(Reuters) – Airbus (AIR.PA), Rolls-Royce (RR.L) and Siemens (SIEGn.DE) have come together to develop a hybrid electric engine as the race intensifies to advance battery technology and electric motors to lower flying costs and move away from fossil fuels.

Dubbed the E-Fan X program, the three companies anticipate flying a demonstrator aircraft in 2020 after ground tests, provisionally on a BAe 146 aircraft.

“We see hydro-electric propulsion as a compelling technology for the future of aviation,” Airbus Chief Technology Officer Paul Eremenko said in a joint statement.

Airbus will be responsible for the control architecture of the hybrid-electric propulsion system and batteries, and its integration with flight controls. Rolls-Royce will be responsible for the turbo shaft engine and 2 megawatt generator, while Siemens will deliver the 2 MW electric motor.

In October, a Seattle-area startup – backed by the venture capital arms of Boeing Co (BA.N) and JetBlue Airways Corp (JBLU.O) – announced plans to bring a small hybrid-electric commuter aircraft to market by 2022.