More from the Energy Storage Front

One of my two questions at the recent wind energy conference asked a panel focused on grid issues what their thoughts were on how storage technologies might impact grid developments. The response was that they were looking into pumped hydro (in relatively flat Nebraska?) or in using the federal dams. With that last option, you shut down the big hydro-electric plants and allow water to build up behind the dam.

Xcel Using Bus-Sized Batteries to Store Wind Energy - MPR- 17 Nov 08

"In southwest Minnesota, near the town of Beaver Creek, Xcel Energy's Frank Novachek showed off a grey metal container about the size of a double-decker bus. Novacheck said the box contains about 20 battery packs, the state's first utility-sized electricity storage facility.

"We're not the only ones using this type of battery, but we're the only ones thus far testing if for wind integration purposes," Novachek said.

The battery storage will help in a several ways. It can provide electricity when there's not enough wind to run the nearby turbines and the batteries will also help during peak demand times. They'll be able to store energy generated during summer nights for example, then release the power the next afternoon when air conditioners are working their hardest and electricity demand peaks."

"But for right now, the only proven method of storing that much electricity involves pumping air under ground.

'We can take that excess wind capacity and use it to store energy in the form of compressed air,' said Kent Holst, who is directing the effort to build this sort of storage system in Iowa. 'And then release it during the high demand hours.'

Holst said, in about four years when the project is finished, wind-generated electricity will drive air compressors. The compressed air will be pumped 3000 feet underground into porous rock that will absorb the air. The porous stone is capped by solid rock which prevents the air from escaping.

'It's kind of like an upside down bowl,' Holst said. 'It's about a mile and a half long and about a mile wide.'"

More from the Energy Storage Front

One of my two questions at the recent wind energy conference asked a panel focused on grid issues what their thoughts were on how storage technologies might impact grid developments. The response was that they were looking into pumped hydro (in relatively flat Nebraska?) or in using the federal dams. With that last option, you shut down the big hydro-electric plants and allow water to build up behind the dam.

Xcel Using Bus-Sized Batteries to Store Wind Energy - MPR- 17 Nov 08

"In southwest Minnesota, near the town of Beaver Creek, Xcel Energy's Frank Novachek showed off a grey metal container about the size of a double-decker bus. Novacheck said the box contains about 20 battery packs, the state's first utility-sized electricity storage facility.

"We're not the only ones using this type of battery, but we're the only ones thus far testing if for wind integration purposes," Novachek said.

The battery storage will help in a several ways. It can provide electricity when there's not enough wind to run the nearby turbines and the batteries will also help during peak demand times. They'll be able to store energy generated during summer nights for example, then release the power the next afternoon when air conditioners are working their hardest and electricity demand peaks."

"But for right now, the only proven method of storing that much electricity involves pumping air under ground.

'We can take that excess wind capacity and use it to store energy in the form of compressed air,' said Kent Holst, who is directing the effort to build this sort of storage system in Iowa. 'And then release it during the high demand hours.'

Holst said, in about four years when the project is finished, wind-generated electricity will drive air compressors. The compressed air will be pumped 3000 feet underground into porous rock that will absorb the air. The porous stone is capped by solid rock which prevents the air from escaping.

'It's kind of like an upside down bowl,' Holst said. 'It's about a mile and a half long and about a mile wide.'"