Hydrogen ferries plan for Western Isles
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A study in the Western Isles is investigating the possibility of using locally-produced green hydrogen to fuel local ferry routes, including the mainland link from Ullapool to Stornoway.
Point and Sandwick Trust (PST), which operates the UK's largest community-owned wind farm at Beinn Ghrideag on the Isle of Lewis, published the feasibility study in collaboration with a number of industry partners.
The project looked at the practical and economic feasibility of using new island wind farms to produce zero-carbon hydrogen fuel for future types of clean emission ferries operating on the established Caledonian MacBrayne routes.
While trials elsewhere have used surplus or ‘free’ electricity to drive small ferries, PST says this does not reflect the full economic cost of switching from marine oil to hydrogen. The Western Isles study is the first to look at the feasibility of using electricity derived from a local wind farm built specifically to power shipping on existing and established ferry routes.
The feasibility study examined the manufacture of the hydrogen using local wind power, the challenges of how to handle, transport and store the hydrogen on local piers, and how the frequency and bunkering requirements of each of the nine routes studied affected the amount of hydrogen fuel required.
In particular the study assessed:
- The most practical locations and likely output and cost of island wind farms
- The cost and operation of electrolysers
- The transport, storage and cost of hydrogen produced from local wind turbines
- The best location and likely cost of local storage facilities
- The frequency and bunkering requirements of nine west coast ferry routes
- The conversion of the marine oil currently used on these routes into their hydrogen equivalents
Speaking of behalf of the Point and Sandwick Trust, project manager Calum MacDonald said: “This is an exciting first step towards a future where zero-emission ferries are serving the Western Isles using hydrogen sourced from local and renewable wind power.
“We need to make our ferries zero-carbon to protect the planet but at the same time we need to use our local, renewable resources to fuel those ferries to protect and strengthen our communities.
“When we have the best renewable resources in Europe on these islands, it would be crazy to replace the import of marine oil with the import of hydrogen. By sourcing the power locally we can create a virtuous and sustainable cycle that benefits both the nation and local communities.”
Of the nine routes analysed, the highest-scoring route using a small ferry on a short crossing was from Barra to Eriskay and the highest scoring route using a large ferry on a long crossing was from Stornoway to Ullapool. The hydrogen requirement for the former would be 219 tonnes and for the latter would be 3676 tonnes.
A single 4.3MW wind turbine generator would be capable of supplying the required hydrogen for the Barra to Eriskay route, while 15 turbines would be required on the Isle of Lewis for the crossing to the mainland.
The potential emissions savings from the replacement of the Barra to Eriskay and Stornoway to Ullapool routes with hydrogen vessels is estimated to be around 676 and 21,815 tonnes of carbon dioxide equivalent per annum respectively, roughly equivalent to taking 147 and 4742 cars off the road each year.
But the cost of using hydrogen would be more than the current price of marine oil, at between 11p and 17p per kilowatt-hour (kWh) compared to 5p for marine oil. However, the project bosses say that if hydrogen produced from renewable resources for marine transport was to be included in the UK government’s Renewable Transport Fuel Obligation mechanism, that price would fall to between 9p and 12p per kWh.
Mr MacDonald added: “The most exciting finding of the study is that the price gap between using imported oil and local renewables is smaller than many would have expected. To close that gap even more we need further progress in the economics of wind farm and hydrogen production, we need to see the climate consequences of marine oil reflected in its pricing and, of course, we need progress in the design and manufacture of ships to make them more energy-efficient.
“I have no doubt that we will continue to see rapid progress being made in these areas and, as they happen, it is essential that local communities are supported and motivated to take advantage of the new hydrogen economy.”
The Scottish Western Isles Ferry Transport using Hydrogen (SWIFTH2) Feasibility Report, part-funded by the Scottish Government’s Low Carbon Infrastructure Transition Programme, was welcomed in the islands.
Councillor Uisdean Robertson, chairman of Comhairle Nan Eilean Siar’s transportation and infrastructure committee, said: “The richness of the Outer Hebrides’ renewable energy resource will allow the islands to make a significant contribution to the UK and Scotland’s green energy targets.
“In addition to energy generation, however, it is essential that we look to new and innovative methodologies to decarbonise our transport infrastructure. The potential of fuelling Calmac ferries using hydrogen offers real potential and as such I welcome these studies and look forward to seeing the next stage of activity on the two west coast routes progressing.”
