Wallonia 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 Flanders page shows the same record, because there is only one Belgian price.

Wallonia and Flanders are forecast separately for wind because they are separate fleets in separate landscapes. For electricity they are not separate at all. Belgium is a single bidding zone, and one day-ahead auction sets one price per hour that every participant in the country pays. 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.

For a generator on the Walloon plateaux this means the price it earns is set by the whole Belgian system rather than by conditions in Hainaut or Namur. Walloon wind is one contributor to it, alongside Flemish wind, Belgian solar, the offshore fleet in the North Sea, demand across the country and what the neighbouring markets are doing. The forecast here is of that national clearing price, which is why the Wallonia and the Flanders 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 Wallonia wind forecast are separate products, scored separately, and each has its own record on this page.

Forecasting wind in Wallonia

Wallonia is the southern region of Belgium, with most turbines across the provinces of Hainaut, Namur and Liège. The forecast covers Walloon onshore wind and is scored against Elia's published day-ahead forecast.

Walloon wind sits higher and more thinly spread than its Flemish neighbour, on the plateaux of Hainaut and Namur and rising eastward towards the Ardennes. The elevation brings a better wind resource along with a rougher and more varied surface, and the fleet is arranged in small scattered clusters rather than dense corridors. Two regions of one small country, an hour apart, therefore present noticeably different forecasting problems.

The benchmark

The benchmark is Elia's own day-ahead forecast for Walloon onshore wind, from Elia Open Data, covering both the distribution-connected and the Elia-grid-connected fleet. As in Flanders, Elia publishes early enough that the benchmark is captured at the time the forecast is issued.

What is published for Wallonia

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.