Safeguarding the sustainability of Scotland’s off-grid communities

The community in Muck has owned and operated its independent electricity grid since 1999. Isle of Muck Power Ltd aimed to make its grid more resilient and to further decarbonise the island’s energy use. The objectives of the project were to:

• increase electricity generation
• replace dated kit
• upgrade infrastructure with easier fault finding
• enhance management and control
• create a more reliable system
• decrease the use of backup power supply powered by diesel.

Isle of Muck Power Ltd received £887,783 from the CARES Off Electricity Grid Community Fund and additional funding from Highland and Islands Enterprise, the MacKintosh Foundation and Mowi to:

• install an additional 17 kW solar photovoltaic (PV) array
• replace storage batteries and associated inverters
• install new 3.3 kV cabling
• install a new junction box to assist with fault-finding.

Foula Electricity Trust operates a local electricity grid on the island of Foula, which the community has owned and operated since 1983. The grid is experiencing an increase in demand after a new woollen spinning mill was built in 2021 and a 4G mast was installed in 2022. The community are also being encouraged to switch to electric heating instead of using fossil fuels, which creates further demand on the grid. To meet these new demands, the grid needed an upgrade to the existing high voltage (HV) side of the system. The project objectives were split into several phases.

The first phase was to upgrade the Foula electricity system HV network to:

• Meet increased demand on the grid caused by switching to electric heating, the new woollen spinning mill and the 4G mast.
• Prepare the grid infrastructure for additional renewable energy generation capacity.

Later phases involved:

• Installing of three new 6 kW wind turbines.
• Doubling the size of the battery storage by installing three new battery banks.
• Installing an additional 30 kW of solar.

Foula Electricity Trust received £224,116.25 from the CARES Off Electricity Grid Community Fund and additional funding from Shetland Islands Council, and Highlands and Islands Enterprise to:

• Replace an existing transformer and add an additional transformer to a new location on the network.
• Install new transformer LV distribution boards and new grid inverters that enable real-time monitoring and direct online access to parameters.
• Add an additional Inverter cluster to the overall system to increase capacity.
• Install a new battery bank.

The Knoydart Energy Security Project was completed by Knoydart Renewables Ltd in June 2023 and involved installing a new hydro pipeline, a mechanical and electrical system, and the design of distribution system upgrades. Knoydart Renewables set out to build on the success of  the initial project through the Knoydart Energy Security Project Extension. To do this project management support and feasibility studies were needed to:

• Further support the resilience of the Knoydart Renewables Ltd grid, and
• Decarbonise heat and transport within the peninsula.

It was found that a network enhancement project would meet these aims by improving the reliability of the electrical distribution system, and preparing the network for new customer connections and increased demand to enable economic growth.

Knoydart Renewables Ltd received £1,014,310 from the CARES Off Electricity Grid Community Fund to:

• carry out undergrounding of existing 11 kV overhead lines
• install a new turbine runner and deflector plate
• install smart meters
• install a 75 kWh – 100 kW battery storage system
• install a grid control system.

The community of Eigg has owned and operated its independent electricity grid since February 2008. Eigg Electric Ltd wanted to decarbonise and future-proof its grid to make the system more resilient as the community works towards its net zero ambitions, with the specific aims of:

• Increasing the resilience of the grid by upgrading previously installed technologies, and
• Preparing the grid to install three 100 kW wind turbines.

Eigg Electric Ltd received £322,254 from the CARES Off Electricity Grid Community Fund to:

• Replace the final three original banks of 4-volt Rolls batteries and add 20% more battery capacity.
• Replace old inverters and install new ones, taking the output to 216 kW.
• Upgrade transformers to support an increased loading at the, An Laimhrig (the island hub), the existing wind farm and at Lochaber Housing site to enable an EV charger.
• Install two electric vehicle (EV) charge points across the island.

Weather conditions posed a challenge for each community project. In August 2024, the west coast of Scotland experienced a record high amount of rainfall, which negatively impacted Knoydart Renewables Ltd’s project. The work on access tracks was delayed as working on steep slopes became challenging for the contractor. Knoydart Renewables Ltd also found it challenging to arrange site visits for contractors over the winter months due to the poor weather and its effect on the site’s accessibility.

