A waste-to-district energy scheme (DHS) on the Shetland Islands in Scotland, that serves the UK’s most northerly town of Lerwick, is now fit for future expansion following installation of a distributed control system (DCS)  from Siemens.
 
The Lerwick DHS scheme pumps hot water around the clock to 1100 homes and other buildings in the Shetland Islands’ capital.
 
The heat is supplied by the local Energy Recovery Plant (ERP), which generates it by incinerating 22,000 tonnes of waste each year from Shetland, Orkney and the Highlands.
 
Both rely on a DCS to manage the entire process, from regulating the ERP’s huge 1100°C furnace to ensuring that pressure and temperature levels are correct as the water is pumped around Lerwick.
 
After 12 years operation of the previous DCS, the Shetland teams were concerned that the system was fast becoming obsolete and would be unable to support ambitious plans for planned expansion.
 
After a tender process, Shetland selected Digital Applications International (DAI) to build a control and reporting solution based on the Siemens SIMATIC PCS 7 platform, for which DAI is an approved integrator.
 
DAI and Siemens ensured that migration to the SIMATIC PCS 7 platform was smooth and on schedule.
 
Thanks to the flexibility of the Siemens technology, the DAI project team was able to build several features into their change-over strategy that kept risk of operational disruption to a minimum.