From an article by Tom Content in the Milwaukee Journal Sentinel:
As an energy producer, wind is fickle: Maybe it’ll blow when you need it. Maybe not.

So the race is on to find more efficient ways to store the electricity wind produces when it’s blowing, so the lights can stay on when it isn’t. A Milwaukee company is smack in the middle of that race – a player in a high-tech sector that local economic strategists hope will become a growth engine for the region.

“Wind has incredible potential to be a significant portion of the nation’s energy supply,” said Kevin Dennis, vice president of sales and marketing for ZBB Energy Corp. “But to be a reliable resource, it ideally needs to be coupled with energy storage and to be flexible in how the power is managed and controlled out to the grid.”

A joint venture between ZBB Energy and Eaton Corp. earlier this month shipped its first rechargeable energy storage system for the renewable power sector to Ireland, where it is being installed alongside a wind turbine that is already providing half the power needed by the Dundalk Institute of Technology.

While Milwaukee’s highest-profile economic development strategy has centered on freshwater technology during the past year, a secondary effort seeks to make the seven-county Milwaukee area a center for advanced battery research, development and manufacturing – exactly the type of work already going on at ZBB and several other area companies.

In addition to the Ireland deal, the ZBB-Eaton partnership recently received an order from Oregon State University for a similar system that will be used as part of research by the engineering school into ways to compensate for the variability of wind power.

“Alternative energy has got everybody’s attention. But part and parcel with that is batteries, because you have to have someplace to store energy, and the battery component is just critical,” said Jim Paetsch of the Milwaukee 7, the regional economic development group.

The biggest local player in the field is Johnson Controls Inc. in Glendale, where research and development work is proceeding on lithium-ion batteries for hybrid-electric and plug-in hybrid cars, including those being developed by Mercedes, BMW and Ford.

In Milwaukee’s Riverwest neighborhood, another company, C&D Technologies, is investing $26 million in upgrades to a battery factory once owned by Johnson.