Supporters of wind power got a boost this week with the release of a new study from scientists at Stanford and the University of Delaware that found there’s plenty of energy available from wind to supply at least half the world’s electricity demand, without harmful effects to the world’s climate.

One of the theoretical objections to wind power on a massive scale is the supposed plateau effect – essentially, the idea that each wind turbine sucks a small amount of energy out of the atmosphere, and that building thousands (or millions) of them would both provide diminishing returns from additional wind farms and have incalculable and possibly destructive effects on the global climate.  In their new study, entitled “Saturation wind power potential and its implications for wind energy,” and published in the Proceedings of the National Academy of Sciences (PNAS), Mark Jacobson, a professor of civil and environmental engineering at Stanford, and Cristina Archer, an associate professor of geography and physical ocean science and engineering at U. Delaware, found that, indeed, such a saturation point exists, beyond which each succeeding turbine would produce less and less power.  That plateau, however, is far beyond what it would take to supply 5.75 terawatts, or around half the world’s total electricity demand.  That would take something on the order of 4 million turbines and would have no effect on Earth’s wind patterns or climate, Archer and Jacobson found, using a three-dimensional, geophysical computer model known as GATOR-GCMOM.  And there’s no technological barrier to doing it by 2030, they add.

Of course, building 4 million wind turbines in the next 18 years raises all sorts of financial, geopolitical, and cultural questions, not the least of which is, Where in the world are we going to get the money to do that?

“To get there, however, we have a long way to go,” Jacobson said, with a scientist’s understatement, in an appearance on NPR’s Science Friday. “Today, we’ve installed a little over 1% of the wind power needed.”

Blue-sky pronouncements like the wind power study tend to cut two ways.  On the one hand, it’s easy to dismiss the idea that we can build nearly 4 million wind turbines in under two decades, given the expense, the certain local opposition, and the possible bird mortality.  Jacobson himself advocates building turbines in high-wind areas like the Gobi Desert, the Great Plains, and the Sahara – an arrangement that would require transmission networks of almost unimaginable scale, crossing some of the least hospitable terrain on Earth.

On the other hand, it’s good to get the more theoretical objections to large-scale renewable energy out of the way up front – and to demonstrate that creating enough renewable energy to replace a large percentage of fossil fuels is not impossible.  It’s just hard and really, really expensive.