With no connection to the UK national grid, Shetland looked to neighbouring Scandinavia for a low-carbon, sustainable heating system model to reduce its reliance on fossil fuels, writes Anthony Harrington.

If Scotland is going to reach its net-zero target by 2045, one of the things that is going to have to change is the way we heat our homes, offices and public buildings. At present some 30 percent or more of the nation’s carbon emissions come from heating these three estates through gas-fired boilers.

By way of contrast, the Scandinavian countries have been using a number of district heating systems for many decades. As a result, they have amassed a considerable body of evidence to show that these systems can have a considerably lower carbon footprint than an equivalent number of individual gas-fired heating units.

The first Swedish district heating system was introduced in Karlstad back in 1948. Other district heating systems were installed through the 1950s, with more following in the 1960s and 70s. Yet in Scotland, despite the proven efficiencies of district heating, we remain heavily reliant on the gas boiler for home heating, while larger gas or oil-fired boilers heat our public buildings.

What makes a shift away from heating individual properties with gas so difficult is that a) gas is cheap and b) households and public buildings already have gas heating installed. There is little incentive for owners to switch unless the government forces the issue.


Both the UK government and Holyrood have talked about banning gas boilers and in fact, Westminster announced, back on 18 November last year, that it planned to ban the installation of new gas boilers from 2023. The Scottish government is planning something similar.

In Shetland, where there is no connection to the UK’s mains gas grid, the community is able to boast a successful, fully functioning district heating system that has been heating some 1300 island homes, public buildings and businesses for some 21 years now.

While the Shetland example does not help to solve the problem of how government could best drive a transition away from the traditional gas fired boilers, it does provide a close-to-home example of a moderately large-scale, successfully functioning district heating system which was modelled, in large part, on the Scandinavian experience.

When the Shetland Islands’ Council decided back in the mid-1990s, to look into ways of implementing a sustainable heating system, it opted to study Scandinavian examples. In particular, as Derek Leask, executive director of the company that runs the Islands’ heating systems notes, the council was interested in waste-to-heating schemes.

“We needed an efficient way of fuelling a district heating system. As well as having no connection to the UK gas network, we also have no connection to the electricity grid. All electric power on Shetland comes from the diesel-fired power station at Lerwick. So a waste-to-heat plant would solve two problems simultaneously. It would provide a superior alternative to sending waste to landfill and would provide heat to a number of homes and buildings,” he explains.

Funding for the project came from both the Shetland Islands’ Council and the Shetland Islands Charitable Trust, a body founded back in 1976 to disburse moneys paid to the Council by oil companies using the new port, and which has since disbursed some £320 million to charitable projects. 

HeraldScotland: Derek Leask, executive director of Shetland Heat Energy and Power LtdDerek Leask, executive director of Shetland Heat Energy and Power Ltd

The Trust owns the district heating system, Shetland Heat Energy and Power Ltd. (SHEAP), which was completed in 1997, with the first customer being connected the following year. The Energy Recovery Plant, owned separately by Shetland Islands Council, transforms some 23,000 tonnes of waste per year into over 6MW/hr of heat energy.

Leask points out that with its northerly location – it is on the same latitude as the southern tip of Greenland – Shetland endures considerably colder winter temperatures than the rest of Scotland.

“We also have significantly windier conditions here, so the wind chill factor is higher. Plus much of the population suffers from fuel poverty. So the fact that the tariffs from SHEAP are considerably lower for our customers than they are for those Shetland homes running on electric storage heaters is a major benefit, quite apart from the carbon reduction factor,” he comments.

However, he points out that households who already have electric storage heaters face a significant financial barrier in switching over to the district heating system. There is some movement across, but it requires the householder to replace their storage heaters with central heating radiators and piping. That is too much of an upfront financial burden for most and would require some form of financial assistance for it to happen.


The problem parallels the dilemma facing the English and Scottish governments when it comes to how to extend district heating systems to homes that are currently using electric storage heaters. Ultimately, both governments will probably have to end up funding or loaning householders and business owners the cash to make the transition.

As Leask points out, district heating systems require premises to have either underfloor heating involving hot water pipes embedded in the floor or to have radiators installed. This makes it relatively simple to swap from a gas boiler to a district heating system, where one is available. But there is no getting around the installation costs if the heating system is off-peak electric storage radiators.

“As of today, we have around 950 domestic customers and 250 commercial customers connected to SHEAP. Plus we provide heating for schools, the hospital, care homes, leisure facilities and other public buildings in Lerwick,” he comments.

One of the key decisions that the Shetland Islands’ Council made when it committed to its district heating project, was to go for a ‘heat-only’ solution.

Leask explains that most energy-from-waste installations look to generate electricity as well as generating heat. The Council took the decision from the outset to focus on a heat-only plant. As a result, Shetland benefits from one of the most carbon-efficient waste-to-energy plants anywhere in the world.

“Going heat-only makes this plant much more efficient, with considerably lower emissions than other waste-to-heat plants,” he comments.




Innovation triumphs over inertia in UK first

One of the biggest obstacles to improvement and innovation is inertia. If we’ve sent waste to landfill for hundreds of years, why change? If we’ve had gas combi-boilers since the 1970s, why replace them with new fangled heat source pumps, solar panels and district heating schemes run off renewable power or waste-to-heat incinerators?

Fortunately for the Shetland Isles, with no connection to the UK gas grid or the UK electricity grid the Shetland Isles Council was able to take an unrestricted look at all options when, in the late 1990s, the council set out to look for a sustainable way of heating residential, business and public buildings in Lerwick,

The resulting district heating system was a first for the UK in that the council chose to deploy a heat-from-waste system focused solely on producing heat. The more standard – and less efficient solution – is for such systems to produce electricity as well as heat.


The full system, which is owned by the Shetland Islands Council and the Shetland Charitable Trust, with the district heating operated by the Shetland Heat Energy and Power company (SHEAP). Derek Leask, SHEAP executive director explains that while municipal waste incineration plants tend to have a poor reputation in the UK, the waste-to-heat plant deployed at Lerwick is both highly efficient and clean.

“Any toxins and other polluting matters are scrubbed and filtered by various technologies so the emissions from the plant are neutralised or minimised.

“Even the waste ash goes to the cement plant. People can be assured that properly installed and deployed energy recovery plants like ours have the potential to really help district heating networks be a weapon in the fight against climate change in the UK,” he comments. He points out that when municipal waste goes to landfill, even after the glass and metals have been removed, about 85 percent of the waste is biomass in one form or another.

Sent to landfill this decays mostly into methane gas, which is about 20 times worse than CO2 as a greenhouse gas. So as well as providing heating for over 1200 domestic, business and public buildings in Lerwick, the plant also provides a solution to the municipal waste collected right across both Shetland and Orkney.


This article is brought to you in association with Shetland Heat Energy and Power Ltd as part of The Herald’s 100 Days of Hope campaign.