NEW YORK – Celebrating Earth Day in the Big Apple, Mayor Michael Bloomberg rides the slightly more than three miles (4.8 km) from Gracie Mansion, his official residence, to Rockefeller Center in one of six electric-powered Nissan Leaf taxis presented to the city for a yearlong evaluation.

“As part of our commitment to zero-emission vehicles for the mass market, Nissan is looking for ways to broaden the use of electric cars, including commercial applications like taxis,” says Joe Castelli, Nissan vice president-commercial vehicles.

The Leaf taxis are being tested for their feasibility for daily operation in New York. But they are not taking the place of the “Taxi of Tomorrow” based on the Nissan NV200, which has been designated as the exclusive taxi to replace the more than 13,000 cabs now plying city streets. The NV200-based cabs won't begin service for another six months.

The NV200 cabs are not EVs, but Nissan plans to test some units with electric powertrains after the program gets under way. New York awarded the Japanese auto maker an exclusive 10-year contract after an open competition to replace the current fleet. It's reported to be worth $1 billion.

“Our relationship with the city provides us the ultimate proving ground to conduct this Leaf taxi pilot (program) to help optimize the use of electric-vehicle technology for future applications,” Castelli says.

Bloomberg says the city's goal is for EVs to comprise one-third of the taxi fleet by 2020, and this evaluation helps New York achieve that target.

Nissan plans to install a number of DC quick chargers around the city to help cabbies quickly recharge their taxis during their shifts. The chargers are designed to replenish Leaf battery packs to 80% of capacity in less than 30 minutes.

In a concession to drivers who are prohibited from turning down any riders, regardless of destination within the city, cabbies will be allowed to not accept fares if the destination would completely diminish the battery-pack capacity.

Nearly 60,000 Leaf units have been sold worldwide, Nissan says.