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Energy efficiency measures in buildings are considered to have great potential for reducing total energy use, and contribute to a reduced climate and environmental impact. In Sweden, however, there is a focus on bought energy, which does not always reflect the environmental and climate impact. Focusing on bought energy means that a house owner may choose an electricity based heat pump instead of district heating (DH), since heat pumps result in less bought energy compared to DH.

The energy system surrounding the buildings is affected by the choice of energy carriers used for heating. This thesis uses three different methods to study how the energy system is affected. In the first part, primary energy use has been calculated for a simulated building with different heating systems, resulting in different electricity and DH demands. The second part studies the impact on peak demand and annual consumption in the power grid and DH system due to different market shares of electricity based heating and DH. In the third part, the life cycle cost is calculated for different heating solutions from both a building and a socio-economic perspective, for 100 % renewable energy system scenarios.

The results show that the choice of energy carrier has a great influence on primary energy use. However, this depends even more on the calculation method used. Which heating solution, and thus which energy carrier, gives the lowest primary energy use varies with the different methods.

The power grid and DH system are affected by the choice of energy carrier. There is a potential to lower peak demand in the power grid by more efficient heat pumps. But an even greater potential is shown by using DH instead of electricity based heating. A larger share of DH also allows the production of more electricity with the use of combined heat and power.

The life cycle cost for different heating solutions also depends on the method used. From a building owner’s perspective, with current electricity and DH prices, electricity based heating is more economical. However, from a socio-economic perspective, with increasing electricity system costs due to a larger share of variable electricity production in a 100 % renewable system, DH becomes more economically profitable in several scenarios.

The choice of energy carrier for heating in buildings affects the energy system to a high degree. A system perspective is therefore important in local, national and global energy efficiency policies and projects.

A common way of calculating the life cycle cost (LCC) of building renovation measures is to approach it from the building side, where the energy system is considered by calculating the savings in the form of less bought energy. In this study a wider perspective is introduced. The LCC for three different energy renovation measures, mechanical ventilation with heat recovery and two different heat pump systems, are compared to a reference case, a building connected to the district heating system. The energy system supplying the building is assumed to be 100% renewable, where eight different future scenarios are considered. The LCC is calculated as the total cost for the renovation measures and the energy systems. All renovation measures result in a lower district heating demand, at the expense of an increased electricity demand. All renovation measures also result in an increased LCC, compared to the reference building. When aiming for a transformation towards a 100% renewable system in the future, this study shows the importance of having a system perspective, and also taking possible future production scenarios into consideration when evaluating building renovation measures that are carried out today, but will last for several years, in which the energy production system, hopefully, will change.

There are different views on whether district heating (DH) or heat pumps (HPs) is or are the best heating solution in order to reach a 100% renewable energy system. This article investigates the economic perspective, by calculating and comparing the energy system life cycle cost (LCC) for the two solutions in areas with detached houses. The LCC is calculated using Monte Carlo simulation, where all input data is varied according to predefined probability distributions. In addition to the parameter variations, 16 different scenarios are evaluated regarding the main fuel for the DH, the percentage of combined heat and power (CHP), the DH temperature level, and the type of electrical backup power. Although HP is the case with the lowest LCC for most of the scenarios, there are alternatives for each scenario in which either HP or DH has the lowest LCC. In alternative scenarios with additional electricity transmission costs, and a marginal cost perspective regarding the CHP investment, DH has the lowest LCC overall, taking into account all scenarios. The study concludes that the decision based on energy system economy on whether DH should expand into areas with detached houses must take local conditions into consideration.

Sweden faces several challenges with more intermittent power in the energy system. One challenge is to have enough power available in periods with low intermittent production. A solution could be to reduce peak demand and at the same time produce more electricity during these hours. One way of doing this is to convert electricity-based heating in buildings to district heating based on combined heat and power. The study analyzes how much a Swedish municipality can contribute to lowering peak electricity demand. This is done by quantifying the potential to reduce the peak demand for six different scenarios of the future heat demand and heat market shares regarding two different energy carriers: electricity-based heating and district heating. The main finding is that there is a huge potential to decrease peak power demand by the choice of energy carrier for the buildings’ heating system. In order to lower electricity peak demand in the future, the choice of heating system is more important than reducing the heat demand itself. For the scenario with a large share of district heating, it is possible to cover the electricity peak demand in the municipality by using combined heat and power.

The Nordic electricity system faces many challenges with an increased share of intermittent power from renewable sources. One such challenge is to have enough capacity installed to cover the peak demands. In Sweden these peaks appear during the winter since a lot of electricity is used for heating. In this paper a mapping of the heat and electricity consumption in a medium size municipality in Sweden is presented. The paper analyze the potential for a larger market share of district heating (DH) and how it can affect the electrical power balance in the case study. The current heat market (HM) and electricity consumption is presented and divided into different user categories. Heating in detached houses not connected to DH covers 25 % of the HM, and 30 % of the electricity consumption during the peak hours. Converting the detached houses not connected to DH in densely populated areas to DH could reduce the annual electricity consumption by 10 %, and the electricity consumption during the peak hours by 20 %.

Energy efficiency measures in buildings are considered to have great potential in order to reduce total energy consumption, and thus contribute to a reduced environmental impact and a better climate. In Sweden, however, the energy performance requirements for buildings are formulated in terms of bought energy, i.e. as bought electricity and district heating (DH), which does not always reflect the environmental and climate impact from a broader perspective. Focusing on bought energy means that many choose an electricity-based heat pump solution in their building instead of DH, since heat pumps result in a smaller amount of bought energy compared to DH.

