Backup power is essential to supply important functions in society with electricity in case of a blackout. Today in Sweden most backup generators are based on diesel fuel and seldom used, but they are still associated with bad environmental impact while operating. What if a backup system could be designed to increase its value and at the same time lower the environmental impact? This study has investigated alternative solutions for backup power and applied them on a specific case. A food providing industry with great variations in their load profile (40 - 240 kW) is looking for a backup solution able to supply the industry for 12 h in case of a blackout. The study started off by investigating different techniques and their suitability for providing backup power, such as diesel generators (DG), battery energy storage systems (BESS), micro gas turbines (MGT) and fuel cells (FC). Most suitable to be compared with the traditional diesel solutions in terms of cost, climate and technique was found to be two hybrid systems. The first one a combination of a DG and BESS and the second a combination of a MGT and BESS. The two hybrid systems were primarily dimensioned to a size of 100 kW (DG/MGT) with a 350/350 kWh/kW BESS based on terms and after analyzing the industry's load profile. The two hybrid systems were compared with a 350 kW DG in two aspects over a time frame of 15 years, life cycle costs (LCC) and carbon dioxide emissions. Compared with only DG the result showed a 15% LCC increase and a 26% emission reduction for the hybrid solution with DG + BESS. For MGT + BESS the LCC increase was 30% but the emission reduction was 52%. Included into the LCC analysis is utilization of the BESS for grid services such as peak shaving, arbitrage and grid support which had a major positive economic impact. The LCC results were however sensitive to changes in some parameters such as investment costs and rates. Finally, the study tried to optimize the cost and climate performance of the two hybrid systems. By reducing a few terms, sizing of the systems could be adjusted. This resulted in both hybrid systems being more profitable and climate friendly with a larger DG/MGT and a smaller complementing BESS for peak loads, outperforming the only DG solution.

To enable the transition to a fossil-free society and ongoing urbanization, where new establishments emerge in the heart of the society, the Swedish electricity system faces new challenges. Building a new powerline to meet the increased power demand is an expensive process, and in an existing grid, there isn’t always room to build new power lines. This leads to a capacity shortage at the local level, fundamentally due to the grid being undersized in areas where there are old power lines with lower rated current. To meet the increased power demand that electrification entails and simultaneously make capacity available for new establishments within the existing grid infrastructure, the potential of energy storage is being evaluated against the traditional solution of building new power lines. The purpose of the present work was therefore to investigate whether energy storage can be a potential solution to make capacity available for future establishments in an area where there is a capacity shortage. The energy storage solutions were evaluated from an economic, environmental, and power quality perspective and compared to building a new power line. This was done from the perspective of a grid company, where neither the market of frequency stability nor the electricity price market were included in the analysis. Based on the existing theory of energy storage, battery storage was chosen as the potential solution. To narrow the scope of the work, an area in Piteå Municipality was selected where a new establishment demands a power with drawal of 3 MW and is located midway between two existing grid lines. Using one year of operational data for the affected grid lines and calculations of their rated current, the performance of the battery storage was simulated, evaluating different battery sizes and energy contents (C-rate). Since the Electricity Act does not allow grid companies to own energy storage, the economic aspect was evaluated based on two different cases of battery rental. The goal is to maintain redundancy with the adjacent grid line with the additional power with drawal of 3 MW, to manage a potential outage without extensive consequences for subscribers. The results of the calculations and simulations show that the current grid line can handle the extra 3 MW requested. However, the battery storage does not relieve the grid sufficiently to prevent exceedingthe maximum capacity of the grid during high loads while maintaining redundancy with the interconnected grid line. The battery storage needs to be larger than 3 MW to relieve the grid as required, which is not economically justifiable. Depending on the rental conditions of the battery storage and which revenues are considered, the profitability of battery storage varies, but with a battery size over 1 MW, regardless of rental conditions, it is not economically justifiable compared to a new power line, which has a significantly longer technical lifespan. For battery storage to be useful in the grid and make capacity available, the grid must have spare capacity. The results also show that the relationship between the size of the establishment and the size ofthe battery storage is not one-to-one, instead, the energy content of the battery storage must be significantly larger to cut the power peaks. An energy content of two times the power, for example, 1 MW and2 MWh, is required for the battery to be advantageous and generate load savings on the grid. However, the battery storage can still relieve the grid to some extent by helping to distribute the current load more evenly, which means that the rated current, which is the limiting factor for short power line lengths, is not exceeded as early.

