Utility studies energy storage in car batteries

In addition to reducing oil consumption and greenhouse gas emissions from standard cars, the plan could help stoke production of plug-in hybrid electric vehicles and give power managers more energy capacity on the grid for hot summer afternoons, speakers said at a "clean technology" investment conference in San Francisco this week.

The utility, a subsidiary of PG&E Corp., "could recharge car batteries through electric outlets during the off-peak overnight hours and recharge the grid from the batteries during critical peak demand periods," said Hal LaFlash, its director of energy policy and planning.

More than 20 states have adopted measures that order electric utilities to add more renewable, cleaner energies such as wind, solar, geothermal and biomass to their energy supplies.

In California, wind power is the biggest renewable energy source, providing more than 2,500 megawatts of electricity. About 4,600 megawatts of wind-generated electricity are projected to be added to meet the state's goal for renewable supplies, LaFlash said.

Minneapolis-based Xcel Energy also is studying so-called smart-grid technologies and the idea of recharging hybrid electric vehicles and feeding excess power back to the grid.

A six-month study in Colorado found that electric cars may reduce the overall cost of owning a car and with new grid technology may cut harmful vehicle emissions by as much as 50%.

More studies will include plug-in electric vehicle field tests and will examine management of battery charging along with the availability of renewable energy, Xcel said.

However, the technology to allow car batteries to feed electricity back to the power grid is probably at least five to six years away, Felix Kramer, founder of CalCars, said at the conference.

CalCars is a nonprofit group that has built about 20 plug-in vehicles since 2004 by outfitting the Toyota Prius hybrid with new lithium-ion batteries.

Improving battery technologies to boost energy density at lower weight and cost is a hurdle, but progress on lithium-ion battery packs could help develop a bigger market for plug-in cars, Kramer said.