Project lead: Rousay, Egilsay and Wyre Development Trust and Heat Smart Orkney
Project partners: Community Energy Scotland, VCharge
Area: Orkney
Main technology: Creation of a new fuel source
Local Energy Challenge Fund award amount: £954,950


The Orkney Islands generate 115% of their energy needs through the Islands’ 23 wind turbines; any excess generated energy is transported to the Scottish mainland via a subsea transmission cable.

In reality, the generation from Orkney’s wind turbines is far higher. When the capacity limits of Orkney’s grid network are reached, wind turbines are switched off – known as being curtailed. Turbine curtailment not only reduces renewable generation; it also threatens the financial viability of wind generation on the Islands. This is a concern, as many turbines in Orkney are community-owned and in addition, an estimated 63% of households in Orkney live in fuel poverty.

Project aims and objectives

The Heat Smart Orkney (HSO) project was developed to address the curtailment of the community-owned Rousay turbine. In the Financial Year 2016-17, Rousay faced a 30% loss in production (~0.7 GWh) and ~£110k loss to its local economy. Funded by the Scottish Government’s Local Energy Challenge Fund, the HSO project developed a small-scale community pilot, in which curtailment of the Rousay turbine was avoided through smart-grid technologies that intelligently control domestic heating devices.

Outcomes and achievements

As part of the project, 108 electric heaters and water immersion heaters were installed in 72 households on the Orkney Islands. During curtailment events, these heating devices were switched on – activating a Demand-Side Management response to reduce curtailment and increase generation payments to the community-owned turbine.

The project avoided 15 MWh and 3.3 MWh of marginal curtailment of the Rousay turbine in 2018 and 2019, respectively. Customer retention and satisfaction throughout the project were incredibly high – reaching over 98% customer retention, and with ~1 in 4 customers reporting a reduction in their fuel bills.

The project is in its Legacy phase, seeking to integrate other generators in the Orkney grid, and to demonstrate it can generate sufficient income to cover its operational costs. An analysis of projected earnings for the HSO model at-scale, expects break-even to be achieved with roughly five turbines and 800 heating devices installed.

The HSO project has had an impact far wider-reaching than its original objectives. It has developed resources and built relationships with local grassroots organisations working to address fuel poverty in the local community, and has created the foundations on which the Smart Islands Energy Systems (SMILE) and Responsive Flexibility (ReFLEX) projects have been built on.

Led by Rousay Egilsay & Wyre Development Trust, the project was delivered by its subsidiary HSO Ltd. – together with its project partners REWIRED (Rousay Egilsay & Wyre Islands Renewable Energy Development), Community Energy Scotland, VCharge (now, Kaluza), Catalyst, and other Orkney-based Development Trusts.