Anthropogenic activities are responsible for the impact of global climate change because of burning fossil fuels releasing harmful gases into the environment. As a result, the global temperature has risen about 1.18 °C since 1880, causing the global sea level to rise by 178 mm over the past century. This is a threat to countries that are closer to the ocean, especially the low-lying countries such as the Maldives. It is predicted if the sea level keeps rising, most of these islands could be below sea level by 2030. The Maldives has a tropical climate requiring cooling to achieve thermal comfort. Electricity is used to provide cooling which is generated by burning fossil fuels. Due to the need for more buildings and the effects of global warming, the demand for cooling has increased, ultimately increasing the emissions. Therefore, this paper investigated the methods to minimize the building cooling demand by creating a building model of a school in Feydhoo, Addu City, Maldives using DesignBuilder software. Also, to analyze the potential of using solar technology in providing cooling for the building, a clean energy source reducing emissions. The base model of the building showed that annual electricity consumption for cooling would be about 200.14 MWh. Based on the base model, multiple building models were created to understand the best option that can lower the cooling demand of the building. The results showed that having a super-insulated timber construction could be a better option by using improved double-glazed low-E windows and an improved cooling system with a COP of 3.2. This lowered the cooling energy demand to about 103.71 MWh. Based on these results, a solar thermal cooling system was simulated using Polysun software which shows that solar thermal collectors were not able to provide the required cooling to run the chiller system. Hence, another option was explored where DesignBuilder software was used to model a solar PV array system to provide cooling for the building. But by using a better air conditioning system (VRF system coupled with a DOAS) to provide fresh conditioned air into the building, improving the indoor air quality. The results showed that the new PV array system was able to provide the electricity required not for cooling but for other electrical requirements (total of 163.31 MWh). It also resulted in a surplus of 1 MWh of electricity exported to the utility grid, achieving a net-positive energy building.

Meeting electricity demand and power shortage remains as a challenge to the people of the Gambia. As the country is undergoing tremendous electricity accessibility expansion [1], to secure the environment for the future generation, it is necessary to consider renewable energy to be the major source of electricity production, to be specific, solar energy. This is because the country experiences the radiation from the sun throughout the year, it is sustainable not only to our environment for the future generations, but also economically. However, due to the intermittent nature of most renewable energy technologies, it is cumbersome to rely on them 100 % as a primary source of electricity production. Nonetheless, with suitable storage technologies, combination of different renewable sources, and intercountry grid connections can enhance to overcome this challenge. In this thesis work, designed and techno economic evaluation was carried out for high PV penetration that will meet 50 % electricity demand of the Gambia in year 2040. Three scenarios were considered in this study, based on the Strategic Electricity Roadmap 2020 to 2040 [1]. These scenarios are high, universal access (AU), and low electricity demand. Economically, 50 % electricity supply to meet the demand is possible for all the three cases. Consideration was mainly put on four key figures, thus, levelized cost of electricity (LCOE), payback period (PBP), net present cost (NPC) and solar fraction (SF). To achieve 50 % SF for the high electricity demand scenario, LCOE and PBP are 0.129 $/kWh and 12 years respectively. As for AU electricity demand case, 50 % SF is achieved with 0.126 $/kWh and 10 years for LCOE and PBP respectively. For low electricity demand scenario, 0.127 $/kWh and 10 years for LCOE and PBP respectively for 50 % SF. However, the optimum design recommended by HomerPro were 45 % SF with LCOE of 0.126 $/kWh and PBP of 9 years for high electricity demand scenario. As for the AU electricity demand case, the optimum design is 48 % SF, LCOE of 0.125 $/kWh, and PBP of 9 years. In the last scenario, which is low electricity demand case, 46 % SF, 0.124 $/kWh LCOE, and 9 years PBP.

