The majority of the existing photovoltaic (PV) systems are dimensioned in such a way that no or only a small part of the production exceeds the buildings internal consumption. This is done because sold electricity to the grid has a lower economic value than if used internally in the building. Therefore commercial buildings, with high consumption during sunny hours, are to prefer when installing PV. Implementing a battery energy storage system in these facilities can lead to higher self consumption of the PV energy and reduced electricity bills. To take full advantage of this potential it requires optimal management of the battery. In this study an optimized battery algorithm was developed to show the full potential a perfectly managed battery can have to reduce cost of electricity within commercial buildings. There are three main charge and discharge patterns for a battery which can reduce the cost on the electricity bill: 1) Charge and discharge at different prices, 2) peak shaving and 3) overproduced PV is stored for later use. By utilizing a battery in an optimal way to reduce the costs as much as possible, batteries will reach break even at battery prices between 1350-2100 SEK/kWh, depending on which scenario evaluated. By implementing forecast based desicion-making, in which the battery operation is optimized with respect to PV and consumption forecasts, the system profitability declines rapidly, especially when using a consumption forecast. A real system would probably profit from basing the battery operation on both forecasts and real time measurements.

This paper presents a mathematical sizing algorithms of a stand alone and grid-connected photovoltaic-battery system for a residential house. The objective is to minimize the total storage capacity with cost of electricity. The proposed methodology is based on a Linear and Non-linear programming involving a real data collected through one year with reference to Hradec Kralove meteorological data and typical load profile in Czech Republic. The algorithm jointly optimizes the sizes of the photovoltaic and the battery systems by adjusting the battery charge and discharge cycles according to the availability of solar resource and a time-of-use tariff structure for electricity. The results show that jointly optimizing the sizing of battery and photovoltaic systems can significantly reduce electricity imports and the cost of electricity for the household. However, the optimal capacity of such photovoltaic battery varies strongly with the electricity consumption profile of the household, and is also affected by electricity and battery prices.

This paper presents a mathematical sizing algorithms of a grid-connected photovoltaic-battery system for a residential house. The objective is to minimize the total storage capacity with cost of electricity. The proposed methodology is based on a Linear and Non-linear programming. We have presents results from a existing PV panel FS-4115-3 for the given climatic conditions and the electricity use profile. Measurements for whole household electricity consumption have been obtained over a period of two months. They were all obtained at one hour interval. The algorithm jointly optimizes the sizes of the photovoltaic and the battery systems by adjusting the battery charge and discharge cycles according to the availability of solar resource and a time-of-use tariff structure for electricity. The results show that jointly optimizing the sizing of battery and photovoltaic systems can significantly reduce electricity imports and the cost of electricity for the household.

I detta examensarbete har syftet varit att undersöka hur man kan minska behovet av att behöva köpa energi till en fastighet med tillhörande byggnader. Fokus har legat på att producera nog med energi för att täcka fastighetsägarnas konsumtion av el. Projektet har även berört energioptimeringsåtgärder av enklare slag. Efter detta gjordes en fysisk genomgång av byggnaderna där mätning också genomfördes dels som underlag för en energibalans, dels som underlag när det undersöktes vilka energisparåtgärder som var ekonomiskt genomförbara, såsom tillläggsisolering av vinden. Sedan samlades det in offerter och annan viktig information, såsom energiproduktion och priser, för att sedan analyseras. Alla delar jämfördes och ställdes mot varandra för att komma fram till det som passade fastighetsägarna bäst. Lagring och vindkraft hade en för lång återbetalningstid gentemot vad ägarna hade efterfrågat då de ville att det skulle vara återbetalat innan produkternas livslängd var slut. Resultatet av vindkraften visade att vindhastigheterna inte kunde fastställas helt eftersom den vindmätning som gjorts har skett 25 km därifrån, vilket leder till en osäkerhet i hur mycket el som kan produceras. Det mest lönsamma var den största av de fyra solcellsparker som jämfördes. Den och det lilla vindkraftverket tillsammans producerar tillräckligt mycket el för att täcka deras behov. Däremot rekommenderades varken vindkraftverket eller batterilagring på grund av återbetalningstiden. Ägarna kan alltså producera den mesta elen med hjälp av solceller, dock inte allt enligt de beräkningar som gjorts. Förutom Vattenfalls solceller rekommenderades att tilläggsisolera vinden samt en laddbox från Vattenfall. Eftersom teorin i examensarbetet skulle baseras på granskade källor och inte på vinstdrivande källor användes studentlitteratur, publicerade rapporter och rapporter från myndigheter. / The purpose of this thesis has been to examine how to reduce the need to buy energy for a property with associated buildings. The focus has been on producing enough energy to cover the property owners' consumption of electricity. The project has also involved simpler energy optimization measures. After this, a physical review of the buildings was carried out, where measurement was also carried out partly as a basis for an energy balance and partly as a basis when examining which energy saving measures were economically feasible, such as additional insulation of the wind. Then quotes and other important information, such as energy production and prices, were collected and then analyzed. All parts were compared to each other to arrive at what best suited the property owners. Storage and wind power had too long a payback period against what the owners had asked for when they wanted it to be repaid before the end of product life. The result of the wind power showed that the wind speeds could not be fully determined since the wind measurement made was 25 km away, which leads to an uncertainty in how much electricity can be produced. The most profitable was the largest of the four solar cell parks compared. It and the small wind turbine together produce enough electricity to meet their needs. However, neither the wind turbine nor the battery storage was recommended because of the payback time. The owners can thus produce most of the electricity using solar cells, but not all according to the calculations made. In addition to Vattenfall's solar cells, it was recommended to insulate the wind and install a charging box from Vattenfall. Since the theory in the degree project should be based on audited sources and not on profit-making sources, student literature, published reports and reports from authorities were used.

