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NREL - National Renewable Energy Laboratory
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Hybrid Electric Drive Systems

The Fleet Test and Evaluation team assesses hybrid electric drive systems in transit buses and delivery trucks and vans. These systems combine a primary power source, an energy storage system, and an electric motor to achieve a combination of emissions, fuel economy, and range benefits unattainable with any of these technologies alone.

Hybrid electric drive systems use less petroleum-based fuel and capture energy created during breaking and idling. This collected energy is used to propel the vehicle in normal drive cycles. The batteries supply additional power for acceleration and hill climbing.

The Fleet Test and Evaluation team works with industry partners to evaluate hybrid electric drive systems operating in vehicles in transit and delivery service. Learn more about the team's fleet evaluations: