The California Energy Commission funded the Heavy-Duty Electric Yard Tractor (HDEYT) project to demonstrate the feasibility of utilizing battery-electric power to achieve routine operation of class-8 yard tractors, which haul loads of up to 59,000 kilograms in a variety of applications in California and around the world. Off-road yard tractors are commonly used at warehouses, distribution centers, ports, rail yards, and other commercial and industrial locations, are high consumers of petroleum, and emit high levels of pollution. Because these sites are usually embedded within large populations or within disadvantaged communities, the tractors have a disproportionately negative effect on the health and welfare of thousands of individuals. HDEYT's battery-electric power was an ideal solution for such tractors, using an electric drive system TransPower began developing in 2011. The HDEYT project enabled TransPower to make numerous improvements to electric propulsion systems and to adapt it to the latest yard trcator model manufactured by Kalmar. A total of five electric tractors were manufactured and demonstrated during the HDEYT project, fulfilling its goal. The success of the HDEYT project spurred Kalmar to commit to electrification of its yard tractors on a commercial scale, and by the end of the HDEYT project Kalmar had purchased 12 more TransPower electric drive systems, with the expectation that tens if not hundreds more would be ordered within the next few years.
