Center for Environmental Research & Technology

Air Quality Improvement Program

The California Air Resources Board (CARB) has awarded the Emissions and Fuels Research Group a $2 million grant to evaluate the emission reduction benefits of hybrid technology for heavy-duty off-road construction vehicles.

This is part of a larger effort by CARB to expand the use of hybrid technology to help meet the goals of AB 118 -- to accelerate development and deployment of the next generation of clean air technologies. The use of hybrid-electric technology in heavy-duty on- and off-road vehicles is at a very early stage of development. Through the recent Hybrid Truck and Bus Voucher Incentive Project (HVIP) more than 650 hybrid trucks and buses have been deployed.

Hybrid technology can provide fuel efficiency benefits of 5 to 20 percent, and potential emission reductions between 25-70 percent. Little is known about the potential benefits of hybrid technologies for construction equipment because of their unique and diverse duty cycles when used in real world applications. The behavior of hybrid equipment, like excavators and bulldozers, will be characterized on a second by second basis, during in-use operations at construction sites. This includes measurements of vehicles’ emissions using Portable Emissions Measurement Systems, and to measure their “activity.”

Previous work at the Center has shown that activity data and emissions data profiles are quite different for various actions, such as digging, lifting, rotating, pushing, moving and transporting materials.

The project will help establish the methodology for making comparisons under such varied conditions. The project will also consider the differences between emerging hybrid implementations by leading manufacturers.

The project may be useful in establishing future inventories -- data which could contribute to a basis for hybrid incentives under AB 118 programs.