A collection of wind data sources in the public domain.
winddata.com – huge array of wind resource data from Denmark and other countries, compiled by DTU. Some wind turbine generation data and structural response data also. Registration is required and not all data is free.
Egmond aan Zee offshore wind farm data — c. four years of meteo data and other useful information from a wind farm site off the Dutch coast.
Wind data discoverable via OpenEI – a wide range of wind maps, wind resource data for many countries
Bonneville Power Administration (USA) – transmission data, wind generation, meteo data, historic wind forecasts
Eirgrid – historic total wind generation, interconnection flows, forecasts and other transmission system level data from Ireland. Open access, no registration required.
Some additional resources:
ESRL NOAA datasets (including reanalysis from NCEP and ERA-Interim) available via this portal