American Airlines have announced that it has entered into a conditional purchase agreement with clean aviation innovator ZeroAvia for 100 hydrogen-electric engines intended to power regional jet aircraft with zero in flight emissions except for water vapor.

ZeroAvia is developing hydrogen-electric (fuel cell-powered) engines for commercial aircraft, which offer the potential for close to zero inflight emissions. The company is flight testing a prototype for a 20-seat plane and designing an engine for larger aircraft such as the Bombardier CRJ700, which American operates on certain regional routes.

ZeroAvia’s hydrogen-electric engines use hydrogen in fuel cells to generate electricity, which is then used to power electric motors to turn the aircraft’s propellers. The only inflight emission is low-temperature water vapour, and the lower intensity electrical systems have the potential to offer significant cost savings.