Combined Assessment of Future Heat Supply and Demand - A Dynamic Systems Approach

In order to meet climate change mitigation targets, the use of fossil fuels has to be reduced and, eventually, be phased out in all sectors. As the heating sector occupies a central place in energy systems, especially in Nordic countries, it is affected by and affects other energy sectors. The demand for space heating and hot water has traditionally been covered by: district heating (DH) systems, whereby buildings are connected through a grid to power plants; and the installation of individual heating technologies within each building. As there are several heating solutions available, the ways in which heating systems will develop in the future when fossil fuels are phased out depend on several factors, which are currently uncertain.As many components of heating systems have long lifetimes, the investments made in the near future will have long-term impacts on the development of heating systems. It will be important to understand how investments and the dispatch of different components depend on the phasing out of fossil fuels and other factors. Therefore, this thesis aims to investigate how the different parts of heating systems develop under different climate policies, electricity prices and heat load profiles.To investigate heating system development when both the supply and demand sides evolve simultaneously, a dynamic systems approach is used in which an expanding heating system is investigated for several decades in the future and new housing is treated heterogeneously.In this thesis, the TIMES modeling framework is used, and the heating system of Gothenburg is applied as modeling case. The demand side is treated heterogeneously by investigating several types of new housing, which means that the resulting cost-efficient solution may be different for different types of housing. The investment cost for new DH grid connections is therefore assessed for each housing type.The modeling results show that the main effect of a climate policy is decreased investments in new natural gas heat-only boilers (HOBs) in the DH supply side. New natural gas HOBs compete with new large-scale heat pumps (HPs) but does not affect new combined heat and power (CHP) plants. Investments are made in large-scale HPs in the cases of increasing and decreasing electricity prices, whereas no investments are made in biomass CHP plants if the future electricity price decreases.The results further shows that apartment buildings use DH exclusively, while single-family housing with low heat demands and small single-family housing with high heat demand are not connected to the DH system at all. The heating solution for large single-family housing with high heat demands is dictated by both future electricity prices and whether a climate policy is introduced. A heat demand load with a higher relative use during wintertime generally discourages the use of individual HPs.The findings of this thesis may be of interest to city planners and DH utilities, as the findings shows that both the DH supply side and the heating solution for new large single-family housing with high heat demand are affected by climate policy, future electricity prices, and the heat load profile

Linear or mixed integer programming in long-term energy systems modeling – A comparative analysis for a local expanding heating system

Most computer models used in energy systems optimization modeling studies are formulated usinglinear equations. However, since linear formulations do not always well reflect real-world conditions,they may not always be adequate as policy and support tools. This is particularly the case for localsystem studies attempting to represent technologies at the individual scale, as in the case for localheating system modeling. Thus, the aim of this paper is to investigate differences in the resultingheating solutions and model solution times for a local expanding heating system. Three differentinvestment cost structures for individual and district heating solutions for the heating of new housingare investigated using linear and mixed integer linear programming. The results show that the use ofdistrict heating is higher for the cost structures that use mixed integer linear programming than it isfor the linear cost structures. This result is attributed mainly to the fact that individual air-to-waterheat pumps benefit from the linear equation formulation due to its high coefficient of performanceduring summertime. This finding is important to consider when modeling local energy systems. Thesolution time is, however, significantly shorter for the linear formulations than for the mixed integerlinear formulations

Communal or individual – Exploring cost-efficient heating of new city-level housing in a systems perspective

As cities expand, new buildings are constructed and they require heating. With increasing integration of the heating and electricity sectors and forecasts of rapid growth in electricity demand, heating choices become critical for the sustainability transition. The main heating options are communal or individual, where the communal option is represented by district heating (DH) and the individual option mainly by heat pumps or biomass heating. Which option is best from the cost perspective depends on the building type and on the energy system development. Thus, this paper investigates cost-efficient heating of new city-level housing in a systems perspective under various scenarios. The investigation was carried out using an energy systems optimization model based on a case representing Swedish conditions. A dynamic approach was used to investigate cost-efficient development of the supply side and demand side simultaneously. The results indicate that the most cost-efficient heating systems are: DH for apartment buildings; and individual heating options for single-family housing with low heat demands. For large single-family housing with high heat demands, the cost-efficient solution depends on the heat demand profile. Higher heat use during winter favors DH and individual biomass boilers, but diminishes the economic feasibility of individual heat pumps

Actuating the European Energy System Transition: Indicators for Translating Energy Systems Modelling Results into Policy-Making

In this paper, we define indicators, with a focus on the electricity sector, that translate the results of energy systems modelling to quantitative entities that can facilitate assessments of the transitions required to meet stringent climate targets. Such indicators, which are often overlooked in model scenario presentations, can be applied to make the modelling results more accessible and are useful for managing the transition on the policy level, as well as for internal evaluations of modelling results. We propose a set of 13 indicators related to: 1) the resource and material usages in modelled energy system designs; 2) the rates of transition from current to future energy systems; and 3) the energy security in energy system modelling results. To illustrate its value, the proposed set of indicators is applied to energy system scenarios derived from an electricity system investment model for Northern Europe. We show that the proposed indicators are useful for facilitating discussions, raising new questions, and relating the modelling results to Sustainable Development Goals and thus facilitate better policy processes. The indicators presented here should not be seen as a complete set, but rather as examples. Therefore, this paper represents a starting point and a call to other modellers to expand and refine the list of indicators