The assumption that wind power is a substitute for peak gas plants is a pretty basic error. The whole market/pricing for renewable power is completely different:
Fossil fuel = cost per megawatt-hour. Plant is relatively cheap. But you pay for the fuel
Renewable = cost per megawatt. Once you've built it, the energy is effectively "free"
At the moment, electricity is more or less the same price regardless of when you want it (Economy 7 excepted), mostly because we get most of it from fossil fuel. If we get a lot of electricity from renewables, this changes. Want power when it's windy? Heck, have all you want. Want it on a calm day? Sorry, gonna cost ya.
Over time, you'll see new & interesting uses for the "spare" power e.g. charging plug-in hybrid cars, together with intelligent appliances that modify their behaviour to minimse your electricity bill e.g. fridges.
As fossil fuel prices go up (hello, Gordon), renewables become more attractive - despite all the drawbacks. Nothing is going to get solved overnight, which is why some currently "uneconomic" technologies are being pursued anyway. This is just sensible planning - it's not rocket science!
PS @david: PV cells can last from around 10 years (early stuff) to at least 30 years (current thin-film). They don't stop working at this point, but they do produce less power (~80% of the original output). Other things to consider: there's a tiny amount of cadmium in them, so you ought to recycle them when you do finally chuck them away. Even if you don't it's a lot better than burning coal for electricity and putting the cadmium up the chimney (~10x less). Greenhouse gas emissions are around 30g/kWh (current tech), vs. 10g/kWh (nuclear), 400g/kWh (combined cycle gas), 900+ g/kWh (coal). Solar cells don't appear to be very efficient (10-20%), but this is approx 10x better than sun -> biomass -> fuel -> electricity. So, PV is a long way from perfect but probably a useful improvement on some of the ways we currently produce power.