Sweden is a large country in terms of area with a relatively cold climate. In this area there are almost 3400 churches spread around the country where about 1700 of them are electrically heated, which makes battery storages suitable. The churches are heated depending on demand and opening hours, during the rest of the time, the temperature is kept low. The churches, like most buildings in Sweden, get electricity from the 50 Hz grid. Due to the intermittent heating, power spikes occur in the grid which are both ineffective and expensive for the owners of the buildings. The purpose of this work is to make the church’s heating more efficient with the help of a well-dimensioned battery storage that can assist during heating. This would result in a more stable heating process and also save a lot of money. During the project a dimensioning tool for battery storage was developed and when applied in a case study revealed that the battery storage would become profitable after 12-18 years, this is longer compared to the estimated battery lifetime which in this report was set to be around 10 years.

In November 2016 all nations agreed to the COP21 Paris agreement, which binds the nations to combat a global temperature rise above 2 degrees Celsius during this century. For this to become reality, modern technologies, such as solar power, electrical vehicles and energy storage, will have to pave way for feasible, sustainable societies. Smart grids could be one of the solutions to how to integrate modern technologies into our conventional electricity grids. If we manage to cut peak electricity demand and achieve an even electricity demand, renewable energy investments become more feasible while other services for the grid owner are provided. In this paper it is investigated what capacity of battery storage that is required to achieve an even electricity demand in a local electrical grid with solar power, demand response and electrical vehicles. Further, an economical analysis of the required battery storage is made by comparing investment costs to potential savings for the end customer, energy trading company and grid owner. The investigation is made by performing a case study in Ramsjö Backe outside Uppsala. Two models are created, one aggregated model containing the whole residential area and one containing a one single family building. The results show that in the aggregated model a 4.03 MWh battery storage was required to keep an even electricity demand 90 % of the year, and for the building a 108 kWh battery storage was required. Results from both models show that it is not economically feasible today to invest in even electricity demand in local electrical grids.

Region Uppsala, who are responsible for the public transport in Uppsala county, are currently building a new city bus depot. Due to capacity shortage in the transmission grid to Uppsala, the operation of the new bus depot must be adapted to a limited power output. In addition to this, the city of Uppsala aims to introduce the first electrical buses by 2021. The purpose of this study was to investigate how electrical buses of different penetration level will affect the power demand at the new city bus depot. The results showed that the current power limitation was already exceeded by 200 kW if 12 electrical buses were to be introduced. Therefore, different technical solutions were evaluated in terms of increasing the penetration level of electrical buses. These solutions were evaluated by a life cycle cost analysis. The cheapest solution was to connect the city bus depot with the regional bus depot. This is possible because the grid connection to the regional bus depot is oversized, compared to its load. However, this solution does not solve the general problem of capacity-shortage in Uppsala and the legality of it must be analyzed further. Two other solutions that were investigated were a local battery storage and a gas engine coupled with a generator at the depot. None of the solutions could solve the power problem at the depot on its own. For a scenario with more than 40 electrical buses, the different technical solutions that were investigated must be combined.

The share of cars being powered by electricity is rising in Sweden. So far, this has seldom been causing queues at charging stations but if the rise continues as expected, it might potentially be a problem in the future. This thesis aims to shed light on when this might become a problem in a certain area and give example of a potential solution for that case. Three scenarios with different shares of cars being electric is analyzed with a simple model of a system with fast chargers for an area with a highly variable traffic flow. The arrival times to the system is derived from measured traffic flow and extrapolated up until 2030 and a charging time is set based on assumed travel behavior. A comparison is made between the expected electricity consumption using this approach and actual data from a fast charging station. The comparison indicates that electric cars are not being used for the winter time cross-country trips analyzed here in the same extent as conventional cars. The potential to keep the number of stationary fast chargers down using a portable solution with Li-ion battery storage with and without attached production of electricity for situations with a higher than normal charging demand is then investigated. A containerized Li-ion battery solution of 760 kWh has the potential to replace two 50 kW fast chargers in the studied case.

