Converting Tallinn's historic centre's (Old Town) heating system to a district heating system

Despite the fact that district heating is viewed as a sustainable and promising solution for urban heating, its expansion in historic areas is fraught with challenges and barriers. This paper examines the heat supply of Old Tallinn's historic centre following the transition to district heating. The study identified the primary issues associated with district heating in the Old Town and developed a methodology to assess the effects of partial and full transitions to district heating in the historic quarter, as well as the challenges associated with these transitions. The methodology includes multiple-criteria decision analysis methods, scenario comparison by indicators, expert interviews, and a comprehensive review and analysis of the legislation. The current situation was compared to four other scenarios: very-easy-to-connect, easy-to-connect, and difficult-to-connect consumers, as well as when all buildings are connected to district heating. According to the results, switching to district heating reduces primary energy consumption by 16%.