01 June, 2025 - Gilbert West
Will North Scotland be able to best last year’s record of 236 full days with zero emissions. It’s looking unlikely and definitely not something I’d bet on. I’ve added a “days remaining in the year” column in the charts for zero days and days classified as very low (below 30gms) so we can track how many days are left in the year. That determines the theoretical maximum for the year. At the time of writing the max still possible is 283 days, but as each day goes by it looks less likely.
Things began to look off during the 1 week Dunkleflaute in February when carbon intensity was in the 300s.
On the surface, if you look at data for North Scotland, you see that wind is making up an even greater percentage of generation so far this year, continuing the steady increase from 51% in 2019 to around 82% this year (year to date). That’s a 4% over last year’s figure, so why is another record likely out of reach?
Well if you dig deeper you can see that generation from gas has almost doubled from 7.5% to 14.3%; most grid regions have increased gas use in 2025 which means continued high domestic electricity prices for you and me. Why, if wind is increasing is gas also increasing?
That's right, all those "taps aff" days (no pun intended) killed hydro.
The dry Autumn 2024 of and driest spring for decades has wiped out hydropower. Last year it contributed 16% of generation in North Scotland. This year it’s barely a trickle as it plummeted to a fraction of a percentage at the beginning of the year and flatlined everywhere at the end of February. The figures are going improving a little and rivers in the West and some in the south are moving out of the danger zone. But we still have Summer ahead.
I’ve added a new chart that focuses on monthly hydropower generation in North and South Scotland and this shows the precipitous fall experienced due to drought in the first half of 2025. The Scottish Parliament Information Centre have a great article, Drouthy Days, that gives a great overview of the rainfall patterns so far this year, the reasons behind the change and the impacts on rivers, agriculture and society (but not energy). I’ve added the link at the bottom of this article.
The chart above shows the monthly percentage of electricity that came from hydro power in the two grid areas of North and South Scotland. It covers the period from January 2021 to date and is a live chart that updates every morning.
Predictably, later Spring and Summer periods of May to September usually have the lowest production percentages.
Production has dropped dramatically in 2025, coinciding with a period of drought.
It will be interesting to see how this affects pumped storage. Even if there’s abundant cheap electricity to pump water into reservoirs that market mechanism only works in there’s adequate water available and that not something the markets can solve.
The “it’s on/it’s off” upgrades/expansion at Drax’s Cruachan Power Station means hydro may be playing a lesser role for the foreseeable future while expansion of the site and valve upgrades take place.
Solar has seen a 300% increase in North Scotland, but going from 0.1% to 0.3% isn’t quite the good news story I was looking for so let’s not crack out the good Whisky yet. Hopefully the increase is due to new installations and this is the start of more balance between wind and solar, but we have also just experienced the sunniest April in a long time.
Further reading (external): Drouthy Days: is Scotland prepared for drought?
You can explore whether wind, solar, gas or nuclear is the main source or electricity in your area through our chart "Share of Electricity by Source" on the charts page.
To explore the data around carbon intensity and where our electricity comes from, check out the Charts page.