The German Fraunhofer IEG has released a fantastic “Low-Temperature District Heating Implementation Guidebook”. The guidebook aims to provide tangible information that will facilitate the implementation of low-temperature district heating (LTDH) systems. These systems provide renewable heat and low-temperature excess heat at a lower cost than high-temperature district heating systems. Through the increased use of low-temperature district heating systems, a significant transformation of basic district heating technology can be accomplished.
This guidebook has been written within the TS2 annex of the IEA technology collaboration programme concerning district heating and cooling (also known as the IEA DHC/CHP programme, www.iea-dhc.org). Started in 2018, the TS2 annex was called ‘Implementation of Low-Temperature District Heating Systems’ and was active until 2021. Several research groups from Austria, Denmark, Germany, Norway, Sweden, and the United Kingdom have been involved in this study. The annex was funded by a task-sharing effort since the work contribution from each partner was financed by national research financing schemes. Kristina Lygnerud from Halmstad University in Sweden coordinated the annex.
The report considers that the introduction of low-temperature heat distribution with supply temperatures below 70 degrees C will increase the profitability of implementing geothermal heat, heat pumps, industrial excess heat, solar collectors, flue gas condensers, and heat storage options into district heating systems.
The low-temperature heat distribution will be a key economic driver together with higher carbon prices for obtaining decarbonisation within the EU because of the larger reduction target of carbon dioxide emissions for 2030.
The report shares an interesting overview on carbon dioxide emissions from all district heating systems in 24 EU and 23 other countries (source: Werner, 2017)
The report provides interesting case studies and highlights the great opportunity in utilising low-temperature geothermal resources and temperatures in urban settings. The cost reduction opportunities (see page 11 of the report), clearly point to the fantastic role geothermal energy can play.