The California Air Resources Board (CARB) has certified a turbine engine developed by Capstone Turbine (Chatsworth, CA) for use in commercial hybrid-electric vehicles. Using a CARB-approved test cycle for testing emissions of microturbine systems, the nitrogen oxide (NOx) emissions of the 30kW Capstone MicroTurbine is 0.26 grams per brake horsepower-hour using compressed natural gas and 0.53 using propane. Particulates using both fuels are virtually undetectable. In comparison to emissions figures published in CARB's database, the natural gas-fueled Capstone MicroTurbine power system has 80 percent fewer NOx emissions than the next lowest-emitting CARB-certified heavy duty bus and truck CNG engine.
In addition to being cleaner than traditional bus engines, the Capstone MicroTurbine is also smaller, lighter and quieter. It has a single moving assembly, no gearbox, no pumps or mechanical subsystems, and no need for oil, lubricants or coolants. Capstone hopes that the MicroTurbine will serve as an onboard generator in hybrid-electric vehicle applications to recharge the hybrid's batteries, greatly extending range and payload capacity. To date, Capstone MicroTurbines have been integrated into buses operating in cities in the US and abroad.
“CARB-certification of the ultra-low emissions of our microturbine for hybrid-electric vehicles is a most important step forward. This is clear validation that there is a solution, available and on the road today, that meets upcoming California and EPA emissions requirements, a claim no other heavy duty engine manufacturer can make," exulted Capstone President & CEO Dr. Ake Almgren.
