Rolls-Royce Holdings Plc said a new aircraft engine designed to slash carbon production over coming decades is ready to be fired up in ground-based tests.

The demonstrator turbine for the so-called UltraFan program has completed assembly and been transported to Rolls’s purpose-built Testbed 80 in Derby, England, where it has been mounted in preparation for activation early next year, the London-based company said in a statement December 19.

Rolls-Royce says the turbine will deliver a 10% improvement in fuel efficiency compared with current-generation engines. The next stage of development will see it spooled up using 100% sustainable aviation fuel, a kerosene replacement that’s set to play a key role in cutting net emissions in coming few years, though currently expensive and in short supply.

While the UltraFan demonstrator has a fan measuring almost 12 feet across and developing 80,000 pounds of thrust, Rolls has designed the engine to be scalable from 110,000 pounds down to 25,000 pounds.

Different versions will therefore be able to power both the wide-body aircraft that Rolls currently serves and much smaller models, allowing the company to re-enter the single-aisle jet market it abandoned in 2011 and which is now a preserve of U.S. rivals General Electric Co. and Pratt & Whitney.

Read more: Rolls-Royce Tests a Jet Engine Running on Hydrogen

With the UltraFan due to be 100% SAF compatible from day one of service, Rolls-Royce has said it’s also considering potential options for hybrid-electric and hydrogen power. Airbus SE is exploring a new aircraft model that would burn liquid hydrogen, making it entirely carbon free.