Energy is critical to the economic growth and social development of any country. Indigenous energy resources need to be developed to the optimum level to minimize dependence on imported fuels, subject to resolving economic, environmental and social constraints. This led to a boost in research and development as well as investment in renewable energy industry in search of ways to meet energy demand and to reduce dependency on fossil fuels. Wind and solar energy are becoming popular owing to abundance, availability and ease of harnessing for electrical power generation. This thesis focuses on an integrated hybrid renewable energy system consisting of wind and solar energy. Sri Lanka, a small island located south of the Indian subcontinent, has been blessed with renewable energy sources. According to the national energy policy a 10% share is targeted from NCRE (Non-Conventional Renewable Energy) sources by 2015 and 20% by 2020 out of total electricity generation in Sri Lanka. This thesis provides an insight into the energy scenario and present situation of renewable energy development in Sri Lanka. According to wind and solar potential maps of Sri Lanka which were developed by NREL in 2003, many parts of the country have potential to developed economic power generation. Through these maps locations were identified where both wind and solar potential is high. A detailed study was carried out in these locations with real time field data. The focal point of this thesis is to propose and evaluate a wind-solar hybrid power generation system for a selected location. Grid tied power generation systems make use of solar PV or wind turbines to produce electricity and supply the load by connecting to grid. In this study, HOMER (Hybrid Optimization Model for Electric Renewables) computer modeling software was used to model the power system, its physical behavior and its life cycle cost. The hybrid power system was designed for Hambantota District in Southern Sri Lanka. Through the simulation process, installation of 8 numbers of 850kW wind turbines and 1MW solar PV modules were identified as most economical to supply average of 3MW load connected to grid where the simple payback period of the system was 3.4 years.

The present report is a reflection on the impact and costs of raw materials involved in renewable energy (RE) technology development. The study is performed in collaboration with ADEME in France and is based on a range of previous studies initiated by ADEME, which aimed to test the limits for the integration of renewables in the energy mix by considering their raw material consumption and identifying the possible impacts if this consumption steadily grows in the future.  The Earth’s material resources are already under heavy pressure, especially the exotic metals used in advanced technologies including renewable energy components and equipment. A sharp rise in material consumption due to a wide deployment of renewable energy could harm the metal markets and endanger the industries that depend on them. Securing a sustainable development path for RE technologies would require avoiding any fast resource depletion. This thesis focuses on several modern RE technologies, identifies their specific raw material consumption and points out some important strategic and economic issues regarding their sustainability. The possible penetration in the energy mix of France of different RE technologies related to their life-cycle and cost implications of the involved raw materials is discussed. The study also compares the requirement of raw materials for a 100%-RE energy system to a more conventional mix where the larger part is allocated to nuclear power and fossil fuels. By identifying the weaknesses and strengths of the renewable energy technologies as far as materials are concerned, the author aims at promoting the idea that a detailed Life Cycle Assessment of a project during the planning phase is a useful tool for the decision process and an important first step towards a more sustainable energy mix.

Namibia is one of the most sparsely populated countries with a total area of 825 600 km2. There are still many residents in the country without access to electricity, and with the present rapid technological development the need for electricity is increasing constantly. However, the expansion of the electricity grid is slow and costly, resulting in that many cannot afford to be connected and therefore a clear need for small scale electricity production has been identified. For this reason it was chosen to investigate this need closer and examine how a small-scale vertical axis wind turbine designed by InnovEd would meet the demand; also to identify suitable sites as well as purchase and maintenance schemes to promote wind turbines or other similar off-grid renewable energy solutions in rural Namibia. Additionally, an identification of possible variations and sensitivity of wind turbine performance and guidance and recommendation for future work were desired. In this study it was chosen to follow a grounded theory where the qualitative data was collected through interviews and general observations during a field trip in northern Namibia. The data were collected for two months in collaboration with the Creative Entrepreneurs Solutions. The results showed that the demand for electricity in rural areas was large but that a small amount of electricity can make a big difference to primarily run the most important devices. Lighting turned out to be most significant for the respondents, even if they would like to run all sorts of electrical equipment for everything if given a reliable and low-cost energy supply. This was in line with the literature that shows that it is normally the next step after meeting the most basic needs. It showed also that the price of electricity was of utmost importance for the local population. Finally, the authors recommend continuing to involve the users in the next stages of development where the major step would be to test the product with the users and to develop reasonable pricing and maintenance procedures. This should be followed by the creation of a local business and production plan for such products to reach a wider market as soon as possible.