Skellefteå Kraft är Sveriges femte största elproducent och störst av de kommunägda kraftbolagen. Den främsta produktionen är koncentrerad i norra Sverige och den mesta energin produceras från vind- och vattenkraft. Sommaren 2017 invigde Skellefteå Kraft dess första storskaliga solcellsanläggning, Röjmyran. Solcellsanläggningen har en installerad effekt på 178,2 kW och består av 540 moduler fördelade på fastighetstaket i tre riktningar. Modulerna är seriekopplade om 31 strängar där varje sträng är kopplad till en strängoptimerare som i sin tur lagrar produktionsdata. På södra taket sitter en referenscell som mäter och lagrar globalinstrålningsdata, modultemperatur och omgivningstemperatur. Denna referenscell är av samma teknik som solcellsmodulerna, således ska parametrarna som uppmäts motsvara samma värden som solcellsmodulerna känner av. Fastigheten är ett så kallat industrihotell, och ägs av Skellefteå Industrihus. Anläggningen är kopplad till elnätet och idag säljs all överskottsproduktion till elnätet. Skellefteå Kraft ville ha hjälp med att dimensionera ett batterilager till Röjmyran och vidare utvärdera elproduktionen som varit sedan solcellsanläggningens driftstart, juli 2017. Arbetet med batteridimensioneringen syftade till att undersöka de ekonomiska konsekvenserna som en implementering av ett batterilager i systemet skulle medföra i jämförelse med dagens situation utan batterilager. Batterilagret dimensionerades med hjälp av ett eget konstruerat Excelverktyg där verktyget jämförde den ekonomiska nyttan av tre olika batteritillämpningar. Ena tillämpningen som undersöktes var demand shift, som betyder att batteriet lagrar överskottsenergi för senare användning när behovet uppkommer. På så sätt kan självförsörjningen i fastigheten öka och mindre el behöver således köpas från elnätet. Den andra tillämpningen var trading, som betyder att batteriet laddar upp från elnätet under tidpunkter som elpriserna är låga, och laddar ur under tidpunkter där priserna är höga. Den tredje tillämpningen som undersöktes var peak shaving, som betyder att batteriet laddas upp under natten för att sedan ladda ur när effekten från elnätet uppgår till ett förutbestämt maxvärde. På så sätt minskar effekttopparna och således utgifterna. Arbetet avgränsades till att undersöka nyttan utifrån fastighetsägarens synvinkel då det främsta syftet för Skellefteå Kraft är att öka kunskaper och erfarenhet med batterilager inför kommande projekt. I dimensioneringen undersöktes olika batteritekniker från tre olika fabrikat, med varierande egenskaper och kostnader. Resultatet visade att det var ett nickelmetallhydridbatteri från Nilar, med en kapacitet på 32,4 kWh lagringskapacitet, som gav det högsta nuvärdet. Vidare utvärderades produktionen från två perspektiv, dels genom att undersöka hur strängarna producerat under de månaderna som anläggningen varit i drift och dels genom att beräkna den teoretiska produktionen utifrån globalinstrålningen som varit i anläggningen och jämföra med den verkliga produktionen. Resultatet från strängutvärderingen visade att produktionen under juli och augusti varierade relativt mycket mellan strängarna. Under september och oktober producerade anläggningen likvärdigt i respektive riktning och under november föll snön, vilket ledde till nollproduktion till mitten av april då snön försvann. Att strängproduktionen varierade relativt mycket under juli och augusti kan bero på att anläggningen precis hade sats i drift, vilket kan ha gett upphov till små driftstopp och omstarter av systemet. Vidare undersöktes huruvida anläggningen producerat enligt vad den teoretiskt sett borde ha gjort, med hänsyn till globalinstrålningen som varit i anläggningen. Det var tyvärr bara möjligt att exportera globalinstrålningsdata för 30 dagar bakåt i tiden, vilket ledde till en avgränsad tid för utvärderingen. Referenscellen var placerad på södra takhalvan, vilket avgränsade utredningen till att bara undersöka hur modulerna på södra taket producerat. Resultatet visade att många större fel inträffat under dessa 30 dagar. Uppdateringar av växelriktaren, filtermontage, säkringar som utlöstes och effektreducering var anledningar till de stora förlusterna som uppträdde under de flesta dagar. Detta ledde till att bara två dagar, av 30 dagar, var jämförbara i syfte att identifiera små förluster. Förlusterna förväntades uppgå till 1,5 % på grund av solsträngsoptimerarens verkningsgrad på 98,5 %, men förlusterna uppgick till 2,9 respektive 2,4 %. Detta behöver inte vara något anmärkningsvärt då modultemperaturen påverkar produktionen relativt mycket. För att i framtiden kunna verifiera hela anläggningens produktion, är en rekommendation att även implementera referensceller i modulernas övriga två riktningar.

