WRONG kind of WIND blamed for renewable red-ink FAIL • The Register

Windfarm operator the Renewable Energy Generation Group has blamed "abnormally low wind speeds" across the UK for greater-than-expected losses.
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It's a uniquely inefficient technology. Windmills must be shut down if the wind blows too hard. And, quite often during the December cold snap, wind plants used more electricity than they generated – just when the electricity was needed the most. (Electricity is drawn from the grid for yaw control, lighting, de-icing, pumps and to power the control mechanisms.)