In Sweden, 90% of multifamily buildings utilize district heat and a large portion is in need of renovation. The aim is to analyze the impact of renovating a multifamily building stock in a district heating and cooling system, in terms of primary energy savings, peak power demands, electricity demand and production, and greenhouse gas emissions on local and global levels. The study analyzes scenarios regarding measures on the building envelope, ventilation, and substitution from district heat to ground source heat pump. The results indicate improved energy performance for all scenarios, ranging from 11% to 56%. Moreover, the scenarios present a reduction of fossil fuel use and reduced peak power demand in the district heating and cooling system ranging from 1 MW to 13 MW, corresponding to 4–48 W/m² heated building area. However, the study concludes that scenarios including a ground source heat pump generate significantly higher global greenhouse gas emissions relative to scenarios including district heating. Furthermore, in a future fossil-free district heating and cooling system, a reduction in primary energy use will lead to a local reduction of emissions along with a positive effect on global greenhouse gas emissions, outperforming measures with a ground source heat pump.

A hydronic pavement system (HPS) is an alternative method to clear snow and ice, which avoids the use of salt, sand, and fossil fuel in conventional snow clearance, and minimizes the risk of accidents. The aim is to analyze the performance of different control strategies for a 35,000 m² HPS utilizing heat from a district heating and cooling (DHC) system. The key performance indicators are (1) energy performance of the HPS, and (2) primary energy use, (3) electricity production and (4) greenhouse gas (GHG) emissions from the DHC system. The methodology uses a simulation model of the HPS and an optimization model of the DHC system. Three operational strategies are analyzed: A reference scenario based on the current control strategy, and scenarios where the HPS is shut down at temperatures below −10 °C and −5 °C. The study shows that the DHC return temperature is suitable for use. By operational strategies, use during peak demand in the DHC system can be avoided, resulting in reduced use of fossil fuel. Moreover, the energy use of the HPS could be reduced by 10% and the local GHG emissions by 25%. The study emphasizes that the HPS may have positive effects on global GHG emissions, as it enables electricity production from renewable resources.

To meet future demands for cleaner water and comply with the revised Urban Wastewater Treatment Directive (UWWTD), many European wastewater treatment plants (WWTPs) will need quaternary treatment to reduce emissions of organic micropollutants (OMPs). Quaternary treatment based on granular activated carbon (GAC) is a promising solution, yet long-term, full-scale operational data remain scarce. This study presents operational experiences from Kivik WWTP in southern Sweden – one of the first full-scale municipal installations in Europe using GAC for OMP removal. The system has treated the full plant flow for over four years, corresponding to more than 50,000 bed volumes. Thirteen of the 15 analyzed OMPs were detected, including six UWWTD indicators. Results show >80% removal of several key compounds, even under highly variable flow conditions. However, flow variability – especially during wet seasons – complicates performance assessment due to dilution and reduced effective contact time. Weakly adsorbing compounds were most affected, while compounds with strong GAC affinity exhibited stable removal throughout the year. The findings highlight the importance of long-term monitoring when evaluating GAC performance and provide valuable input for future design, regulatory compliance and cost estimation of quaternary treatment systems.

A district heating and cooling (DHC) system can be a viable piece of the puzzle in the efforts of reducing the greenhouse gas (GHG) emissions. Especially if the DHC system include combined heat and ...