The IEA defines energy security as:“Energy security refers to the uninterrupted availability of energy sources at an affordable price.”
Energy security then must ensure that at every instant generating capacity meets demand, otherwise we have blackouts. Moving from fossil fuels to wind power threatens energy security because it increases the likelihood of a shortfall in supply. Such an event occurred last December (2012) at 5pm when with peak demand at 56 GW – All of UK ‘s wind turbines delivered essentially nothing (<0.1GW). Doubling the number of turbines to 10,000 would have made no difference whatsoever. Since then several coal stations have closed and energy security has diminished.
The recent Channel 4 program “blackout” shows how quickly society collapses during any extended blackout. DECC beware !
An over-reliance on wind power will increase the likelihood of blackouts. The only way out would be to store huge amounts of energy cost effectively and this is highly unlikely. There are just not enough mountains in the UK for pumped hydro storage.