The power system operator constantly matches the electricity generation available to electricity demand. No power plant is 100 per cent reliable, and wind power is variable but predictable, allowing hours or even days for system operators to compensate for changing wind conditions. Wind farm sites are chosen after careful analysis of wind patterns. This enables a forecast of output to be made – information which can be made available to the network operators who will distribute the electricity.
The power grid is designed to cope with power plants shutting down unexpectedly; wind energy is often referred to as ‘intermittent’, but ‘variable’ is a much better word. What is ‘intermittent’ is a nuclear power plant which can (and often does) go from 1,000 MW of production to zero in less than one second; that will never happen with wind power.