The German initiative Energiewende aims to decrease their dependence on nuclear andfossil-based energy, and to increase the share of variable renewable energy sources (V-RES).This transformation calls for new technical solutions that can meet future stakeholderneeds. Distributed battery storage (DBS), which can be used as a complement to theunreliable V-RES, is such a solution.In this thesis, the possibilities for incorporating DBS into the German energy market werefirst analyzed. This was followed by calculations of the economic potential for DBS, and lastlya possible business model for Vattenfall associated with the identified businessopportunities was developed. The assessment shows big opportunities of incorporating DBSinto the future energy system since it can increase the reliability and stability of thedecentralized generation of V-RES. DBS will also be the cheapest solution for an averagehousehold 2030, making the technology a profitable solution. A suitable business model hasalso been identified for Vattenfall, which focuses on the activities of leasing the DBS-units toprosumers and utilizing excess capacity for ancillary services to TSO’s and DSO’s. Theancillary services that can be utilized include frequency regulation and peak shaving.Theoretically the thesis contributes with knowledge about the increasing possibilities of DBSbecoming a large part of the future German power system. The thesis will also be a practicaltool for utilities on how to adapt their business offering with regards to the new market.

Access to electricity might in some parts of the world seem evident. However, Ethiopia struggles to provide its large and growing population with electricity. Although around all the households in the capital Addis Ababa are connected to the electricity grid, the grid is unreliable and results in daily outages. As the photovoltaic (PV) potential in Addis Ababa on the other hand is great, this thesis examines the feasibility and profitability of decentralized PV adoption with battery and hydrogen storage respectively. Based on an ongoing construction project in the sub-city Yeka, Addis Ababa, a reference building was used to simulate the PV systems with battery and hydrogen storage. Furthermore, a load profile based on time-use diaries was developed and used in the simulations, as data on household electric consumption was non-existent. The load profile resulted in an average daily use of 1341 kWh and a 165 kW peak for all of the 130 apartments in the reference building. The results of the simulations indicated that neither of the two systems were feasible nor profitable to implement on the reference building. The PV-system with battery storage was cheaper and required less installed PV capacity, however the cost of energy for both systems was significantly higher than the current cost of energy in Ethiopia. The installed PV capacity of both systems exceeded the maximum capacity that was feasible on the reference building.

