Cummins Power Generation, Minneapolis, Minn., has developed new generator sets on both the small and large end of its gen-set range, along with new switchgear for emergency and standby power applications.

The new 150 kW model GGLB spark-ignited natural gas gen-set is designed to provide full-rated standby power for backup and emergency power applications. The new generator set features a heavy-duty GM 8.1 L four-cycle natural gas engine that is torque matched to a high-capacity Newage ac alternator for handling motor starting loads. An electronic governor provides precise frequency regulation for powering sensitive loads and the unit also accepts 100% of the nameplate standby-rated load in one step in compliance with NFPA 110, Level 1, the company said.

"The new 150 kW model GGLB spark-ignited generator set is both user-friendly and environment-friendly," said Colette Weiser, market manager for Commercial Standby Generator Sets, Cummins Power Generation. "The basic control system is easy to operate and includes system protection features, digital engine speed control and transfer switch compatibility. The industrial, spark-ignited V-8 engine burns clean natural gas for exceptionally low exhaust emissions."

A wide range of options and accessories is available with the generator set to allow configuration for specific onsite power applications. The optional PowerCommand 2100 generator set control adds microprocessor-based features such as remote start/stop, integrated voltage regulation, alarm and status message display, output metering and auto-shutdown at fault protection for high reliability.

Several alternator sizes offer selectable motor-starting capability with low reactance, the company said. Available permanent magnet generator excitation delivers enhanced motor-starting and precise voltage regulation for nonlinear loads such as variable speed motor controls and UPS systems. The standard cooling system allows full-rated load operation up to 50[degrees]C ambient air temperature. Available weather-protective and sound attenuated enclosures permit installations at outdoor and noise-sensitive sites.

On the larger end, Cummins Power Generation has introduced a new low-BTU generator set series specifically designed to run on the dilute methane gas mixture produced by natural decay in landfills, sewage digesters or methane emitted from coal seams. The new GQ series generator sets produce a continuous 1570 kW (50 Hz) or 1750 kW (50 and 60 Hz) running on landfill or digester gas containing very low thermal energy, while producing low exhaust emissions. Multiple units can be paralleled for higher power production at larger landfill sites.

"Industry studies indicate that, globally, landfills represent an immense untapped energy resource," said Trevor Passmore, general manager for Energy Solutions, Cummins Power Generation. "In North America alone, candidate landfills can produce enough methane gas to support a total generating capacity of approximately 1500 MW. Currently, much of this potential energy is being flared off or vented into the atmosphere. This new generator set will provide landfill operators, utilities and independent power producers with a proven generating solution to make use of this energy resource. In addition, since methane gas released to the atmosphere has about 20 times the greenhouse effect of carbon dioxide and hence global warming potential, burning methane in a generator set can reduce its environmental impact by a factor of about 20."

Minimum pretreatment is required for the landfill gas to remove particulate matter and excess water vapor. Any additional pretreatment is dependent on the quality of the gas at a particular site and project economics.

Powered by modified versions of the model QSV81G 16-cylinder and QSV91G 18-cylinder natural gas reciprocating engines, the new GQ series 1570 kW and 1750 kW low-BTU generator sets feature an enlarged fuel delivery system, double-safety gas shut-off valves, and special coatings and bearing materials to withstand the corrosive contaminants typical in landfill gas.

A Cummins low-BTU generator at a landfill site in Shrewsbury, England, has accumulated more than 5700 hours of operation. Future installations include a wastewater digester site in the Canary Islands and the Viridor Waste Management landfill near Edinburgh, Scotland. At Viridor, Cummins Power Generation is developing a complete turnkey 3.5 MW power plant using two low-BTU generator sets running on methane from the landfill. The electricity produced at the site will be used to run a nearby cement works. An additional pair of low-BTU generators will be installed during the next two years to take advantage of the site's estimated 20-year supply of methane. "Consistent with our goal of providing total energy solutions, Cummins Power Generation can deliver this new product in a number of ways," says Passmore. "For example, we can deliver a Build-Own-Operate (BOO) power plant, or provide application design, installation and project management for a turnkey power plant. Supply of only the generator set, open or containerized, is also available."