With district heating toward a sustainable future : System studies of district heating and cooling that interact with power, transport and industrial sectors

The aim of this thesis is to identify measures which should be taken in DH systems (DHSs) in order to contribute to the development of the DHSs and other energy systems (especially transport, industrial and power sectors) toward sustainability. Four business strategies were analysed: delivering excess heat from biofuel production industry to DHSs, conversion of industrial processes to DH, integration of biofuel production in DHSs and integration of DHdriven absorption cooling technology in DHSs. Delivering excess heat from biofuel production industry to DHSs was analysed with a focus on the biofuel production costs for four biofuel production technologies. Integration of biofuel production and integration of DH-driven absorption cooling technology in DHSs were analysed with a focus on Stockholm’s DHS, using an optimisation model framework called MODEST. When the conversion of industrial processes to DH was analysed, DHSs and industrial companies in Västra Götaland, Östergötland and Jönköping counties were used as case studies; a method for heat load analysis called MeHLA was used to analyse the effects on the local DHSs. The results showed that when considering biomass an unlimited resource, by applying the abovementioned business strategies DH has a potential to reduce global fossil fuel consumption and global GHG emissions associated with power, industrial and transport sectors. DH producers may contribute to the sustainable development of the  transport sector by buying excess heat from the biofuel production industry. This business strategy results in lower biofuel production costs, which promotes development of biofuel production technologies that are not yet commercial. Moreover, introduction of large-scale biofuel production into local DHSs enables development of local biofuel supply chains; this may facilitate the introduction of biofuel in the local transport sectors and subsequently decrease gasoline and fossil diesel use. Conversion of industrial processes from fossil fuels and electricity to DH is a business strategy which would make the industry less dependent on fossil fuels and fossil fuelbased electricity. DH may also contribute to the sustainable development of the industry by buying waste heat from industrial processes, since this strategy increases the total energy efficiency of the industrial processes and reduces production costs. Furthermore, DH has a possibility to reduce fossil fuel consumption and subsequently GHG emissions in the power sector by producing electricity in biomass- or waste-fuelled CHP plants. When the marginal electricity is associated with high GHG emissions (e.g. when it is produced in coal-fired condensing power (CCP)) plants, the reduction of the marginal electricity production (due to the conversion of industrial processes from electricity to DH and due to the conversion of compression cooling to DHdriven absorption cooling) results in higher environmental benefits. On the other hand, the introduction of biofuel production into DHSs becomes less attractive from an environmental viewpoint, because the investments in biofuel production instead of in CHP production lead to lower electricity production in the DHSs. The increased DH use in industry and introduction of the biofuel production and DH-driven absorption cooling production into the DHSs lead to increased biomass use in the DHSs. Because of this, if biomass is considered a limited resource, the environmental benefits of applying these business strategies are lower or non-existent.Syftet med denna avhandling är att identifiera åtgärder som bör vidtas i FJV-system (FJVS) för att bidra till en hållbar utveckling av FJV och andra relaterade energisystem som transport, industri- och energisektorn. Fyra affärsstrategier är analyserade: att leverera överskottsvärme från produktion av biobränsle för transportsektorn, konvertering av industriella processer till FJV, integration av biobränsleproduktion för transportsektorn i FJVS och integration av FJV-driven absorptionskylteknik i FJVS. Att leverera överskottsvärme från produktion av biobränsle till transportsektorn analyserades med fokus på kostnader för fyra olika produktionstekniker. Integration av biobränsleproduktion till transportsektorn och integration av FJV-driven absorptionskylteknik i FJVS analyserades på Stockholms FJVS med optimeringsmodellen MODEST. När konvertering av industriella processer till FJV analyserades, användes FJVS och industriföretag i Västra Götaland, Östergötlands och Jönköpings län som fallstudier. Metoden MeHLA som används för analys av värmebelastning tillämpades för att analysera effekterna på de lokala FJVS. Resultaten från studierna visar att när biomassa anses vara en obegränsad resurs har FJV en potential att minska den globala konsumtionen av fossila bränslen och de globala utsläppen av växthusgaser som förknippas med transport-, industri- och energisektorn, for samtliga analyserade affärsstrategierna. FJV producenter kan bidra till en hållbar utveckling av transportsektorn genom användningen av överskottsvärme från produktion av transportbiobränsle. Den analyserade affärsstrategin ger lägre produktionskostnader för transportbiobränsle vilket främjar utvecklingen av produktionsteknik som ännu inte är kommersiell. Dessutom möjliggörs utveckling av lokala försörjningskedjor av transportbiobränsle på grund av den storskaliga produktionen av transportbiobränsle i lokala FJVS. Detta kan sedan underlätta införandet av transportbiobränsle i lokala transporter och även minska användningen av bensin och fossil diesel. Konvertering av industriella processer från fossila bränslen och el till FJV är en affärsstrategi som skulle göra FJV-branschen mindre beroende av fossila bränslen. Att använda spillvärme från industriprocesser ökar den totala energieffektiviteten i de industriella processerna och minskar produktionskostnaderna. Genom att dessutom öka FJV-användningen inom industriella produktionsprocesser och genom att konvertera eldriven kompressionskyla till FJV driven komfortabsorptionskyla, minskar säsongsvariationerna av FJV lasten, vilket leder till ett bättre utnyttjande av produktionsanläggningar för FJV. Om produktionsanläggningarna för baslast i FJVS är kraftvärmeverk, leder dessa två affärsstrategier till en ökad elproduktion i FJVS. När marginalproducerad el förknippas med höga utsläpp av växthusgaser (t.ex. när det produceras i koleldade kondenskraftverk), resulterar en minskning av den marginella elproduktionen (på grund av konvertering av industriella processer från el till FJV och på grund av konvertering eldriven kompressionskyla till FJV-driven absorptionkyla) i minskade globala emissioner av växthusgas. Om man däremot tittar på införandet av produktion av transportbiobränsle i FJVS är denna affärsstrategi mindre attraktiv ur ett miljöperspektiv. Orsaken till detta är att investering i produktion av transportbiobränsle istället för i kraftvärmeproduktion, leder till minskad elproduktion i FJVS. Den ökade FJV-användningen inom industrin och införandet av produktion av biobränsle för transportsektorn och FJV driven absorptionskylproduktion i FJVS leder till en ökad användning av biomassa i FJVS. När biomassa anses vara en begränsad resurs, är de miljömässiga fördelarna med att tillämpa dessa affärsstrategier relativt låga eller till och med obefintliga