Yes / The cost of electricity produced by thermal power plants in Republic of Djibouti is relatively high at about $0.32/ kWh. This is due to its dependence on imported oil coupled with fluctuating oil prices. Consequently, the customer pays a high electricity bill. However, Djibouti is endowed with indigenous renewable energy resources such as a good solar irradiance of 5.92 kWh/ m2 day, a potential geothermal energy estimated up to 1000 MW, and few sites with annual wind speed higher than 6 m/s. The goal of this paper is, therefore, to assess an economic evaluation of different grid connected hybrid renewable energy systems to a residential urban house located in Tadjourah city (11.7913◦ N, 42.8796◦ E) in the North-Eastern part of Djibouti to reduce the cost of electricity from the grid. To reach this objective, a powerful software tool called HOMER (Hybrid Optimization Model for Electric Renewables) has been used to find the optimum hybrid energy system using real wind and solar irradiation data. The results obtained from this study show that the best economical suited combination of hybrid renewable energy system is a PV-Wind grid connected system. This study shows also that potentially the indigenous renewable energy contribution, in Tadjourah, can be as much as 77 % with 47 % of solar and 30% of Wind energy. The Net Present Cost, the Levelized Cost of Energy, and the operating cost of the optimal HRES are $337, $0.002/kWh and $1,025/year, respectively. When compared with the average cost of grid-only connection of $0.32/kWh, the optimal hybrid renewable energy system is more economical and will save 51 % of the cost that the customer must pay when using only the electricity from the grid.

Global warming is one of the biggest challenges today, and the construction sector is one of the main sectors contributing to climate change. Due to this, using environmentally friendly materials in construction is an important decision against global warming. This thesis aims to evaluate the most important building envelope components to achieve a house in Sweden to become near net-zero energy building (ZEB). Due to this, different ecological insulation materials, and window types were presented, analyzed, and evaluated to choose the most energy-efficient alternatives for the Utsikten village project. In terms of reduction of electricity bought, renewable energy on-site photovoltaic (PV) and ground source heat pump systems are used. In this study, numerical simulations for building envelope components such as windows, ground floor, external walls, and roofs were performed to evaluate the thermal performance of the components by IDA ICE and UBAKUS. The primary energy for different building cases has been calculated to evaluate thermal performance and energy classification levels to identify the most environmentally friendly solutions. There is a variation of ecological material for insulation that can be used for different parts of the building envelope. In general, ecological insulation material has less life expectancy but a much lower environmental impact compared to minerals and synthetic materials. However, there are also some limitations to using some ecological insulation materials in the ground construction. This study also shows how several pane glasses, gap dimensions, gas fill gap, and Low-E coating impact the energy performance of the windows and the building. Simple solar PV panel simulation shows that the maximum electricity production on a site is very related to orientation, tilt, and sun exposure. The result of this master thesis shows that it is possible to reach near-net-zero energy building by enhancing building envelope components and using renewable energy sources for heating, cooling, and electricity production.

To reach the Swedish goal of reaching a completely fossil-free electricity sector by the year 2040, there is a need for an increased rate of installed renewable electricity sources. Companies have the opportunity to work towards this goal by investing in solar power technologies, which results in a lowered electricity bill, and an additional revenue when electricity is sold to the grid. As a result, the investment usually pays back within a reasonable timeframe. GEHAB is a company located that is located in Alvesta, Sweden, and they are interested in investing in rooftop solar power. This thesis investigates the potential and effects of such an investment at the company through energy simulations. This is done through four different scenarios, which aim at finding the largest possible installation, the most cost-optimal installation, according to the Levelized Cost Of Energy (LCOE), the impact of an added battery installation and finding the current issues with becoming a net-zero consumer of electricity. Finally, a sensitivity analysis was made to investigate how different factors impacted the LCOE. The results showed that the most cost-optimal size for the company to invest in was a 215 kWp installation, which is smaller than the maximum possible size of 335 kWp that can be installed on the rooftop. Such an installation would have an LCOE of -366 SEK/MWh when the avoided costs are included. The discounted payback time of that investment was 11.3 years. The involvement of batteries showed that they would lead to a higher LCOE and for the largest possible solar installation size, including a battery, means that it would not pay back within the lifetime of the PVs. Finally, the net-zero electricity consumption scenario found that currently, the largest issue to reach this scenario is that there is a regulation that limits solar installations to 500 kWp to avoid an energy tax.

