When the wind is blowing, the great plains could generate enough power to supply all of America, but storing and moving energy to supply those places where the wind isn't blowing, the sun isn't shining and the tide isn't coming in is a significant technological challenge that we're still figuring out.
On Ars Technica, Megan Geuss rounds up some exciting power-storage technologies, some in widespread use, some still under development. I was familiar with some of these, like pumped storage, but others, like the clever use of ice as a storage medium to offset cooling costs in places with cold nights and hot days (like southern California, where I live) were new to me.
Like many of these energy storage systems, thermal storage is a dramatic departure from what a common person would think of as a "battery." Much like compressed air and pumped storage, thermal storage systems take electricity when it's cheap (usually at night) to freeze water. During the day, that ice is melted and circulated through a system that allows the neighboring facility to be cooled without running energy-intensive air conditioning in the middle of a hot day (when demand for electricity is already high and generating stations are inefficient because generators need to power cooling functions).
Thermal energy has its appeal in hot areas with cool nights, especially in California and the southwest. In May, thermal energy system builder Ice Energy partnered with NRG Energy to deliver 1,800 "ice batteries" to commercial and industrial customers of Southern California Edison, the local utility.
Here are humanity’s best ideas on how to store energy [Megan Geuss/Ars Technica]