Dissertations / Theses on the topic 'Renewable energy resources'

The global energy system is dominated by the use of fossil fuels. This system suffers from several problems, such as different environmental issues, while the long-term energy security is sometimes questioned. As an alternative to this situation, a transition to a global energy system based on renewable energy technologies, to a large extent solar and wind energy, is commonly proposed. Constructing the technology needed for such a transition requires resources and how fast this could happen is somewhat disputed. This thesis explores methods to assess the potential constraints for realizing such a transition by looking at potential technology growth rates and outlooks of production of the required natural resources. The thesis is based on three papers presenting case studies that look at growth rates of wind energy as well as future production outlooks of lithium and phosphate rock. Using different types of growth patterns reaching proposed installed capacities of wind power, annual commissioning requirements are investigated, taking account for the limited life expectancy oftechnology. Potential outlooks of mineral production are explored using resource constrained curve-fitting models on global lithium production. A more disaggregated model looking at individual countries are used on phosphate rock production to investigate new perspectives on production outlooks. It is concluded that the growth rates of individual energy technologies affect the resource requirements and prospective constraints on energy transitions. Resource constrained modelling of resource production can provide spans of potential outlooks for future production of resources required for anenergy transition. A higher disaggregation of the modelling can provide new perspectives of potential constraints on future production. These aspects should be further investigated when proposing alternative future energy systems.

This work presents a detailed study of the scheduling of power and energy resources in renewable energy communities (RECs). The study has been developed starting from the analysis of a single basic unit of the community, i.e., the prosumer and its microgrid, to the scheduling and expansion of the energy community concept with several prosumers through several scenarios. The individual scheduling problem of the prosumer has been studied as a day-ahead deterministic problem and as a multistage stochastic problem to consider uncertainties associated with energy generation and energy consumption. Furthermore, an approach has been formulated to consider the integration of bidirectional charging services of electrical vehicles within a local energy system with the presence of renewable generation. Moreover, this thesis focuses on the scenario in which direct energy transactions between prosumers located within a REC are allowed in addition to the energy transactions with the external energy provider. The day-ahead scheduling problem has been addressed by a centralized approach and by a distributed approach based on the alternating direction method of multipliers (ADMM). The developed approaches provide the scheduling of the available energy resources to limit the balancing action of the external grid and allocate the internal network losses to the corresponding energy transactions. Finally, the thesis presents a coordinated day-ahead and intra-day approach to provide the optimal scheduling of the resources in a REC. In this case, the ADMM-based procedure, which is aimed at minimizing the total energy procurement costs, is adapted to cope with the impact of the fluctuation of both the local energy generation and demand during the day. To achieve this, a day-ahead multistage stochastic optimization approach is combined with an intra-day decision-making procedure, able to adjust the scheduling of the energy resources according to the current operational conditions.

The clothing industry is one of the most affected branches of the economy in crisis conditions such as the global Covid-19. If the production of textiles took place in the existing conditions, many companies would stop because the labor costs are high. From the processing of raw materials, through the production of textiles, all the way to the production of clothing, the greatest chance to return to real trends is the energy transition, technological transfer and adjustment of workers. The aim of this paper is to point out the possibilities that would keep the textile industry in line with global trends in the use of renewable energy sources.

With the increasing attention and support behind plug in hybrid electric vehicles, research must be conducted to examine the impacts of vehicles on electric distribution and transmission systems. This research aims first to model the behavior of vehicle battery chargers during system disturbances and mitigate any impacts. A distribution test system example is modeled and several different vehicle charger topologies are added. Faults are applied to the distribution system with vehicle chargers connected and the results are examined. Based on these results, a control strategy to mitigate their negative impacts is suggested. Photovoltaic panels are then added to the system and the study is repeated.

Several services that plug in hybrid electric vehicles are capable of providing to the electric system are presented in order to allow electric vehicles to be seen as an asset to electric systems rather than a burden. These services are particularly focused on an electric system such as might be found on a college campus, which in this case is represented by the Clemson University electric distribution system. The first service presented is dynamic phase balancing of a distribution system using vehicle charging. Distribution systems typically face problems with unbalance. At most large car parks, a three phase electric supply is expected even though current standardized chargers are single phase. By monitoring system unbalance and choosing which phase a vehicle is allowed to charge from, unbalance between phases is reduced in a distribution system. The second service presented is a decentralized vehicle to campus control algorithm based on time of use rates. Using time of use electricity prices, discharging vehicle batteries during high prices and recharging at low prices is explored. Battery degradation as well as limits placed by required vehicle range availability are included in the decision on whether to charge or discharge. Electric utilities will also benefit from a reduction of load at peak times if vehicles discharge back to the campus. A comparison with stationary battery energy storage is included.

Energy is a crucial factor when it comes to development. Among other electricity is important when advancing the living standards of a society as it facilitates various actions and mechanisms. Through the past years social trends such as increased population have put energy and electricity systems under stress as they have often been based on limited and unsustainable fossil fuels. A need for a shift from the conventional fuels to renewable sources becomes more prominent and development needs to be performed in a sustainable way. Ethiopia is one of the countries who have expressed a desire to reach sustainable development by adapting United Nations’ Sustainable Development Goals. This project focuses and analyzes more specifically Ethiopia’s relation to, and possibility of reaching Goal 7 - sustainable energy for all. It attempts to find a future configuration of energy sources which will create an electricity system which will benefit the economy, the social aspect and the environment. The aim is to have a cost-efficient energy mix which supplies all of Ethiopia’s inhabitants with electricity without having to contribute with any carbon dioxide emissions. A literature review is performed to obtain country specific information such as geographical predispositions, and a field trip to Addis Ababa is conducted where data regarding the electricity system is collected. Modelling is then carried through by usage of tools MoManI and OnSSET and the obtained results show a continuous trend in all scenarios where solar and wind compromise the biggest part of electricity production in 2030 and after. Every scenario also allows all inhabitants access to electricity by year 2030. Further, four out of five scenarios ensures elimination of carbon dioxide emissions by 2022, and all five by 2030.

Thesis (M. S.)--Economics, Georgia Institute of Technology, 2010.
Committee Chair: Vivek Ghosal; Committee Member: Byung-Cheol Kim; Committee Member: Chun-Yu Ho; Committee Member: Tibor Besedes. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Increased share of Renewable Energy Sources (RES) in the generation mix requires higher flexibility in power system resources. The intermittent nature of the RES calls for higher reserves in power systems to smooth out the unpredictable power fluctuations. Grid-tied energy storage systems are practical solutions to facilitate the massive integration of RES. The deployment of Battery Energy Storage Systems (BESS) on the power grids is experiencing a significant growth in recent years. Thanks to intensive research and development in battery chemistry and power conversion systems, BESS costs are reducing. However, much more advancements in battery manufacturing as well as additional incentives from the market side are still needed to make BESS a more cost-effective solution. Planning and operation of the BESS significantly influence its profitability. It is quite important to find optimal sizes of batteries and inverters. Sizing of the BESS for two different applications is addressed in this work. In the first application, the BESS is co-located with Pumped Storage Hydro (PSH) to meet the Day-Ahead (DA) schedule of wind generation. In the second application, a method for BESS sizing in the presence of PV-induced ramp rate limits is proposed. In this thesis, two methods based on Receding Horizon Control (RHC) for the optimal operation of the BESS are introduced. A co-located BESS and wind farm is considered in both methods. In one method, electricity market participation is not considered, and the goal is solely meeting the DA schedule utilizing the BESS. A novel predictive control method is proposed in this part and the efficiency of the method is evaluated through long-run simulations using actual historical wind power.

In the second scenario, market participation of the BESS is taken into account. The deviation from the DA schedule can be compensated through the BESS, or by purchasing power from the real-time electricity market. The optimization problem based on physical and operational constraints is developed. The problem is solved through an RHC scheme while using updated wind power and electricity price forecasts. In this thesis, a Ridge-regression forecast model for electricity price and an ARIMA forecast model for wind power are developed. Simulation results using actual historical data for wind power and electricity price demonstrate that the proposed algorithm increases the average daily profit. In order to evaluate the impact of the BESS lifetime and price on average daily profit, different scenarios are defined and simulated. Although they increase the complexity of the problem, much more realistic result might be obtained when all details and constraints are considered.