The work focuses on the methods used to develop one particular sub-part of a computer tool for optimizing the final cost of energy in offshore wind parks : the linking infrastructure for bringing electrical power ashore. The thesis is the outcome of a 6-month cooperation with AREVA Wind, within the Wind Plant Solutions department, and is based on previous work done by AREVA, their proprietary database, as well as on publically available technical data. Exporting power from an offshore electrical substation down to the grid connection point is nowadays a critical bottleneck in the development of offshore wind energy, where project optimization and cost reduction are for many viewed as powerful levers capable of increasing dramatically its competitiveness on the electricity market. The approach and methodology used to develop the model, along with challenges and difficulties encountered are exposed. The necessary outputs are defined, the related equations are carefully examined and give way to choices, simplifications and assumptions so that governing inputs are identified. Eventually, a project optimization algorithm is described and evaluated against available data from existing offshore developments, focusing primarily on decreasing the overall cost of electrical transmission and on the proper choice of technology for the particular project. The impact of the proposed algorithm and its sensitivity to varying parameters, as well as its precision and reliability have been estimated and validated with encouraging results allowing for immediate implementation in the industry.  In the thesis, for confidentiality purposes, fictive though realistic scenarios are computed, results presented and commented on, conclusions drawn. Finally, implementation and analysis of results on large-scale projects also provides with better understanding of upcoming challenges inherent to new technologies on the verge to be introduced as the industry keeps growing.

The state of Minnesota has an extreme weather climate, with cold winters and humid hot summers. In a residential building, space and water heating account for about 61% of the total energy consumption. A combination heating system is an innovative idea that integrates the space heating and water heating systems as one unit to achieve improved performance and efficiency over two independent systems. This analysis will focus on air for space heating, as it is a common system used in the applicable location. Benefits of the system include a smaller footprint, simplified installation and maintenance, a single fuel input and exhaust, and increased efficiency. More testing and research is required, however, to make them an economically feasible option. Twenty combination units of varying designs and manufacturers are installed and monitored in qualifying households throughout the Hennepin County area in Minnesota for about eight months to determine the efficiency and performance of these relatively new systems. These results will be extrapolated to a typical year with the goal to define the ideal combination system type by comparing the calculated system performance to the original existing system performance at each site, the load stress on the system (low, average, and high), the performance of the system on a heating design day, the federal regulation criterion for standard systems, and the different combination systems being researched in this study. It is determined that the tankless type 2, with a 7.5 liter (2-gallon) reserve storage tank, is the most efficient combination system during a typical year in Minnesota. Better insulation is required for storage tanks to reduce stand-by losses. System installation guidelines and design packages will improve performance and maintenance issues. The combination system could be improved by implementing other design strategies such as segregating the space heating and domestic hot water loops or introducing renewable energy to replace the natural gas fuel input. / Staten Minnesota har extrema väderförhållande, med kalla vintrar och varma fuktiga somrar. I en bostadsbyggnad, energi för uppvärmning och varmvatten står för ungefär 61% av totala energianvändningen. Ett kombi-system för uppvärmning är en innovativ idé som integrerar de båda tidigare nämnda funktionerna i samma enhet, som samtidigt har förbättrad prestanda och effektivitet jämfört med två separata system. Föreliggande arbete fokuserar på uppvärmning, då det är ett av de vanligaste system inom det geografiska området som studeras. Fördelar med det föreslagna systemet är att det är mindre platskrävande, enklare installation, enklare underhåll, enbart en bränslekälla och rökgaskanal, samt ökad verkningsgrad. För att säkerställa systemets ekonomiska utfall behövs dock mer prover och forskning. 20 olika relativt nya på marknaden kombisystem med olika konfigurationer och från olika tillverkare har installerats och mätts på under åtta månader i ett antal hushåll i Hennepin County, Minnesota, för att bestämma dess verkningsgrad och prestanda. De erhållna resultaten extrapoleras till ett helt år för att identifiera den mest gynnsamma systemkonfigurationen, genom att jämföra beräknade årseffektivitet med det ursprungliga systemet i respektive byggnad. Analysen inbegriper belastningsnivå (låg, medium, hög), prestanda för uppvärmning under designdag, och jämförelse med federala bestämmelser för standardsystem. Analyserna visar att system utan tank, typ 2, med en 7.5 liters reservtank, är den mest effektiva kombisystemet för ett typiskt år i Minnesota. Bättre isolering behövs för att minska stand-by-förluster från ackumulatortanken. Adekvata installationsriktlinjer kan förbättra prestanda och nödvändigt underhåll. Kombisystemet kan förbättras genom att även implementera ytterligare designstrategier, så som separata uppvärmnings- och varmvatten rörsystem samt att introducera förnybara bränslen istället för naturgas.

