A few extracts from Sustainable Energy - without the hot air, which has the math on Wind power:
Let’s be realistic. What fraction of the country [the UK] can we really imagine covering with windmills? Maybe 10%? Then we conclude: if we covered the windiest 10% of the country with windmills (delivering 2 W/m2), we would be able to generate 20 kWh/d per person, which is half of the power used by driving an average fossil-fuel car 50 km per day.
And on flying:
Flying once per year has an energy cost [per person] slightly bigger than leaving a 1 kW electric fire on, non-stop, 24 hours a day, all year.
And also a bunch of other things, from cars to hot water to solar power. Conclusion: basically, we're all in big trouble.