Master of Landscape Architecture
Department of Landscape Architecture/Regional and Community Planning
Mary C. Kingery-Page
Rural Kansas communities are almost entirely dependent on large energy corporations. These corporations, in turn, are almost completely dependent on fossil fuels for energy production. Three major implications exist within these dependencies: 1) the dependence of rural communities on large corporations reduces the potential of a local economy to support itself; 2) the dependence on fossil fuels has severe environmental impacts; and 3) fossil fuels are non-renewable resources and will inevitably be exhausted. A rural Kansas community has resources necessary to achieve and maintain energy independence in a renewable manner. The design of these systems in regard to economy, society, aesthetics, technology, and ecology will play a key role in sustaining these resources into the future. The intent of the project is to create a tool for rural communities to evaluate localized renewable energy potential using Washington, Kansas as an example. Several questions were addressed to determine the capacity and feasibility of each local energy resource: What renewable energy resources are available to a rural Kansas community and are they sufficient for the community to achieve energy independence? How can the resource or its production be designed and maintained in regard to its environmental impact and long-term viability? What are the implications of energy independence for the community’s identity? Because each question is dependent upon the answer to a previous question, a decision tree was the most viable method for the project’s analysis and development. Research into the technology and science associated with each resource provided a general knowledge of the definitions associated with and processes necessary to determine the feasibility of the resource. For resources receiving a positive feasibility rating, analysis continued with a basic cost/benefit analysis that compares potential costs involving implementation and maintenance with the payback, offsets, and incentives involved in utilizing each resource. Analysis of each feasible resource continued with site suitability analysis. The analysis of each resource resulted in resource maps showing potential implementation locations for three renewable resources studied: hydro, wind, and solar. The maps and accompanying graphics communicate the integration of renewable energy technologies into the existing community’s identity.

Conventional power systems are predominantly composed of centralised large-scale generation sites that provide electricity to a large number of customers in a top-down unidirectional fashion and through transmission and distribution networks. To increase penetration of Renewable Energy Resources (RES) into this traditional power system and promotion of Distributed Energy Resources (DER) concept as an effective solution to deal with the challenges being faced in the conventional power system such as the energy losses, peak demand, peak generation, the infrastructure depreciation, and environmental effect, Microgrid (MG) concept is introduced. MG is defined as a locally controlled small unit of the power system that usually is in interaction with the main grid and is regarded as the building blocks of future Smart Grids (SGs). However, these systems are also capable of operating independently and isolated from the main grid, particularly in remote areas where access to the main grid is impossible or there is a disruptive event on the power system. The emergence of cutting-edge advances in the energy conversion and energy storage technologies and their commercial availability as well as introduction of various lucrative grid services that both grid and customers can benefit from derived the planners and engineers to further expand the flexibility, resilience and efficiency of MGs. To achieve this, Multi-Energy Microgrid System (MEMGS) concept as an expanded definition of MG was introduced to improve the efficiency of conventional energy systems, reduce air pollution as well as energy utilisation. MEMGS incorporates various energy technologies such as axillary boiler, gas turbine, RESs, thermal and battery energy storage systems that are fed by multiple energywares such as gas and electricity to supply multiple types of demands simultaneously such as electrical, heating and cooling loads. However, the integration of clusters of various technologies and concurrent delivery of different energy services causes additional complexities into the modelling and optimisation of these systems due to the potential interactions of energy vectors and various technologies at the consumer level. The economic viability of MGs and MEMGSs rely on the configuration and operating management of the technologies. Therefore, is a need to develop an effective and efficient planning framework that can handle the interaction complexities and nonlinearities of the system, determining the most appropriate architecture, selecting the energy conversion and energy storage technologies and energy supply alternatives from a candidate pool. This thesis aims at addressing these challenges by initially developing a comprehensive and accurate dynamic model for MGs and MGESs components, investigating the technical and economic aspects, the nonlinear behaviour, maintenance and degradation phenomena, and uncertainties associated with technologies through Mixed-Integer Linear Programming (MILP) and Mixed Integer Quadratic Programming (MIQP). Then the established model is employed to establish and propose a multi-objective linearised planning optimisation approach. The architecture and choice of equipment of MEMGSs involve various elements such as availability and costs of the energy sources and equipment, and characteristics of the energy demand. Considering these factors, the proposed strategy allocates the size of the components utilised in the MGs and EMMGSs while meeting the defined performance indices such as degradation factor, reliability and grid power fluctuations smoothing indices. Once, the configuration and capacity of components are optimally determined, efficient energy management is required. The last part of this research focuses on energy management system scheduling and optimisation where the EMS scheduling module for MGs and MEMGSs are inspected considering the Time of Use tariff, peak shaving and valley filling functions, degradation of energy storage devices, along with the operating criteria and cost of the energy conversion units. Moreover, a real-time EMS solution is provided to deal with intermittent behaviour of RESs while participating in arbitrage market. The real-time EMS manages the energy flow optimally according to the acquired real-time data and its deviation from the original schedule attained in the scheduling optimisation stage. The primary objective of the EMS module development is to maximise profit while improving the performance of the MEMGSs. Throughout this research, the MILP and MIQP optimisation approach is adopted to achieve a fast convergence while avoiding complexity and long computation time that would cause due to the nonlinear behaviour and complex interaction of the technologies. Finally, having a practical insight into the challenges and concerns with connection adjacent MGs in distribution networks, an efficient centralised EMS optimisation framework is proposed to cope with the limitations and optimise the performance of the system, considering power losses, voltage deviations and nonlinear degradation of the components. The primary objective of this section of research is to achieve the optimal techno-economic solution.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text

Wind is now established in Europe as a major 'renewable energy' resource, but its large scale exploitation is increasingly limited by environmental issues. Hence, on the way to a more sustainable development, it is desirable to seek ways to incorporate it into small scale embedded generation. As a first step, a prototype of a small scale Ducted Wind Turbine has been developed and tested, which seems to be feasible for integration into a conventional building. The wind flow around the building generates differential pressures which may cause an enhanced massflow through the turbine. This thesis is concerned with the investigation of the flow through building integrated duct configurations. Hence, pressure and wind speed measurements have been carried out on a wind tunnel model at different angles of incident wind. Different duct geometries with attached spoilers have been tested, and it was confirmed that wind speeds up to 30 % higher than in the approaching free stream are induced in the duct, in some cases tolerating an angle of incident wind up to 60°. The experimental work proceeded in parallel with Computational Fluid Dynamics modelling. Adaptive gridding of the complex full model geometry required a two dimensional approach, which was used to compare the predicted flow behaviour qualitatively. Three dimensional simulation of the flow field in the building integrated duct could be compared with experimental results. A new flow field mapping approach was initialised to form a two stage process in which conditions in the large-scale flow domain, modelled in a coarse three dimensional simulation, are used as boundary conditions for a localised simulation of the duct flow. Based on performance measurements of a free standing prototype in field trials and the experimentally determined wind speed in the duct, a power prediction model was developed. For the Scottish climate, the proposed device compares favorably with conventional small wind turbines and photovoltaics. The presented work evaluates the concept of harvesting wind energy in the built environment and provides outlines for the future design of a building integrated Ducted Wind Turbine module.

This thesis uses data collected over three summers in 2010, 2011 and 2012 at the Isle of May National Nature Reserve, Scotland to examine top predator presence and behaviour in a moderately fast tidal stream site. Fieldwork consisted of an intensive land based observation survey of seabirds at sea, acoustic monitoring of small cetaceans and the deployment of a suite of oceanographical tools to simultaneously collect data on a fine temporal scale over a study area of ~1.5km2. The aim of the study was to examine the potential effects of marine renewable energy developments on top predator behaviour in a tidal stream site by addressing some of the key data gaps such as habitat use in tidal stream areas, dive behaviour and collision and disturbance risk assessment. Acoustic detections of harbour porpoises were investigated as a function of physical environmental variables. Strong links between porpoise presence and increased thermal stratification and chlorophyll levels were detected along with a very strong diurnal pattern with increased detections at night. There was no relationship with tidal state. The habitat use of five species of breeding birds at sea adjacent to breeding cliffs was examined to gauge what environmental factors drive habitat use at these sites. Counts of foraging kittiwakes were examined in relation to environmental variables and while strong temporal trends emerged there was no link with oceanographic features. The study site was predominately used for loafing (non foraging behaviour) and so species specific temporal variation in loafing behaviour was analysed. Strong seasonal and diurnal trends in loafing emerged for all species which could be linked to differences in their breeding phenology. These results can be used in assessing and mitigating disturbance to these birds from marine renewables developments. Age specific variation in dive behaviour in the European shag was examined to determine whether newly fledged juveniles were at a greater risk of collision with tidal turbines than adults. Juveniles initially demonstrated a shorter dive duration than adults but after 4-6 weeks their dive duration had significantly increased. However age specific difference in dive behaviour in relation to water depth iii remained unchanged over time with juveniles showing no relationship between dive duration and water depth while adults increased dive duration in deeper water. The implications of this result for assessing age specific collision risk for this species is discussed. Results from this study were used to populate a framework for assessing collision and disturbance risk to seabirds in the near shore area adjacent to the breeding colony from a small scale tidal turbine development scenario. A method was developed to quantify risk by combining relative abundance data, behavioural data and published data on activity budgets for four species; guillemots, razorbills, puffins and shags. The output from this thesis has practical applications for informing the temporal and spatial scale of data collection and survey design in environmental impact assessments regarding marine renewable energy developments with emphasis on understanding the mechanistic links driving predator behaviour. Results can also be used to design appropriate mitigation procedures to prevent disturbance to loafing or foraging birds.