Heladhanavi 100MW Diesel Power Plant in Puttalam, Sri Lanka consists of six 18V46 Wartsila turbocharged air cooled engines. Specific fuel consumption of the engines varies with the ambient conditions. It has been seen in hotter days fuel consumption is higher comparatively to cooler days. This study was conducted as per the requirement to find out the reasons behind this variation of the fuel consumption and to quantify the effects on the efficiency with respect to the charge air properties in relation to temperature and humidity. The effect of charge air temperature was analyzed performing two sets of experiments. A combustion analysis experiment (experiment 1) was performed to monitor what happens inside the combustion chamber during day and night times. Simultaneously a fuel consumption test was performed using the direct method with the fuel flow meter and energy dispatch readings taking in to the consideration. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. A flue gas analysis test (experiment 2) was performed to determine the efficiency variation in day and night times through the indirect method. Along with this analysis the direct method was followed up to calculate fuel consumption to compare the results from the both tests. A humidity analysis inside the charge air receiver was carried out simultaneously to investigate the humidity effect on the combustion. It was confirmed the specific fuel consumption is positively affected by the charge air temperature while the efficiency is negatively affected. From the literature review it was found out the humidity in charge air affects positively on the fuel consumption while efficiency is negatively affected. The charge air temperature affects the ignition delay period so that the peak pressure and then the combustion efficiency. The efficiency improvement is further confirmed by the flue gas analysis experiment as the losses in the flue gas reduce in night time comparatively to the day time. Finally it can be concluded that under the prevailing ambient conditions in Puttalam, Sri Lanka, the effect of charge air temperature is more prominent than the effect of humidity on the combustion process. Therefore, proper cleaning and maintaining of the charge air coolers are the most important factors to maintain the charge air temperature and relative humidity inside charge air receiver at a lowest value. / <p>På uppdrag av Högskolan i Gävle</p>

This thesis investigates the possibility to use machine learning algorithms to predict the losses due to icing in the Stor-Rotliten wind farm that is situated in the north of Sweden and operated by Vattenfall. The inputs for the machine learning are historical mesoscale modelled variables that are derived from a Weather Research and Forecasting Model code that is tuned for icing (WRF-model). An ice model has been updated and improved so that it would achieve a better indication of icing, based on the equations from Lasse Makkonen. A more accurate model of a wind turbine considers the turbine blade as a rotating cylinder at 85% of the length of the blade and not as vertical cylinder that stands still. Besides this, the variables from the mesoscale data are used as inputs for the machine learning algorithm. The targets are energy production losses due to icing that is computed from historical SCADA data that covers the same time frame as the WRF data. To reduce the complexity and the computational time of the system a statistical variable selection algorithm, called mutual information, is used with the MILCA toolbox for Matlab. The target for the variable selection and the machine learning is the average loss of power per wind turbine per hour. This is extracted from the production data from Vattenfall. The goal with the thesis is to relate the modelled mesoscale data with the production data (SCADA). The overall result of the study is that the neural network method offers a suitable and more accurate way to predict the losses from icing on wind turbines, but there is some work still to be done to reduce the errors in the input variables.

