CONCORD, ONTARIO- Toyota's popular Prius first hit the North American market in 2000, and in another year or two the owners of those first hybrid cars, including environmentalist David Suzuki, will have to face the reality of replacing their vehicle's battery system, according to

One option is to put in a new version of the same nickel-metal hydride battery that to-date has powered all Prius hybrids. But Ricardo Bazzarella, president and co-founder of Concord-based Hymotion, hopes to tempt those car owners with another option.

Hymotion develops battery packs for the Prius based on more powerful, longer-lasting lithium-ion technology. The two-year-old company has also become an expert in retrofitting the cars into "plug-in hybrids," meaning the battery system can be charged by plugging it into a standard 120-volt electrical socket.

A plug-in hybrid running on a lithium-ion battery back can travel more than 34 miles on a single charge, using just a trickle of gasoline for acceleration. Most drivers on an average day travel less than that.

Given the choice, Bazzarella believes many existing Prius owners will go for Hymotion's system, particularly if he can get prices down.

"The battery pack replacement is going to be a big market in the future," says the soft-spoken 37-year-old. "We're already getting interesting emails and phone calls from those who have older Priuses, and they're in the market for a new-battery pack."

He founded the company in 2005 with partner Akos Toth, vice-president of research and development. They met each other while working with Mississauga-based fuel-cell developer Hydrogenics Corp., back when the two engineers had a keener interest in hydrogen-powered cars.

Bazzarella, a University of Waterloo graduate with an expertise in mechanical engineering, and Toth, a University of Toronto graduate focused on electrical engineering, learned a lot about vehicle systems while at Hydrogenics, but they also grew to realize that the market for fuel-cell vehicles was too far off.

Hoping to tap a more immediate opportunity, they turned their attention to hybrid vehicles, left Hydrogenics and formed Hymotion. By the end of their first year, they had generated $120,000 in revenue, partly by doing plug-in hybrid retrofits.

Their decision to switch gears proved prescient. Not only are sales of hybrid cars taking off, but there is also a fast-growing interest in the plug-in concept. Municipalities and states across the United States have launched plug-in hybrid pilot projects, and one was recently announced in Toronto.

Politicians at all levels continue to call for the development of a plug-in hybrid market as a way to help reduce U.S. dependence on foreign oil. It has become a bi-partisan cause and the subject of much study, even finding its way into President George W. Bush's state of the union address.

As a result, technology companies are in a race to develop a superior battery system for plug-in hybrids, and conferences dedicated to the technology are springing up, including an event scheduled in Winnipeg for Nov. 1 and 2.

Perhaps most important, major automakers such as General Motors and Toyota have jumped on the bandwagon, announcing – their intention at some point to mass-produce this next-generation of hybrids. GM, recently introduced its Volt plug-in concept car.

Hymotion's main supplier of batteries is A123Systems, a developer of lithium-ion technology based in Massachusetts.

A123 has signed an agreement with GM that will see the companies co-develop A123's technology for the auto giant's new Chevy Volt plug-in concept car. GM has said the Volt will lead the auto industry in a new direction.