Hydrogen plane startup ZeroAvia had secured $21.4 million in a funding round led by Energy Ventures to develop zero-emission commercial aircraft.

Hydrogen plane startup ZeroAvia said on Wednesday it had secured $21.4 million in a funding round led by Bill Gates’ Breakthrough Energy Ventures to develop zero-emission commercial aircraft.

Backers for the California-based startup, which has completed 10 test flights with a six-seater propeller plane powered by hydrogen, included Amazon and energy giant Royal Dutch Shell.

Hydrogen, which produces water when it burns, is seen as a potential alternative for the aviation industry, a major user of fossil fuels. Hydrogen can be made from fossil fuels or from water using electrolysis, although this an expensive process.

“This is a capital-intensive industry, so having investors to help you through the process is very important,” ZeroAvia Chief Executive Val Miftakhov told Reuters, saying a plane was “a power-hungry machine, especially on take off.”

ZeroAvia, which has been conducting test flights in Britain, aims for commercial flights of up to 500 miles using 10- to 20-seat aircraft by 2023 and commercial jets able to haul up to 200 passengers 3,000 miles by 2030.

Miftakhov said his startup expected to have planes for cargo flights in operation before commercial passenger planes.

With the latest round, ZeroAvia has raised $34.4 million, providing it with cash to scale up its technology for larger aircraft. It has also teamed up with British Airways to explore how the carrier could shift to hydrogen-powered planes in future.

Amazon’s backing comes from its $2 billion Climate Pledge Fund. The online retailer, which aims to run a carbon neutral business by 2040, has ordered electric vans from Daimler AG’s Mercedes-Benz and startup Rivian.

Shell’s funds came from its Shell Ventures a unit which has been boosting investments in solar and other renewables.

Hong Kong-based venture capital firm Horizons Ventures was also among the investors.

Originally Published at US News