The map, publicly available on the WPA website, includes detailed data on wind conditions in the whole of the USA, gathered at an altitude of 50 and 80 metres from the ground and with a resolution of 2,5 kilometrers. Additionally, it reports offshore resources to be found about 90 km away from the shore, with data collected at an altitude of 90 metres and a resolution of 200 metres.
Values are updated as of March 2010, this being the first time national data are brought up to date since 1993.
The information that immediately stands out when analysing the map is that, unlike what most people think, the Earth’s most abundant resources are not found close to the coasts. In California, for instance, one of the States with the greatest amount of resources, very few areas have an average wind speed exceeding 6 metres/second.
On the contrary, in the USA, the greatest concentration of wind resources is found in the extended internal plains, whose extremely vast (and very scarcely populated) lands can count on winds with an average speed of more than 8-10 metres per second.
Also offshore areas have an excellent potential. Based on the new data, the NREL (one of DOE’s most renowned research labs) esteemed that, considering only areas with winds blowing at more than 7 metres/second, and presuming a wind turbines density of 5 MW per square kilometer (practically only one turbine/sq km), the offshore wind farm capacity that can be installed totalizes more than 4 million MW.