The first went in in April 2011. They have been recording every half hour ever since — and for fourteen years the market that decides what your electricity costs read only the total. Forty-eight numbers a day, collapsed to one, and the shape put back on from one of eight national curves. That stopped last November, and the first thing the real data showed was a peak that wasn't there.
One thing to be clear about from the start: this is a story about houses. Britain's larger business sites have been settled on their actual half-hourly consumption for decades, and mid-sized ones since 2017. Offices, factories and shops have had a market that knows what they really did for as long as most of their meters have existed. It was homes — and only homes — that got the average.