The surrounding energy system of the buildings is affected by the choice of energy carriers used for heating. How the energy system is affected is studied in this thesis using two different methods. In the first part, primary energy consumption has been calculated for a simulated building with different heating solutions, representing different electricity and DH demands. In the second part, the impact on total consumption in the surrounding power and DH networks due to different market shares of electricity-based heating and DH has been studied. The second part also includes an analysis of the potential to produce electricity using combined heat and power (CHP) in different scenarios depending on the market share of DH. This part has been carried out as a case study for the Swedish municipality of Falun.

The results show that the choice of energy carrier has a great influence on primary energy consumption. The resulting primary energy consumption does, however, to an even greater extent depend on the calculation method used. Which heating solution, and thus also which energy carrier, gets the lowest primary energy consumption varies in the different methods.

The surrounding power and DH networks are also affected to a great extent by the choice of energy carrier. There is a huge potential to lower peak demand in the power grid by avoiding electricity-based heating. The potential to produce electricity using CHP is also increased with a larger market share for DH. In Falun, reduced electricity demand and increased electricity production using CHP make it possible to cover the peak power demand using only electricity production from CHP. In comparison, 10 % of the peak power demand was covered by electricity from CHP in 2015.

The choice of energy carrier for heating in buildings affects the surrounding energy system to a high degree, and is therefore an important aspect to take into account in both local, national and global energy efficiency projects. 

The building sector accounts for a large part of the energy use in Europe and is a sector where the energy efficiency needs to improve in order to reach the EU energy and climate goals. The energy efficiency goal is set in terms of primary energy even though there are different opinions on how to calculate primary energy. When determining the primary energy use in a building several assumptions are made regarding allocation and the value of different energy sources. In order to analyze the difference in primary energy when different methods are used, this study use 16 combinations of different assumptions to calculate the primary energy use for three simulated heating and ventilations systems in a building. The system with the lowest primary energy use differs depending on the method used. Comparing a system with district heating and mechanical exhaust ventilation with a system with district heating, mechanical exhaust ventilation and exhaust air heat pump, the former has a 40% higher primary energy use in one scenario while the other has a 320% higher in another scenario. This illustrates the difficulty in determining which system makes the largest contribution to fulfilling the EU energy and climate goals.

Renovation of existing buildings is important in the work toward increased energy efficiency and reduced environmental impact. The present paper treats energy renovation measures for a Swedish district heated multi-family house, evaluated through dynamic simulation. Insulation of roof and façade, better insulating windows and flow-reducing water taps, in combination with different HVAC systems for recovery of heat from exhaust air, were assessed in terms of life cycle cost, discounted payback period, primary energy consumption, CO2 emissions and non-renewable energy consumption. The HVAC systems were based on the existing district heating substation and included mechanical ventilation with heat recovery and different configurations of exhaust air heat pump.Compared to a renovation without energy saving measures, the combination of new windows, insulation, flow-reducing taps and an exhaust air a heat pump gave up to 24% lower life cycle cost. Adding insulation on roof and façade, the primary energy consumption was reduced by up to 58%, CO2 emissions up to 65% and non-renewable energy consumption up to 56%. Ventilation with heat recovery also reduced the environmental impact but was not economically profitable in the studied cases. With a margin perspective on electricity consumption, the environmental impact of installing heat pumps or air heat recovery in district heated houses is increased. Low-temperature heating improved the seasonal performance factor of the heat pump by up to 11% and reduced the environmental impact.

Since a large share of the total European primary energy is consumed in the building sector, buildings have to become more energy efficient in order to reach the goals of the European energy efficiency directive. In Sweden, focus has been on lowering final energy consumption, not primary energy consumption. A relevant question today is whether a general understanding of the primary energy concept is needed to encourage selection of better energy efficiency measures from an environmental perspective. There are however uncertainties of how to calculate primary energy consumption since different primary energy factors (PEF) are used by different actors, especially for district heating (DH) and electricity (EL.).

In this study total primary energy consumption was calculated for a residential building before and after several renovation measures were made. The major change after the renovation was that a large share of the DH was substituted by heat from an exhaust air heat pump and solar collectors. A range of commonly used PEFs were assessed.

The evaluation showed that the energy efficiency measures reduced the total primary energy consumption for most combinations of PEFs. The most essential was how the DH was valued. A low PEF for DH in combination with most of the PEFs for electricity could even result in higher total primary energy consumption after the renovation.  

Sweden faces several challenges when more intermittent renewable power is integrated into the energy system. One of the challenges is to have enough electrical power available in periods with low production from intermittent sources. A solution to the problem could be to reduce the electricity peak demand and at the same time produce more electricity during peak hours. One way of doing this is to convert electricity based heating in buildings to district heating (DH) based on combined heat and power (CHP).

The study analyzes how much a medium sized Swedish municipality can contribute to lower the electricity peak demand. This is done by quantifying the potential to reduce the peak demand for six different scenarios of the future heat market volume and heat market shares regarding electricity based heating and DH in 2050.

The main finding is that electricity consumption will be reduced by 35-70 % during the peak hour (and 20-40 % on a yearly basis) for all the six scenarios studied compared with the current situation. If the aim is to lower the electricity peak demand in the future, the choice of heating system is more important than reducing the heat demand itself. For the scenario with a large share of DH, it is possible to cover the electricity peak demand in the municipality by using CHP.