More cities are buying buses built using the GM-Allison diesel hybrid powertrain. Louisville, KY, is adding five to its metro fleet. The Transit Authority of River City (TARC) used a $3 million federal grant for the hybrid buses, which are due to be in service by the end of the year.

Manufactured by Gillig, the buses provide 60-percent-greater fuel economy and up to 90-percent-cleaner emissions than the 1989 conventional diesel transit buses they are replacing. The GM split parallel hybrid system also delivers superior torque, derived from the dual electric motors used to launch from a stop, and 50-percent-better acceleration than conventional diesel buses.

Gillig also is exploring diesel-hybrid powertrains from ENOVA (earlier post on this company’s work with China’s FAW) and Dana/Alstom.

Separately, BC Transit, the agency responsible for transit systems across British Columbia, has bought six 12-meter GM Allison diesel hybrid buses, with delivery set for spring 2005.

Three of the buses will go to the Victoria Regional Transit System and three to the Kelowna Regional Transit System. These buses are built by New Flyer, which expects to have 309 hybrid buses (including gasoline-electrics) in operation. New Flyer uses the ISE/ThunderVolt series hybrid electric drive and a Ford Triton V10 gasoline, ultra low emission engine for its gasoline-electric buses.

There are currently 330 GM-diesel-hybrid-equipped buses operating in North America. According to GM, if America’s nine largest cities were to replace their existing fleets of a combined 13,000 transit buses with hybrid buses, the nation would save approximately 40 million gallons of fuel a year.

Let’s talk about that for a moment. Take a base cost of $600,000 for a diesel hybrid bus, and a $400,000 cost for a conventional bus (these figures are probably a bit low, but let’s assume that volume manufacturing would trim prices a bit.) Switching that 9-city fleet to diesel hybrids would cost an incremental $200,000 per bus, or $2.6 billion. At $2 a gallon, recouping that extra cost would take 32 years. At $5 a gallon, 13 years; $6 a gallon, 10.8 years—and now you’re getting into the range of the average age of bus fleets.

This is clearly overly simplistic, and doesn’t even factor in other clean platforms such as CNG. But the principle holds. Fuel savings alone won’t make up the difference in the short term even with ongoing hikes in the price of oil. Transit authorities can’t hike fares that much. The extra money for converting bus fleets to hybrids or alternative fuels would have to come from federal or state grants—as, indeed, it is in most of the cases about which I am writing. Considering some of the other types of things on which our tax dollars are spent, this seems like a pretty good deal.