Current hydro-turbines aim to capture the immense energy available in tidal movements, however commonly applied technologies rely on principles more applicable in hydroelectric dams. Tidal stream currents, such as in Coastal Georgia, are not strong enough to make such turbines both efficient and economically viable. This research proposes a novel low-energy vortex shedding vertical axis turbine (VOSTURB) to combat the inefficiencies and challenges of hydro-turbines in low velocity free tidal streams. Some of the energy in tidal streams is extracted naturally from vortex shedding; as water streams past a bluff body, such as pier, low pressure vortices form alternatively on each side, inducing a rhythm of pressure differentials on the bluff body and anything in its wake. VOSTURB aims to capture this energy of the vortices by installing a hydrofoil subsequent to the bluff body. This foil, free to oscillate, translates the vortex energy into oscillatory motion, which can be converted into a form of potential energy. The presented research will act as a 'proof of concept.' It aims to assess such foil motion, or the ability of VOSTURB to capture vortex energy, and begin to assess the amount of tidal energy that can be theoretically harnessed. In this study a small scale model of VOSTURB, a cylindrical bluff body with a hammer shaped hydrofoil, was tested in a hydraulic flume for various mean flow speeds. Tangential accelerations of the foil's center of gravity were obtained through the use of an accelerometer. The acceleration data was analyzed utilizing Fourier analysis to determine the fundamental frequency of the wing oscillations. The available power to be harnessed from the oscillatory motion was then estimated utilizing this fundamental frequency. Ultimately it was found that the frequency of the VOSTURB foil oscillations corresponded highly with the theoretical frequency of vortex shedding for all moderate to high flow speeds. Low speeds were found to produce inconsistent and intermittent small oscillations. This signifies at moderate to high flow speeds, VOSTURB was able to transform some vortical energy into kinetic. The maximum average power obtained 8.4 mW corresponded to the highest flow velocity 0.27 m/s. Scaled to Rose Dhu prototype conditions this represented 50 W at a flow velocity of 0.95m/s, the maximum available at Rose Dhu. Although it was ascertained that VOSTURB could consistently capture some of the vortical energy; the percentage of which could not be calculated with certainty. Thus, the average kinetic power assessments of the foil were compared to the available power of the mean flow for each flow speed calculated by two methods: (1) over the foil's swept area; (2) the area of fluid displaced by the bluff body immediately in front of the foil. The maximum efficiency of the foil, found for the fastest flow speed was at 18% and 45% respectively. It was found that both average foil power, available flow power, and efficiency all decreased with a decrease in flow velocity. This study can serve as only a preliminary study for the effectiveness of VOSTURB as a hydro-turbine for tidal power. In the experiments, the foil was allowed to oscillate freely with little resistance. Future testing of VOSTURB needs to observe whether the vortex energy can overcome the resistive torque introduced by a generator to induce oscillatory motion as well as further optimize the foil design. While the testing in this project assesses the kinetic energy or power of the vortex shedding, this future testing will provide insight into the actual work that can actually be converted into potential energy or power. Complementing this research, both a Harmonic Analysis of Least Squares (HAMELS) and a Complex Empirical Orthogonal Function (CEOF) Analysis was conducted on available surface height and current velocity data separately from an available Regional Ocean Modeling System (ROMS) model of Coastal Georgia. Such analysis were conducted to observe spatial and temporal tidal patterns advantageous to a possible prototype installation of a tidal turbine such as VOSTURB. The more conventional HAMELS analysis, which isolates components of a signal with a certain frequency, identified temporal and spatial patterns attributed to tidal constituents. CEOF analysis, where major patterns of variance are identified not according to prescribed frequencies, was employed to identify any patterns possible not attributed to the tidal constituents. This study was also in part to observe whether the CEOF analysis could identify any patterns of tidal propagation that could not be resolved by the HAMELS analysis. The CEOF and HAMELS analysis of the surface height output produced very similar results: major modes of surface height variation due to the diurnal and semidiurnal tidal constituents propagating up the estuary. The CEOF results did not produce any additional information that could not be found through the HAMELS analysis of the constituents and presented such results in an arguably more convoluted manner. In addition, the surface height analysis provided no direct insight into areas more advantageous to tidal power. The CEOF analysis of the vector current velocity data however did provide some insight. The CEOF of the current data was able to isolate patterns of variance corresponding to the tidal constituents. However, the CEOF was also able to identify local 'hotspots' of high current magnitudes not resolved by HAMELS. These local areas of high current magnitudes, most likely due to changes in hydrodynamic conditions such as channel constrictions, are advantageous for tidal power applications. These general areas could serve as a starting point for the location selection process for a possible prototype installation of VOSTURB if the area was refined more. Ultimately for a prototype installation of VOSTURB, further experimentation and analysis is required for both the turbine design and placement, such as a power conversion methodology for the turbine and a more spatially resolute set of data to perform a CEOF analysis on. With these tasks completed, the prototype installation will be part of a larger effort between the Georgia Institute of Technology and the Girl Scouts of America to create completely sustainable "Eco-Village" on Rose Dhu Island, GA. With an extensive community outreach planned to educate the public, Rose Dhu, along with championing hydrokinetic energy, will serve as a paradigm for sustainable design and energy.

The increasing demand for energy and the increased depletion rate of nonrenewable energy resources call for research on renewable alternatives. Mapping the availability of these resources is an important step for development of energy conversion projects. For this purpose, the wave power potential along the Atlantic coast of the southeastern USA, and the tidal stream power along the coast of Georgia are investigated in this study. Wave power potential is studied in an area bounded by latitudes 27 N and 38 N and longitudes 82 W and 72 W (i.e. North Carolina, South Carolina, Georgia, and northern Florida). The available data from National Data Buoy Center wave stations in the given area are examined. Power calculated from hourly significant wave heights and average wave periods is compared to power calculated using spectral wave energy density. The mean power within 50 km of the shore is determined to be low, whereas higher power is available further offshore beyond the 3500 m contour line. The tidal stream power potential along the coast of the state of Georgia is evaluated based on the NOAA tidal predictions for maximum tidal currents and three dimensional numerical modeling of the currents with Regional Ocean Modeling System (ROMS). The modeling results are validated against the available measurements. This region has low to moderate average tidal currents along most of the coast, but with the possibility of very strong local currents within its complex network of tidal rivers and inlets between barrier islands. Tidal stream power extraction is simulated with a momentum sink in the numerical models at the estuary scale to investigate effect of power extraction on the estuarine hydrodynamics. It is found that different power extraction schemes might have counterintuitive effects on the estuarial hydrodynamics and the extraction efficiency. A multi-criteria method that accounts for the physical, environmental and socioeconomic constraints for tidal power conversion schemes is proposed to select favorable locations and to rank them according to their suitability. For this purpose, the model results are incorporated into a Geographical Information System (GIS) database together with other geospatial datasets relevant to the site selection methodology. The methodology is applied to the Georgia coast and the candidate areas with potential are marked.

Pakistan, though being one of the most rich in renewable energy resources, faces serious energy crises and has a shortfall of about 6 GW electric energy. Most of the resources are untapped until today. The fuel for electricity production is being imported and is of high cost. The government is trying to fulfill the energy requirements of the industries and urban areas where rural areas are at the lowest priority. Pakistan was hit by flood disaster in 2010. There are number of organizations, governmental and private, that are trying to provide shelters and basic necessities to the flood affecties even until today. Village Goth Mehdi Farm in Sajawal area of Sindh is one of the examples of a newly built village for the flood affecties. It has been built with the help of Pakistan Navy, however, the village is bereft of electricity. This report presents three different designs for the electrification of the flood affected village, consisting of 20 houses, a mosque, a community centre, toilets and street lighting, in Sajawal, Pakistan by utilizing available renewable energy resources using sustainability approach. Supply of clean water and energy for cooking purposes was also investigated. However, it was identified in the site visit that villagers were using a mechanical hand pump to pump the underground clean water for daily usage which did not require further alternative. The village is surrounded by wheat fields and trees, and villagers used wood as fuel for cooking. Dehydrated animal dung of cattle was also used as fuel source. The Sajawal area is located in the wind corridor of Sindh and also receives sun light of high insolation level. Thus, wind turbine (WT) or/and PV module can be used for electricity generation, respectively. Based on such advantages three electricity generating systems are proposed. Option #1: solar energy by using 19 kilowatt Photovoltaic (PV) system with off grid inverter and battery bank to cater the load of the village, Option #2: wind energy by using 20 kilowatt wind turbine with a battery backup and Option #3: hybrid PV and WT system with 5.8 kilowatt PV system combine with 10 kilowatt wind turbine and battery backup. These systems have been designed by keeping social, economical and environmental aspects in account. The financial comparison showed that the option # 1 required highest amount of capital cost with respect to other options, while option # 3 needed lowest initial investment for installation. Moreover Option 1, solar system, was found to be the most expensive option when battery replacements (every 3 years) were considered over a 20 years life time. Option 3, hybrid wind and solar system, was concluded to be the most economical solution for the Goth Mehdi farms.

