Hydraulic hybrid buses from the U of MN

Something has got to be done soon! Oil is running out. A decrease in supply leads to higher prices at the pump. Not only is oil expensive, but it is also a source of environmental pollution. Question: how do we deal with the decreased supply and address the pollution that we ourselves have been responsible for causing? One possible answer: hydraulic hybrid vehicles.
       All hybrid vehicles utilize more than one source of fuel. The purpose is to decrease the dependence on conventional internal combustion engines, thus reducing the demand for oil and the negative environmental impact. There are several types of hybrids, including electric, solar power, fuel cell, and hydraulic. The hydraulic hybrid technology was originally developed by the EPA in 2001. Unlike electric hybrids, which have been used in the bus application in many places throughout the world, including the Twin Cities Metrotransit, this type of hybrid does not use expensive parts (such as a battery), which also pollute the environment in the processes of production and transportation. Hydraulic buses use accumulators in lieu of batteries, which are cheaper to manufacture and more environmentally friendly (they use compressed nitrogen gas). A hydraulic hybrid technology works by recapturing energy lost during breaking. Because of this, “Hydraulic hybrid drivetrains are particularly attractive for vehicles that engage in routine stop-and-go driving, such as urban delivery trucks, mail trucks, or school buses.”  (http://www.nextenergy.org/services/strategic/workinggroups/wg_hydraulichybrid.aspx)
             Buses, with their frequent stops, would thus make a suitable application for this technology. Students at the University of Minnesota Mechanical Engineering department are currently working on this project, under the leadership of Dr. Kim Stelson, the director of CCEFP (Center for Compact and Efficient Fluid Power), which has been headquartered here since 2006. “The Center is a consortium of seven engineering universities across the Midwest… The Center is currently developing a proposal for modifying a bus from St. Cloud-based New Flyer bus company to create a new kind of hybrid bus, a hydraulic hybrid, that stores energy like an electric hybrid and doubles the fuel economy of standard buses, making gas sippers out of gas gulpers." (http://fresh-energy.org/index.php/blog/Who-knew-Fluid-hydraulics-is-cool..html)