The degree project was carried out in collaboration with Halmstad Fastighet AB. Two separate buildings with different uses of energy have been analyzed. The focus was on evaluating near-zero energy houses with solar power plants and associated battery storage to investigate profitability and dimensioning to form the basis for future constructions. Both properties are near-zero energy houses but differ in the use of electrical energy. It is currently unclear how the change in the dimensioning of the solar power plant and the battery storage will affect the profitability of two properties with different uses of energy. The method was quantitative. Simulation models in the Polysun software were created with the properties' reference house. Based on the simulations, profitability calculations were made to describe the difference in profit when changing the dimensioning. The work concludes that the total profitability increases with the size of the solar power plant, regardless of energy use, and battery storage is not profitable without price changes. / Examensarbetet gjordes i samarbete med Halmstad Fastighet AB. Två olika fastigheter med olika elanvändning har analyserats, där fokuset låg på att utvärdera nära-nollenergihus med solkraftsanläggningar och tillhörande batterilager för att undersöka lönsamhet och dimensionering som ska ligga till grund för framtida byggnationer.  Båda fastigheterna är nära-nollenergihus men skiljer sig åt i användning av elenergi. Det är idag oklart hur förändringen av dimensioneringen av solkraftsanläggningen och batterilagret påverkar lönsamheten i två fastigheter med skilda användning av elenergi. Metoden är av kvantitativ karaktär. Simuleringsmodeller i programvaran Polysun skapades med två fastigheter och dess solkraftsanläggningar med tillhörande batterilager som referens.Utifrån simuleringarna gjordes lönsamhetsberäkningar för att beskriva skillnad i vinst vid förändring av dimensionering. Slutsatserna av arbetet är att den totala lönsamheten ökar ju större solkraftsanläggningen är oavsett elenergianvändning och batterilagret är idag inte lönsamt utan prisförändringar.

This paper examines the possibility of adding a photovoltaic(PV) power station to an already planned wind park in terms of profitability. At this time, southern Sweden’s grid is facing a number of challenges and is hurting economic development. Hybrid parks have showed to be able to tackle some of those challenges. This study has used a two-scaled methodology to analyse which solar PV size is the optimal to be co-located to the wind park of 24MW[Office1] . The results show that the 21MW size is the ideal one. In addition, to complement the findings, an analysis has been conducted to determine which battery size would be the optimal size to be added to the hybrid system. The results showed that a 1MW/1MWh battery storage would be the ideal size, however, it is possible that a 5MW/MWh battery storage might produce better results if peak shaving is included. All the scenarios in this study have been analysed in terms of IRR.

No / An isolated micro-grid network with limited generating capacity would most likely, end up having operational challenge either due to increasing number of customers, or introduction of new loads onto the network. This is in view of an observed scenario especially in developing countries whereby as load demand increases, installed PV capacity often do not receive commensurate expansion. So, in order to prevent network failure, each user can be allocated certain amount of limited power supply which should not be exceeded. These allotments are dynamic, and they vary at regular time intervals every day depending on their historic load profile data. This work is therefore based on managing power supply from a PV-source operating as an isolated micro-grid with storage capabilities. A power supply scheduling mechanism is introduced which allocates maximum power capacity for every user. Hence communities detached from the grid can enjoy electricity despite shortfalls in power supply capacity. The obtained results evaluated under three scenarios show that allocating energy limits to each user depends on the current capacity of the battery as well as the forecast load demand. This allotment is enforced using variable circuit breakers whose cut-off point is varied based on the prevailing energy demand and supply requirements.

Sweden’s energy system is facing major changes in the near future in order to reducecarbon emissions and to switch to sustainable energy sources. PV systems havebecome a sensible alternative for homeowners that want to be a part of this changeand at the same time reduce the cost of their electricity bill. To further improve theutilization of their PV system and to handle the intermittent nature of solar power,battery storages have become an interesting system complement. This thesisinvestigates how batteries can provide smart services; load shift and peak price energyutilization to a household. This is done by developing an optimized battery algorithmmodel that can provide these smart services which is compared to a simple batteryalgorithm. The results show that the developed battery optimization model works asintended. It performs both load shift and peak price energy utilization. The economicanalysis shows that the most profitable PV system and battery configuration is a 20kW PV system with a 5 kWh battery. The system has an internal rate of return, IRR,of 2.3% which does not reach Vattenfall’s weighted average cost of capital, WACC, at7%. The results also show that the battery cost is an important factors for a system'sprofitability. A larger battery system is more expensive and the increased yield doesnot cover the increased cost. Further research is needed to implement the optimizedbattery as a functional application since the model has access to a perfect forecast andthus a method for forecasting PV production and load profile of the household arecrucial to get similar results.