I Sverige används mycket energi för uppvärmning av bostäder och lokaler. För att uppfylla det ständigt ökande behovet av värme, byggs exempelvis nya värmeproducerande anläggningar som komplement i fjärrvärmesystem. Samtidigt finns det outnyttjad energi i industrin som i sin produktion får värme som oönskad biprodukt. Denna rapport undersöker möjligheten att utnyttja denna biprodukt från industrin för att tillföra energi till ett befintligt fjärrvärmenät och lagra i ett säsongsvärmelager. När värmebehovet ökar under den kalla delen av året, skall säsongsvärmelagret bidra med värme. Idén är att lagret skall ersätta delar av de värmeproducerande anläggningarna som utnyttjas i Halmstads fjärrvärmesystem. Målet är att all fossil bränsleanvändning skall kunna tas bort. Rapporten undersöker även ekonomiska lönsamheten samt miljövinsten i att ersätta del av biobränsleanvändningen. I Halmstad finns ett stålverk, Höganäs Halmstadverken, som kan bidra med överskottsenergi i form av värme. Rapporten genomför beräkningar på industrins potential att leverera prima värme till fjärrvärmenätet. Med hjälp av beräkningar och simuleringar i Microsoft Excel tas ett system med lämplig lagringsmetod samt spillvärme från lokal industri fram. Detta system skall optimeras med hänsyn till ekonomiska och miljömässiga förutsättningar. Resultatet visar att Halmstads förutsättningar är goda för att integrera ett groplager samt att det finns potential att leverera spillvärme från Höganäs Halmstadverken. Storlekarna på vattenburna säsongsvärmelager optimeras till 200 000 m3 för ersättning av endast fossila bränslen respektive 550 000 m3 för ersättning av fossila och biobränslen. Spillvärmeeffekten från Höganäs Halmstadverken beräknas till 15 MW. De ekonomiska kalkylerna resulterar i en årlig vinst på upp till 8 miljoner kronor med en payoff-tid på 8 år. Den totala miljövinsten i minskade växthusgasutsläpp blir 4 800 ton koldioxidekvivalenter per år. / In Sweden, a great deal of energy is used for residential and commercial heating. To fulfill the ever increasingly need for heat, new heating plants is built to complement the district heating system. At the same time there is unused energy in industry, which produces heat as an unwanted byproduct. This report evaluates the possibility to use this byproduct to supply energy to a district heating system and store it in seasonal heat storage. When the heat demand increases during the cold season of the year, the seasonal heat storage contributes with heat energy. The idea is to replace parts of the heating plants in Halmstad with heat storage and waste heat. The aim is to exclude usage of all fossil fuels. This report will also evaluate the economical prerequisites and environmental benefits in replacing biofuels. A steelworks company, Höganäs Halmstadverken, is situated in Halmstad. This industry could contribute with surplus heat, which is calculated in this report. With help of calculations and simulations in Microsoft Excel, a system with adequate heat storage method and surplus heat from local industry is formed. This system is optimized concerning economic and environmental matters. The results reveal that Halmstad's conditions are favorable to integrate pit heat storage and there is potential to deliver waste heat from Höganäs Halmstadverken steelworks. Sizes of seasonal heat storage is optimized to 200 000 m3 for replacing fossil fuels respectively 550 000 m3 for replacing fossil fuels and biofuels. Waste heat effect is calculated to 15 MW. The economical calculations results in an annual profit up to 8 million SEK with a payoff equal to 8 years. The environmental benefits consisting of reduced greenhouse gases are calculated to 4 800 tons carbon dioxide equivalents annually.

<p>When a combined heat and power plant produces heat and power it often faces a deficit of heat load during the summer or other periods of time. This heat is often unnecessarily cooled away or the power production has to be reduced or shut off. If it is possible to store heat from periods with low heat demand to periods with high heat demand one can get many benefits. Among these benefits are: increased power production, decreased operation with partial load, uniformly distributed load.</p><p>To be able to store heat in situations like this long-term thermal heat storages are needed. In this thesis five different types of stores are presented: rock cavern storage, tank storage, pit water storage, borehole storage and aquifer storage. In this thesis the principles of the different storages is presented and experiences from operation in Sweden, Germany and Denmark are also presented.</p><p>The thesis contains a calculation of costs for the types of thermal heat storages that are suitable for use in a combined heat and power plant. To be able to function in a combined heat and power plant, a long-term thermal heat storage must be able to handle a high charge and discharge output. Storages that can meet these demands use water as store medium.</p><p>The conclusion is:</p><p>Pit storages are interesting if the capacity is below 20 000 m^3.</p><p>For capacities between 20 000 to 50 000 m^3, tank storages are most suitable.</p><p>Rock cavern storages are interesting if the capacity is larger than 100 000 m^3.</p><p>For capacities between 50 000 to 100 000 m^3, either rock cavern storages or connected tank storages are appropriate.</p>

When a combined heat and power plant produces heat and power it often faces a deficit of heat load during the summer or other periods of time. This heat is often unnecessarily cooled away or the power production has to be reduced or shut off. If it is possible to store heat from periods with low heat demand to periods with high heat demand one can get many benefits. Among these benefits are: increased power production, decreased operation with partial load, uniformly distributed load. To be able to store heat in situations like this long-term thermal heat storages are needed. In this thesis five different types of stores are presented: rock cavern storage, tank storage, pit water storage, borehole storage and aquifer storage. In this thesis the principles of the different storages is presented and experiences from operation in Sweden, Germany and Denmark are also presented. The thesis contains a calculation of costs for the types of thermal heat storages that are suitable for use in a combined heat and power plant. To be able to function in a combined heat and power plant, a long-term thermal heat storage must be able to handle a high charge and discharge output. Storages that can meet these demands use water as store medium. The conclusion is: Pit storages are interesting if the capacity is below 20 000 m^3. For capacities between 20 000 to 50 000 m^3, tank storages are most suitable. Rock cavern storages are interesting if the capacity is larger than 100 000 m^3. For capacities between 50 000 to 100 000 m^3, either rock cavern storages or connected tank storages are appropriate.