Reciprocating Engines

Reciprocating internal combustion (IC) engines are the traditional technology for emergency power all over the world. They have the lowest first costs among DER technologies. The capital cost of a basic gas-fueled generator set (genset) package ranges from $300-$900/kW, depending on size, fuel type , and engine type. Overall engine cost ($/kW) increases with size.

The total installed cost can be 50-100% more than the engine itself. Additional costs include balance of plant (BOP) equipment, installation fees, engineering fees, and other owner costs.

The pie chart shows an example breakdown of the total installed cost of a 550 kW natural gas IC engine.

Natural gas is usually less expensive than diesel fuel for the same heat content. If the IC engine is to be used for a large number of hours per year, the total cost to operate the gas unit may be lower. Natural gas may not be available at all locations, while diesel can be transported anywhere. However, diesel engine emission levels are higher and their use is significantly restricted in California.

Maintenance costs of gas and diesel IC engines range between $0.007-$0.015/kWh and $0.005-$0.010/kWh respectively.