CO2 emission evaluation of energy conserving measures in buildings connected to a district heating system – Case study of a multi-dwelling building in Sweden

When taking action to fulfill the directives from the European Union, energy conserving measures will be implemented in the building sector. If buildings are connected to district heating systems, a reduced heat demand will influence the electricity production if the reduced heat demand is covered by combined heat and power plants. This study analyze five different energy conserving measures in a multi-dwelling building regarding how they affect the marginal production units in the district heating system in Gävle, Sweden. For CO2 emission evaluations, two different combinations of heat and electricity conserving measures are compared to an installation of an exhaust air heat pump. The different energy conserving measures affect the district heating system in different ways. The results show that installing an exhaust air heat pump affects the use/production of electricity in the district heating system most and electricity conserving measures result in reduced use of electricity in the building, reduced use of electricity for production of heat in the district heating system and an increase of electricity production. The conclusion is that electricity use in the building is the most important factor to consider when energy conserving measures are introduced in buildings within the district heating system in Gävle. •Investigates how the district heating system in Gävle is affected when the heat demand is reduced.•Different energy conserving measures are simulated in a building and the results are analyzed.•Three different combinations of energy conserving measures are investigated.•Different allocation methods are used to analyze the impact when electricity use/production alter.•Results in a tendency for climate effects for the three combinations, despite allocation method.