Detroit Edison, Sandia Laboratory join DOE for battery system

DETROIT, Nov. 29, 2000 — Detroit Edison, the principal operating subsidiary of DTE Energy Co. (NYSE: DTE), is working with the U.S. Department of Energy and Sandia National Laboratory to test a prototype for a transportable Advanced Battery Energy Storage System (ABESS).

The device has the potential to improve reliability for customers and meet increasing demand for high-quality, low-cost electricity.

“Utilities will need to consider opportunities to modify their distributed resources as well as their transmission and distribution systems,” said Ron A. May, vice president, Energy Delivery and Service. “The DOE has recognized the potential for utility energy storage and supports programs to develop advanced battery systems.”

Detroit Edison will provide the electric utility distribution circuit to test the ABESS as a load leveling and power quality device. In operation, the battery system will be discharged during the day and charged at night. The ABESS consists of a 200 kW/ 400 kWh zinc-bromine battery manufactured by ZBB Technologies, Inc. in Wauwatosa, Wis. and a power conditioning system manufactured by Inverpower Controls Ltd. in Burlington, Ontario.

When connected to an electric power circuit known to have daily seasonal customer peak demand, ABESS reduces peaks in the electrical load by adding energy to the circuit at predetermined times. When the peak use period passes, the system will be recharged using energy from the power grid when energy cost is lower. The power conditioning system (PCS), which contains a power inverter, changes AC to DC and vice versa while controlling the charge and discharge of the battery along with providing voltage stability.

The zinc-bromine flow battery is an emerging technology that has attractive advantages for utility energy storage applications. The major advantages are that it has three to four times the energy storage capacity compared to lead acid batteries and requires less space. In addition, can be completely discharged without damage and it’s almost entirely constructed of plastic. The best application for these batteries is a two- to six-hour discharge with an appropriately designed PCS.

A unique aspect of the prototype is its mobility. The ABESS team designed the entire system to be housed on a 40-by-8-foot trailer, so it is possible for one battery system to be used in multiple areas.

Detroit Edison is an investor-owned electric utility serving 2.1 million customers in Southeastern Michigan, and the principal operating subsidiary of DTE Energy, a Detroit-based diversified energy company involved in the development and management of energy-related businesses and services nationwide. DTE Energy announced plans in October 1999 to merge with MCN Energy Group, parent company of Michigan Consolidated Gas Co., a natural gas utility serving 1.2 million customers in Michigan. The proposed company, DTE Energy, would be the largest energy utility in the state. Information about DTE Energy is available on the World Wide Web at http://www.dteenergy.com