Flanders wind power and Belgian day-ahead electricity price forecast

Forecasting the Belgian electricity price

Belgium is a single bidding zone, so one day-ahead price covers the whole country. OpenWindCast forecasts all 24 hours of tomorrow's delivery day, using only information available before the auction closes. The Wallonia page shows the same record, because there is only one Belgian price.

Belgium trades as one bidding zone. However the country is divided for wind reporting, the electricity market is not: a single day-ahead auction sets one price per hour that every Belgian participant pays, and it closes at 12:00 CET for the following delivery day. Every forecast here uses only information that was available before then, and covers all 24 hours, in euro per megawatt hour.

Flanders carries the larger of Belgium's two onshore wind fleets, but that output reaches the market as part of one national total rather than as a Flemish price of its own. So does Walloon wind, so does Belgian solar, and so does the offshore fleet in the North Sea. What is forecast here is the price the whole zone clears at, which is why the Flanders and the Wallonia pages show the same 24 hours.

The auction clears once and the price it sets is final, which is what makes the record on this page possible. Each published forecast is written once and never changed, and the price the auction actually cleared at is placed beside it hour by hour as soon as it settles, including on the days the forecast was wrong. Hours are the CET auction day, which is also Belgian local time.

The price forecast and the Flanders wind forecast are separate products, scored separately, and each has its own record on this page.

Forecasting wind in Flanders

Flanders is the northern region of Belgium and one of the most turbine-dense onshore areas in Europe. The forecast covers Flemish onshore wind and is scored against Elia's published day-ahead forecast.

Flanders fits a great many turbines into flat, low-lying and heavily developed ground, along the coastal polders, around the port areas and beside the motorway corridors. The terrain itself is about as simple as European wind gets, so the local wind field is comparatively straightforward. What is not straightforward is density. Turbines packed closely together sit in each other's wakes, and an intensively built landscape is aerodynamically rough, so the relationship between the free-stream wind and the power actually delivered is not the clean curve a single isolated turbine would follow.

The benchmark

The benchmark is Elia's own day-ahead forecast for Flemish onshore wind, taken from Elia Open Data. Belgium is the one place where Elia publishes early enough that the benchmark can be captured at the same time the forecast is issued rather than later in the day.

What is published for Flanders

One value per day: onshore wind output at 11:00 local time tomorrow, as a load factor and in megawatts. Once Elia's own forecast for that day is published it is captured and held fixed, and once the metered output is settled both forecasts are scored against it. Every day is added to the record above and nothing is removed or rewritten later. How this is measured.