A fifth of the world’s population currently lives without access to electricity. Moreover millions of people die each year in diarrheal diseases worldwide due to poor hygiene and unsafe water. The off-grid fisherman’s village Quirimize is situated in Mozambique’s northernmost province, Cabo Delgado that has one of the lowest electrification rates in the whole country. The fishermen in Quirimize have in previous studies shown a self-expressed demand for ice for fish preservation. Access to ice could increase their income by enabling them to sell fish at a higher price, directly to fish markets. The most conventional way to provide electricity to off-grid societies is through a grid-tied distribution system or by diesel generators when the grid is not available. Grid electrification is however expensive when trying to electrify rural and remote areas. This report proposes a technical design of the Polygeneration Unit (PU) that is able to provide Quirmize with electricity, water and ice. Data for this study have been collected from contact and meetings with suppliers of technology, other relevant actors in the sector of rural development and energy and online databases. The Polygeneration Unit that only consists of renewable energy technologies (RETs) is simulated using the collected data. This study shows that the Polygeneration Unit as a renewable option is more economical viable than other more conventional methods of electrification such as grid extension or power supply from a diesel generator. The study also investigates the opportunity for ice production through absorption refrigeration and shows that this, theoretically, could be used as a complement to compression refrigeration.

This study focuses on the efficient use of solar energy for a certain region in the Mediterranean basin. Solar thermal energy becomes increasingly popular and the available solar market is investigated with the aim of selecting and assessing a pilot region for a promising solar application. The work herein focuses on estimating the potential of three different 100% solar-driven integrated systems to cover the entire cooling and heating demand of a selected single family house solely by solar energy. The three different alternative systems are presented and examined in detail for the actual case study application. The sample house within the chosen region is located on the south coast of Turkey. The entire thermal demand of this house for both cooling during summer and heating during winter has first been properly calculated. Characteristic features of the house and the typical design parameters for the region have been analyzed, as well as and their daily and annual variations. Heat loss and heating/cooling load calculations have been done with respect to these specifications and to ASHRAE regulations. After finding the building`s demands for the comfort temperature, the three different solar-driven systems are simulated for a practical application to the sample house. Required mechanical equipment and parasitic load consumption has been investigated for each system and investment cost analyses have been performed respectively. Simplified payback times for each alternative system are calculated and discussed. Payback period sensitivity analysis was attempted for two different locations featuring different grid pricing regulations. As a conclusion, feasibility analysis for the three examined types of solar-driven integrated heating and cooling systems has been attempted, which gives a good representation of the potential solar energy market in the Mediterranean region. Also some suggestions are offered to the companies which develop and market solar heating/cooling systems.

