Falkirk-based Alexander Dennis Ltd (ADL) is adding hydrogen fuel-cell buses to its range of low- and zero-emission vehicles.

This technology, which requires a refuelling infrastructure for sustainably sourced hydrogen, has been developed on an Enviro400 double-deck bus over the past two years, through extensive collaboration between ADL’s engineering teams and Arcola Energy Ltd (a London-based hydrogen and fuel-cell system integrator).

The hydrogen-powered Enviro400 has an electric driveline with axle-mounted motors.

The on-board battery is charged by feeding hydrogen from secure tanks to a fuel-cell system, where it is converted to electricity; no external battery charging is required, and the vehicle’s only emission is water vapour.

A prototype bus has been through several design iterations to optimise performance and ensure the highest standards of regula-tory and safety compliance.

It has successfully completed route-shadowing trials in several UK cities, and operators supporting these trials have commented positively on the performance achieved.

ADL (www.alexander-dennis.com) is now taking orders for this bus and will be working with cities, bus operators and other stakeholders around the UK to further explore the potential for hydrogen fuel-cell buses.

Chief executive Colin Robertson said: “ADL continues to support bus operators around the UK by collaborating with them to develop new technologies.

“Hydrogen fuel-cell technology is part of the mix of solutions, and we are delighted to now offer this option to the industry.”