This study has been conducted as a Minor Field Study (MFS) and focuses on the electrification process of Rayal, a remote village in the Far Western Development Region of Nepal. The purpose of the study was to investigate the possibilities of providing electricity based on renewable energy resources to Rayal, both from a technical and a socio-economical point of view. Preliminary research in Sweden was complemented by a field study in Rayal between February and April 2013. Wind power, solar power and micro hydro power were investigated as potential sources of energy. Wind power was considered as unsuitable, due to the low wind speeds in the village as well as poor infrastructure in the country. Solar power and micro hydro power were both calculated based on three different demand scenarios. The results indicate that, depending on the demand and paymentability of the villagers, both solar and micro hydro power could be considered as good options. Solar power is, however, only economically feasible for covering the basic needs of lighting. At higher loads micro hydro power is more economically viable. Excess electricity could be utilized by community facilities, to improve education and health. Alternatively, it could be used to power electrical agricultural equipment which could improve productivity and hence stimulate economic growth in the village.
Denna studie har utförts i form av en Minor Field Study (MFS) och fokuserar på hur en elektrifiering skulle kunna ske av Rayal, en avlägsen by i Far Western Development Region i Nepal. Syftet med studien är att undersöka vilka möjligheter som finns för att elektrifiera Rayal med hjälp av förnyelsebara energikällor, både ur ett tekniskt och från ett socio-ekonomiskt perspektiv. De tre olika teknikerna som har undersökts är vindkraft, solkraft samt småskalig vattenkraft. Vindkraft har uteslutits som lämpligt alternativ, på grund av för låga vindhastigheter i byn, samt bristande infrastruktur i Nepal. Solkraft och vattenkraft har undersökts utifrån tre olika behovs-scenarion. Resultaten visar att, beroende på efterfrågan och betalningsförmågan hos byborna, kan både sol och småskalig vattenkraft betraktas som lämpliga alternativ. Solkraft är dock endast ekonomiskt försvarbart vid mindre projekt, som täcker det grundläggande behovet av belysning. Vid ett större behov är småskalig vattenkraft en mer ekonomisk lösning. Detta ökade behov skulle till exempel kunna vara samhällsförbättrande anläggningar, för att höja utbildnings- och hälsonivån. Ett annat ökat behov skulle kunna vara elektriskt drivna jordbruksmaskiner för att förbättra produktiviteten och därigenom stimulera den ekonomiska tillväxten i byn.

Worldwide energy consumption is estimated to double between 2008 and 2035. Over-dependence on energy imports from a few, often politically unstable countries, and unpredictable oil and gas prices, pushes energy to a critical agenda. While there is an agreement that we need to change the production and consumption of energy, there is still disagreement about the specific changes that are needed and how they can be achieved. The conventional energy plans relying primarily on fossil fuels and nuclear technologies, which are in need of transformation due to limited resources and carbon dioxide emissions. Energy efficiency improvements and renewable energy should play a leading role in the America's energy future. Energy and environmental organizations believe that renewable energy and energy efficiency can meet half of the world's energy needs by 2050. This thesis describes a model that predicts renewable energy portfolios for the Southern portion of the United States, by evaluating multiple renewable energy sources such as solar, wind, hydropower, biomass, and geothermal. The Southern US is divided into three regions: Southwest, South Central, and Southeast, which are chosen given their location and the level of abundance of renewable resources, thereby minimizing inefficiencies and losses associated to the present generation system. A mathematical predictor takes into account variables such as supply/demand, non-renewable/renewable sources, and time. From the results, the Southwest and South Central regions confirm an surplus of renewable electricity by 2050, but the Southeast region does not have enough renewable resources to detach itself from the use of fossil fuels. The South Central region begins producing a surplus of renewable energy in 2014 and reaches an excess amount of 14,552 billion KWh by 2050. This means there will be no need to transfer electricity over long distances, which will increase the overall efficiency of electrical generation.

Renewable energy in Libya, in particular solar and wind energy, can partly cover current local energy demands. It can also, through connections to the Middle East, Africa and Europe, provide neighbouring countries with electricity. Additionally, with the increase in energy demand around the world, and the international effort to reduce carbon emissions from fossil fuels, there has been a drive in many oil-rich countries to diversify their energy portfolios and resources. Libya is currently interested in utilising its renewable energy resources in order to reduce the financial and energy dependency on oil reserves. This research investigates the current utilisation and the future of renewable energy in Libya, and the challenges and opportunities for investment in renewable energy in Libya. This study has explored the possibility of utilising the available renewable energy resources in Libya to offer the Libyan government a strategy for providing sustainable energy resources. This is expected to reduce carbon emissions, and help achieve an economically, socially and environmentally sustainable energy future. Interviews have been conducted with managers, consultants and decision makers from different government organisations, and have included energy policy makers, energy generation companies and major energy consumers. A comprehensive survey has been conducted to evaluate several characteristics of domestic energy demand and energy consumption in Libya. The findings have indicated that, despite the recent political changes and the challenges that face the implementation of renewable energy technologies in Libya, renewable energy opportunities are still strategically of high importance. Solar and wind energy are considered the main sources of renewable energy for Libya. It has been found that energy demand is increasing in Libya and that renewable energy could be a solution to cover some of this demand. In addition, the results have indicated that there are no clear policies that support the implementation of renewable energy projects within Libya, and no clear legislation aimed at the types of technical, commercial and environmental issues which must be addressed for the implementation of renewable energy projects in Libya. Legislations governing the legal support for facilitating the spread of renewable energy in Libya are also limited. Moreover, there is a need to attract investors in renewable technologies by enhancing the country's infrastructure and improving the existing investment regulations.

As electric vehicles (EVs) become more popular, the utility companies are forced to increase power generations in the grid. However, these EVs are capable of providing power to the grid to deliver different grid ancillary services in a concept known as vehicle-to-grid (V2G) and grid-to-vehicle (G2V), in which the EV can serve as a load or source at the same time. These services can provide more benefits when they are integrated with Photovoltaic (PV) generation. The proper modeling, design and control for the power conversion systems that provide the optimum integration among the EVs, PV generations and grid are investigated in this thesis. The coupling between the PV generation and integration bus is accomplished through a unidirectional converter. Precise dynamic and small-signal models for the grid-connected PV power system are developed and utilized to predict the system’s performance during the different operating conditions. An advanced intelligent maximum power point tracker based on fuzzy logic control is developed and designed using a mix between the analytical model and genetic algorithm optimization. The EV is connected to the integration bus through a bidirectional inductive wireless power transfer system (BIWPTS), which allows the EV to be charged and discharged wirelessly during the long-term parking, transient stops and movement. Accurate analytical and physics-based models for the BIWPTS are developed and utilized to forecast its performance, and novel practical limitations for the active and reactive power-flow during G2V and V2G operations are stated. A comparative and assessment analysis for the different compensation topologies in the symmetrical BIWPTS was performed based on analytical, simulation and experimental data. Also, a magnetic design optimization for the double-D power pad based on finite-element analysis is achieved. The nonlinearities in the BIWPTS due to the magnetic material and the high-frequency components are investigated rely on a physics-based co-simulation platform. Also, a novel two-layer predictive power-flow controller that manages the bidirectional power-flow between the EV and grid is developed, implemented and tested. In addition, the feasibility of deploying the quasi-dynamic wireless power transfer technology on the road to charge the EV during the transient stops at the traffic signals is proven.

