LONDON, Sept 13 (Reuters) - Britain’s energy network operator National Grid stopped a number of wind turbines in Scotland for a third consecutive night on Monday, the operator said, as high winds threatened to cause an overload in power output and block the grid.
“There was some curtailment again last night due to high wind generation and low demand - 650 MW (megawatts), about 13 wind farms,” a spokesman for National Grid said.
On Saturday and Sunday night, 750 MW and 300 MW of wind capacity was shut down as remnants of hurricane Katia hit the British mainland, creating wind speeds of 75-80 miles per hour.
When high power output from wind farms, mainly located in Scotland, coincides with low electricity demand periods at night, the local transmission network overloads. In these scenarios National Grid cuts off a number of wind farms to ease congestion.
National Grid data showed wind power production reached around 3,100 MW overnight on Monday, compared with a new record high of 4,500 MW set last week.
Forecasts for Tuesday and Wednesday were lower, ranging between 1,000 and 2,500 MW.
Wind turbines generate power at wind speeds of 16 metres per second (m/s) in the best conditions but shut down when speeds exceed 26 m/s.
In 2010 wind generation provided 4.2 terawatt-hours of energy, covering 1.3 percent of UK demand. (Reporting by Karolin Schaps, editing by Jane Baird)