Eigg Electric Ltd, Foula Electricity Trust and Isle of Muck Power noted that weather-related ferry cancellations had at times prevented contractors from working during the agreed dates. Eigg Electric Ltd highlighted that rescheduling was a significant challenge due to accommodation and contractor availability, as well as limited spaces on the ferries.

The remote locations of the sites presented specific supply chain challenges for each community. Isle of Muck Power Ltd struggled to find companies willing to provide a quote and to get comparison quotes from local businesses. It was also difficult to get specialist staff to the site due to the lengthy travel time to the island. Planning work in advance was another challenge due to unpredictable weather conditions.

Knoydart Renewables Ltd faced delays in engineers being available to install components of its hydro turbine runner and experienced delays in the arrival of components for the replacement deflector. This set the project timelines back. Knoydart Renewables Ltd also had challenges with its smart meter trials, as its 4G mast did not offer 2G, which was needed for the meter to run. This meant a second, more expensive meter was needed, which required additional communication equipment for each transformer.

Foula Electricity Trust’s supply chain issues were mostly around civil construction costs. Its contractor submitted high costs after expressing concerns around the logistics of carrying out work on the island.

Cash flow, budgeting and managing timelines were reoccurring points across projects. Project management was vital in being able to manage budgeting while accounting for changes in project scopes.

Foula Electricity Trust and Knoydart Renewables Ltd found it challenging to deal with natural conditions and pre-existing systems on site. Figuring out cable routes also took time and planning.

Foula Electricity Trust, Knoydart Renewables Ltd and Isle of Muck Power Ltd also experienced challenges in getting new technologies to communicate with pre-existing infrastructure.

Given the challenges of working in these remote locations, all projects had to extend their timelines for project completion.

Knoydart Renewables Ltd, Muck Power Ltd and Foula Electricity Trust all received project management support from a member of the Energy Mutual team. The project manager helped coordinate communications with funders, suppliers and contractors. This approach gave organisation members more time to focus on other project work.

Having a dedicated project manager was valuable for managing project timelines, budgets and claims. When delays occurred outwith the organisation’s control, the project manager was able to quickly update timelines and keep a clear view of progress against targets.

The project manager had also worked on remote and off-grid projects in the past. This meant the project manager understood the challenges when dealing with remote locations, getting quotes for planned work and arranging travel with contractors.

Eigg Electric Ltd benefited from its longstanding working relationship with contractors Wind & Sun, Bowers Electricals Ltd and Russet Engineering. A representative from Eigg Electric Ltd said these contractors are “familiar with the grid setup, as well as with the challenges that the island can face such as weather, ferry cancellations, and logistical problems.” Eigg Electric Ltd worked with Energy Saving Trust’s Transport Scotland team to provide technical review support. The feedback provided was used in the final contract with Eigg Electric Ltd’s selected EV chargepoint supplier, StorTera who provided a bespoke EV chargepoint solution.

Knoydart Renewables Ltd had design requirements for cabling contracts set by Donfield Consulting, with Foula Electricty Trust and Muck Power Ltd technical requirements set by Natural Power. This ensured suppliers submitted their bids based on a clear technical scope. Natural Power also reviewed applications from Knoydart Renewables Ltd and Foula Electricity Trust, checking if the projects were viable based on milestones, technical methods, and the value for money of the quotes received.

Locogen carried out the feasibility study for Knoydart Renewables Ltd’s Energy Security Extension project. It forecasted future electricity needs and explored different ways to decarbonise heat. The feasibility of expanding the existing network or creating renewable microgrids was also explored.

Knoydart Renewables Ltd worked with Gilkes and StorTera to trial the addition of a battery storage system to improve the water usage efficiency of its hydro turbine. Knoydart Renewables Ltd’s  project manager from Energy Mutual shared “This was the first time the team at Gilkes had attempted this type of integration but through close collaboration and several trials, we managed to use the battery to support the hydro turbine and reduce the flow of water to the turbine, which means more water can be saved in the reservoir during dry periods”.

Muck Power Ltd benefited from its main contractor Enerveo’s expertise when upgrading its infrastructure to make it easier to find faults and integrate new technology with existing systems. Their technical knowledge also helped in understanding the safety requirements for new grid connections.