Andelen laddbara bilar som används i Sverige ökar stadigt och nätbolagen står inför en utmaningvid dimensionering av elnätet när elektrifieringen medför en högre energi- och effektanvändning.Tekniska verken Linköping Nät AB använder idag typkurvemetoden och så kallade BETTY-kurvorför att utföra olika dimensioneringsberäkningar i elnätet med hjälp av programvaran Trimble NISEnergy. Tekniska verken vill undersöka möjligheten att ta fram nya typkurvor och implementeradem på en del av elnätet för att se hur elbilsladdning påverkar belastningsgrad samtspänningssänkning.Detta examensarbete har studerat teorin bakom typkurvemetoden och hur den har implementeratsi Trimble NIS Energy. Med hjälp av timvärden från utvalda kunder med elbil har sedan nyakundkategorier tagits fram för småhus utan elvärme samt för en ren elbil. Den nya kategorin 1006-Elbil hade ett mönster för typkurvorna som visade att laddning skedde främst under kvälls- ochnattetid, med en topp på ca 1,3 kW under tidig morgon.Påverkan av elbilsladdning har undersökts för två nätstationer i olika delar av elnätet genom attförst addera den framtagna elbilskurvan till 50 % av hushållen och sedan till 100 % av hushållen.Dessa värden är valda för att simulera att om 10 år beräknas ca 50 % av alla hushåll i Östergötlandäga en elbil och om 30 år antas alla hushåll äga en elbil.Beräkningsresultaten visade att transformatorns belastningsgrad var den parameter som påverkadesmest eftersom kablarnas belastningsgrad var lägre och spänningsfallet alltid höll sig inom gränsenpå ±10 % av nominell spänning. Nätstation S721 ligger i ett område med fjärrvärme ochgrundbelastningen för transformatorn innan elbilar adderades låg på ca 40 % av märkeffekt. Efteratt ca 130 elbilar adderats, enligt simuleringen 30 år i framtiden, ökade transformatornsbelastningsgrad till ca 80 %. Nätstation S683 ligger i ett område utan fjärrvärme och hade en högregrundbelastning på transformatorn med ca 70 % av märkeffekt. Vid simuleringen som motsvarar30 år i framtiden adderades ca 40 elbilar och belastningsgraden ökade till 99 %.Det gjordes även en simulering enligt Tekniska verkens instruktioner för projektering av ny- ochombyggnation av elnätet som innebär att till varje hushåll adderas en tänkt elbilslast om 5,5 kWsom sker mellan kl. 00-05. Dimensioneringsberäkningen som utfördes med den extra lasten visadeatt transformatorer och kablar blev överbelastade i båda områdena.Beräkningsresultaten visar att det kan skilja stort beroende på vilken last vi kan anta attelbilsladdning i hushåll kommer att ha i framtiden. Om laddmönstret följer den skapade kategorin1006 sker laddningen ganska utspritt mellan kunderna och påverkan blir inte lika stor som vid densista beräkningen med antagandet om att varannan kund laddar samtidigt. / The proportion of rechargeable cars used in Sweden is steadily increasing and the grid companiesface a challenge in dimensioning the electricity grid when electrification results in a higher energyand power consumtion. Tekniska verken Linköping Nät AB currently uses the type-curve methodand so-called BETTY curves to perform various dimensioning calculations in the electricity gridusing the Trimble NIS Energy software. Tekniska verken wants to investigate the possibility ofdeveloping new type curves and implementing them on a part of the electricity grid to see howelectric vehicle (EV) charging affects the degree of loading and voltage reduction.This thesis has studied the theory behind the type-curve method and how it has been implementedin Trimble NIS Energy. With the help of hourly values from selected customers with EV, newcustomer categories have since been developed for single-family homes without electric heatingand for EV charging. The new category 1006-Electric car had a pattern for the type curves thatshowed that charging took place mainly during the evening and night, with a peak of about 1.3 kWin the early morning.The impact of EV charging has been investigated for two substations in different parts of the gridby first adding the developed EV curve to 50% of households and then to 100% of households.These values are chosen to simulate that in 10 years it is estimated that about 50% of all householdsin Östergötland own an electric car and in 30 years all households are assumed to own an electriccar.The calculation results showed that the transformer loading level was the parameter most affectedbecause the loading level of the cables was lower. The results also showed that the voltage dropalways remained within the limit of ±10% of nominal voltage. The S721 substation is in an areawith district heating and the basic load for the transformer before electric cars were added wasabout 40% of the rated power. After about 130 electric cars were added, according to the simulation30 years in the future, the transformer's loading level increased to about 80%. The S683 substationis in an area without district heating and had a higher basic load on the transformer with about 70%of the rated power. In the simulation corresponding to 30 years in the future, about 40 electric carswere added and the loading level increased to 99%.A simulation was also carried out according to Tekniska verken's instructions for designing newand rebuilding the electricity grid, which means that an EV charging load of 5.5 kW is added toeach household. The dimensioning calculation performed with the additional load showed thattransformers and cables became overloaded in both areas.The calculation results show that impact of EV charging on the grid can differ greatly dependingon the future charging pattern. If the charging pattern follows the created category 1006, thecharging takes place quite scattered between the customers and the impact will not be as great asin the last calculation with the assumption that every other customer charges at the same time.