V2G electric buses could balance power load, save money

A new study from University of Delaware’s College of Earth, Ocean, and Environment (CEOE) shows that electric school buses that feed power to the grid—employing technology called vehicle-to-grid (V2G) pioneered by the university—could save school districts millions of dollars.

Electric school buses would be practical, because they generally travel limited distances twice a day—well within the range of a full charge. In addition, the V2G technology makes sense because the buses are not in use for much of the day, enabling them to provide power to the grid during peak demand hours.

Newswise quotes Jeremy Firestone, CEOE professor of marine policy and director of the Center for Carbon-free Power Integration, as saying, “I see neighborhood kids waiting for and riding school buses out my window or when walking my dog. Electric buses have the benefit of kids not standing around or having their windows open while diesel fumes are being released.”

Researchers, who studied existing bus routes in a mid-sized suburban school district in Delaware, determined that over the 14-year expected life of a fleet of buses, a V2G fleet could save $38 million, despite a V2G bus's initial cost of $260,000, vs. $110,000 for a diesel bus.

The study, titled “A Cost Benefit Analysis of a V2G-Capable Electric School Bus compared to a Traditional Diesel School Bus,” will appear in the August 1 issue of Applied Energy.

The study builds on earlier research at the University of Delaware involving a project undertaken in conjunction with NRG Energy Inc. That project, involving a fleet of 15 electric cars, demonstrated that the cars could give and take power from the electric grid.

At the time of the earlier project, Willett Kempton, professor in the College of Earth, Ocean, and Environment (CEOE), research director for the Center for Carbon-free Power Integration, and inventor of the grid-integrated-vehicle technology, said the technology minimizes the need for large generators to ramp up and down quickly to adjust for fluctuating demand. “It’s an important service, this balancing service,” he said. “It’s not a new service, but we are doing it in a very different way. Our system responds faster, is less expensive to operate, and it does not burn fuel or create pollution. The batteries are storage devices, so we can take off excess electricity and we can push back when there is not enough. We are providing a power balancing service rather than power generation.”

With V2G technology, electric cars and buses essentially become distributed energy storage systems, whose, design and test were described in earlier articles here and here. Grid storage was also instrumental in the revival of battery maker A123, which recently announced that it would sell that business to NEC to refocus on transportation. With V2G, transportation and grid-storage applications merge.

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