Balancing investments in building energy conservation measures with investments in district heating – A Swedish case study

We investigate the cost-optimal mix of reduction in the space heating (SH) demand in buildings, achieved through investments in energy conservation measures (ECMs), and investments in the local district heating (DH) system. The work includes three modeling scenarios, which differ with respect to SH demand reduction targets (no supply side targets) for buildings: without a target (only fuel price drives demand reduction); with a total demand reduction (for the building stock); and with a specific demand reduction (to reach a specific kWh/(m2∙y) value for individual buildings). Special emphasis is placed on the choice of ECMs in buildings. For the scenario without a target for SH demand reduction, the least-cost option is a combination of investments in ECMs, heat generation and in storage technologies, yielding a SH demand reduction of 24% already by Year 2030, and thereafter a decrease of 28% up to Year 2050. The reductions are achieved mainly through investments in ventilation heat recovery systems and insulation of roofs. The scenarios that include SH demand reduction targets give similar demand reductions of about 60% by 2050, as compared to 2020. However, the investment cost for fulfilling the specific target scenario is higher than that for the total target scenario.