Wind is an intermittent, or variable, source of energy, although turbines individually generate around 70-80% of the time and variations are predictable on the whole.
The effects of intermittency will increasingly be mitigated in various ways. Beyond 2020 it is expected tools such as demand-side management, electricity storage and interconnection – as well as more conventional forms of ‘back-up’ generation – will play a greater role in tackling intermittent output from renewable forms of electricity generation.
The intermittent nature of wind means we do need alternative back-up generation for when wind speeds drop. But for most of the time it will be possible to generate significant amounts of electricity from wind, thereby reducing the amount of fossil fuels we need to consume.