12th International Symposium on District Heating and Cooling

The <strong>12th</strong> <strong>International</strong> <strong>Symposium</strong> on District Heating and Cooling,September 5 th to September 7 th , 2010, Tallinn, EstoniaMODELLING DISTRICT HEATING COOPERATIONS IN STOCKHOLM – ANINTERDISCIPLINARY STUDY OF A REGIONAL ENERGY SYSTEMD. Magnusson 1 , D. Djuric Ilic 21 Department of Thematic Studies – Technology and Social Change, Linköping University,SE-581 83 Linköping, Sweden2 Department of Mechanical Engineering, Division of Energy Systems, Linköping University,SE-581 83 Linköping, SwedenABSTRACTIn this paper, a combination of methods from socialscience (interviews) and technical science (modelling)have been used to analyse the potential forcooperation in the present and future district heatingsystem in Stockholm. The aim of the paper is to explorebarriers and driving forces for energy cooperation in theStockholm district heating system and to analyse thepotential for combined heat and power generation inthe system. In the study it was found that with betterconnectivity in existing systems, the annual systemcost would decrease by approximately 10 million €, andwith new CHP plants a similar potential exists. There isalso a large potential for decreasing the local andglobal emissions of CO2 with CHP plants. The resultsfrom the interviews showed that the existingcooperation has a long history and is working welltoday. The advantages are higher supply security andeconomic benefits, while disadvantages are a need formore administration and control because of a morecomplex system. That the barriers to cooperation areseldom technical is another conclusion. With thecombination of methods, we have gained a betterunderstanding of the actual potential for thedevelopment of the system.NOMENCLATURECO 2 – carbon dioxide;LECO 2 – local emissions of CO 2 ;GECO 2 – global emissions of CO 2 ;CHP – combined heat and power;BCHP – CHP plants fuelled by solid biomass;NGCHP – CHP plants fuelled by natural gas;TGC – tradable green certificates;GHG – greenhousegas.1. INTRODUCTIONSwedish district heating has a long history and is todayone of the dominant heating forms with approximately55% of market share, and an annual energy productionof approximately 55 TWh[1]. The first system was builtin Karlstad in 1948 and during the following decadesthe largest cities built their own systems, as was thecase in Stockholm [2]. Because of the large amount ofenergy in the systems, the fuel used in the plants has amajor impact on greenhouse gas (GHG) emissions,and there is also a large potential for using combinedheat and power (CHP) technology in the systems. CHPtechnology is becoming more important as a part ofcreating sustainable energy systems, which forexample can be seen in the EU directive for promotionof cogeneration [3]. In Sweden, as well as inStockholm, large investments are made in building newCHP plants, in large part thanks to the electricitycertificate system [1]. Another important potential withCHP generation is through the Electricity Directive of1996, in which the EU prescribed common rules forcreation of an open and competitive electricity market[4]. With a fully integrated electricity market, theSwedish prices of electricity can be expected toincrease. However, as long as they are lower thanEurope‘s there is a large potential for exportingelectricity. From a marginal power productionperspective, which will be discussed further in thepaper, there is a potential for decreasing globalemissions of CO 2 , if the exported electricity comes fromnon-fossil fuels.A large enough system is an important prerequisite forinvestment in CHP plants, in order to take advantage ofthe economy of scale of district heating and CHPgeneration. In Stockholm, the largest urban region inSweden, there are already well-developed districtheating systems. The systems started as smaller unitsthat gradually have been interconnected and todayconsist of three large networks. However, since thereare eight different energy companies in the city region,a working cooperation between the energy companiesis important. With this in mind we will analyze how theactors perceive existing and future cooperation. Thestudy is conducted with an interdisciplinary approachwhere interviews have been combined with modellingthe systems' performance with present and possiblefuture interconnections, present plants and future CHPplants, and finally with a hypothetical introduction ofnatural gas. The aim of the paper is to explore barriersand driving forces for energy cooperation in the288