Parole chiave: petrolio; risorse rinnovabili; governance; gestione delle risorse naturali; ambiente; futuro. Lo scopo di questo studio è di analizzare il ruolo dell'industria petrolifera e il processo di transizione energetico nell'economia norvegese, al fine di comprendere il rapido percorso evolutivo della Norvegia, trasformatasi in meno di 30 anni da economia rurale, a potenza petrolifera, fino ad essere oggi uno dei paesi più ricchi e ‘green oriented’ del pianeta. Molta importanza viene data in particolare ai piani futuri che il governo norvegese sta attualmente ponendo, al fine di superare le questioni della crescente domanda energetica e dell'emergenza climatica. Entrambi infatti sono argomenti critici su piano globale, ma rappresentano una sfida speciale per la Norvegia, il cui territorio settentrionale è situato al di sopra del circolo polare artico, un'area che comprende le zone più sensibili agli effetti dei cambiamenti climatici, ma il cui sottosuolo dovrebbe offrire ricchi giacimenti petroliferi in grado di soddisfare la sete energetica per molti altri decenni. Due capitoli della tesi sono dedicati all'analisi di questo particolare argomento: il capitolo 3, rivolto al caso dell'Artico, e il capitolo 4, nel quale si esamina il progressivo sviluppo e utilizzo delle fonti energetiche rinnovabili. Il materiale necessario per condurre questo studio è stato raccolto durante il mio periodo di mobilità (12 mesi) tramite il progetto Erasmus+ presso la ‘Norwegian University of Science and Technology - NTNU’ di Trondheim, che è anche uno dei principali centri di ricerca e sviluppo nel campo delle tecnologie eco-compatibili, e nel settore tecnico/economico dell'industria petrolifera. Le mie fonti non sono state solo articoli, libri e lezioni: parte delle opinioni e dati sono stati raccolti anche attraverso la mia presenza nel pubblico della ‘Energy Transition Conference’ che si è tenuta il 26 marzo 2019 a Trondheim, dove il Sottosegretario di Stato Norvegese al Ministero del Petrolio e dell’Energia, insieme ad un gran numero di delegati di aziende ed esperti del campo, si sono incontrati e hanno confrontato le proprie opinioni circa il futuro del settore energetico. L'analisi di tutti i contenuti raccolti mostra una chiara consapevolezza della comunità norvegese del proprio percorso di successo nel campo energetico nel corso dei decenni. I norvegesi devono gran parte della loro ricchezza nazionale al petrolio, ma allo stesso tempo riconoscono che esso non sia una risorsa stabile, a lungo termine ed ecologica, nella quale confidare per il futuro dell'economia del paese, del benessere delle prossime generazioni e dell'ambiente.

South Africa relies heavily on fossil fuels, particularly coal, to generate electricity and it is a well known fact that the use of fossil fuels contributes to climate change, as it produces greenhouse gases (GHGs). In fact, internationally South Africa is the 17th highest emitter of GHGs (Congressional Research Service (CRS), 2008). Coupled with the environmental consequences of fossil fuel use, South Africa has a further responsibility of addressing the inherited backlog of electricity provision to the rural, and previously disadvantaged communities. In an attempt to address these two problems, the government issued the White Paper on Renewable Energy. In this paper, renewable energy alternatives are proposed to replace a portion of traditional electricity generating methods. Concentrator photovoltaic (CPV) energy generation is one such renewable option available to government. CPV uses optic elements (such as lenses) to concentrate sunlight onto solar cells. Owing to the light being concentrated, the cells in CPV use less semiconductor material, which makes them more efficient in comparison to conventional photovoltaic (PV) cells. CPV is a technology that operates well in regions with high solar radiation. As such, South Africa is particularly well suited for this technology, with average solar radiation levels ranging from 4.5 to 6.5 05 ℎ/. CPV is also well suited for off-grid application, which addresses electricity demand in remote rural areas. This study is an economic project analysis of the installation, operation, maintenance, and decommissioning of CPV technology in a rural area in the Eastern Cape, South Africa. The study area chosen for this purpose is the Tyefu settlement in the Eastern Cape. Tyefu was deemed ideal for this type of analysis due to four characteristics. Firstly, Tyefu is a remote rural settlement at the end of the national grid. Secondly, the community is very poor and previously disadvantaged. Thirdly, many households are without Eskom generated electricity. Lastly, the study area is located in an area with ideal irradiance levels for CPV. Two methods of economic project analysis are applied to this case study, namely a costbenefit analysis (CBA) and a cost-effectiveness analysis (CEA). Additionally, two types of CBA are performed, namely a private CBA and a social CBA. The private CBA evaluates the Tyefu electrification project from a private investor's perspective and the social CBA evaluates the project from society's point of view. The CEAs carried out compare the costeffectiveness of the traditional PV technology to that of CPV in terms of private and social costs. The private costs and benefits of the CPV project were identified and valued in terms of market prices. Then, this cost benefit profile was used to calculate net benefits which in turn were discounted to present values using a private discount rate of 6.42 percent. Three decision making criteria were generated, namely the net present value (NPV), the internal rate of return (IRR) and the benefit cost ratio (BCR). Sensitivity analysis was carried out by varying the private discount rate and the bidding price. The social costs and benefits of the CPV project were identified and valued in terms of shadow prices. This cost benefit profile was used to calculate net benefits. The net benefits were discounted to present values using a composite social discount rate equal to 5.97 percent. The same decision making criteria used in the private CBA were used in the social CBA and a sensitivity analysis was completed by varying the social discount rate. In terms of the private CEA, the costs were identified and valued in terms of market prices. All costs were brought to present values using the private discount rate of 6.42 percent. In terms of the social CEA, the costs were identified and valued in terms of shadow prices. All costs were brought to present values using the social discount rate of 5.97 percent. The cost-effectiveness (CE) ratios calculated have identical denominators since the annual output for both technologies are identical - both CPV and PV systems deliver 30 300 kWh per annum. This output is based on the demand of the given case study. The private CBA showed unfavourable results. The private CBA has a NPV of R2 046 629.01, the IRR is undefined (this is due to no sign change being present in the cost benefit profile), and has a BCR of 0.365. However, the social CBA yielded positive results, with a NPV of R125 616.64, an IRR of 8 percent (which exceeds the social discount rate of 5.97 percent), and a BCR of 1.045. The CEA showed that the CPV is more cost-effective than the traditional PV both in terms of private and social costs. The private CE ratio of CPV is R4.23/kWh compared to PV's CE ratio of R4.39/kWh. Similarly, the social CE ratio of CPV is R3.51/kWh compared to PV's CE ratio of R3.69/kWh. CPV rollout appears to be socially efficient on a small scale according to the social CBA. Consequently, the CPV project is not seen as desirable in terms of the private CBA as the benefit (income received per kWh) in the private analysis is too small to outweigh the costs of implementing and running a CPV plant in Tyefu. On the other hand, a redeeming factor is that CPV may be feasible privately, for large scale applications. A major reason for the CPV project not being appealing to private investors is that the maximum bidding price of R2.85/kWh (as at August 2011) is not high enough for private investors to undertake the CPV project. The sensitivity analysis of the bidding price showed that the bidding price of R2.85/kWh needs to be increased in the range of 250 percent (R7.13/kWh) and 300 percent (R8.55/kWh) for a great enough incentive to exist for private investors. It is thus recommended that policymakers take this into consideration when formulating policy. In terms of the social CBA, it is recommended that government undertake CPV projects of this kind, as it will be a socially desirable allocation of resources. If government were to pursue these types of projects, it is recommended that CPV be implemented as it is more cost effective than PV.

Although Crete is an island highly utilizing renewable energy sources (RES) for heat and power generation, their further applications in agriculture would result in many socioeconomic and environmental benefits. The use of renewable energies integrated in greenhouses in Crete is nowadays rather limited, and it could be increased in the future since the resources are abundant and the technologies are mature, reliable and cost-effective. Solar energy, solid and gaseous biomass, and low enthalpy geothermal energy could be used in order to provide heat, cooling and electricity to greenhouses to cover part or all of their energy needs. The positive impacts of their use include: additional income to the farmers, a reduction of greenhouse gas emissions due to energy use in them, an increase of employment in the local community and a decrease of energy dependency in Crete. The establishment of zero CO₂ emissions greenhouses due to energy use in Crete is currently feasible and cost-effective with the use of the existing renewable energies being available on the island. Unexploited renewable energy sources like landfill gas in Crete can also be used effectively for heating them. Biomass is currently used mainly for heat production in Crete, but new applications could be realized in the future including power generation and the production of biofuels. Olive kernel wood, a byproduct of the olive kernel oil producing industry, is extensively used in Crete for heat production. Besides heat generation, it could be used for the co-generation of heat and power and this process could be profitable under some conditions. Olive kernel wood could also be used as a raw material together with olive tree prunings for the manufacture of wood pellets in Crete. The work included in this thesis investigates various innovative uses and applications of sustainable energies in Crete, Greece, which could contribute to the promotion of energy sustainability in the agricultural sector of the island.

