Abstract The most common application of Distributed Generation (DG) is for reliability reasons. After experiencing an interruption, backup generators can be started to supply electricity to critical loads. The next most common application for DG is peak load shaving. During time periods of high energy demand or high energy prices, on-site generators are started up and used to serve part of the on-site loads. So DG can increase reliability of power supply, reduce loss of interruption and solve the problem of peak loads. Due to the high costs, only a few were installed. In order to investigate their economic values, in this thesis, several economic assessment methods are used to evaluate the cost-benefit of DG. Test results have revealed that, unless it is for environment protection reasons, the investment of DG is of little value if the fuel cost is high, and the electricity and the customer interruption costs are low. Keyword : Distributed Generation¡Mpeak load shaving.

Climate change and energy efficiency has become a matter of concern in recent times; therefore, energy efficiency of buildings has drawn major attention. According to the European Commission, EU countries must improve energy efficiency of existing buildings by retrofitting and renovating the buildings. A case study of a renovated commercial building is considered in this degree project. A model of the building is developed in the IDA Indoor Climate and Energy (IDA ICE) software. The model is then augmented to include renovations in the building. Further, the model is simulated in IDA ICE before and after renovations to investigate the impact of renovations on energy consumption of the building for one year. The simulation results indicate peak demands of district heating that occur in the coldest days of the year. The peak demands of energy are expected to increase the district heating cost because they serve as a basis for new pricing model introduced by the energy providers. Hence, it is important from the customer point of view to reduce the peak loads for cost shavings. The project work also provides an insight into the alternative source of energy such as heat pumps to reduce the peak load demands of district heating.

The Swedish electrical grid has historically been robust and reliable, but with increased electrification in numerous sectors, out-phasing of nuclear power and a high market diffusion of wind power, the system is now facing challenges. The rotational energy in the system is expected to decrease as a result of higher shares of intermittent energy sources, which can affect the stability of the grid frequency negatively. To manage increased frequency drops, the new Fast Frequency Reserve (FFR) market will be implemented by June 2020 in the Nordic power system. Simultaneously, it is expected that the demand of electricity will increase significantly in the transport and industry sectors in the coming years. Several DSOs already today indicate challenges with capacity and power security and have or will implement power tariffs as an economic incentive to prevent these problems. For energy intensive customers, such as industries, it will become important to reduce power peaks to avoid high grid fees. Several peak load shaving strategies can be utilized by industries to reduce their power peaks and thus the power tariff. The aim of this study is to economically analyze peak load shaving for Swedish industries. This is done using Li-Ion BESS and DSM, and to maximize the utilization of the BESS by including energy arbitrage and FFR market participation into the analysis. Firstly, a literature review is conducted within the topics of peak load shaving strategies, energy arbitrage and ancillary services. Secondly, data is gathered in collaboration with WSP Systems – Energy, the initiators of the project, to conduct case studies on two different industries. These cases are simulated in the modeling software SAM, for technical analysis, and then economically evaluated with NPV. Also, nine scenarios are created for the emerging FFR market concerning the number of activations per year and the compensation price per activation. The results from the case studies indicate that peak load shaving of 1 – 3 % with BESS provides a positive NPV for both case industries. However, higher percentages result in negative NPVs when no additional revenue streams are included. When considering energy arbitrage, it is concluded that the additional revenues are neglectable for both industries. Participating in the FFR market provides similar trends in the results as before. The exception is valid for scenarios with high numbers of FFR activations