Hydrogen-fueled vehicles are one form of what is becoming known as "clean" transportation, or vehicles that pollute the air considerably less than those that run on fossil fuels.

Thanks to the efforts of clean transportation proponents like the Power Authority, the days of moving people, goods and services without total dependence on finite supplies of fossil fuels are here. In the future, the challenge will be to do that job better, with even less impact on the environment, and at lower cost. Fuel prices, ecological disruptions and national security concerns have all propelled America's interest in developing cleaner-running vehicles.

With partners across the state and around the world, the Power Authority is continuing to advance the technology toward maximizing the benefits of clean transportation in the near- and long-term.

One promising development scheduled to debut in 2006 is the plug-in hybrid electric vehicle (PHEV), which combines the best of both electric and hybrid-electric technologies.

NYPA is working with the Electric Power Research Institute and a nationwide group of utilities to introduce an example of this "next generation" prototype- DaimlerChrysler's PHEV Sprinter van.

A conventional hybrid-electric vehicle relies on an internal combustion engine for its primary source of propulsion and the power to charge its battery pack for electric operation. The plug-in hybrid gets some of its juice directly from the electric grid, via a standard wall outlet. Plug-in hybrids are designed to travel "all-electric" for the first 20 or 30 miles, sufficient range for half the drivers in America, whose daily trips are typically 25 miles or less. When the PHEV's battery does run down, the vehicle switches automatically to its internal combustion engine until it can be recharged. This renewed emphasis on batteries has helped make efficiency a priority.

"The earliest electric vehicles had range problems; they couldn't travel that far without being recharged for an extended period of time," explained Helen Eisenfeld, a director in NYPA's 15-year-old Clean Transportation Program. "When hybrid-electrics came along, the range problem was resolved, but in making these cars bigger, faster and more powerful, we've lost efficiency.

"Now, the plug-in hybrids have manufacturers going back to the original concept of what a hybrid should be, a vehicle that relies more on a battery and less on fossil fuel. This new technology may actually bring us back full circle, to the point where we can go 'all-electric' again," she said.

Because PHEVs can be recharged in about four hours using an ordinary 110- or 220-volt outlet, it is expected that vehicle owners will recharge at home overnight, during off-peak hours when electricity demand—and costs—are lower. And as renewable power sources are developed by utilities, plug-in hybrids will actually become cleaner, since their electricity will increasingly come from non-polluting generation.

Under the first phase of DaimlerChrysler's demonstration project, four PHEV Sprinter vans will be delivered to the United States in 2006. The NYPA-sponsored vehicle will be placed with The New York Times, a NYPA power customer, for evaluation on the streets of New York City in a project supported in part by Consolidated Edison. Additional Sprinter vans will be introduced around the country in coming years, with NYPA and its clean transportation allies promoting expanded use of plug-in hybrid electrics, first in specialty niche markets and later with the general population.