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The data on my UK electricity generation page is automatically updated every day. A couple of months ago I was looking at the latest update and noticed some of the top level records had changed but not on the previous day. It's not unusual for recent data to get updated but now the data was saying a number of electricity generation records had been broken on 26th June 2023, over 2 years ago.

Initially I thought this was an error in the data and it would be corrected at some point but here we are 2 months later and the data remains the same. So what's up? Why was the data updated and why so long after the actual event?

I did some Googling for uk electricity generation 26th June 2023 but nothing turned up. I also did a search on Bing and my page came up as the top result so that's nice but it couldn't tell me anything special about that day. I even tried asking ChatGPT, which proved even less useful. 

So all we can do is look at the data for the day and for the previous day. The 25th was a good day for solar and wind generation and as the sun disappeared, gas started to ramp up as it usually does. But at 6pm, gas generation started to fall fairly dramatically until 10pm. Then it continued to fall but at a much slower rate. This continued until 5:30am on the 26th, when gas reached virtually zero generation. After this, things fairly rapidly returned to normal.

So what happened? Why did gas generation reach a new record low that we've never got close to again? One possibility is that this a data glitch, but why was did it appear in the data set two years after the event? One reason this looks like it could be the correct answer is that it doesn't look like we were actually producing enough power during the evening of the 25th (although it is possible we were importing more than usual).

But a more interesting theory is that this was actually an experiment to see how the grid coped with mostly clean energy sources. It's my undersanding that electricity generation that involves turbines helps keep the grid's AC frequency in sync, so there have been some questions about how we deal with that when most of our electricity comes from renewables. The fact this weirdness happened in the middle of the night and the gradual withdrawal of gas from the mix gives some credence to this theory. And if that is what happened, the fact we haven't come close to these low levels of fossil fuel usage again may suggest the test was not completely successful.

Anyway, I am going to ask NESO what is happening with that day's data and will let you know if I get a response.

I've updated the postcode data on the site with the latest ONS data. There are problems with the locations of 15 new Northern Irish postcodes, which I've removed for the moment. This is something of an improvement from the last release which initially misplaced all Northern Irish postcodes. If you spot any other problems, let me know

Much quicker this month, England and Wales house price data for July 2025 is now on the site. More of the same, prices creeping up (although possibly going negative some time soon) and a low number of sales

A little late this month due to me being busy, but the house price data for England and Wales has been updated on the site. Prices still seem to be finding their new level after the Stamp Duty change and sales volumes still seem to be in the doldrums

The main reason I set up the UK electricity generation page was to see the progress we are making on the road to a clean grid. One of things I was hoping to see was fossil fuels get pushed off the grid completely for a short period of time. There has been talk of that happening some time this summer, but it hasn't happened yet and the lowest levels for fossil fuel use were over a year ago.

There may well be sound reasons for this but it is somewhat disappointing. So I came up with my own statistic to show we are making progress. Count up the time we are producing more than 30GW of power from low carbon sources, because 30GW is the UK's average electricity demand. I'm only including wind, solar, nuclear and hydropower in this calculation because I'm not a fan of biomass. And in June 2025 we managed to achieve this for 27 hours in total, a new high. This broke the record of 15.5 hours set the previous month. 

If you squint, you can see the UK's clean grid coming over the horizon. 

I've uploaded the latest house price data to the website. Last month I noted the sudden drop in prices and assumed it was a data glitch but we are still seeing it this month. I've now realised stamp duty rates have changed and this is likely one cause of the drop in prices, basically a repeat of what happened in the summer of 2021

I'm a little late with this (not entirely my fault) but I have uploaded the latest data from the ONS to the website. It all seems in order but let me know if you spot any problems

I've uploaded the latest Land Registry data for April 2025 to the site. The latest month is always incomplete but this is particularly evident this month, with the average sale price dropping massively. I'd suggest ignoring this data point for the moment. The annual data is more reliable and shows prices continuing to tick up but sales still low.

UK electricity generation on 22nd May was fairly typical for a reasonably sunny summer's day.

Gas generation was low in the middle of the night because demand was low. As the day started, demand increased and gas generation increased but was limited as solar generation ramped up. Then as solar dropped off but demand remained high in the evening, gas generation went up yet again. You can see this repeating on most sunny summer days.

Now imagine we had twice the solar capacity we have today. We'd actually be able to turn off gas power stations in the middle of the day. That would be a pretty big deal in itself. But now imagine we had enough battery capacity to store the excess solar energy so we don't need to turn the gas power stations on for some of the evening hours. Keep on ramping up solar capacity and we'd eventually be able to store enough electricity for the evening and the nights, refill them during the day and keep going. We could go days without using fossil fuels.

Anti-renewables people often say "what happens when there's no sun or wind?". Even reasonably pragmatic people will say something similar. It's not an unreasonable point to make, in the middle of winter we can go days or weeks with little sunshine and not much wind and we'd need an absolutely huge fleet of batteries to deal with that scenario. But the batteries required to deal with getting from one sunny day to the next is much smaller. Even in the famously grey and gloomy UK, it's probably something that's worth doing. 

There's a politician in the UK who has a simple solution to every problem. His last simple solution to our problems was to leave the EU, it would appear that didn't fix everything because he's back with some more simple solutions. One of them is to dump renewable energy and get back to good old reliable fossil fuels. Like with all his solutions it's based on a half truth at best. This site gives a breakdown of where the money from our electricity bills goes and in 2025 about 20% of our bills go on some kind of renewables subsidy. But go back to 2022 and closer to 5% of our bills were going to renewables because the price of gas was driving the wholesale price of electricity and gas prices had shot through the roof. Even in 2025, the biggest part of our bills comes from the wholesale price of electricity, which is still mainly driven by the price of gas.

But what will happen in the future as more and more renewables come online? We can make a good guess by analysing the generation data from NESO and the price data from Exelon. I've taken the data for 2025 and here's a graph of electricity price against the percentage of fossil fuels being used to generate it.

That big spike in price between 50 and 60 percent squashes the graph so it's difficult to see what the trend is from this graph, but I put it in because it show a couple of interesting things. First is that the price of electricity can fall below zero, but it only ever happens when we have a lot of renewables online. I guess it might be a good time to invest in batteries, charge them when prices are low or negative and and sell the electricity when prices have gone back up. The second thing to note is the insanely high prices when we don't have renewables available. That's gas fired power stations making a killing because they can...

So if we put this data in buckets of 10% we can get a clearer picture of what's going on

This makes it pretty clear that as less fossil fuels are used to produce electricity, the price drops. Building more renewable capacity and batteries will put us on the left of the chart more frequently so prices in general should be lower. I will caveat that statement by saying I am no expert on the workings of the electricity market, so can't guarantee things are that simple...

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