MID will test cells that store green energy

A $14 million federal grant will help pay for large batteries to store some of the wind energy tapped by the Modesto Irrigation District.

The batteries will allow the district to sell that power during peak demand, rather than just when the wind is blowing, Tom Stepien of Primus Power Corp. said Wednesday.

He is chief operating officer of the Alameda-based company, which won the grant to produce the batteries from the U.S. Department of Energy this week. It's part of the federal government's $787 billion economic stimulus package, the American Recovery and Reinvestment Act.

The batteries, to be installed next year at a yet-to-be-determined location in the district, will store 25 megawatts of electricity. That is a small part of total demand, which can top 600 megawatts on summer days, but it will displace some of the power generated from natural gas, Stepien said.

"This will allow a utility like MID to run their equipment in a cost- effective, uniform and less-polluting manner," he said.

The MID has 100 megawatts of wind power, from Solano County and Washington state. It expects 50 more with a project to be completed next year in Oregon.

The batteries also can store solar power, which is a tiny part of the MID's resources but could grow.

Stepien said details on how the batteries work are a trade secret, but he likened them generally to how a cellular telephone is recharged.

The $14 million is part of a $46.7 million effort to develop the technology, also funded by Primus and possibly the California Energy Commission, Stepien said. The company was founded in 2006.

The MID will take part in a five-year demonstration of the batteries at no cost to its ratepayers.

"Our role in this project is to test this energy technology in real-world conditions," district spokeswoman Melissa Williams said.

The MID aims to get 20 percent of its energy from renewable sources by 2017. The target would be 33 percent by 2020 if a recent executive order from Gov. Schwarzenegger is carried out.

Wind and solar power are key parts of the effort to combat the global climate change believed to be caused by the burning of fossil fuels. Without batteries or other types of storage, they can be used only when the wind is blowing or the sun is shining. That does not always match peak demand, such as when people use air conditioners on summer evenings.

The grant was one of 32 totaling $620 million that Energy Secretary Steven Chu announced Tuesday in Ohio for "smart grid" demonstration projects around the nation.

The funding includes $25 million for a plan by Pacific Gas & Electric Co. to store power by compressing air in an underground rock formation near Bakersfield.

The MID last month got a $1.49 million stimulus grant from the Energy Department for other smart grid efforts.

They will include voltage controls at substations, advanced meters for the Mountain House community near Tracy, and a pilot program allowing some customers to save money by using power in off-peak times.

Bee staff writer John Holland can be reached at or 578-2385.

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