Hey Mr. Green, 

In cases where the land for wind or sun power is scarce, it would seem that batteries could be attached to existing wind turbines to store energy when the windmills are producing more than can be immediately used. Why is this not done? 

—Frank in Racine, Wisconsin

In some cases, batteries are being hooked up to wind power systems for the purpose of storing surplus solar, wind, or other clean power, which can then release that power later, although their share of the total power storage remains quite small (some predict that batteries could store about 4 percent of the world’s total power output in the next 20 years). 

The cost of installing these storage battery systems is the biggest problem. For example, it has been estimated that it could cost anywhere between $8,600 and $14,600, which could basically double the total price of a solar installation. Of course, as is often the case with new technologies, this cost can be expected to diminish over time.

While battery innovations are alluring, we should stay focused on basic conservation of energy. Our electrical consumption is 11,664 kilowatt-hours (kWh) per capita. By comparison, in Denmark and Japan it is 5,603 kWh and 7,383 kWh, respectively, to name just a few countries doing far better at saving energy than we are. The U.S. per capita consumption back in 1960 was only 4,054 kWh. As my father shouted some years ago, “Turn off the goddamn lights.”