Classification of Measures for Dealing with District Heating Load Variations-A Systematic Review

The highly varying character of district heating (DH) demand results in low capacity utilization of the DH plants, as well as increased use of fossil fuels during peak demand. The aim of this study is to present an overview and a comprehensive classification of measures intended to manage these load variations. A systematic literature review was conducted based on previously defined search strings as well as inclusion and exclusion criteria. Two scientific databases were used as data sources. Based on 96 detected publications, the measures were categorized as (1) complementing DH production in heat-only boilers (HOBs), or geothermal or booster heat pumps (HPs) (usually controlled by the DH company), (2) thermal energy (TE) storage in storage units or in the network (controlled by the company), and (3) demand side measures, which can be strategic demand increase, direct demand response (DR), or indirect DR. While the company has control over direct DR (e.g., thermal storage in the thermal mass of the buildings), indirect DR is based on communication between the customer and the company, where the customer has complete control. The multi-disciplinary nature of this topic requires an interdisciplinary approach

Economic and environmental benefits of converting industrial processes to district heating

The aim of this study is to analyse the possibilities of converting production and support processes from electricity and fossil fuels to district heating in 83 manufacturing companies in three different Swedish counties. A tool for heat load analysis called Method for Heat Load Analysis (MeHLA) is used to explore how the conversions would affect the heat load duration curves in local district heating systems. Economic effects and impacts on global emissions of greenhouse gases are studied from a system perspective. The study has been conducted considering two different energy market conditions for the year 2030. The results show that there is a potential for increasing industrial district heating use in all analysed counties. When comparing all three counties, the greatest potential regarding percentage is found in Jönköping, where the district heating use in the manufacturing companies could increase by nine times (from 5 GWh to 45 GWh annually). The industrial district heating use could increase by two times (from 84 GWh to 168 GWh annually) in Östergötland and by four times (from 14 GWh to 58 GWh annually) in Västra Götaland. The conversion of the industrial production processes to district heating would lead to a district heating demand curve which is less dependent on outdoor temperature. As a result, the utilization period of the combined heat and power plants would be prolonged, which would decrease district heating production costs due to the increased income from the electricity production. In all analysed counties, the energy costs for the companies decrease after the conversions. Furthermore, the increased electricity production in the combined heat and power plants, and the decreased electricity and fossil fuel use in the industrial sector opens up a possibility for a reduction of global greenhouse gas emissions. The potential for the reduction of global greenhouse gas emissions is highly dependent on the alternative use of biomass and on the type of the marginal electricity producers. When the marginal effects from biomass use are not considered, the greenhouse gas emissions reduction is between 10 thousand tonnes of CO2eq and 58 thousand tonnes of CO2eq per year, depending on the county and the type of marginal electricity production plants. The highest reduction is achieved in Östergötland. However, considering that biomass is a limited resource, the increase of biomass use in the district heating systems may lead to a decrease of biomass use in other energy systems. If this assumption is included in the calculations, the conversion of the industrial processes to district heating still signify a  potential for reduction of greenhouse gas emissions, but this potential is considerable lower

