Store Power in Super Batteries

Mar 23, 2009 - Vince Beiser - Wired Magazine

Photo: James Day

Problem
Electricity is the ultimate just-in-time commodity, sent off to consumers as soon as it's generated. But solar and wind installations produce power only when the sun is shining or a breeze is blowing. If you could bank that energy when it's abundant and release it later as needed, you'd have a more reliable, more environmentally sound power grid.

Solution
Obama's stimulus package includes $2 billion in grants for battery development. For power grids, sodium-sulfur technology is the best bet. It's more efficient and power-dense than zinc-bromide or lead-acid, and in Japan, where NaS batteries are made, enough have been installed to power the equivalent of at least 155,000 homes. Later this year or next, American Electric Power, a major utility serving 11 midwestern states, will install 4 megawatts' worth of NaS cells in Presidio, Texas. That's on top of the 6 megawatts of battery power AEP installed in three other states last year. "We wanted a real thing that really works," says Ali Nourai, AEP's manager of distributed energy resources. "We didn't want to send a technician out every other day to fix some experimental system." Regulatory uncertainties still abound, but utilities across the US plan to bring sodium-sulfur systems online. Soon, more and more cities will come with batteries included.

Other Energy Storage Technologies

Compressed Air
Off-peak power forces air into a sealed space (like an abandoned mine or salt dome); when energy is needed, the air is released and burned with natural gas to spin a turbine.