UNTIL LAST year, the people of Canna, the westernmost of the Small Isles archipelago, depended on diesel generation for their electricity, and a small grid provided by the National Trust for Scotland, as the island is not connected to the National Grid.

This week, however, they were waiting to hear the results of the Scottish Green Energy Awards 2019, which has shortlisted the island's renewable energy project for the Best Community Project Award.

Back in 2009, the community decided to decrease their noise, pollution and carbon emissions by establishing a renewable energy supply. A feasibility study found that a hybrid system of wind and solar would be a viable option for the island if supplemented by battery storage. Detailed design was carried out in 2015 with planning permission secured by early 2016.

Project funders were approached and support was forthcoming from The Big Lottery Fund's Growing Community Assets Programme, Local Energy Scotland and the Scottish Government's CARES - Innovation and Infrastructure Fund programme, SSE's Highland Sustainable Development Fund, Highlands and Islands Enterprise and the National Trust for Scotland.

The Canna Renewable Energy and Electrification (CREE) scheme now comprises:

•159kW of battery storage;

•30kW of wind, in the form of six turbines;

• 30kW of ground mounted Solar PV array;

• Electrical grid and control infrastructure (inverters etc);

• Sheds for battery storage and control equipment.

The six turbines are served by a small inverter shed which in turn links by cable into the existing electricity distribution network. The wind turbine array works in conjunction with a bank of photo-voltaic cells. Both feed electricity via inverters to the battery storage located within a new 9 x 9m shed. The 159kWh battery bank also links to the electricity distribution network and will make use of the existing diesel generators as a back-up power supply.

The project also utilises smart technology to autonomously balance supply and demand through use of the battery bank, and using remotely-triggered auxiliary heat loads. This enables the generators to run as efficiently as possible, further reducing runtime.

The use of wind and solar PV on the Canna grid ensures a diverse mix of generation which can supply the island in all seasons. When there isn’t enough wind or sun to meet demand, the system turns the generators on automatically, running on full power for a short period until the batteries are fully charged.

The CREE replaced the old diesel generators in October 2018 and was officially opened in April this year by the Scottish Minister for Connectivity, Energy and the Islands, Paul Wheelhouse MSP.

The project is now maintained and administered by members of the Canna community operating a private company limited by guarantee (CREEL). All work is currently undertaken on a voluntary basis.

Canna resident and CREEL secretary Liz Holden said: “We’re delighted that our energy project is now completed and has been shortlisted for a Scottish Government Energy Award.

“The figures from the first year of operation show a big reduction in the use of diesel and in the production of carbon dioxide. As well as reducing noise and pollution the new scheme gives us the capacity for future expansion and we’re grateful to all our supporters.”

In the first year of its operation, it is reckoned that CREE's total generation was 138,724kWh, of which 93% was renewable, and diesel usage was around 2500 litres, a 94% reduction on previous years, saving 100.9 tonnes of carbon dioxide.