Economic and environmental benefits of converting industrial processes to district heating

The aim of this study is to analyse the possibilities of converting production and support processes from electricity and fossil fuels to district heating in 83 manufacturing companies in three different Swedish counties. A tool for heat load analysis called Method for Heat Load Analysis (MeHLA) is used to explore how the conversions would affect the heat load duration curves in local district heating systems. Economic effects and impacts on global emissions of greenhouse gases are studied from a system perspective. The study has been conducted considering two different energy market conditions for the year 2030. The results show that there is a potential for increasing industrial district heating use in all analysed counties. When comparing all three counties, the greatest potential regarding percentage is found in Jönköping, where the district heating use in the manufacturing companies could increase by nine times (from 5 GWh to 45 GWh annually). The industrial district heating use could increase by two times (from 84 GWh to 168 GWh annually) in Östergötland and by four times (from 14 GWh to 58 GWh annually) in Västra Götaland. The conversion of the industrial production processes to district heating would lead to a district heating demand curve which is less dependent on outdoor temperature. As a result, the utilization period of the combined heat and power plants would be prolonged, which would decrease district heating production costs due to the increased income from the electricity production. In all analysed counties, the energy costs for the companies decrease after the conversions. Furthermore, the increased electricity production in the combined heat and power plants, and the decreased electricity and fossil fuel use in the industrial sector opens up a possibility for a reduction of global greenhouse gas emissions. The potential for the reduction of global greenhouse gas emissions is highly dependent on the alternative use of biomass and on the type of the marginal electricity producers. When the marginal effects from biomass use are not considered, the greenhouse gas emissions reduction is between 10 thousand tonnes of CO2eq and 58 thousand tonnes of CO2eq per year, depending on the county and the type of marginal electricity production plants. The highest reduction is achieved in Östergötland. However, considering that biomass is a limited resource, the increase of biomass use in the district heating systems may lead to a decrease of biomass use in other energy systems. If this assumption is included in the calculations, the conversion of the industrial processes to district heating still signify a  potential for reduction of greenhouse gas emissions, but this potential is considerable lower

Integration of biofuel and DH production - Possibilities, potential and trade-off situations : A review

There are several barriers to increased use of biofuel in the transport sector (e.g., shortage of feedstocks, high production costs, and relatively low energy yields from standalone biofuel plants). One possible solution is integration of biofuel and district heating (DH) production. This study aims (1) to identify challenges (e.g. tradeoffs) related to integration and to suggests possible ways of dealing with these challenges, (2) to highlight factors that may influence effects on global GHG emissions from integration, (3) to highlight factors which should be considered when evaluating economic aspects related to integration. After conducting a systematic review using a prescribed and structured protocol, 38 articles were identified as relevant for this study. These articles present four different approaches for integration: delivering the excess heat from biorefineries to DH networks, utilising DH in biofuel production processes, integrating biofuel production with existing DH facilities, and building new polygeneration biofuel production facilities in DH systems (DHS).If investments in biofuel compete with combined heat and power (CHP) production, the electricity price and the premium paid for renewable electricity influence profitability in CHP plants investments and therefore even profitability in investments in biofuel production. Competition should also be considered when weighing environmental benefits (the influence on global GHG emissions). Competition can create trade-offs related to DHSs operating conditions, limited local and global biomass availability, and limited available heat sinks. To deal with these trade-offs and to avoid suboptimization, stakeholders in regional planning, investors and policymakers should cooperate.All identified studies noted that a comprehensive approach is needed to evaluate profitability aspects and effects on global GHG emissions.For instance, utilising excess heat or residues from a biofuel production process in a DHS requires consideration of alternative DH production and alternative fuels. If electricity is one of the by-products from the biofuel production, alternative electricity production should also be considered. The majority of the studies dealt with economic performance of integration. Some of the factors found to influence profitability include available heat sink, alternative DH and electricity production, expected operation patterns, energy policy and energy market conditions. The potential for reducing global greenhouse gases (GHG) emissions depends on alternative DH and electricity production but also on biomass availability and alternative biomass users