In order to reach climate goals regarding the reduction ofcarbon dioxide in the environment, the decarbonisation of the transport sector plays a crucial role. Along with this revolution, electric vehicles will most likely be a candidate to replace market shares from gasoline and diesel. The deployment of electric cars is now starting to increase, by over 2 millions electrical vehicles running on the streets world wide in year 2016, which is more than the double compared to previous year. This master thesis examines home charging and its impact on the distribution grid of two types, one in a smaller urban area and one in a rural area in the Swedish city Sala. Different integration levels of electric vehicles are examined regarding voltage drop, relative loading of conductors and transformers, and the voltage symmetry with charging only on one phase. The simulations are made in the NIS-based system dpPower based on charging data from Grahn et.al.(2013), and the study of powerpeaks is made in Matlab with the use of consumption data from customers. The results show that the transfomer is the only limitation in the grid of the urban area, which fails at an integration level of 50 percent at 11 kW of charging. Compared to the grid in the rural area which reacts more strongly of home charging. In this case it is most likely to fail at 30 percents integration at 3,7 kW of charging. Also a greater accuracy has to be taken into account here regarding the placing of one phase-chargers at different phases. This in order to not exceed the 2 percent limit of voltage symmetry. With the aim to reduce power peaks, the grid seems to benefit from high demand response and local battery storage, which reduce the power peaks to an extent that could be comparable to reducing the integration level of electric vehicles from 50 to 30 percent.

This study has examined what services grid-connected energy storage systems can provide to the electricity grid in Sweden. In particular, energy storages in the form of batteries have been examined. This has been done by studying existing literature and current installations of grid-connected batteries. A total of 13 different services were identified: arbitrage, capacity firming, curtailment minimization, electric supply capacity, black start, frequency regulation, voltage support, transmission and distribution congestion relief, reduced transmission grid costs, increase of self consumption, end-consumer power quality, time-of-use bill management and backup power. Furthermore, a grid-connected battery storage system that will be installed by Vattenfall was modelled and simulated in this paper. The results showed that the battery storage system can mitigate congestion in the transmission grid, as well as providing the grid with frequency regulation. This can generate a revenue of 3 million SEK annually.

The installed capacity of electricity produced from solar power has increased over the years and will do so even further. A lot of companies are investing in so-called solar parks to create large scale electricity production from solar power. With intermittent energy sources such as solar power comes challenges for the electricity net where storage systems can play an important role to handle these challenges. Storage systems connected to renewable energy can also be a way to increase the economic benefits of a system.  This study investigates whether a lithium-ion battery system connected to a solar park is economically profitable, and in that case under which circumstances. This is done by focusing on a solar park in Uppsala, Sweden, owned by Vasakronan AB. Different grid-connected services provided by the battery that could generate income were identified and chosen for the study which were arbitrage, a local flexibility market and frequency regulation. The usage of the battery for each and a combination of these services were modelled and simulated in Matlab (2020). Each individual case was created as its own model for three different battery capacities (2, 4 & 8 MWh). To investigate whether a case was profitable or not, the internal rate was calculated for each model. This was also done for a longer lifetime of the battery and for lower investment costs as a sensitivity analysis. The results show that a system of this kind is only profitable for one case which is if a 2 MWh battery is used for the frequency regulation services FFR and FCR-D. This results in an internal rate of 6% which is higher than the rate of return of 5% that Vasakronan requires. The conclusions of the study is that it is difficult to make an investment in a battery system that is only charged from a solar park profitable.