In what’s believed to be a first in Scottish salmon farming, the new hybrid power system at Scottish Sea Farms’ Loch Spelve farm on Mull intelligently switches between generator and battery power as the farm’s demand requires. Since its installation in September 2020, the system has already offset more than 32,000 kgs in carbon – comparable to the weight of a standard fuel tanker – and saved on diesel use.

The initiative is part of Scottish Sea Farms’ drive to make its activities more sustainable and contribute to the Scottish Government’s ambition to be net zero by 2045.

Sam Etherington, founder of Aqua Power Technologies which designed, built and monitors the system said that the technology has been in existence for 20 years and is typically used in cars, underground trains and off-grid homes. But it had not been deployed on a salmon farm until he approached Scottish Sea Farms with his novel adaptation for the sector.

Neatly housed in a two-metre long cabinet, the hybrid system includes 24 batteries and a control panel. It works alongside the conventional diesel generator, cleverly monitoring the power demand and seamlessly switching between generator power and battery power.

At times of greater demand, during feeding for example, power is handed back to the diesel generator which simultaneously charges the hybrid’s batteries.

During lower demand, the hybrid takes over, remaining on 24/7 to power comparatively low loads such as environmental logging systems and lights.

The system also includes a real-time monitoring platform providing an insight into the farm’s power use profile and giving the company scope to manage that even better.

Scottish Sea Farms Environment Manager Sheena Gallie said: ‘This level of monitoring of our power use is something we wouldn’t have had otherwise.’

The total annual carbon offset is estimated at 79,400kg, and the annual net saving in diesel costs, based on today’s price, is calculated at around £18,000.

Loch Spelve Farm Manager Alan Tangny said: ‘We used to be filling our diesel tank at least once a week and now we’re probably getting four times longer between fills.’

Looking to the future, Etherington explains: ‘The hybrid system can be remotely configured farm by farm, according to power needs, to yield the highest savings. The peak feeding times are between 10.30am and 2.30pm so all those other hours before and after, the hybrid maintains power to the farm, enabling savings to be made.’

Scottish Sea Farms Environment Manager Sheena Gallie said: ‘Off the back of the success of the Spelve system, we will be looking to work with Aqua Power Technologies to identify other farms where energy use profiles would indicate its suitability. There is a clear opportunity for the company to reduce its reliance on fossil fuels and, in doing so, significantly reduce carbon emissions.’

Watch our short animation on how the hybrid power system works here.