Scotland's ferries are part of the nation’s fabric and one of its most vital forms of transport. They are a tourist attraction as much as a rural lifeline, plying scenic routes to the islands and beyond.

Caledonian MacBrayne’s fleet of vessels, sailing to the Hebrides and Clyde islands, are particularly iconic.

They gently furrow their way across magnificent seascapes, framing a timeless picture of a remote, rural, unspoiled and green Scotland where humankind is overwhelmed by the brooding beauty of nature.

Only the reality isn’t always quite like that. Most of the country’s ferries still burn polluting fossil fuel, and quite a lot of it. This is often evident in emissions from their funnels, which can vary from a wisp of smoke to thick black clouds pouring into the sky.

However, things are changing.

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CalMac in particular has shown a determination to be proactive in the fight against climate change, with three of its vessels – the MV Hallaig, MV Catriona and MV Lochinvar – now powered by a low carbon hybrid system using traditional diesel along with lithium ion battery power.

These ferries are on three short routes: Sconser on Skye to the Isle of Raasay; Lochranza, Arran to Claonaig, Kintyre; and Fishnish on Mull to Lochaline on the nearby mainland.

The weather is important as the vessels achieve greater efficiency using electric power on short and sheltered runs, but overall the company is pleased with their performance.

“On the Raasay run with MV Hallaig, we can achieve up to 30 per cent carbon savings,” says Klare Chamberlain, CalMac’s Environmental Manager. “On a bad day, it can be about seven or eight per cent. It’s all down to what the wind and tide is doing.

“A lot of the savings come down to operators and the skipper running the vessel in the most efficient way. There are some days when the crews can get 100 per cent of their journeys on the battery, which is amazing.”

In another attempt to cut carbon emissions, CalMac has two more hybrid vessels on order that will be fuelled by cleaner liquefied natural gas (LNG) alongside conventional diesel.

HeraldScotland: Klare Chamberlain, Environmental Manager at CalMac Ferries LimitedKlare Chamberlain, Environmental Manager at CalMac Ferries Limited

However, there have been disputes about costs with the shipbuilder, Ferguson Marine in Port Glasgow, claiming that because of unforeseen complexities, it will lose nearly £40 million on the deal. Both vessels have still to be delivered, though it is hoped they will enter service on routes from Ardrossan and Uig next year.

“Using LNG will provide fantastic air quality improvements,” Klare Chamberlain adds. “Using this as a fuel means that nitrogen oxide (NOx) emissions can virtually be eliminated. And there are carbon improvements as well.”

Studies are ongoing into the potential future use of hydrogen fuel cell technology for ferries. This would be completely clean, though risk and safety issues still have to be fully evaluated.

“If it can be done, it will be great for us, though it’s still at an early stage.”

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In Norway – seen as a global climate change pioneer – ferries powered entirely by batteries and charged from shore connections have been in use since 2015 on shorter routes such as fjord crossings and coastal waterways.

These vessels may eventually become fully automatic, and it is anticipated that by 2022, the reduction in Norwegian carbon dioxide emissions should be the equivalent of taking 150,000 cars off the road.

As long as there are infrastructure upgrades in terms of power supply, it is not implausible that in the future Scotlan could also employ all-electric vessels on some more sheltered routes.

With technological advances being made quickly and the demand for carbon-free transport intensifying globally, what is the CalMac fleet of more than 30 vessels likely to look like in 15 years’ time?

“A lot of our vessels are coming towards the end of their lives. They are 30 years old. The Scottish Government wants to get the longest life possible out of its assets, so any new ferries we get will be expected to last for the same 30 years.

“That takes us up to 2050, when the International Maritime Organisation’s targets for the shipping sector [to reduce greenhouse gas emissions to at least 50 per cent of 2008 levels] really kick in. Any ships we invest in need to be ready to deliver those.

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“So I’d hope that in the next 10 to 15 years, we’d have a fleet certainly capable of meeting a 50 per cent carbon reduction on where we’re at now, if the technology is there.”

CalMac sees the introduction of new and greener technologies as a vital part of its role as a public body in demonstrating corporate and social responsibility – Chamberlain’s appointment as Environmental Manager two years ago represented a tangible expression of this.

While the largest benefit of decarbonisation will be an environmental one, with air quality in particular improved, there is also a cost benefit.

Put simply, achieving lower carbon means burning smaller amounts of conventional fuel, and that leads directly to lower bills. Over a decade, it could save CalMac £500,000.

“We simply have to create a sustainable environment,” Klare Chamberlain says. “We have a responsibility to serve both our island communities and decarbonisation.

“There is a significant expectation that we will run a modern green fleet, and that’s what we’re aiming to do.”

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The Herald’s Climate for Change initiative supports efforts being made by the Scottish Government with key organisations and campaign partners. Throughout the year we will provide a forum in The Herald newspaper, online at herald.scotland.com and in Business HQ magazine, covering news and significant developments in this increasingly crucial area.

If you are interested in contributing editorially or interested in becoming a Climate for Change partner, please contact Stephen McTaggart on 0141 302 6137 or email stephen.mctaggart@heraldandtimes.co.uk