National Renewable Energy Laboratory

Fleet Test & Evaluation

Hybrid Electric Drive Systems

The Fleet Test and Evaluation team assesses hybrid electric drive systems in buses. 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.

Many states offer incentives for transit agencies that incorporate cleaner, more efficient technologies into their bus fleets. Hybrid electric drive systems are a good option for transit agencies because they use less petroleum-based fuel and capture energy created during breaking and idling. This collected energy is used to propel buses in normal drive cycles. The systems' 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 in buses. For more information, choose the following links.