Cummins and Liberty Energy announced that the industry’s first natural-gas variable-speed, large-displacement engine to power Liberty’s digiPrime hydraulic fracturing platform will be deployed in the first half of 2025. The companies entered into a strategic partnership in June 2024 to develop the technology jointly for the completions services market.

In the oil industry, completion services arethe processes and technologies used to prepare a well for production after it has been drilled—such as hydraulic fracturing.

The Cummins HSK78G natural gas engine was first launched in March 2019 as part of a fixed-speed generator set for the power generation market. Designed to provide reliable power, regardless of the natural gas source or the operating environment, the engine reached new levels of efficiency and improved total cost of operation. The recent development effort for Liberty’s digiPrime platform leverages the already successful HSK78G platform and improves the 78-Liter natural gas spark-ignited engine’s response time and load-acceptance during operation.

Cummins HSK78G

The digiPrime pump, anchored by a 3,000 horsepower Cummins natural gas variable speed engine, is a direct drive solution with outstanding thermal efficiency. This pump configuration translates into reduced fuel costs and is one of the lowest emissions solutions in the completions market.

Further savings can be found from the maintenance and servicing of the HSK78G variable speed engine. Projected data estimates an increase of four times the engine’s life to overhaul maintenance interval when compared to a standard diesel engine, keeping the units in the field and operating for longer. The simple mechanical drive system utilizing the HSK78G engine can also be serviced by the same mechanical technicians as diesel engines, making adoption of this technology much easier.

One of the key benefits of the HSK78G base engine that makes it inherently suited to the well-servicing industry is its adaptability and flexibility. The engine has a high tolerance to fluctuations in the methane content of the fuel and can operate across various gas compositions—offering customers greater flexibility on their fuel source when in the field. Furthermore, it is designed to be compatible and adapt across multiple well-servicing transmissions. This solution, with its front power take-off, will also provide customers with options to support auxiliary power needs on location when operating below peak load.

Hydraulic fracturing requires high-horsepower pumps (typically diesel or electric) to inject the fracturing fluid at pressures between 5,000 and 15,000 psi. Fracturing pumps commonly range from 2,000 to 2,500 hp. Frack fleets can consist of 20 to 30 pumps, resulting in a total power requirement of some 40,000 to 75,000 hp (≈ 30 to 55 MW).