Renewable energy resources (RESs) are significantly integrated in distribution networks to promote green technologies in future power systems. The idea of microgrids (MGs) is developed for the efficient use of RESs through an appropriate control, monitoring and management system. Control and management of MGs are challenging tasks along with numerous economic and environmental benefits. The challenges of MGs operation include tie-line power fluctuations that have an adverse effect on the stability and quality of distribution networks. Tie-line power control in a residential MG is difficult due to dependency on RESs as a primary generation unit in MGs. Motivated by these, this thesis investigates the tie-line power control issues in grid-connected residential MGs and applies several controls and optimisation methods to achieve a smooth tie-line power satisfying system boundary conditions. First, a dynamic energy management system (EMS) is designed to reduce the tie-line fluctuation in a grid-connected MG through an indirect grid power control strategy. A fuzzy logic-based EMS is proposed to control the battery power due to the variations in generations and loads. The net power demand and battery state of charge (SoC) of an MG are considered inputs of the fuzzy controller to determine the battery power by keeping the battery SoC within limits. An offline optimisation method is used to optimise the membership functions and rules to shape the performance parameters. Thereafter, a golden section search-based non-linear programming method is applied to design a battery power management system to minimise the tie-line fluctuation in an MG counting the system constraints and disturbances. Two other rule-based methods are also demonstrated for comparative analysis of the proposed methods in terms of predefined performance parameters. Afterward, a dynamic grid power control method is presented to control the interlink inverters in grid-connected MGs. A grid power controller is designed based on a complete model of the MG systems to achieve a constant tie-line power on typical days of the year. The designed controller can effectively smooth tie-line fluctuation in a grid-connected residential MG. The charging/ discharging of the battery is controlled by a DC-DC converter which is also responsible to provide a stable DC bus to the input of an interlink inverter. The reference tie-line power is determined by a MG controller based on statistical power generations, load demand and battery SoC. Moreover, an eigenvalue-based stability analysis is performed to show the sensitivity of system parameters on system stability. Furthermore, the tie-line power control in a networked MG (NMG) is investigated to obtain a smooth tie-line power in an NMG connected to a common bus. A model predictive control-based distributed power flow controller is proposed to control the interlink inverters of the NMG in a distributed manner. Charging/ discharging of battery is controlled by a decentralised model predictive power controller to provide a stable DC voltage for MGs. Communication between MGs is performed for sharing the status of the tie-line power along with the scheduled tie-line reference. The information from the network is used to determine the instantaneous reference grid power of individual MGs for achieving a smooth tie-line power for the network. Inverter switching actions are performed to minimise the difference between predictions and references. In addition, a comparative study with a decentralised operation of MGs is conducted to show the benefits of networked operation. All the proposed methods are tested through rigorous case studies to validate the performance despite the variations in input and output system disturbances. Comparative analysis among different methods is also conducted to demonstrate the performance variations through adopting different methods. For the simulation experiment set up, MATLAB SIMULINK Simscape Electrical is used to develop a designed system model of MGs and experimental models of the proposed methods. Experiments are performed using real weather and residential load information in Queensland, Australia. The results demonstrate that the proposed methods have achieved the design objectives to solve the tie-line fluctuation problem of grid-connected residential MGs.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
Full Text

Native American lands have significant renewable energy resource potential that could serve to ensure energy security and a low carbon energy future for the benefit of tribes as well as the United States. Economic and energy development needs in Native American communities match the energy potential. A disproportionate amount of Native American households have no access to electricity, which is correlated with high poverty and unemployment rates. Despite the vast resources and need for energy, the potential for renewable energy development has not fully materialized. This research explores this subject through three separate articles: 1) a case study of the Navajo Nation that suggests economic viability is not the only significant factor for low adoption of renewable energy on Navajo lands; 2) an expert elicitation of tribal renewable energy experts of what they view as barriers to renewable energy development on tribal lands; and 3) a reevaluation of Native Nation Building Theory to include external forces and the role that inter-tribal collaboration plays with renewable energy development by Native nations. Major findings from this research suggests that 1) many Native nations lack the technical and legal capacity to develop renewable energy; 2) inter-tribal collaboration can provide opportunities for sharing resources and building technical, legal, and political capacity; and 3) financing and funding remains a considerable barrier to renewable energy development on tribal lands.

Les technologies de l'information et de la communication, adoptées par le Smart Grid, ont été utilisées pour améliorer le contrôle du système électrique. Aujourd'hui, les objectifs sont, entre autres, de permettre une intégration efficace des ressources énergétiques renouvelables (RES), de maintenir la sécurité de l'approvisionnement énergétique et d'encourager le futur marché de l'énergie. En conséquence, la mise en œuvre d'un tel système nécessite l'échange de données entre les applications de réseau intelligent existantes et nouvelles. Pour rendre cela possible, une plate-forme de communication polyvalente est nécessaire, de sorte que la principale question à laquelle cette thèse répond est : que serait une telle plate-forme ? L'objectif de ce travail est de concevoir, mettre en œuvre une plate-forme de passerelle de télémétrie à faible coût, open source et résiliente, capable d'intégrer les applications de réseau intelligent existantes et futures. Cette plate-forme est optimisée et testée à l'aide d'une variété d'outils de simulation, d'analyse, de mise en œuvre réelle et de prototypes. Dans notre cas, cette plate-forme est capable d'intégrer des compteurs d'énergie conformes DLMS /COSEM avec LoRaWAN, où une étude des performances LoRaWAN, dans un environnement réel est effectuée. LoRaWAN a été choisie comme une solution de dernier kilomètre à faible coût, longue portée et fiable pour le comptage intelligent de l'énergie dans les zones urbaines où une solution à courte portée peut ne pas être optimale, cependant, DLMS/COSEM a été choisi car il s'agit du protocole d'application standard mondial pour le comptage, le contrôle de l'énergie et il est largement accepté en Europe et aux États-Unis. La combinaison de ces deux protocoles présente des défis importants tels que la conception d'un module interopérable qui peut être facilement intégré dans l'infrastructure existante et capable de répondre aux exigences de transmission LoRaWAN et DLMS/COSEM en termes de temps de transmission et de taille des paquets. En outre, il y a toujours des défis de sécurité à considérer, par conséquent, nous proposons une approche basée sur la combinaison des technologies Secure Element (SE) et Blockchain pour fournir une plate-forme sécurisée de bout en bout. SE a été utilisé pour fournir aux nœuds IoT une certaine puissance de calcul et Blockchain a été utilisé pour améliorer l'intégrité et la sécurité. Blockchain est utilisé pour certifier les données transmises, les fournir aux applications distribuées (DApp) et pour conduire à la démocratisation du marché de l'énergie. Cette thèse est composée de 5 chapitres qui sont résumés ci-dessous : Le chapitre 1 vise à décrire l'évolution du réseau énergétique conventionnel en définissant et en décrivant le système AMI. Le chapitre 2 donne un aperçu des progrès actuels et à venir de l'IoE en Europe. Le système allemand a été discuté en détail car il a été utilisé comme architecture de référence de notre passerelle développée. Les chapitres 3 et 4 proposent la conception et le déploiement d'un système open-source, low-cost et modulaire basé sur la technologie de télécommunication LoRa pour les applications de comptage d'énergie. Le prototype conçu sera présenté en détail, en plus la mise en œuvre et les résultats des tests seront expliqués et discutés. Le chapitre 5 représente la passerelle énergétique développée pour le commerce d'énergie P2P de quartier. Notre hypothèse est que la passerelle développée permettra le marché local de l'énergie sans l'intervention des services publics où les petits prosommateurs peuvent participer ainsi un bon investissement des ressources énergétiques renouvelables. Ce manuscrit qui avait commencé par une introduction se termine par une conclusion générale sur cette étude et rappelant les résultats originaux obtenus à laquelle se rajoute une partie, perspectives que ce travail permet d'envisager. Des listes d'acronymes et de références sont également présentées
Information and communication technologies (ICTs), adopted by the Smart Grid (SG), have been used to improve the control of the power system beyond that implemented in the conventional grid. Todays the objectives are, among others, to enable efficient integration of the renewable energy resources (RES), to maintain security of energy supply and to encourage the future energy market. As a result, the implementation of such a system requires the exchange of data between legacy and new smart grid applications. To make this possible, a versatile communication platform is required, so the main question that is answered in this thesis is: what would such a platform be?The objective of this work is to design, implement and evaluate a low-cost, open-source, resilient telemetry gateway platform capable of integrating existing and future smart grid applications. This platform is optimized and tested using a variety of simulation, analysis, real implementation and prototypes tools.In our case this platform is capable to integrate DLMS / COSEM compliant energy meters with LoRaWAN, where a study of LoRaWAN performance, when transporting energy metering packets, in a real-world environment is performed. The LoRaWAN technology has been chosen as a low-cost, long-range, and reliable last-mile solution for smart energy metering in urban areas scenario where a short-range solution may not be the optimum one, however, DLMS / COSEM was chosen since it is the world standard application protocol for smart energy metering, control, and management and it is getting widely accepted in Europe and US. The combination of these two protocols presents significant challenges such as designing an interoperable module that can be easily integrated into the existing infrastructure and is able to meet both LoRaWAN and DLMS/ COSEM transmission requirements in terms of transmission time and packet size. In addition, there are always some security challenges to consider, since cyber-attacks can not only threaten the consumer's privacy but they can even lead to a compromised system with direct impact on the safety of individuals and the activities of society. Therefore, we propose an approach based on combining Secure Element and Blockchain technologies to provide an end to end IoT secure platform. Secure Element has been used to provide IoT nodes with some computational power where Blockchain has been used to enhance integrity, transparency, and security it is used to certify the transmitted energy metering data and to provide these data to Distributed Applications (DApp). In this way, producers and consumers will be able to trade energy (especially from distributed renewable energy sources) over the existing infrastructure, using Blockchain technology, thus leading to the democratization of the energy market.The manuscript of this thesis is composed of five chapters which are summarized below:Chapter 1 is intended to describe the evolution of the conventional energy grid by defining and describing the Advanced Metering Infrastructure (AMI) system.Chapter 2 gives an overview of the current and upcoming IoE advancements in Europe was.The German system was presented and discussed in details since it was used as reference architecture of our developed energy metering gateway.Chapters 3 and 4 present the designing and deployment of an open-source, low-cost, and modular system based on LoRa telecommunication technology for energy metering applications. The designed prototype will be presented in details, in addition the implementation and testing results will be explained and discussed.Chapter 5 represents the developed energy gateway as a use case for neighborhood P2P energy trading. Our assumption is that the developed gateway will enable the local energy market without the intervention of the utilities where small prosumers can participate thus a good investment RES. Lists of acronyms and references are also present in this manuscript