The East African Community (EAC) is an intergovernmental organisation comprised of six countries, five of which are classed as having a low development level and one of which is classed as medium. The region has low rates of human development and electrical connectivity but is committed to meeting the universal access and clean energy goals of Sustainable Development Goal 7. This thesis seeks to explore the renewable energy potential of the EAC at a regional level. There is little study of the energy situation of the EAC as a specific region, contrasting this work to the majority of similar analyses that focus on the national or sub-Saharan level. The potential for solar PV and wind power in the EAC was examined through an analysis of existing energy systems, a simplified multi-criteria analysis through geographical information systems, and a comparison with similar work by the International Renewable Energy Agency (IRENA). The region was shown to have a small but growing electricity sector and a primary energy system dominated by traditional biomass. The mapping analysis identified large areas across all studied countries as potentially suitable for on- or off-grid renewable energy. It also highlighted issues with the results of IRENA’s work in its current form. Solar PV and wind energy potential across the EAC is shown to be high, with a low carbon electricity sector consequently a possibility for the region in the future. / Den Östafrikanska Gemenskapen (EAC) är en mellanstatlig organisation av sex länder. Fem av de länderna har en låg utvecklingsnivå och en är klassificerad som medelnivå. Regionen har låg mänsklig utveckling och tillgång till elkraft men har bestämt att uppfylla globala målen 7: säkerställa tillgång till ekonomiskt överkomlig, tillförlitlig, hållbar och modern energi för alla. Denna uppsats utforskade potentialen för förnybar energi i den EAC på en regional nivå. Potentialen för solenergi och vindkraft i EAC undersöktes genom en analys av befintliga energisystem, en förenklad multikriterianalys genom geografiska informationssystem (GIS) och en jämförelse med liknande arbete från den International Renewable Energy Agency (IRENA). En liten men växande elsektor och ett primärt energisystem dominerat av traditionell biomassa identifierades i regionen. Kartläggningsanalysen identifierade stora områden i alla studerade länder som lämpliga för förnybar energi på, eller utanför, elnätet. Analysen fann också problem med resultaten från IRENAs arbete med Global Atlas of Renewable Energy projektet. Det finns god potential för sol- och vindkraft i EAC och möjligheten av ett lågkoldioxidenergisystem är diskuterade som en potential framtid för regionen.

Investment in solar power is increasing in Sweden and especially the smaller installation below 20 kW which is typical for villa roofs. Potential prosumer can use a solar map, an interactive online tool, to investigate the solar potential of their roof based on a geographical data. A study analyzing several solar concludes that the results vary greatly depending on the tool and assumptions made by the provider. This thesis aims to determine the most effective online communication techniques for communicating the cost and benefit of solar PV to potential prosumers. The overall aim of effective communication is based on utility, framing, and trust. To achieve the aim semi-structured interviews and a technical verification of a solar map in Karlstad. The website of Karlstads Energi operates by asking theuser to mark their roof area and enter their yearly electricity consumption. The ability to effectively convey information that is useful, attractive, and trustworthy is based on the user. There is not one perfect design that will work for all users as the users have different knowledge and interests going in which varies the utility. The framing that is the most favorable is using the yearly production in kWh described as a financial investment focusing on savings from the system together with environmental aspects. Users base the trust of the results on more than the figures. Previous brand recognition as well as opinions from previous users weigh in when evaluating the results before decision making. / Alternativ titel: Utvärdering av en Solkarta – Hushållsinvesteringar i solceller som prosument  Investering inom Solkraften ökar i Sverige, speciellt mindre installationer under 20 kW vilket är typiskt för villatak. Potentiella prosumenter kan använda en solkarta, ett interaktivt onlineverktyg, för att undersöka solpotentialen på sitt tak baserat på geografisk data. En studie som analyserade flera solkartor drar slutsatsen att resultaten varierar mycket beroende på verktyget och de antaganden som skaparen gjort. Detta examensarbete syftar till att fastställa de mest effektiva onlinekommunikationsteknikerna för att kommunicera kostnaden och nyttan av solenergi till potentiella prosumenter. Där effektiv kommunikation bygger på användbarhet, presentation och tillit. För att uppnå syftet genomförs semistrukturerade intervjuer och en teknisk verifiering av en solkarta i Karlstad. Karlstads Energis solkarta fungerar genom att be användaren att markera sin takyta och ange sin årliga elförbrukning.  Förmågan att effektivt förmedla information som är användbar, attraktiv och pålitlig baseras på användaren. Det finns inte en perfekt design som fungerar för alla användare eftersom användarna har olika kunskaper och intressen vilket påverkar användbarheten. Den presentationen som är mest fördelaktig är att använda årsproduktionen i kWh som beskrivs som en finansiell investering med fokus på besparingar från systemet tillsammans med miljöaspekter. Användare baserar förtroendet för resultaten på mer än siffrorna. Tidigare varumärkeskännedom samt åsikter från tidigare användare väger in när man utvärderar resultaten innan beslut fattas.

