The 21st Century Grid (by Joel Achenbach, National Geographic, July 2010).

Discussion of the Grid, a bit of its history, need for significant improvement, and power storage.

Regarding storage, the following is interesting:

Actually the U.S. can already store around 2 percent of its summer power output—and Europe even more—behind hydroelectric dams. At night, when electricity is cheaper, some utilities use it to pump water back uphill into their reservoirs, essentially storing electricity for the next day. A small power plant in Alabama does something similar; it pumps air into an underground cavern at night, compressing it to more than a thousand pounds per square inch. During the day the compressed air comes rushing out and spins a turbine. In the past year the Department of Energy has awarded stimulus money to several utilities for compressed-air projects. One project in Iowa would use wind energy to compress the air.

Another way to store electricity, of course, is in batteries. For the moment, it makes sense on a large scale only in extreme situations. For example, the remote city of Fairbanks, Alaska, relies on a huge nickel-cadmium, emergency-backup battery. It’s the size of a football field.

Lithium-ion batteries have more long-term potential—especially the ones in electric or plug-in-hybrid cars. PJM is already paying researchers at the University of Delaware $200 a month to store juice in three electric Toyotas as a test of the idea. The cars draw energy from the grid when they’re charging, but when PJM needs electricity to keep its frequency stable, the cars are plugged in to give some back. Many thousands of cars, the researchers say, could someday function as a kind of collective battery for the entire grid. They would draw electricity when wind and solar plants are generating, and then feed some back when the wind dies down or night falls or the sun goes behind clouds. The Boulder smart grid is designed to allow such two-way flow.

-RichardH