Stormy February drives offshore energy production to new record


Monthly production exceeded the 1 TWh mark for the first time. February 2022 thus easily surpassed the previous monthly record (878 GWh) of October 2020. The 8 wind farms on the Belgian North Sea produced 14.3% of Belgium’s electricity demand. The turbines on land generated 676 GWh. In total, wind energy accounted for almost a quarter (23.9%) of Belgium’s electricity demand.

The winter months traditionally provide the best production figures. Due to the higher wind speeds and the absence of windless days, the wind turbines run at a higher capacity on average. The capacity factor, a measure of the productivity of a power plant, was 67% this month. This means that, on average, turbines are producing electricity at two-thirds of their maximum capacity. In February 2022, they supplied electricity to the grid 98.8% of the time.

In the past few weeks, the wind farms came up with good daily figures and it gradually became clear that a new record was within reach. The persistent wind caused the previous record for the month of October 2020 to be broken as early as 24 February. Finally, in the last hours of the short month of February, at 8 p.m., a record monthly production of 1 TWh was reached for the first time.

A Belgian family consumes an average of 291 kWh of electricity per month. In February, the 399 offshore wind turbines thus produced enough electricity for approximately 3.4 million Belgian families in the same period.

Over the whole month of February, offshore wind accounted for 14.3% of electricity consumption. Onshore wind turbines accounted for 9.6%. Wind energy thus provided 23.9% of the electricity consumed during February. On Sunday 20 February, a remarkable share in electricity demand was achieved: wind energy (onshore and offshore) accounted for 37% of total electricity consumption in Belgium that day.

Storm Eunice

Thanks to the sustained wind, the wind farms were able to produce at 75-90% of their maximum power in the third week of February. At the same time, storms Dudley and Eunice were predicted. On 17 February, grid operator Elia sent an official storm warning to the wind farms, whereupon they took extra precautionary measures.

As the wind blows harder at sea, an offshore wind turbine is designed to produce electricity at very high speeds (up to 110 km/h). If higher wind speeds are detected, the turbine automatically switches to safety mode. In concrete terms, this means that the turbine switches to the ‘feathered position’: the blades position themselves differently depending on the wind, which reduces the impact on the turbine and the foundations. The ‘feathered position can also be activated at lower wind speeds. The blades are therefore not clamped in a fixed position, but continue to rotate freely in a protective position. Above the maximum speed (cut-off speed), no electricity is supplied to the grid to protect the rotor.

On 18 February, this happened between 15:45 and 16:30, when storm Eunice hit the Belgian North Sea the hardest. It was the first time in Belgian offshore wind history that all wind turbines collectively went into safety mode. Production resumed at 5 p.m., but was prevented by two ships that went adrift during the storm and ended up in the wind farm zone. For safety reasons, the surrounding wind turbines were shut down. The vessels involved were later successfully towed away. In the morning of 19 February, production was restored to maximum capacity.

Despite the alertness surrounding storm Eunice, the turbines continued to inject power onto the grid for 97% of the day. In the end, production clocked at 28 GWh, or 11% of total electricity demand on 18 February (256 GWh).