and compensation prices, where positive NPVs for all levels of peak load shaving can be concluded. The peak load shaving strategy DSM is implemented for one of the industries, where efficiency measures are concluded to have the most impact on the economic evaluation. If all efficiency measures would be implemented, the electricity consumption would be reduced by 17 %. Additionally, the power peaks would be reduced with 18 % and result in a significantly more positive NPV than peak load shaving using BESS. A sensitivity analysis concerning BESS capital cost and power tariff price concludes that the BESS price has a strong relation to the NPV, where a BESS price reduction of 60 % results in an NPV increase of at least 100 %. BESS prices have decreased the past years and are expected to keep decreasing in the future. Hence, investments in BESS can become more profitable and attractive in the coming years. Finally, for future research, it is recommended to combine the methodology from this study together with a load forecasting method. This combined methodology could then be practically applied to case specific industries with high peak loads. / Det svenska elnätet har historiskt sett varit robust och pålitligt, men i takt med ökad elektrifiering i flera sektorer, utfasning av kärnkraft samt ökad mängd installerad vindkraft ställs nu systemet inför nya utmaningar. Bland annat förväntas rotationsenergin i systemet minska som ett resultat av högre andelar intermittenta energikällor i systemet. För att hantera detta kommer den nya Fast Frequency Reserve (FFR) marknaden finnas tillgänglig från och med juni 2020. Samtidigt förväntas även efterfrågan på el inom transport- och industrisektorn öka markant de kommande åren. Redan idag är effektbrist ett problem i vissa regioner, vilket kan komma att förvärras. Många nätägare ska eller har redan infört effekttariffer för utnyttjande av deras elnät, vilket är ett ekonomiskt incitament för att hantera effektproblematiken där kunder med en mer flexibel elkonsumtion kommer gynnas. För större elförbrukare, som exempelvis industrier, kan det bli ekonomiskt betydelsefullt att sänka sina effekttoppar och därmed undvika höga nätavgifter. För att minska effekttoppar finns ett flertal så kallade peak load shaving-strategier, som kan utnyttjas av industrier för att minska kostnaderna för effekttariffen. Syftet med denna studie är att analysera peak load shaving för svenska industrier, med hjälp av ett Li-Ion batterilagringssystem och efterfrågeflexibilitet, samt maximera utnyttjandet av batteriet genom att inkludera energiarbitrage och deltagande i FFR-marknaden i analysen. Ett första steg i arbetet är att utföra en litteraturstudie för de berörda områdena. I ett andra steg insamlas data tillsammans med WSP, initiativtagaren av projektet, för att kunna göra en fallstudie på två industrier. För dessa fallstudier undersöks de tekniska förutsättningarna för att implementera peak load shaving-strategier genom modellering i simuleringsprogrammet SAM. Sedan utreds de ekonomiska förutsättningarna för fallstudierna, där NPV används som ekonomiskt nyckeltal. Dessutom skapas nio scenarion för den kommande FFR-marknaden för att uppskatta kostnader och inkomster. Resultatet av fallstudien visar att 1 – 3 % kapade effekttoppar med batterilagring ger ett positivt NPV för båda industrierna. Över 3 % blir resultatet negativt utan ytterligare inkomstströmmar inkluderade. Energiarbitrage konstateras att bidra med marginella positiva fördelar. Vid inkludering av FFR-marknaden i analysen erhålls liknande trender i resultaten, bortsett från scenarion med relativt högt antal avrop och pris. I dessa fall blir även 4 – 10 % kapade effekttoppar ekonomiskt attraktiva. För en av industrierna utvärderas efterfrågeflexibilitet, där effektivisering av elkrävande processer har störst inflytande på resultatet. Vid implementering av samtliga effektiviseringsåtgärder skulle elkonsumtionen minska med 17 %. Dessutom minskar effekttopparna med 18 %, vilket resulterar i ett signifikant mer positivt NPV, jämfört med användningen av batterilager. En känslighetsanalys gällande batteripris och effekttariffer, konstaterade att batteripriset har en stark påverkan på NPV. Vid en batteriprisminskning på 60 % ökar NPV med minst 100 %. Därmed kan batteriinvesteringar bli mer gynnsamma och attraktiva om batteripriser fortsätter att falla, vilket flera prognoser indikerar. Slutligen rekommenderas framtida studier att kombinera metodiken från detta arbete med en prognostiseringsmetod för elanvändning i industrier. Denna kombinerade metod kan sedan praktiskt tillämpas på fallspecifika industrier med höga effekttoppar.

