Put in the "too good to be true" tray?

The story has been around for a week, but I should note it:

Erecting wind turbines on the world’s best offshore sites could provide more than enough clean energy to meet global electricity demand, according to a report.

A detailed study of the world’s coastlines has found that offshore windfarms alone could provide more electricity than the world needs – even if they are only built in windy regions in shallow waters near the shore.

Analysis by the International Energy Agency (IEA) revealed that if windfarms were built across all useable sites which are no further than 60km (37 miles) off the coast, and where coastal waters are no deeper than 60 metres, they could generate 36,000 terawatt hours of renewable electricity a year. This would easily meeting the current global demand for electricity of 23,000 terawatt hours.