Scottish and Southern Electricity Networks (SSEN) Distribution has today confirmed its intentionto transition Lerwick Power Station into standby operation mode when Shetland is connected to the mainland electricity system in November 2024.
The station, which currently undertakes full duty operations in meeting Shetland's electricity demand needs, will provide standby operation until 2035 at the latest.It will operate in line with SSEN's other back-up stations on Scotland's islands, with similar staff levels as currently in place.
The network operator has been reviewing options for a reliable, innovative and cost-effective backup solution to support the security of supply to Shetland once the islands are connected to the mainland GB electricity system via SSEN Transmission's 600MW (megawatt) HVDC transmission link.
Following extensive technical and commercial analysis of options available, SSEN Distribution submitted its proposal on back-up arrangements to Ofgem in December 2020. Following subsequent engagement with the regulator, SSEN will nowinclude its proposals as part of its upcoming business plan for the RIIO-ED2 price control period, which incorporate:
- The use of Lerwick Power Station in standby operation modefrom November 2024until 2035following successful commissioning of the transmission link and the new Grid Supply Point (GSP) connecting the transmission and distribution systemsat Gremista.
- The installation of innovative interruption avoidance equipment by November 2024 to provide continued security of supply to homes and businesses on the islands in the event of planned or unplanned outages on the transmission link.
By transitioning the operation of Lerwick Power Stationto standby-only mode, SSEN Distribution estimates a 97% reduction in carbon emissions compared to running the station on a 24/7 basis.The station has been subject to ongoing investment including a replacement 6MW engine, installed earlier this year, which utilises enhanced efficiency and emissions abatement technology. An 8MW battery solution will also be in place later this year, providing wider flexibility and carbon reduction benefits.
The interruption avoidance equipment will ensure continued security of supply for the 30 minutesto1 hour period as the backup power station is started in accordance with all relevant codes and standards. The technology to be usedwill be determined by a procurement exercise later this year andis anticipated to comprise of fast response and energy storage in addition to network stability equipment.
Mark Rough, Director of Operations, SSEN Distribution, said:
"By transitioning Lerwick Power Station to operate as a standby station, we're implementing the most economic and reliable solution available, using an existing and trusted asset.
"The combination of the backup power station alongside innovativeinterruptionavoidance equipment will ensure we continue to provide a safe, secure and reliable supply of electricity to the homes and businesses that rely on us to keep the power flowing across the islands.
"This solutionwill result in a substantial reduction incarbonemissions, and as net zero strategies and pathways crystallise ata national and local level, the continued use of the power station provides the flexibility to transition to alonger-termsustainablesolution if reliableand cost-effectivetechnology emerges before 2035."