L'utilisation de systèmes de stockage par chaleur latente constitue une solution permettant l'effacement du chauffage d'un bâtiment résidentiel pendant les périodes de forte demande. Une telle stratégie peut avoir pour objectif le lissage des pics d'appel en puissance du réseau électrique. Cependant, la faible conductivité des matériaux à changement de phase (MCP) qui constituent ces systèmes et le besoin d'une puissance de décharge importante imposent l'utilisation de matériaux dits "architecturés" afin d'optimiser la conductivité équivalente des matériaux stockeurs. Nos travaux s'intéressent plus particulièrement à la méthodologie pour la conception de matériaux pour ces systèmes afin de satisfaire aux exigences de stockage d'énergie et de puissance de restitution. La méthodologie proposée dans ces travaux de thèse est dénommé « Top-down methodology ». Cette méthodologie comporte trois échelles : l'échelle bâtiment (top), l'échelle système et l'échelle matériau (down). L'échelle bâtiment a comme objectif de spécifier le cahier des charges. A l'échelle système, des indicateurs de performance sont définis. Enfin, à l'échelle matériau, l'architecture du matériau solution est proposée. Un outil numérique modélisant le système de stockage par chaleur latente de type échangeur de chaleur air/MCP à été développé pour évaluer les indicateurs de performance. Ce modèle numérique est vérifié avec un cas analytique et validé par comparaison avec des données expérimentales. La méthodologie développée est mise en œuvre dans un deuxième cas d'étude pour le même type de système de stockage. L'analyse du système via les nombres adimensionnels permet d'obtenir des indicateurs de performance du système. A l'issue de cette étape, les propriétés matériaux et fonctionnelles optimales du système sont donc connues. Enfin, un matériau architecturé est alors proposé afin de satisfaire les exigences du système de stockage. Nous montrons alors que par l'intermédiaire d'une plaque sandwich contenant des clous et du MCP les propriétés matériaux nécessaires sont obtenues. De plus, afin de satisfaire aux exigences en termes de propriétés fonctionnelles, le design du système est modifié en ajoutant des ailettes sur les surfaces d'échange. Nous montrons que avec 20 ailettes de 3mm d'épaisseur sur la surface d'échange de la planche à clous, le chauffage est effacé pendant 2h lors de la période de forte demande journalière pendant l'hiver. / The use of energy storage systems that exploit latent heat represents a promising solution to erase the heating demand of residential buildings during periods of peak demand. Equipping a building with such components can contribute to the goal of peak shaving in terms of public electricity grid supply. Significant drawbacks, however, are the low thermal conductivity of Phase Change Materials (PCM) that typically constitute such systems,and the requirement for a high rate of discharge. Consequently, the use of so-called architectured materials has been put forward as a means to optimize the effective conductivity of storage materials. Our work is focused upon the development of a methodology to design optimal materials for such systems that meet the criteria of energy storage and energy output. A so-called “top-down metholodogy” was implemented for the present work. This approach includes three scales of interest: building (top), system and material (down). The aim of the building scale analysis is to formulate a set of general design requirements. These are complemented by performance indicators, which are defined at the scale of the system. Finally, at the scale of the material, the architecture of the identified material is elaborated. A numerical simulation tool was developed to determine performance indicators for a latent heat energy storage system comprising of an air/PCM heat exchanger. This model was tested against a benchmark analytical solution and validated though comparison to experimental data. The developed methodology is applied to the specific case of an air/PCM exchanger latent-heat energy storage system. The system is analysed through the study of dimensionless numbers, which provide a set of design indicators for the system. As a result of this stage, the optimal material and functional properties are thus identified. Finally, an architectured material is proposed that would satisfy the design requirements of the storage system. We demonstrate that an arrangement composed of a sandwich of planar layers with nails and PCM can offer the required material properties. Furthermore, in order to meet the desired functional properties, the system design is modified by the addition of fins at the exchange surfaces. With the addition of 20 fins of 3mm thickness attached to the exchange surface of the sandwich panel, the storage system eliminated the heating demand for 2 hours during the period of high daily demand in winter.