A new site has started providing free data for wind and solar energy installations. Basically, it helps determine if they will suitable for your site. Check out Firstlook and I believe you need to register to get all the data.
If you are planning a PV installation or wind turbine this site can help you figure out from the beginning if it will be able to generate power based on solar irradiation or wind speeds. You'll need some knowledge and ability to interpret and apply the data.