Electrical distribution networks face many operational challenges as various renewable distributed generation (DG), such as solar photovoltaic (PV) systems and wind, become part of their structure. Unlike conventional distribution systems, where the only unpredictable aspect is the load level, the intermittent nature of DG poses additional uncertainty levels for distribution system operators (DSO). The voltage quality problem considers the most restrictive issue that hinders high DG integration into distribution grids. Voltage deviates from the nominal grid voltage limits due to the excess power from the DG. DSOs are accustomed to improving the voltage profile by optimal adjustments of the on-load tap changers, voltage regulator taps and capacitor banks. Nevertheless, due to the frequent variability of the output energy from DG, these devices may fail in doing the needful. Battery energy storage systems (BESS) and smart PV inverter functionalities are regarded as promising solutions to promote the seamless integration of renewable resources into distribution networks. BESS are utilized to store the surplus energy during the high penetration of renewable DG that causes high voltage levels and discharge the stored energy when the distribution grid is heavily loaded, which leads to the low voltage levels. Smart PV inverters regulate the network voltage by controlling the reactive power injection or absorption at the inverter end. This dissertation proposes a management strategy that coordinates BESS and smart PV inverter reactive power capability to improve voltage quality in the distribution systems with high PV and wind penetrations. The proposed management method is based on a bi-level optimization algorithm consisting of upper and lower optimization levels. The proposed method determines the optimal location, capacity, numbers and BESS charging and discharging rates to support the distribution system voltage and to ensure optimal deployment of BESS. Case studies are conducted to evaluate the proposed voltage control method. The large size PV system and wind turbine impacts are studied and simulated on the modified IEEE-34 bus test feeder. In addition, the proposed method is applied to the modified IEEE low voltage test feeder to investigate the effectiveness of installing residential rooftop PV systems on the distribution system's voltage. Experimental results show promising outcomes of the proposed method in controlling the distribution networks' voltage. In addition, a day-ahead forecast of PV power output is developed in this dissertation to assist the DSOs to accurately predict the future amounts of PV energy available and reinforcing the decision-making process of batteries operation. Hybrid forecasting models are proposed based on machine learning algorithms, which utilize support vector regression and backpropagation neural network, optimized with three metaheuristic optimization algorithms, namely Social Spider Optimization (SSO), Particle Swarm Optimization (PSO) and Cuckoo Search Optimization (CSO). These algorithms are used to improve the predictive efficacy of the selected algorithms, where the optimal selection of their hyperparameters and architectures plays a significant role in yielding precise forecasting outcomes. / Doctor of Philosophy / The need for more renewable energy has grown significantly, and many countries are embracing these technologies. However, the integration of distributed generation (DG), such as PV systems and wind turbines, poses several operational problems to the distribution system. The voltage problem represents the most significant issue that needs to be addressed. The traditional voltage control equipment may not cope with the rapid fluctuation and may impact their service life. The continuous developments in the battery energy storage systems (BESS) and the smart PV inverter technologies result in increasing the hosting capacity of DG. BESS can store the excess power from the distributed generators and supply this energy to the grid for different operational objectives. On the other hand, the advanced PV inverter's reactive power capability can be exploited from which the grid can attain many benefits. This dissertation aims at providing a reliable control method to the voltage profile in distribution networks embedded with high PV and wind energy by optimal coordination between the operation of the BESS and the smart PV inverter. In addition, the solar forecasting can mitigate the uncertainty associated with PV system generation. In this dissertation, the PV power forecasting application is applied in the distribution system to control the voltage. Through utilizing PV power forecasting, the decision-making for battery operation can be upheld and reinforced. The BESS can store the surplus energy from the PV system as needed and supply it back in low PV power incidents. Experimental results indicate that proper coordination between the BESS and smart PV inverter is beneficial for distribution system operation that can seamlessly integrate PV and wind energy.

