Refuse vehicles use a lot of fuel, which costs money and pollutes the air. However, hybrid vehicle technology has been considered too expensive to be practical for really heavy vehicles like garbage trucks. That is, until now, thanks to Charles Gray’s team at the EPA’s National Vehicle and Fuel Emissions Laboratory in Ann Arbor, Michigan. Gray’s team invented and developed a new hybrid technology for heavy vehicles. “Hydraulic hybrid” technology uses hydraulic accumulators for energy capture and storage instead of batteries, and it’s starting to hit the road now as a result of a truly impressive technology transfer effort by the EPA. Early commercial vehicles now in use in Michigan and Florida communities show fuel savings of 30-50%, along with significant savings in brake replacements, resulting in an attractive payback for fleet owners.
Creating an entirely new kind of powertrain for a vehicle is a big deal. And the EPA’s hydraulic hybrid technology is complex, requiring the development and extensive redesign of numerous new components and vehicle controls software. So how did the EPA succeed in getting this technology commercialized? The answer is work, innovation, persistence, and partnerships.

To transfer the technology to industry, the EPA’s nominated managers and technology transfer coordinators negotiated Cooperative Research and Development Agreements (CRADAs) with two large, global, U.S.-based suppliers of hydraulic components, Eaton Corporation and Parker-Hannifin Corporation, to build and evaluate novel prototype hydraulic components that could be used to create a viable hydraulic hybrid vehicle. Through these separate CRADAs, the EPA engineers worked tirelessly to transfer their knowledge to the industry partners, and both the EPA’s and its partners’ expertise in the technologies grew. The EPA’s nominees further implemented innovative CRADA structures to incentivize and accelerate commercialization of the technology. All EPA inventions were licensed to the partners. This arrangement served to incentivize active and unfettered collaboration with the industry partners on the CRADA-specific technology efforts, while simultaneously allowing EPA engineers to pursue EPA-invented alternative technology choices that could further improve efficiency or otherwise be useful to commercialization later.