Socioeconomic potential for introducing large-scale heat pumps in district heating in Denmark

Denmark has a national political goal of a 100% renewable energy supply in 2050. This requires a comprehensive transition of the energy system. For some decades, district heating in Denmark has been contributing to high fuel efficiency as well as to the integration of the electricity and heating sectors. Large-scale compression heat pumps would improve the integration between the district heating and power sectors by utilising the fluctuations in the supply from wind power, solar photo voltaic and other sources. Previous studies indicate that the introduction of heat pumps in Denmark will have a positive impact on the total costs for energy supply in the transition towards 100% renewable energy. In this paper, this is further investigated to assess the feasibility of heat pumps in the Danish energy system. The assessment is made by applying two different energy system analysis tools, named EnergyPLAN and MODEST. The comparison and discussion of these tools is a secondary purpose of the study. In general, the results show a potential for introducing heat pumps in Denmark between 2 and 4 GW-thermal power and a total potential benefit around 100 M(sic)/year in 2025. (C) 2016 Elsevier Ltd. All rights reserved.Funding Agencies|Innovation Fund Denmark [0603-00498B]</p

Stockholms fjärrvärmenät idag och imorgon : en tvärvetenskaplig studie av ett regionalt energisystem

Fjärrvärme spelar en viktig roll i strävan mot ett hållbart samhälle. Därför har vi i denna studie studerat Stockholms fjärrvärmenät och de aktörer som påverkar dess utformning. Syftet med studien har varit att undersöka drivkrafter och hinder för att utveckla fjärrvärmenäten i Stockholm. Vidare har syftet varit att studera hur aktörerna samverkar på kommunal och regional nivå för att bibehålla och/ eller vidareutveckla energisamarbeten. Fjärrvärmenätet har modellerats utifrån sex olika scenarier i optimeringsprogrammet MODEST. Genom scenarierna har vi kunnat testa dagens nät med bättre sammankopplingar, byggande av kraftvärmeverk samt naturgas som bränsle i kraftvärmeverken. Vidare har kvalitativa intervjuer med kommuner, energibolag, intresse- och branschorganisationer samt regionala aktörer genomförts. Studien visar att Stockholms fjärrvärmenät redan idag är väl sammankopplat vilket innebär att de ekonomiska vinsterna med ytterligare sammankopplingar inte är särskilt stora. Modelleringarna pekar dock på att byggande av kraftvärme, både med biobränsle och med naturgas, har en viss ekonomisk potential. En positiv effekt är också minskningen av de globala utsläppen av växthusgaser. Vinster med samarbeten och sammankopplingar från energibolagens sida är framförallt ökad driftsäkerhet och driftsoptimering samt möjligheten att samordna revisioner. För att samarbeten ska fungera är dock ekonomisk vinst för samtliga parter samt jämlika förhållanden dem emellan en förutsättning. Det är inte tekniska problem som hindrar utökade sammankopplingar, snarare är det ökat behov av planering och administration som försvårar utökat samarbete mellan bolag. Genom resultatet från intervjuerna kan slutsatsen dras att ett glapp finns i synen på samverkan mellan bolag och kommuner. Detta oavsett om bolagen är kommunalt eller privat ägda. Att energibolagen ska drivas på bolagsmässiga grunder kan vara en förklaring till detta. Energiplanering från kommunernas perspektiv har kommit att handla om klimatfrågan i hög utsträckning och ses ofta som synonymt med miljöarbete. Energiplaneringen har därmed fått högre status och flyttats närmre kommunledning. Samtidigt sker energiplanering på många olika nivåer, inom och mellan kommunerna samt på regional nivå, vilket gör det svårt att få ett samlat grepp om frågan. Också bolagen har olika syn på det regionala perspektivet vilket pekar på att det saknas ett fungerande regionalt organ där bolag och kommuner kan samverka. Även om både energibolagen och kommunerna är positivt inställda till fjärrvärme som teknik ser framtiden för fjärrvärmebranschen något osäker ut. Minskade värmelaster på grund av energieffektiviseringar och klimatförändringar bidrar till osäkerheten. Samtidigt väntar en utredning om tredjepartstillträde som potentiellt kan innebära stora förändringar för branschen. Genom att alla bygger kraftvärme kan det vara ett sätt att ändra marknadsinriktning från värme till el för att ge ökad lönsamhet. Det går inte heller att bortse från att Stockholmsregionen har goda förutsättningar för att införa ett tredjepartstillträde där kunderna själva kan välja fjärrvärmeleverantör.District heating (DH) plays an important role when aiming for a sustainable society. Due to this the focus in this study is on the Stockholm region district heating systems and the actors who influence the shaping of it. The aim of the study is to explore driving forces and obstacles in order to develop the district heating systems in Stockholm. Moreover we investigate energy collaborations on the regional and municipal level. Method used for the study includes modelling and qualitative semi-structured interviewing. The district heating systems has been modelled from sex different scenarios in the optimization program MODEST. We have been able to test the present network with better level of connections, with the building of new combined heat and power plants and with natural gas and bio fuels as fuels. Interviews with municipalities, energy companies and interest groups have been performed. The result of the study indicates that the central heating systems in Stockholm today are well connected and the gains of further connections are relatively small. The optimizations imply that the establishment of new combined heat and power plants, with either natural gas or bio fuels, has an immense economic potential. Another positive effect is lower emissions of greenhouse gases. The gains of collaborations and further connections of the nets from the view of the energy companies are above all an increased dependability and optimizing of the operation as a whole. Also the possibility to co-operate with company revisions is regarded as an advantage. In order to get well functioning co-operations between the companies economical profit for all parties, as well as equal conditions, is required. Worth mentioning is the fact that it’s not technical difficulties that restrains further connections of the DH-systems. The need of extended management and planning are a more plausible obstruction for increased co-operation between companies. An existing gap between the companies and the municipalities due to how they co-operate is visualized through the interviews. Whether the companies are owned by the municipalities or not is in this regard not important. That the energy companies are to be managed under businesslike conditions could explain this. Municipal planning has from the view of the municipalities come to be synonymous with environmental work. This trend has increased the status of energy planning, and has also moved within the organisation closer to the municipal executive board. At the same time energy planning is carried out at many different levels, within and between the municipalities but also on the region level. A consequence of this is that energy planning is hard to get a grip off. The companies also have different approaches to the regional perspectives, which point to the conclusion that a working regional body for coordination of the joint interest of the municipalities and the energy companies is needed. Even though both the energy companies and the municipalities are positive towards the technology of district heating the future for the district heating business is somewhat uncertain. Decreasing heath loads due to increasing energy efficiency and climate change is contributing to the uncertainness. Also the upcoming commission of what is called “Third Part Access” (TPA) could change the business at a large extend. Changing business orientation is an alternative that the energy companies may have to consider. The current trend of new establishment of combined power and heating plants makes it’s possible for the companies to start producing and selling electricity. The Third Part Access can also be an advantage for the businesses in the Stockholm region since it opens up the possibility for customers to choose which district heating provider they want