Despite the country's rural electrification programme, kerosene is the predominant source for lighting, and unsustainable and polluting woody biomass is virtually the only option available for cooking. The rural population also struggles with unsafe drinking water in terms of widespread arsenic contamination of well water. The present work has taken an integrated approach in an attempt to mitigate problems through small-scale polygeneration, a concept linking renewable energy sources to these energy needs via novel energy conversion systems. Anaerobic digesters (AD) for biogas production are promising in the rural setting, and field surveys have identified problems in the construction, maintenance and operation of existing AD, particularly in overall performance of household digesters. Based on these results, a number of operational and technological improvements are suggested for employing digesters in polygeneration units. This study also examines one approach for small-scale, low cost arsenic removal in groundwater through air gap membrane distillation, a thermally-driven water purification technology. Integration of biogas production with power generation and water purification is an innovative concept that lies at the core of feasibility analyses conducted in this work. One of the case studies presents a new concept for integrated biogas based polygeneration and analyzes the techno-economic performance of the scheme for meeting the demand of electricity, cooking energy and safe drinking water of 30 households in a rural village of Bangladesh. The specific technologies chosen for the key energy conversion steps are as follows: plug-flow digester; internal combustion engine; and membrane distillation. One major concern is local feedstock availability for the digester, since a single feedstock is impractical to serve both cooking, lighting and water purification systems. In this circumstance solar PV could be a potential option for integrated hybrid systems. / Bangladesh har varit föremål för en svår energikris (bristande el- och gasnät) de senaste tre decennierna. Landsbygden, som innefattar 75 % av befolkningen, har varit särskilt drabbad. Trots landets elektrifieringsprogram av landsbygden är fotogenlampor den företrädande ljuskällan, medan förorenande och ohållbar träbaserad biomassa är praktiskt taget det enda alternativet för matlagning. Landsbygden kämpar samtidigt mot osäkert dricksvatten, på grund av utbredd arsenikförgiftning av brunnsvatten, med negativa hälsoeffekter som följd. Tillgång till ren energi och säkert dricksvatten är verkliga behov bland de fattiga på landsbygden, för ökad välfärd. Detta arbete antar ett integrerat tillvägagångssätt för att försöka lösa dessa problem genom småskalig polygenerering. Detta koncept länkar samman förnyelsebara energikällor av biomassa och sol med energibehoven, genom nya energiomvandlingssystem. Anaerobiska rötkammare för biogasproduktion är lovande för landsbygdsmiljö, även om det för närvarande råder en betydande klyfta mellan den tekniska och kostandseffektiva potentialen och faktisk implementering på grund av bristande tekniskt kunnande och tillgång på råmaterial, höga installations- och driftkostnader, och begränsade användartillämpningar. Intervjuundersökningar visar på problem i konstruktion, underhåll och drift av befintliga anaerobiska rötkammare. Särskilt den generella prestandan hos hushållsrötkammare identifieras som bristfällig. Utifrån dessa resultat föreslås en rad drift- och teknikförbättringar för att utnyttja rötkammare i polygenereringssystem.   Denna studie undersöker även en metod för småskalig och kostnadseffektiv arsenikrening av grundvatten genom membrandestillation med luftspalt (Air Gap Membrane Distillation, AGMD), vilket är en termiskt driven vattenreningsteknik. Resultat från en experimentell undersökning visar att den undersökta AGMD-prototypen är kapabel att uppnå utmärkt separationseffektivitet med hänsyn till arsenikrening. Parametriska studier med fokus på varierande kylvattentemperatur illustrerar möjligheten att integrera AGMD-teknik i diverse termiska system. Integrering av biogasproduktion med kraftproduktion och vattenrening är ett innovativt koncept som utgör kärnan av förstudierna utförda i detta arbete. En av studierna visar ett nytt koncept för biogasbaserad polygenerering och analyserar den techno-ekonomiska prestandan av metoden för att möta efterfrågan av elektricitet, matlagningsvärme och säkert dricksvatten för 30 hushåll i en Bangladeshisk by på landsbygden. De specifika tekniker som valts för energiomvandlingsstegen är