Photo: Dieter Heinemann/Westend61/Corbis

Electric and hybrid cars have made quite an impact on the auto market, largely due to public concern over climate change and rising gas prices. But, skeptics are quick to point out, the Toyota Prius and Tesla Roadster may not be a squeaky clean as they seem. They need batteries for power, and if those aren’t produced  and disposed of with respect for the environment, then the supposedly green cars are no better than their conventional counterparts.

The batteries in gasoline-powered cars are made of different materials and serve a different purpose, but pose the same concerns. So which batteries are the most eco-friendly?


The Problem with Lead

Most cars on the road today have lead-acid batteries. While under the hood, there’s nothing to worry about. But because exposure to lead can cause brain and kidney damage as well as a variety of other health problems, it’s crucial to properly deal with it (as well as the acid) while the battery is being assembled and after it is disposed of.

These batteries can be recycled; the lead and acid can be reused in new batteries. According to Battery Council International, 97% of all battery lead in the United States is recycled. However, the Environmental Defense Fund, in a 2003 study titled “Getting the Lead Out,” argued that ”closer inspection reveals that lead is released to the environment at many points during vehicle manufacture,use and disposal.”

Considering that as of that year there were 2.6 million metric tons of lead in car batteries in the US, there’s legitimate cause for concern. This is especially true in countries with less stringent environmental regulations, where battery recycling is considerably less common. Mass lead poisonings have followed careless dumping of car batteries in China, Cambodia, Indonesia and Kenya.

Photo: Car Culture/Corbis

Is Lithium the Solution?

The batteries used in electric and hybrid cars are usually lithium-ion. Like lead, lithium needs to be carefully controlled and can be reused once the battery that uses it is defunct.

As an example, the battery used by the Tesla Roadster is manufactured in Japan according to strict laws. It does not contain any heavy metals or toxic materials like lead, mercury, or cadmium. Common sense would have it that car owners who care enough about the environment to buy an electric car would also make sure that the battery is properly recycled at the end of its life.

In a 2010 study, a team from the Swiss Federal Laboratories for Materials Science and Technology performed a life cycle analysis of a battery-electric vehicle and found that the environmental impact of a lithium ion battery is pretty small.


And the Winner Is…

When it comes to going green, lithium ion batteries clearly beat lead-acid ones. They don’t contain toxic chemicals, they save thousands of gallons of gasoline over their lifetime, and they don’t lead to mass poisonings.