Rolls-Royce Power Systems reduces emissions by switching to renewable diesel for engine tests

Photo: Rolls-Royce

Rolls-Royce announced April 16 that it is continuing its drive towards becoming a lower-carbon business with engine tests for its mtu diesel engines in Friedrichshafen, Augsburg and Ruhstorf in Germany now carried out on hydrotreated vegetable oil (HVO), also known as renewable diesel.

By the end of 2025, the company had saved around 3,200 metric tons of CO2 as a result of switching to renewable diesel derived from vegetable oils and waste materials.

Emissions of soot particles and nitrogen oxides also fell significantly.

The switch began with initial test runs in September 2024, with further facilities switching over the following year until, finally, the key diesel engines of the mtu Series 4000 for ships, trains and energy systems were all being tested with HVO in Germany.

In Friedrichshafen, this reduced CO2 emissions from testing facilities—called test benches—by around 25 percent in 2025, compared to operation with fossil diesel.

In 2026, Rolls-Royce expects even greater savings, as the test benches will be operated with sustainable fuel all year round.

“Decarbonizing our operations is a clear corporate priority for us,” said Nicholas Templin, the executive vice president of production, logistics and quality management at Rolls-Royce Power Systems. “Through our solutions, we are also supporting our customers’ sustainability goals. The switch to HVO is an important step towards even more sustainable manufacturing of our products. Our experience has been entirely positive—using HVO makes the production of our products even more sustainable and has proven its worth in operational use.”

In 2025, the average price difference between HVO and B7 diesel was around 10 cents per liter.

Rolls-Royce has been testing and approving its key mtu engine series for HVO and other sustainable fuels compliant with DIN EN 15940 since 2021.

The major advantage is that HVO can replace fossil diesel without the need for technical modifications to the engines.

In addition to reducing CO2 emissions, HVO offers further environmental benefits.

The fuel burns more cleanly, reducing particulate emissions by 40 percent or more and nitrogen-oxide emissions by up to 8 percent.

Depending on the production process and raw materials used, CO2 emissions over the entire lifecycle can be reduced by up to 90 percent compared to fossil diesel.

As HVO is produced from renewable raw materials and, in part, from waste, the greenhouse gases emitted across production, transport and use amount to no more than those previously sequestered during the growth of the biomass.

Numerous Rolls-Royce customers are already successfully using HVO with mtu engines—including in trains, ships, mining machinery, data centers and energy systems.

Deutsche Bahn has been using sustainable fuel in its vehicles since 2022, thereby reducing its carbon footprint.

Data centers, such as the Eco Datacenter in Sweden, also run their emergency generators on HVO.

The mining group Rio Tinto now operates its dump trucks in large mines in California and Australia using sustainable fuel.

Rolls-Royce said it supports its customers in switching to HVO—from selecting suitable products to advising on technical and regulatory frameworks.