Salmon farmer charges ahead with hybrid power barge and boat
Scottish Sea Farms has taken delivery of its first purpose-built hybrid feed barge as part of a plan to build a more sustainable fleet.
The Polish-built 200-tonne steel barge supplied by Scale AQ is in operation at SSF’s Lismore West farm at the mouth of Loch Linnhe.
The barge has been designed to improve energy efficiency while also reducing environmental emissions and is part of an upgrade at the farm, which has had its maximum allowed biomass increased from 1,130 to 1,925 tonnes and been fitted with larger pens, new nets and new moorings.
The barge combines a fully recyclable 150kW lithium-ion hybrid battery system with a diesel engine powered generator and is expected to rely on battery power between 50% to 70% of the time, including during feeding.
SSF also recently acquired its first hybrid workboat, the Laurence Knight, contracted from Mull-based Inverlussa Marine Services.
Innes Weir, SSF’s regional director for the mainland, told the company’s newsletter, The Source, that the barge represented a significant step forward in terms of cutting waste and saving costs.
“With a hybrid system, the generator can be run at peak efficiency, producing a great deal more kilowatts of energy per litre of fuel.
“And by running a generator more efficiently but not as often, you reduce wear and tear on the engine and so make savings on maintenance and servicing.”
Fuel savings are estimated at between 20 and 45%, with generator maintenance costs around 75% lower over three years.
The hybrid system switches automatically between batteries and generator, once programmed, and can be managed remotely and monitored in real-time.
“If we’re using, say, 50kW or less then we’ll run on hybrid power and if we’re using more than 50kW we’ll run on the generator,” said Weir.
“The generator can recharge the batteries and use its power to run systems. The batteries, once sufficiently charged, are big enough to run the feeding system and then the generator will switch off.
“As you go through the day, you’ll find the generator will be on for some of the time and then it will be batteries, and as the batteries discharge, the generator will come back on while the batteries are recharged.”
Lismore West farm manager Alasdair MacAulay said day-to-day operations would become much easier, with all the barge functions, including the 87 batteries, fuel pumps and feeding system, controlled online.
“All we have to do is go on our tablets to keep account of how much feed is in the silos and how much we’re using. We’ve also got cameras downstairs so if there are any issues we can see them from upstairs, and there’s an overhead camera on the barge that can oversee all the pens.
“Even if we can’t get out to the farm, we can ensure the feed pipes are connected properly and haven’t been damaged by bad weather, so it’s a win for health and safety too.”
With the battery capacity large enough to run underwater lights throughout the night, as well as other low wattage functions, there will be no demand for an overnight generator, reducing noise as well as the barge’s carbon footprint.
Other benefits of the new barge include an onboard crane, which means not having to wait for a boat to move equipment around. And the bilge pumps are fitted with sensors to pump water automatically, a further safety feature.
SSF has previously used a bespoke pilot hybrid power system that was retrofitted on to a feed barge in Loch Spelve, Mull.
Designed, built and monitored by UK company Aqua Power Technologies, it reduced generator on-time by an average of 77%, and saved 31,488 litres of diesel and 83 tonnes of CO₂ during its first full-year of operation.
The farm is now fallow, and the pilot system is being re-housed elsewhere.