‘Tis the season for mulled wine, family time, and unusual electricity patterns. It is getting colder, which makes us wonder if we are “California dreamin’ on such a winter’s day.” We don’t quite have California’s famous solar ‘duck curve’ — but we do get that unmistakable winter evening ramp, the collective moment when Britain gets home, turns the heating up, and the system flexes accordingly. We are steadily working, pacing ourselves so we can get to the point where we slow down towards the end of the month. It is a season where we feel closest to our friends and family, a time for gratitude and storytelling – so we’d like to start by sharing curious tales of the grid during this festive season.
As we all know, Christmas is a time for relaxation. Christmas Day and Boxing Day are two of the quietest days on the grid, with demand far below a normal winter weekday as schools, offices and shops shut down. It is one of the very rare national days on which most commercial operations halt (even in London!). Boxing Day is usually the day on which the least energy is consumed, followed by Christmas. On a trip back to the UK’s Christmas Day 2022, peak demand was as low as 30 GW during the lunchtime settlement periods. It was exceptionally mild weather, and embedded renewables helped keep net demand on the transmission system unusually low. The unusual demand drop and renewable high made it feel like summer… a Christmas miracle.
Low demand means that most of the supply can be met by renewables. Looking back to 2020, if one single good thing happened in a very odd period of festivities, it was that Christmas 2020 was the first coal-free Christmas since the electricity age began in the 1880s with zero-carbon sources supplying >50 % electricity. Boxing Day pushed that even further, with around 80% of the day’s power coming from low-carbon sources. Electricity supply was as green as a real Christmas tree.
However, what would the holiday season be without a little bit of chaos?
So, Christmas lunchtime is one of the lowest loads by 10-15. Flashback to 2019: peak Christmas Day demand was 33.3 GW versus a November high of 46 GW. In times like these, voltage management and ramp-up rates come to star in some riveting entertainment, invoking our ever-present need for electrical management. The first dramatic turn is that in regions like Eastern England, Scotland, and the Southwest, DSOs have documented occasions where demand falls so low that voltage rises above statutory limits… such as Christmas time. Here, the never-welcome guest appears… curtailment. Active Network Management (ANM) is triggered with a downward dispatch to shut down the imbalance caused, limiting normal operations.
Thankfully, more Christmas miracles are happening. Flexibility is coming into the picture with batteries, demand response, and electric vehicle fleets coming to the rescue to avoid wasting the perfectly good, clean electrons. Who needs Santa Claus? Jingle bells, Batman smells, Robin laid an egg… and the electricity grid took us for an energetic carousel… and it goes on.
While Christmas is about downtime, New Years Eve is about living it up. New Year’s Eve produces sharp, short-duration demand spikes of the entire calendar: the “midnight surge”. Live it up, we do! We, Great Britain, can ramp in the GW scale within 30 minutes. Between 23:30 and 00:30, ESO historical data shows a highly unusual pattern: load falls as people leave parties or prepare for the countdown. Then, it surges immediately after midnight as we all switch on simultaneously. It’s a very different shape to Christmas Day, where peaks are flatter and more stretched out (as are we).
On the morning of New Year’s Day, we stretch out again, as we see demand collapse again as well. As we know, New Year’s Day morning is where most of our resolutions are dozing and resting, before the year starts ramping up.
Here, at Blake Clough, our resolution is to grow in quality and scope. We strive to understand where the electricity grid is at and where it’s going with the purpose of decarbonising our energy systems. We aim to inform you sharply, insightfully, and with precision on all things power-networks We offer engineering, strategic, and now market solutions to ambitious electrical resolutions of your own.
We wish you a wonderful, exciting, and restful festive season from the depths of our bio-electricity-powered brains (and hearts).
