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Energy / Surplus heat from power station to be diverted into district heating scheme

The project has received support from the Scottish Government

Lerwick Power Station. Photo: Shetland News

A “GROUND breaking” new system of recycling surplus heat from Lerwick Power Station to supplement the town’s district heating scheme has been launched.

As part of its normal day-to-day operations, Lerwick Power Station produces heat which would normally be safely dissipated into the sea.

But under this new system, it will instead be supplied to Shetland Heat Energy and Power (SHEAP) to it help it cope with peaks in demand during the winter.

The Lerwick district heating scheme uses heat generated from burning rubbish in the town’s energy recovery plant to provide hot water to homes and businesses in the area.

The new system is one of the first of its kind in the UK, and it has been designed using Danish district heating expertise and delivered under a tight schedule by local contractors.

SHEAP executive director Derek Leask said: “We are delighted to see this ground-breaking project reach fruition.

“As far as we are aware, there is no other district heating company in the UK that takes industrial waste heat on this scale from elsewhere and recycles it into a network that supplies more than 1,200 customers.

“For 20 years we have been buying generated heat from the island’s Energy Recovery Plant, which involves burning local non-recyclable refuse from Shetland and Orkney.

“The incinerator here, which is owned by Shetland Islands Council, generates heat in the form of hot water, and this is then circulated through an underground network of pipes, running through the main streets of Lerwick.

“This network is over 40km in total length and consists of a flow and return main line with connection supply pipes to each individual customer.

“For the larger part of the year, the town’s heating requirement is adequately met by the energy recovery plant.

“However, we do hit a peak period in the winter when demand outweighs supply.

Photo: SHEAP

“By taking the surplus heat from Lerwick Power Station through this new initiative, we can successfully balance supply and demand – and can increase the environmental credentials of the system.”

The waste heat initiative comes on the back of an upgrade to the incinerator last year.

The combined effect of this upgrade and the new waste heat project is said to virtually eliminate the supplementary ten per cent of oil burn which was required to meet peak demand during the winter months, saving around 600,000 litres of oil over the course of the year.

The resulting carbon saving achieved is equivalent to planting 64,000 trees per year.

In response to the announcement minister for zero carbon buildings Patrick Harvie said: “The Scottish Government welcomed the opportunity to support Shetland Heat Energy and Power to transform their supply of heat through the Low Carbon Infrastructure Transition Programme.

“Where surplus heat is available, as here in Lerwick, it provides an opportunity to supply a local heat network, heating local homes and businesses.

“Local heat networks will form a much larger part of our energy future so I look forward to getting updates on the progress.”

Darren Hitchin, SSEN’s embedded generation manager at Lerwick Power Station, said: “The technology in our new, recently installed, engine has presented us with this opportunity to work with SHEAP, and this new initiative is a great way for our company to make a tangible, measurable difference in the Shetland community.

“By recycling this surplus heat into Lerwick’s community heating network, the new system will help with peak demand over the winter months and, at the same time, it lowers our own carbon footprint, consistent with our target to reduce our emissions in line with 1.5 degree science-based targets.

“Looking forward, when Shetland is connected to the GB transmission network in 2024, we will work together with the team at Lerwick Power Station to co-ordinate our incinerator shut-downs with days when the standby engine is running.

“This will mean that we can maximise the waste heat from this resource.”

SHEAP is owned by Shetland Charitable Trust.

Leask added: “It’s thanks to the trust’s continued support that we have been able to take these very significant projects forward to a position where SHEAP now supplies roughly a quarter of all the annual energy used for heating and hot water in Shetland.”