In a mostly windy and damp location, Orcadians have, over centuries, had to find ways to keep themselves warm using the sources of energy available to them locally.

Historically, the landscape has provided fuel in the form of peat and driftwood. Peat was once one of the most valuable commodities in the islands. As Ernest Marwick noted in Peat Fire Fancies, there were laws about peat cutting, one of which was: ‘The poor may take as many peats from the nearest moss as will keep them warm, but not to sell.’

When peat was sold, says Marwick, it was very cheap. In the 16th century a fathom of peats, at least 500 cubic feet, was worth six shillings Scots – sixpence or 2.5p in the decimal era. Until coal became cheap and plentiful, Edinburgh was a valuable market for Orkney peat. While the best peat was set aside for export, locals burned the rough sods that they called yarpha peats or flaymeurs.

To this day, houses in rural areas have rights to sections of hills to cut peat from, and a handful of families still do.

More commonly though, islanders are reliant on alternative heating fuels including electricity, oil, and solid fuels particularly in the absence of mains gas, following its disconnection in 1973.

Heat pumps

Heat pumps

Orkney has relatively high winter temperatures with little frost and snow, making it a suitable location to use heat pumps. The devices work by extracting heat from the environment and transforming it into the central heating and hot water.

In 2022 the islands were host to over 2,000 devices, including air-to-water, air-to-air, ground-to-water, and seawater heat pumps. In the most recent energy audit, 2019, ground source heat pumps made up 88% of the units installed in that year.

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Storage heaters

Storage heaters

By using electricity at off-peak times, storage heaters work by slowly warming thermal bricks which gradually release heat during the day. In the 1980s and 1990s, trials were carried out in Orkney where storage heaters were installed with mechanical time switches to determine a cheap rate period.

By 2017, storage heaters were the most common form of heating, estimated to be present in at least 1000 homes. A number of barriers were identified with older storage heater models including limited control over the system and high running costs, particularly in comparison to heat pumps. There is, however, potential for modern high heat retention storaqe heaters, which have been retrofitted into older housing stock as well as installed in new-build properties in Orkney as low-carbon heating, to be used as ‘batteries’. Systems have been developed to allow them to take charges at times of low demand throughout the day, rather than only overnight, and so help with demand-side management.

Solid fuels

Solid fuels

The third most common heating fuel source in Orkney is solid fuel, which includes peat, coal and manufactured solid fuels. Although figures for solid fuel usage are low, most recent estimates suggest that 7.5% of households use some kind of solid fuel in conjunction with central heating systems.

Coal is estimated to be the most commonly used solid fuel in Orkney, with manufactured solid fuels, such as wood pellets, being second most popular, followed by peat.

Oil

Oil

The second most common commercial and domestic heating fuel in Orkney is oil, specifically kerosene. In 2019, the estimated import of kerosene was over 9000 tonnes, producing over 115 GWh of energy and 28,000 tonnes of CO2 the majority for domestic use.

In comparison to gas boilers, carbon emissions are greater and prices are more variable, usually higher. Additionally, as the oil needs to be imported to the islands, there is a greater carbon footprint and fewer suppliers meaning less competition on price.

Heating Source in Domestic Properties in Orkney (EPC data 2022)

Data from the energy performance certificate (EPC) surveys of 6537 houses in Orkney in March 2022 showed that the majority of homes, around 70%, used electricity as their primary mode of heating, in the form of storage heaters (32%) and heat pump central heating systems (32%) occasionally supported by panel heaters and focal point fires.

Heat pump examples

Over the last 15 years, Orkney Islands Council (OIC) have been installing various models of heat pumps in public buildings and their housing stock, with Orkney Housing Association Ltd also having installed a mix of heat pump technologies in over 3000 of their properties.

Through this work, a significant amount of learning has taken place which is now being shared to ensure the success of installations going forward.

Notable examples of heat humps in Orkney include ground source heat pumps at Kirkwall Grammar School, Stromness Primary School, Papdale Halls, and the Pickaquoy Centre. This is now the preferred source of heat for new public buildings and one has recently been installed at Glaitness Primary School extension.

Unusually, a seawater heat pump can also be found in OIC’s Warehouse Building in Stromness. The unit has been shown to be more efficient than the air-to-water units.

Stromness library (Credit Colin Keldie)
Heating pipe install under Stromness pier 2022 (Credit Colin Keldie - EMEC)

Opportunities

Finding a way to generate sustainable and affordable heat is an important part of decarbonisation plans. Particularly as Orkney has historically been reported to have one of the highest levels of fuel poverty in the UK, despite having generated more electricity than it has used on an annual basis for the past ten years.

Orkney Islands Council are continuing work to support the transition towards heat pumps in both new builds and retrofitting existing buildings.

Going forward, heat pumps could be linked with batteries to store energy during off-peak times, and reduce demand on the electrical network. As the support for this technology continues, expertise in installation and servicing is developing, making this route seem the most viable in the coming years.