What will we do with all the dead batteries from electric cars?

Clockwise from top left: Electric car batteries from EV Innovations, Nissan, Magna International and Chevrolet. Center: A battery pack from Nissan.

A decade from now, owners of electric cars, having driven their share of clean and green miles, may encounter a dashboard light flashing an unwelcome message: Check battery.

Their first concern, quite likely, will be the expense of a replacement, which could be $10,000 or more based on today's prices, though production breakthroughs might lower costs by then.

The battery array of an all-electric Nissan Leaf is displayed in May at a lithium-ion battery plant in Tennessee. (The Associated Press)

But eco-conscious drivers will soon turn to the matter of a final resting place for their worn-out batteries. A bulky 500-pound lithium-ion battery pack will never be a candidate for curbside recycling. And improper disposal would undo the good accrued through years of zero-emissions motoring.

This situation is years away, of course. Few lithium-ion-powered cars are on the road, and estimates of the battery packs' lifespan -- no one knows for sure -- range upward from seven years. Even so, battery suppliers and electric utilities are already working to establish a recycling stream.

The stakes are high for such efforts. All of the parties -- battery makers and automakers -- are hoping to be seen as conscientious product stewards so that electric cars have a chance to thrive. They also want to wring every last bit of value from the batteries.

To grasp the good and bad of product stewardship, consider two common examples: tires and conventional lead-acid batteries.

Every year millions of worn-out tires are removed from America's cars. About a third are retreaded or recycled, but many end up abandoned and hundreds of millions are in storage awaiting the arrival of an economically feasible use. Tires are banned from most landfills because they are bulky and trap pockets of methane. Lacking a viable end use, the bald tire is a prime example of poor product stewardship.

The gold standard of effective stewardship is the old-fashioned lead-acid car battery. According to the trade group Battery Council International, 97 percent of battery lead is recycled. In the last decade, manufacturers have developed an infrastructure to minimize the chances of discarded batteries ending up in landfills.

Although depleted lithium batteries can also be broken up and recycled (see sidebar), electric-car builders and battery makers say that when a battery pack is no longer able to provide full performance or driving range, three-quarters of its energy capacity still remains.

That is why, in the long term, electric utilities may be the answer to where electric car batteries will be put out to pasture. With increased use of renewable energy sources such as wind and solar, there's a growing need for storage devices to hold the captured energy. Utilities such as Duke Energy of North Carolina and Southern California Edison have started prepping battery-management systems to do just that.

"We're expecting electric vehicles to not only benefit the environment, but also to help the electric system work more effectively by absorbing some of the power produced in off-peak periods by wind generators," says Ted Craver Jr., chief executive of Southern California Edison's parent company, Edison International.