Wind could feed world's total energy demand
There's enough power available in winds to meet the whole of the world's energy demand, says a Carnegie Institution for Science report.
Clearly, if turbines are taking energy from winds, the winds themselves are slowed. Equally clearly, there must be a point at which adding more turbines fails to extract any more energy - and it's this point the team has focused on finding.
Using models, they worked out that more than 400 terawatts of power could be extracted from surface winds - those which can be accessed by turbines supported by towers on land or rising out of the sea.
More than 1,800 terawatts could be generated from winds throughout the atmosphere, harvested by turbines attached to kites.
Today, mankind uses about 18 TW of power.
The team's aware that, if taken to the limit, there would be 'substantial' climate effects from wind harvesting. But, they say, at the current level of global demand, these effects would be small - as long as the turbines were spread out, rather than clustered in just a few regions.
All in all, they say, wind turbines might affect surface temperatures by about 0.1 degree Celsius and affect precipitation by about one percent. Overall, the environmental impact wouldn't be substantial, they claim.
"Looking at the big picture, it is more likely that economic, technological or political factors will determine the growth of wind power around the world, rather than geophysical limitations," says researcher Ken Caldeira.