation. Is this based on some insider knowledge or is this the grid equivalent of the railway trainspotter 😉

#20 hoggy

Maxwell bit of both
I work in the power generation industry (Terravolt originally began as a private way of me waking up in the morning to check if something was running and therefore not wasting my time driving to it only to find it was off & I couldn’t do any work)

But equally I am quite sad so as a hobby I try and keep on top of this kind of thing.

Amusingly I thought I’d caused the 2019 blackout as I’d literally just pressed the go button on a site - the same time everything went off. I laugh now but at the time it wasn’t so funny trying to figure out what was going on & why the whole plant just cut its own throat…

#21 Maxwell

hoggy Excellent. And a nice site, I like the your data has been successfully retrieved. And we are all a bit sad when the grid goes down. So, the next time you press a button please make sure it’s the right button 😉

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#22 T-M

hoggy In the late 80'a I was a student on an undergound visit to a coal mine in the Rotherham area. One of the other students leant against an electrical panel while we were stopped in a roadway while the instructor explained something to us, and he accidentally pushed an emergency trip button and cut off all power to about 4 coal faces. The tannoy system went berserk as people tried to find out why all their machines had died. To restore power to the coal faces, people had to start where we were and walk back into the faces switching things back on as they went. Must've lost about a million tons of coal that day. Hope they didn't bill him.

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#23 wrighar

mrand31

One of the DC's I worked with in the late 80's, early 90's, converted 3 phase to DC, and then that back to AC, to get a stable frequency for the mainframes. Water cooled they were back then.

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#24 mrand31

In the 'early' days, disk drives often had synchronous motors.

Ended up in South Korea to do a power station steam turbine performance test in '85 and couldn't read any of my programs off the disk drive. Hewlett Packard managed to locate one of the set of two toothed belt pulleys in Japan, but not a pair anywhere in the world.

The computer had a built in tape drive and I had a several months old copy of my programs on tape, plus a printout of 30,000 lines of more recent code. several weeks spent typing ensued, while also trying to boss/herd the running of transducer and thermocouple cables around the station.

Eventually managed to source an inverter from a little company called Lucky Goldstar (yes, them!). Ran the computer and disk drives off it for the duration of the work.

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#26 Blasteh

Went back to look at my data and there's quite a prolonged dip that goes below 49.8 a few times (orange boundary)

#27 Maxwell

Not sure where the Guardian got its times from. But unless there is a lag (no pun intended) between NESO seeing the numbers drop and the effects being seen by customers then the drop below the 49.8 on the 23rd was sometime between 18:30-19:00 (based on the data I posted previously here from hoggy Terravolt data). And similarly on my own inverter.

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#28 TX200

Maxwell what kind of lag? How much?
If it's an hour out, could they be reporting in GMT?

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#29 NormC

Maxwell My data corresponds with that.

I was exporting to the grid at the time and the inverter reduced it's frequency to match that of the grid.

#31 26Left

Three articles in Saturday's Times following ter leaking of a report produced by the energy consultancy Cornwall Insight in April:

Net-zero race ‘risks blackouts and higher bills’
A whistleblower claims the national grid operator is ‘flying blind’ because it cannot accurately forecast supply from renewable sources
https://www.thetimes.com/uk/politics/article/net-zero-blackouts-bills-national-grid-z88zz3l8v

Secret report that exposed the fragility of our electricity system
After Britain’s grid started behaving strangely during the heatwave in June, whistleblowers reveal risks of the green transformation
https://www.thetimes.com/uk/environment/article/secret-report-neso-electricity-system-8xvvsh030

Solar power is booming. Now engineers must prevent a grid crisis
Surging numbers of household panels are making electricity supplies volatile, and control room staff are being forced to manage dangerous imbalances
https://www.thetimes.com/uk/environment/article/solar-power-grid-crisis-73gqs5m2j