The cost of wind energy

I read a very interesting analysis regarding the total cost of using wind power to generate electricity on The Register. Basically, the idea is that since wind is not guaranteed to blow all the time, you need to have back-up energy generating capacity to keep the energetic system in balance. There are various theories and proposals to fix this problem like: wind doesn't blow in one region/country but might blow in another one so the spread of wind mills will create a balance, or when you have excess wind you can use a part of the energy to pump some water uphill and use hydro-energy as back-up when the wind doesn't blow. This study demonstrates that in the case of UK these solutions are not feasible (using statistics regarding the wind intensity patterns), so in the end you need to have gas/coal back-up power plants. This leads to a total different cost of wind energy. It's interesting to see who will pay this cost. Normally the ones who install wind mills should be asked to pay for the back-up capacity too.