Intermittency “no obstacle to wind power success”

Wind turbines can ‘keep lights on’ as a major power source, reports say.

Wind farm developers everywhere will be heartened by three UK reports this summer addressing ‘intermittency’ – and assuring us that it’s much less of a problem than is sometimes claimed.

Because the wind only blows at the required speed to keep the blades turning for 70-85% of the time, wind energy is often portrayed as too unreliable to be a major power source for the grid, needing watt-for-watt back-up from other forms of generation to ‘keep the lights on’.

It turns out this is an overstatement. Separate reports* from both the National Grid and the Pöyry Consultancy conclude that – regardless of the turbines’ location – only modest back-up capacity is needed to provide adequate cover.

Analyst David Milborrow has calculated that – even if wind were to make up 40% of UK electricity generation – managing its variability would add only 0.55 pence to the average unit cost. According to Milborrow, the prime culprit of intermittency isn’t wind at all: “Thermal [coal, gas and nuclear] plant breakdowns generally pose more of a threat to the stability of electricity networks than the relatively benign variations in the output of wind plants”.

The British Wind Energy Association has described Milborrow’s own report, Managing Variability, as “the last nail in the coffin of the myth of intermittency”. – Roger East

* Operating the system beyond 2020 (National Grid); Impact of intermittency: How wind variability could change the shape of the British and Irish electricity markets (Pöyry Consultancy)