The feasibility of a PEM hydrogen storage system in a municipal setting using prosumer excess solar power has been investigated. The feasibility was determined upon key performance indicators payback time, internal rate of return (IRR) and net profit margin. The project was done as a case study on Södertälje municipality, Stockholm, Sweden. Different business models were compared to determine the optimal operation scheme. Potential showstoppers were also explored. Literature study and interviews were combined into a system model in Excel which breaks down costs and profits over a 20-year timeline. A sensitivity analysis was performed to measure the stability of yearly net profits during changes in electricity price and hydrogen market price. The available excess solar power was identified and used to size a system consisting of an electrolyser, storage tanks and fuel cells. A daily system was deemed best, where electricity is accepted during the day and discharged during the night. Hydrogen is also sold as a commodity for vehicular charging, and oxygen is compressed into a refill station for hospitals and manufacturers. The results were simulated in two operational scenarios; a Standard scenario and a Truck scenario, the latter which has no fuel cell and more hydrogen is sold at the expense of electricity. The payback time is 5 years for the Standard scenario and 4 years for the Truck scenario. They have an IRR of 4% and 32% after 5 years and a net profit margin of 63% and 86% respectively. The sensitivity analysis shows <6% change in yearly net profits for the Standard scenario and <12% change in the Truck scenario when electricity price and hydrogen market price fluctuatesby 50%.
Genomförbarheten för en PEM vätelageranläggning på kommunnivå användandes av solcellägares överskottsel har undersökts. Genomförbarhetens grad bedömdes efter konsumentprisindex återbetalningstid, intern avkastning (IRR) och nettovinstmarginal. Projektet utfördes som en fallstudie på Södertälje kommun. Olika affärsmodeller jämfördes och potentiella problem identifierades. Litteraturstudie och intervjuer kombinerades till ett system för kostnader och intäkter över en 20 år livstid som modelleradesi Excel. En känslighetsanalys utfördes för att se effekten på årliga vinster när elpriset och marknadspriset för väte ändrades. Det tillgängliga solcells överskottet identifierades och användes för att välja storlek på systemet innehållandes bränslecell, elektrolyserare och förvaringstank. En daglig drift dömdes passa bäst, där lagret fylls på dagen och urladdas på natten. Vätet säljs också som en råvara till fordon och syret komprimeras till en påfyllningsstation för sjukhus och industriella processer. Resultaten simuleras i två scenarier; ett Standardscenario och ett Truck scenario där inget bränslecell finns och mer väte säljs på bekostnad av elektricitet. Återbetalningstiden är 5 år för Standard scenariot och 4 år för Truck scenariot. De har en IRR på 4% och32% efter 5 år och en nettovinstmarginal på 63% och 86% vardera. Känslighetsanalysen visar en <6% ändring i årliga vinster för Standard scenariot och <12% i Truck scenariot när elpriset eller marknadspriset för väte fluktuerar 50%.

Electrification of low-income rural areas that have a limited connection or no access to electrical grids is one of the most demanding challenges in developing countries such as Peru. The international commitment to stop global warming and the reduction in the cost of renewable sources of energy have reduced the prices of fossil fuels in some cases. This has opened the way to the current research which proposes a hybrid energy system (HES) based on the use of renewable sources of energy. Therefore, a renewable electricity system (HRES) was set up at the village of Monte-Catache in the Cajamarca region, which is one of the poorest areas of Peru. Surveys and field studies were used to evaluate the socioeconomic characteristics, availability of renewable energy resources, and energy demand of this region. Potential energy sources were evaluated, and isolated photovoltaic systems with a battery bank were found to be the most appropriate according to the results obtained in the simulation with HOMER. This proposal constitutes an interesting contribution for future energy solutions in isolated and low-income rural areas.
Revisión por pares

Large-scale deployment of low-carbon energy technologies is important for counteracting anthropogenic climate change and achieving universal energy access. This thesis explores potential growth rates of technologies necessary to reach a more sustainable global energy system, the material and energy flows required to commission these technologies, and potential future availability of the required resources. These issues are investigated in five papers. Potential future growth rates of wind energy and solar photovoltaics, and the associated material requirements are explored, taking the expected service life of these technologies into account. Methodology for assessing net energy return and natural resource use for wind energy systems are analyzed. Potential future availability of lithium and phosphate rock are also investigated. Estimates of energy and materials required for technologies such as wind energy and photovoltaics vary, and depend on the assumptions made and methods used. Still, it is clear that commissioning of low-carbon technologies on the scale required to reach and sustain a low-carbon energy system in coming decades requires significant quantities of both bulk materials and scarcer resources. For some technologies, such as thin film solar cells and electric vehicles with lithium-ion batteries, availability of materials could become an issue for potential growth rates. Future phosphate rock production could become highly dependent on few countries, and potential political, social and environmental aspects of this should be investigated in more detail. Material and energy flows should be considered when analyzing growth rates of low-carbon technologies. Their estimated service life can indicate sustainable growth rates of technologies, as well as when materials are available for end-of-life recycling. Resource constrained growth curve models can be used to explore future production of natural resources. A higher disaggregation of these models can enable more detailed analysis of potential constraints. This thesis contributes to the discussion on how to create a more sustainable global energy system, but the methods to assess current and future energy and material flows, and availability of natural resources, should be further developed in the future.

The use of an attached sunspace is one of the most popular passive solar heating techniques. One of the main drawbacks of the sunspace is getting over heated by the sun energy during the hot season of the year. Even in northern climates overheating could be problematic and there is a considerable cooling demand. Shading is one of the most efficient and cost effective strategies to avoid overheating due to the high irradiation especially in the summer. Another strategy is using ventilation system to remove the excess heat inside the sunspace. However this rejected energy can be captured and stored for future energy demands of the sunspace itself or nearby buildings. Therefore the Solar blind system has been considered here for the shielding purpose in order to reduce the cooling demand. By considering the PV/T panels as the solar blind, the blocked solar energy will be collected and stored for covering part of the heating demand and the domestic hot water supplies of the adjacent building.  From a modeling point of view, the sunspace can be considered as a small-scale closed greenhouse. In the closed greenhouse concept, available excess heat is indeed utilized in order to supply the heating demand of the greenhouse itself as well as neighboring buildings. The energy captured by PV/T collectors and the excess heat from the sunspace then will be stored in a thermal energy storage system to cover the daily and seasonal energy demand of the attached building. In the present study, a residential building with an attached sunspace with height, length and width of 3, 12 and 3.5 meters respectively has been assumed located in two different locations, Stockholm and Rome. Simulations have been run for the Solar blind system integrated with a short-term and a long-term TES systems during a year to investigate the influence of the sunspace equipped with a PV/T Solar blind on the thermal behavior of the adjacent building. The simulated results show that the Solar blind system can be an appropriate and effective solution for avoiding overheating problems in sunspace and simultaneously produce and store significant amount of thermal energy and electricity power which leads to saving considerable amount of money during a year.

Master's Thesis considers the idea of use of renewable energy sources for the generation of electricity. On the basis of reports on climate warming, the European Union took measures, which are mandatory for all Member States and aimed to increase the share of renewable energy in total energy production by 2010. Czech Republic has committed itself to produce 8% of energy from renewable energy sources, the government has created a system of subsidies to renewable energy sources and a system of redemption prices. These measures make energy very expensive. This work deals with the origin of these measures, which are reports on global warming. My work is also comparing predictions on the future status, as well as examining the advantages of investing in renewable energy sources and comparing the prices of subsidized energy with other types of energy.

