Top Ten Smart Grid

9. Energy Storage: NKG Insulators

Energy storage at the utility level is now accomplished almost entirely with the old-fashioned method of pumping water uphill at low electricity demand times, then letting it spin a turbine when demand is high. But there aren't too many more places to build new pumped hydroelectric projects – and integrating intermittent renewable resources like wind and solar power will require a lot more storage.

While solutions like compressed air energy storage are being promised at prices approaching those of pumped hydro – $250 to $500 per kilowatt-hour – it is limited to sites with power plants and underground caverns able to hold the air (see Startup ES&P to Store Electricity in the Air).

So for distributed storage so far, the largest-scale grid power storage projects underway have used sodium sulfur batteries - and so far, the leading maker of those high-temperature, high-volume batteries is NGK Insulators.

The Japanese company has installed its batteries in wind power storage projects with American Electric Power (NYSE: AEP), Xcel Energy and Tokyo Electric Power Co., which had partnered with NGK to develop the batteries (see Batteries for the Grid and GridPoint to Manage Wind Power Battery Storage).

Sodium-sulfur batteries have high efficiencies and the ability to deliver energy at full power without reducing lifespan or reliability – important considerations for grid storage (see Green Light post). Their problem remains high price – about $4,000 per kilowatt-hour for AEP's project, and still about $3,000 per kilowatt-hour, according to Sam Jaffe, senior research analyst with IDC company Energy Insights.

That could open the way for lithium-ion batteries from companies like A123 Systems and Altair Nanotechnologies to compete in the grid storage field they've just begun to enter, Jaffe said. Altair has small storage projects underway with Indianapolis Light & Power and another with regional transmission operator PJM, and A123 has a project with power generation utility AES Corp., Jaffe said (see A123 Batteries to Help Stabilize Electric Grid).

The key for lithium-ion batteries will be economies of scale that come from meeting what is expected to be a boom in demand from electric and hybrid vehicles, he noted. With billions of federal stimulus dollars earmarked for helping lithium ion battery manufacturers expand in the United States, and President Barack Obama pledging to push for 1 million plug-in hybrid and electric vehicles on America's roads by 2015, lithium ion batteries should become a lot less expensive soon, he said.