LinkedIn·Tuesday, 25 August 2026·1d ago

In 2021, the cheapest power in Belgium was at night. So far this year, it is at one o’clock in the afternoon. This is six years of Belgian…

Nina Waffenschmidt

CEO at PerPetum Energy

In 2021, the cheapest power in Belgium was at night. So far this year, it is at one o’clock in the afternoon. This is six years of Belgian day-ahead prices, each hour set against the average of its own day. In 2021 the low point fell between three and four in the morning, about a quarter under that average, and the afternoon barely moved. This year three in the morning sits exactly at the average, and one in the afternoon has dropped to four tenths of it. The evening peak has shifted an hour later, from seven to eight, and climbed well above where it used to sit. One answer to a curve like this is to take yourself out of it. That is what a power purchase agreement does: one price per megawatt hour, agreed once, held for fifteen or twenty years. Whatever the market does over that period, up or down, the price on the invoice is the one that was signed. For a company whose energy bill is large enough to show up in its results, that alone is worth a great deal. It is a large part of what we do. What it fixes is the price. What it does not fix is when a site uses its power, and that gets decided again every day. Once against tomorrow's forecast, when the next day's prices are known and a plan is made. Then again inside the day itself, when the forecast turns out to be slightly off – a cloud where the sun was expected, a batch that ran longer than the schedule said. Both of those decisions sit on the shape of the day. And the shape of the day is the thing on this chart that will not hold still. That is why one half of the work sits before anything is built. Reading where these curves are going, and designing a plant's energy system around that: what it generates, what it stores, what it can move to another hour. That part is hard to correct later. The other half runs for the next twenty years, because the curve it was designed against will have moved on. Which hours a site can shift, and what that is worth, is not a question you answer once.