BRUSSELS, Feb 28 (Reuters) - Belgian bus maker Van Hool said on Wednesday it had agreed to sell 40 hydrogen-powered vehicles to the German cities of Cologne and Wuppertal, saying it was the largest such order in Europe to date.
An alternative to battery-powered electric vehicles, hydrogen is a technology which also produces no carbon emissions, converting hydrogen into electric energy from a fuel cell.
Last year, the heads of some of the world's biggest oil companies and automakers agreed to push investments in hydrogen technology, saying it could cut annual carbon emissions by 6 billion tonnes by 2050.
Van Hool said Cologne had placed the order after testing two hydrogen buses from May 2014.
"This unique order, the largest ever for hydrogen buses in Europe, is a serious shot in the arm for the use of hydrogen technology in public transport," said Chief Executive Filip Van Hool.
The buses, powered by fuel cells made by Canadian group Ballard Power Systems Inc, would be built in Belgium and delivered from the second half of 2019, Van Hool said.
While hydrogen is often produced from natural gas, proponents say its production from renewable energy sources offers a solution to the storage issues often associated with intermittent solar and wind energy.
Critics say storing renewable electricity as hydrogen is less efficient than using batteries.
Last year, Germany said it would introduce world's first trains powered by hydrogen fuel cells into service, with 14 emission-free trains due to transport passengers in Lower Saxony from 2021. (Reporting by Robert-Jan Bartunek; editing by Philip Blenkinsop)