Exploring residential energy efficiency measures and distribution of renewable energy generation through sector interactions: a case study in Visby, Sweden

Abstract

Increased use of cogeneration in district heating (DH) systems is important in the pursuit towards a low-carbon society, particularly in light of the ongoing electrification across multiple sectors. Apart from reducing CO2 emissions, cogeneration also contributes to additional income for the DH system owner. Nonetheless, it is important to be aware that the economic and environmental performance of DH systems are directly connected to the energy use within DH networks. This research investigates sector interactions associated with the introduction of a biomass combined heat and power (CHP) and residential energy renovation according to (life cycle cost) LCC optimum and Swedish energy targets, with a focus on CO2 emissions and the system cost of the energy utility company. The study object consists of a DH system in Visby, Sweden, and 920 historic residential building undergoing energy renovation. The results show a profitability of 905–915 MSEK for the DH system with the integration of a CHP. Global CO2 emissions decrease by 32.6–33.1 ktonnes/year, 9.0–9.2 ktonnes/year, and 19.9–20.1 ktonnes/year, for marginal coal-condensing power (limited biofuel), natural gas combined cycle power (limited biofuel), and European average production, respectively. In addition, sensitivity analyses confirm the benefits of cogeneration related to both economics and CO2 emissions based on changes in key parameters of the DH system.