Zero-emissions ultracapacitors recharge in minutes

When the bus driver started the new electric engine, it was so quiet he turned the key twice to make sure it was running.

“It was really quiet. That was one of the first things I noticed,” said Arvil Gonzalez, an American University graduate student who took a test ride in the ultracapacitor minibus when it arrived last week for a campus demonstration. “It felt more like being pulled in a wagon than riding in a bus.”

The bus was the first vehicle in the U.S. powered completely by ultracapacitors, which recharge in minutes and could greatly reduce noise pollution in cities around the country, said Dan Ye, chief executive officer of Sinautec Automobile Technologies in Arlington.

The bus is also cheaper and cleaner to operate than a diesel bus. It consumes no fossil fuels and doesn’t produce any tailpipe emissions, either.

Ultracapacitors don’t rely on slow chemical reactions to store and release their energy. Instead, they quickly absorb a charge and store electrons on layers of plates, which can release the charge just as quickly — the way a rug can hold static electricity and transfer it when you touch a metal doorknob.

“Its a brilliant concept,” said ultracapacitor expert and Massachusetts Institute of Technology electrical engineering professor Joel Schindall. “Its not well suited for electric-only cars, but it is practical to stop a bus every few city blocks.”

Sinautec helped introduce 24 full-size ultracapacitor buses to Shanghai three years ago, and along with Foton America Bus Co. Inc. of Germantown, Tenn., is planning to introduce as many as 60 buses in the American marketplace next year.

While most battery-powered vehicles take hours to recharge, this new generation of electric vehicles recharges in 90 seconds, said Foton chief executive Cliff Clare Jr.

The downside is that they lose their charge almost as quickly. That’s the major problem with ultracapacitor-powered vehicles, said Mr. Schindall.

Right now, ultracapacitor vehicles must recharge about every five miles. By January it will be up to 10 miles, and a year from now it could be as many as 30 miles, Mr. Clare said.

While public transportation systems could be adjusted to meet these recharge demands for city buses, regular drivers will not appreciate the frequent interruptions to keep their personal vehicles running, Mr. Schindall said.

He would like to see mass installations of electric charging stations at bus stops and gas stations around the country.

“Then I don’t have to be driving and worry, ‘Gosh, it’s 20 miles home. Am I going to make it?’ Most people are not going to put up with that,” he said.

Price is another factor. An ultracapacitor bus can cost as much as $600,000, which is at least 50 percent more than the cost of a regular bus that runs on diesel, Mr. Clare said.

But these vehicles could save transit agencies and motorists money in the long run by eliminating common expenses such as engine tuneups and daily diesel fill-ups, he said, adding that the electric buses could cut fleet maintenance costs by 85 percent.

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