District heating scheme to cut out oil

The peak load boiler station where the heat exchanger will be installed inside the guts of Lerwick's district heating scheme HQ at Gremista.

LERWICK’S pioneering district heating system is about to go even greener with a £1.6 million loan from the Scottish government.

Shetland Heat Energy and Power (SHEAP) has been given the green light to install a two megawatt heat exchanger that will tap warmth from the sea in Lerwick harbour.

The exchanger, built by Glasgow-based Star Renewable Energy, should be fully operational by the end of this year. Once installed, it will allow the heating scheme to stop burning oil as a back up to the local incinerator.


SHEAP operations manager Steven Peterson says the heat exchanger will reduce carbon emissions rather than add new customers.

SHEAP operations manager Peterson explained the waste to heat incinerator produces 6.3MW of heat, but demand goes up to 8MW in winter, leaving a shortfall of around 2MW.

At the moment that shortfall is met by burning oil, but this should no longer be necessary in the future.

“The primary aim is not to increase the number of households joining the district heating scheme, but to offset some of the oil we burn with a renewable source,” Peterson said.

The system will work by drawing seawater into the exchanger at 8°C and returning it at 3°C, having extracted 5°C of warmth. It works on the same principles as a refridgerator, except the other way around.


Lerwick’s district heating scheme currently has 1,200 customers, mostly households, but also some larger commercial and non-domestic properties such as the Gilbert Bain Hospital, Clickimin Leisure Complex and the various care centres.

Announcing the loan on Wednesday, Scottish energy minister Fergus Ewing said the government was helping to “maximise the economic opportunities from Scotland’s low carbon sector”.

He said: “Heat is estimated to account for over half of Scotland’s total energy use and is responsible for nearly half of Scotland’s greenhouse gas emissions, so the imperative to take action is very clear.”

Dave Pearson of Star Renewable Energy said the government’s investment in this innovative project was a significant step towards “decarbonisation of heating”