A new Stanford University study concludes that wind farms off the coast of California would ultimately produce between 25 and 100% of California’s energy needs.
http://www.physorg.com/news116519900.html
However, little power transmission capacity currently exists in the parts of Northern California where the winds are most suitable (where the population is less dense), and a number of hurdles must be overcome such as adapting wind turbines for deeper water and mitigating the environmental and aesthetic impact of offshore wind farms.