FERRY bosses are to seek European funding for the development of a "zero emissions" passenger ferry which would be powered by a hydrogen fuel cell and charged using surplus renewable energy.

Engineers at Caledonian Maritime Assets Ltd (CMAL), the Scottish Government quango which owns the passenger vessels, harbours and other ferry infrastructure across the west of Scotland, has been engaged in a long-running feasibility study with partner agencies in Europe and North America to explore the potential for the technology in a marine environment.

Hydrogen is already being used as a fuel source in cars and buses, with research underway to develop it for the rail industry.

Bosses at CMAL, who have already reduced fossil fuels by rolling out two battery-diesel hybrid passenger ferries with a third currently in the pipeline, believe the logical next step is to cut out emissions entirely.

CMAL's 'Hy Seas 2' project aims to create a ferry which generates hydrogen through electrolysis - where an electric current is used to break up water molecules into hydrogen and oxygen. The hydrogen can then be stored and 'burned' to power the vessel, emitting only water vapour.

Meanwhile, the electricity for the electrolysis could be supplied by tidal and windfarms. Islands such as Orkney already generate more electricity than they use.

Andy Crossan, projects director at CMAL, said: "They can't get rid of the electricity they make, it's going to waste. This way, a ferry could charge overnight in the harbour and the islands would be paid for the electricity the ferries use."

A three-year feasibility study partly funded by £200,000 from Scottish Enterprise has concluded that the innovation is technically and commercially possible, and CMAL is preparing to submit its final report by December this year.

The findings will be used to apply for EU funding to build a prototype ferry, which is expected to take around three years to create. Collaborators include Edinburgh-based Logan Energy; BAE Systems in the US; Ballard Power, a hydrogen fuel specialist in Vancouver; and Holland's Imtech Marine.

Although some hydrogen-powered ferries already exist, they are tiny in comparison to what is being attempted in Scotland.

A 12-seater passenger vessel launched in Bristol in 2013 but was abandoned six months later with the operator blaming high running costs.

Rotterdam has a hydrogen-powered sea ferry which can cover short distances using a 10kiloWatt fuel cell, but ferries serving the Western Isles and Hebrides would require roughly 50 times as much power.

Mr Crossan added: "There is tremendous support and enthusiasm from both the public and private sectors to make this happen, as well as the backing of the Scottish Government. We have the skills, talent and ambition here in Scotland and our work so far has found no technical or other reason why the first ferry of this kind cannot be constructed here in Scotland."