följande: plugg-flödesrötkammare, förbränningsmotor och en AGMD-enhet. Termodynamisk utvärdering inklusive mass- och energibalans av systemet undersöktes tillsammans med produktionskostnaden för elektricitet, matlagningsgas, och säkert dricksvatten. Även återbetalningsperiod och internräntan undersöktes. För att bemöta energi- och arsenikproblemen i Bangladesh, indikerar resultaten att detta polygenereringssystem är mycket mer konkurrenskraftigt och lovande (med avseende på produktionskostnaderna) jämfört med andra tillgängliga tekniker. Ett viktigt problem för rötkammaren är tillgången till lokalt råmaterial, eftersom en ensam källa till råmaterial är opraktiskt för att tillgodose efterfrågan från både matlagning, belysning och vattenrening. I detta fall kan solceller vara ett potentiellt alternativ för integrerade hybridsystem. Teknisk värdering och optimering har genomförts för elektricitet med verktyget HOMER (Hybrid Optimization of Multiple Energy Resources), för ett polygenereringssystem beläget i byn Panipara i Faridpur. Resultaten visar att systement kan tillgodoses det dagliga elektricitetsbehovet och samtidigt producera 0.4 m3 matlagningsbränsle och 2-3 L/person rent dricksvatten. Kostnadsuppskattningar visar att denna metod är högst gynnsam jämfört med andra förnyelsebara alternativ (t ex vind-, vatten-, biobränslebaserad- eller geotermisk energi). / <p>QC 20170419</p> / SIDA – the Swedish International Development Cooperation Agency, Department for Research Cooperation, SAREC- project no. SWE-2011-135 / STEM-Fjärrsyn project 2014

No presente trabalho, o desempenho energético e ambiental de potencias rotas de produção de hidrogênio gaseificação da biomassa via leito fixo (LFX) e leito fluidizado (LFL) e de energia solar fotovoltaica foram estudados com base na metodologia de Avaliação do Ciclo de Vida (ACV). Após a revisão da literatura e a descrição dos procedimentos de análise, os resultados da ACV são apresentados e discutidos em termos de Demanda Acumulada de Energia (CED), Tempo de Retorno de Investimento em Energia (EPBT) e danos relacionados à Saúde Humana (SH), Qualidade do Ecossistema (QE) e Recursos Minerais e Combustíveis Fósseis (RMCF). No cômputo geral, o LFL é mais favorável para a produção de hidrogênio, embora os dois sistemas de gaseificação apresentem desempenho energético e ambiental similares. Comparativamente, o sistema fotovoltaico apresenta um EPBT maior (4,55 anos) do que os encontrados nos dois sistemas de conversão da biomassa (1,65 anos no LFL e 1,77 anos no LFX). Por outro lado, o sistema de energia solar fotovoltaico é o mais ambientalmente recomendável para a produção de hidrogênio, tendo em vista a menor contribuição em relação aos danos majoritários (saúde humana). Dentro do escopo do estudo, os sistemas avaliados apresentam mais características de complementaridade do que competição. Neste caso, enfatiza-se a importância de uma análise dos fatores econômicos e sociais pertinentes a cada país ou região, bem como dos processos posteriores de reforma e/ou purificação e eletrólise da água, considerando também o seu inteiro ciclo de vida. / In the present study, the energy and environmental performance of hydrogen potential routes biomass gasification systems by fixed bed and fluidized bed and the solar photovoltaic power plant were studied based on Life Cycle Assessment (LCA) methodology. After reviewing the literature and analytical procedures description, the results of life cycle assessment are discussed in terms of Cumulative Energy Demand (CED), Energy Payback Time (EPBT) and damages related to Human Health (SH), Ecosystem Quality (QE) and Mineral and Fossil Fuels Resources (RMCF). Although the two gasification systems have similar energy and environmental performance, the LFL is more favorable for hydrogen production. Regarding the photovoltaic system, this has a greater EPBT (4.55 years) than those found in the two systems of biomass conversion (1.65 and 1.77 years in the LFL and LFX, respectively). On the other hand, the solar photovoltaic system is the more environmentally suitable for hydrogen production, since its contribution related to human health impact is smaller than gasification systems. Within the scope of the study, the evaluated systems have more features of complementarities than competition. In this case, we emphasize the importance of analyzing the economic and social factors that are relevant in each country or region, as well as the subsequent process for hydrogen production (purification and water electrolysis) also considering the entire life cycle of systems.