Using flexible energy system interactions amongst industry, district heating, and the power sector to increase renewable energy penetration

Swedens goal of 100% renewable electricity generation by 2040 requires investments in intermittent electricity production (e.g. wind power). However, increasing the share of intermittent electricity production presents challenges, including reduced flexibility of electricity production. A strategy for overcoming this issue is developing flexibility in electricity consumption. This study analyses the potential for using flexible industrial processes, heat pumps (HP), and combined heat and power (CHP) plants in Swedish district heating systems to increase the share of wind power capacity without compromising grid stability. The simulation tool EnergyPLAN was used to assess the potential contribution of these strategies. The analysis includes a range of annual wind power production between 45 and 60 TWh. The required electricity imports and critical excess electricity (that can neither be used nor exported due to transmission line limitations) were used to evaluate the systems stability. Managing the operation of CHP plants, HPs, and industrial processes in a flexible way is challenging, but these strategies may still play a decisive role in increasing the share of renewable electricity production and reducing demand peaks in cities. Whilst HP regulation is better at reducing excess electricity production at lower wind power capacities (from 32 to 15% for the analysed interval of wind power production), CHP regulation becomes more relevant when wind power capacity increases (from 14 to 39%). Like HP regulation, flexibility in electricity demand in industrial processes had a greater percentage contribution at lower wind power capacities. Combining HP, CHP regulation, and flexible electricity demands in industry can reduce excess electricity production by 68-80% and electricity imports by 14-26%. Wind power contributing to grid stabilisation reduces excess electricity production but does not reduce electricity imports