Wärtsilä will supply its internal combustion engine technology for two new U.S. power plants.

The order was placed by a major American investor-owned utility in the Upper Midwest. The customer was not disclosed. Wärtsilä said the engines were selected primarily for their grid-balancing capabilities as the utility expands its integration of renewable energy, notably wind and solar.

The two plants will operate with Wärtsilä 34DF dual-fuel engines. The first plant will generate an output of 28 MW from three engines, while the second will provide 47 MW of power from five engines. All eight engines will run on natural gas and will have the capability to use light fuel oil if natural gas is not available.

The fast-starting and stopping flexibility of the Wärtsilä engines was a major consideration in the award of these contracts. Rapid grid balancing is necessary to offset the intermittency of supply as the share of renewables in the system is increased to support the utility’s decarbonization ambitions. The operational flexibility of Wärtsilä’s technology enables full output to be reached in a matter of minutes. The engines will also provide black start capability to increase the system’s resiliency and reliability.

“The flexibility to achieve effective and efficient grid balancing is an essential element in realizing the environmental benefits that renewables offer. This is the future for power generation, and it’s available today,” said Jon Rodriguez, Energy Business Director, Engine Power Plants, Wärtsilä North America.

Current Wärtsilä gas engine power plants can use up to 25 vol% hydrogen blends in natural gas. Though Wärtsilä engines can be operated on even higher hydrogen-blend levels, fuel tests are restricted to the limit of 25 vol% hydrogen for natural gas systems, according to the international equipment standard IEC/EN 60079-20-1.