Over the Easter weekend, electricity demand set a record low, hitting 15.2GW on Sunday night. That’s 3.1GW below the Easter minimum last year. Average demand over the whole weekend was 21GW, a 2.1GW drop from last year.
That’s despite Easter being eight days earlier (shorter days, more lighting), less sunny (more lighting), almost a degree colder (more electric heating) and a little bit windier (more electric heating). We’d have expected more consumption; what we got was a lot less.
These numbers use Elexon’s National Demand (ND) definition, which treats all solar farms and most of the smaller wind farms as negative demand. So in fact, during the weekend an average of 3.5GW of green electricity from smaller sources was slipping quietly through to customers over the distribution networks, out of sight of the large Grid Supply Points where real-time demand measurement is done. It’s not true that the wind and solar farms aren’t metered at all – if you didn’t have a meter, you wouldn’t get paid – but those meters are read once a day, not every minute or second.
This embedded generation masks some of the demand. It means that customers were consuming 3.5GW more than the ND number shows. But this effect was in play last year as well, and was actually slightly larger, at 3.7GW. So the true demand drop from last year to this was a robust 2.3GW.
The COVID-19 lockdown is the obvious cause, bringing a large drop in activity across most industrial and commercial sectors. The fall might have been even greater had it not been for the pivot which many businesses made towards critical supplies for the NHS.
The missing demand is roughly equivalent to two large nuclear stations. Not that those were switched off – it’s commonly known that nukes don’t like to flex, and they make that clear through their pricing. Turning off just one nuclear station in the balancing mechanism would have cost consumers around £10 million for every hour of shutdown. If that sounds like silly money, it’s supposed to be. The nuclear generators are telling National Grid ESO to look somewhere else – anywhere else – if they need to turn down generation.
Not everything is as rigid as a nuke. Still, at the low point leading up to 5am on Easter Monday morning, every station that National Grid turned off was paid to forego generation – even the CCGTs, where a switch-off saves on the gas bill.
Throughout the weekend, we also saw positive energy being delivered in the Balancing Mechanism. This is normal: regardless of demand, National Grid ESO is almost always balancing in both directions. When demand is very low, some power stations have to be turned not down but off – and in that state it takes a lot longer to get electricity from them to cope with normal fluctuations. This is a gap that small, embedded generators like CHPs, or fast-acting merchant plant like batteries, can help to fill.
That’s what we at Flexitricity, together with our customers, were doing over the Easter weekend, with our operations team still covering every site 24 hours/day, but under lockdown conditions.
There’s more of this to come. At some point, industry and commerce will start going back to work, and perhaps so will the schools. In the meantime, every demand dip starts from an already-low demand figure. If both renewables and nuclear are generating at high levels, National Grid ESO will continue to keep us busy as they manage inertia, headroom and footroom on the system.
This is a taste of the future. National Grid ESO has already announced that it will be ready to operate the system with no indigenous carbon-emitting generation from 2025. To do that will require participation from a much greater variety of flexible consumers, pushing down the size curve through commercial and retail buildings and out into electric vehicles, heat pumps and heat stores.
It will also require more batteries – from larger, strategically located merchant battery farms to much smaller units screwed onto garage walls. Fortunately, we’re just now at a place where this has all become possible. With the advent of Balancing Mechanism Wider Access (BMWA), and the imminent launch of the Dynamic Containment end-state frequency response product, the market became ready just in time. Given that the market is now open for all sizes and types of flexibility and we’re seeing forecasts that indicate the balancing and ancillary markets will grow to £2 billion by 2030, I’ve no doubt that many more consumers and generators will be eager to take advantage of this opportunity.