The UK wind debate assumes that wind farms operate at roughly their average output most of the time. According to this new paper by Dr. Capell Aris’, this assumption is not true. Power comes only extremely intermittently and variably and there are long periods of negligible efficiency, particularly during the long winter months when power is most needed. A 10GW wind fleet would need approximately 9.5GW of fossil capacity to guarantee its output. A summary from the report of Dr. Aris' findings is provided below. The full report can be accessed by clicking the links on this page.