Construction contractors in Sacramento, California, are being offered free rental of a low-emissions LPG spark-ignited gen-set developed by Cummins West as part of a one-year emissions reduction program. The gen-set produces fewer emissions in comparison to a Tier 2 diesel-powered system, and fuel is the contractors’ only expense. The project began in July 2005, with the purpose of showing how propane is an alternative to diesel power. The cost savings and air emission mitigation credits given to participants are hoped to be incentives for purchasing the units for ongoing use.
With enough energy output to power work tools or act as an energy source for mobile office trailers, the 60-kW gen-set is driven by a 6.8 L, V-10 Ford LPG engine. Cummins states that the gen-set’s emissions output is .29 g/bhp-hr NOx, .06 g/bhp-hr HC, .10 g/bhp-hr CO, and an undetectable level of particulate matter. The unit of measurement used is the weight, in grams, produced by the engine per mile of driving and divided by the brake horsepower of the engine. This provides a measurement of emissions products in grams per brake horsepower per mile. The measurements are taken over a preset drive cycle, designed to duplicate all modes of engine operation. The cycle is known as the FTP 75 (Federal Test Procedure).
When the trailer-mounted unit is rented, it can be configured for 120-V single phase or 480-V three-phase service. Included with the gen-set are four propane tanks that provide twelve hours of operation at full load. Refueling the system can be accomplished by having propane delivered to the job site or by removing the tanks and taking them to be filled. Both options prevent soil and water contamination.
At the end of the one-year emissions reduction program, Cummins West, the exclusive distributor of Cummins products for central and northern California and Hawaii, will add the gen-set to its rental line, and it will be available at a nominal rate.
Partnered in the project with Cummins is the Sacramento Metropolitan Air Quality Management District, which coordinates the efforts of local, state, and federal agencies; businesses; and citizens to achieve and maintain healthy air quality for the city. The Propane Education & Research Council, Autumn Wind Associates, and Western Propane Gas Association are also involved with program funding, management, evaluation, outreach, assistance, and fuel storage and supply.