Scotland has committed to achieving net-zero greenhouse gas emissions by 2045. Heat is at the core of Scotland’s energy system, accounting for approximately half of the energy consumed by homes and businesses. This makes heat the biggest element of Scotland’s energy use and its largest source of emissions. The Scottish Government (in line with advice from the Committee on Climate Change) has identified heat networks, or district heating, as one of the ‘low-regret’ options - low cost and with relatively large benefits - for heat decarbonisation. Its Climate Change Plan 2018[1] (CCP) focuses on significant reductions in emissions from buildings, both residential and non-domestic.

This study supports the emerging regional and national policies associated with the development and deployment of low-carbon heat networks (or district heating) by examining potential waste heat sources in Scotland that have received limited attention. Heat networks, or district heating, involve providing heat to homes and businesses via insulated pipes in the form of hot water or steam.

The study assesses the waste heat potential of 10 different sectors (distilleries, breweries, bakeries, paper and pulp, laundry, supermarkets, data centres, electricity substations, waste-water treatment plants (WWTP), and landfill) using a variety of data sources and calculation steps.

Waste heat potential:
  • The study has identified a waste heat potential of circa 1,677 GWh across some 932 sites in Scotland.
  • The largest waste heat potential was estimated to be in the distillery and waste-water treatment sectors. Bakeries and paper and pulp are the other sectors with high waste heat potential.
Opportunities:
  • Data centres, breweries, supermarkets, laundries, bakeries and paper and pulp sites have relatively high heat demand in their local areas. As a result, these may provide potential for district heating (DH) opportunities.
  • 237 sites (equivalent to 25% of all the waste heat sites we identified, with a total waste heat potential of 146,554 MWh), have an existing DH scheme within 500m.
Recommendations:
  • Further investigation is recommended on the technological aspects of waste heat recovery from WWTPs, distilleries and paper and pulp mills, as these sectors have relatively higher theoretical waste heat potential.
  • There is a need to review and assess the heat recovery technologies suitable for capturing waste heat from electricity substations.
  • The viable distance for the distribution and use of waste heat will vary depending on several factors. Further research in this area and/or reviews of the technical and commercial aspects of recovering and re-using waste heat in district heating systems would be advantageous.
  • As only a simplified proximity analysis was undertaken, it would be advantageous to conduct additional analysis to explore the opportunities for supply / demand matching in more detail.