Esta dissertação é uma reflexão sobre os distúrbios climáticos devido à actividade humana e sua dependência histórica dos combustíveis fósseis para produzir energia. Chama a atenção para a necessidade do uso de energia renovável e que medidas podem ser tomadas para tal, respondendo a algumas questões neste contexto: que tipo de estruturas existem para produzir diferentes tipos de energia renovável? E no caso específico dos parques eólicos: que impactos podem ter na paisagem? O objectivo da tese é identificar os critérios mais importantes a considerar no planeamento de áreas destinadas à instalação de parques eólicos. Assumindo que a produção de energia renovável exige a instalação de estruturas, é importante uma análise cuidada no planeamento destas áreas. A tese não estabelece regras aplicáveis a todos os casos. Cada paisagem tem as suas próprias características e é percebida de forma diferente por cada pessoa; ABSTRACT:The study is a reflection on the climate disturbances due to human activity and its historic dependence on fossil fuels to produce energy. It notes the need for the use of renewable energy and what steps can be taken for such, addressing some issues in this context: what kind of structures exists to produce different types of renewable energy? And in the specific case of wind farms: what impacts have in the landscape? The aim of this thesis is to identify the most important criteria to consider when thinking about planning an area for a wind farm installation. Assuming that the production of renewable energy requires the installation of structures, is important to care on the planning of these places. The thesis does not establish any formula that applies anywhere. Each landscape has its own characteristics and is perceived differently by the people.

The purpose of this research is to develop methods that reduce energy consumption in a residential building in a hot and humid climate region (Thailand) using efficient architectural building components and renewable energy (solar energy) to produce electricity, domestic hot water, and supplemental cooling by night sky radiation. Improving the architectural building components, including building materials, is an option to reduce energy consumption in a building. Using renewable energy sources is another option to reduce the consumption of non-renewable energy. In residential buildings, solar energy has been utilized for space heating and domestic hot water using active solar collector systems and for generating electricity using photovoltaic (PV) systems. One photovoltaic system, the hybrid photovoltaic-thermal (PV-T) collector system, has been developed by several researchers over the last 20 years. The hybrid photovoltaic-thermal (PV-T) collector system is a combination photovoltaic (for producing electricity) and solar thermal collector (for producing hot water). Theoretical and experimental studies of this collector have highlighted the advantages of the hybrid PV-T collector system over separate systems of PV and solar collector in term of system efficiency and economics. Unfortunately, very little experimental data exists that demonstrates the advantages of a combined system. Therefore, one of the objectives of this study conducted was an experimental study of this system as an auxiliary energy source for a residential building. Night sky radiation has also been studied as a cooling strategy. However, no attempt so far could be found to integrate it to a hybrid PV-T collector system. The night sky radiation strategy could be operated with the hybrid PV/T collector system by using existing resources that are already present in the solar system. The integration of the night sky radiation into the hybrid PV-T collector system should yield more productivity of the system than the operation of the Hybrid PVT system alone. The research methods used in this work included instrumentation of a case-study house in Thailand, an experimental PV-T collector system, and a calibrated building thermal simulation. A typical contemporary Thai residential building was selected as a case-study house. Its energy use and local weather data were measured and analyzed. Published energy use of Thai residential buildings was also analyzed as well to determine average energy consumption. A calibrated computer model of the case-study building was constructed using the DOE-2 program. A field experiment of the thermal PV system was constructed to test its ability to simultaneously produce electricity and hot water in the daytime, and shed heat at night as a cooling strategy (i.e., night sky radiation). The resultant electricity and hot water produced by the hybrid PV-T collector system helped to reduce the use of non-renewable energy. The cooling produced by the night sky radiation also has to potential to reduce the cooling load. The evaluation of the case-study house and results of the field experiment helped to quantify the potential reduction of energy use in Thai residential buildings. This research provided the following benefits: 1) experimental results of a hybrid PV-T solar collector system that demonstrates its performance compared to typical system of separate photovoltaic and solar collector, 2) results of night sky radiation experiments using a photovoltaic panel as a radiator to demonstrate the performance of this new space cooling strategy, and 3) useful data from the case-study house simulation results and guidelines to assist others in transferring the results to other projects.

Rural development by means of providing uninterruptible power supply has become a priority among developing countries. Nigeria especially has on its top agenda the mandate to provide clean and cost-effective means of energy to the rural communities, hardest hit by wave of incessant outages of electricity supply. Renewable Energy (RE), a clean form of energy that can be derived from natural sources is widely available throughout Nigeria but is not harnessed. In this dissertation a Cost-Benefit Analysis (CBA) framework is proposed for renewable energy towards rural community development in Nigeria as indicated in the 18-point recommendations of Energy Commission of Nigeria (ECN). Moreover, a cost-benefit analysis tool is formulated and developed from the CBA framework in order to analyze comparatively the costs and intangible benefits of renewable energy projects for rural application. A case study demonstrating the working methodology of the proposed framework is presented in order to establish the cost-benefit components by assessing the comparative cost-benefit analysis of RE at a rural site of Nigeria. Erinjiyan Ekiti rural area is located for CBA assessment with three RE resources (solar, wind and small hydro) selected for consideration. Through the application of Contingent Valuation Method (CVM), the respondents' willingness to pay for RE supply is obtained and RE benefits in monetary terms computed. Using three economic decision criteria namely: Net Present Value (NPV), Benefit-Cost Ratio (BCR) and Internal Rate of Return (IRR); the three RE resources are ranked according to their economic viability. The result of the analysis provides useful insight to investors and decision makers into how RE projects in rural community should be conducted. Foremost, it is revealed that all three RE options will be economically viable if implemented, though adequate caution must be taken when making a decision. Based on the CBA assessment, the Small-Hydro Power (SHP) option is ranked as the most viable option. However, this is swiftly negated if RE social impact, such as the spiritual belief of the rural dwellers, who rely on the only potential river as a medium of communication with their ancestors, are taken into consideration. Furthermore, a sensitivity assessment of the three RE options revealed that only solar photovoltaic (PV) option is marginally viable, thus turns negative upon an assumed increase in discount rate of only 17%. Herein, the proposed CBA framework provides a useful insight into an efficient method of appraising RE projects in rural communities. A CBA simulation tool is formulated and adapted from the CBA framework to enable quicker, reliable and automated means of assessing RE projects with a view to making wise investment decision.
Thesis (M.Ing. (Development and Management Engineering))--North-West University, Potchefstroom Campus, 2009.

Includes bibliography.
For many years, power systems were vertically operated; large power generation plants produced all of the electrical power. This kind of generation is often related to adequate geographical placement such as water sources, coal sources etc. The power is then transmitted towards large consumption centres over long distances using different high-voltage transmission levels. This operating structure was built on the basis of economy, security, and quality of supply. This very centralized structure is operated by hierarchical control centres and allows the system to be monitored and controlled continuously. The generation is instantly adjusted to match consumption by monitoring the frequency, on the basis of very elaborate load forecasting models. The voltage is also controlled to be within specific limits by means of appropriate coordination of devices such as, generators, online taps changers, and reactive compensation devices. The power system operation is changing due to the restructuring and continuous growth in the demand however, due to major changes in the legislative framework for the power sector and the fast movement towards liberalization of the electricity markets, renewable energy sources were introduced to distribution systems. These units are of limited size (2MVA or less) and can be connected directly to the distribution network or on the customer side of the meter. Efforts to reduce CO2 emissions related to electricity generation, and to reduce fuel imports, have led to a significant increase in the deployment of renewable energy generation technology. Renewable energy sources (RES) are predicted to play a key role in the power distribution systems; they are the key to a sustainable energy supply infrastructure because of their inexhaustible and none polluting nature. However, the integration of renewable energy resources create special technical and economical challenges that have to be comprehensively investigated in order to facilitate the deployment of these renewable energy sources units in the distribution system. This dissertation investigates the renewable energy resources, types, advantages and disadvantages of renewable energy resources, the prospects of renewable energy resources in South Africa and Nigeria, challenges facing the integration of renewable energy resources into the distribution network.

2014 - 2015
In recent years, progresses have been made in developing cleaner and more efficient technologies to produce, transmit and distribute energy. Pledges made in the recent summit in Paris (21°conference of the parties - COP21, Paris 2015) and Marrakech (COP22, Marrakech 2016) on climate changes promise to give new impetus to the move towards a lower-carbon and more efficient energy system. Nowadays, mandatory energy efficiency plans are expanding worldwide to cover over a quarter of the total global consumption. Furthermore, renewables represent almost half of the world’s new power generation capacity. The deepening penetration of renewable energy resources (RESs) has forced grid operators to deal with both technical and economic challenges to harness as much green energy as possible from them. Renewable plants, solar photovoltaic (PV) based and wind farms, are often small-medium scale generation plants connected at the distribution network level. The conventional distribution networks were designed to be operated as passive networks but with the continuing integration of RESs must accommodate bi-directional flows. Indeed, the implementation of the Smart Grid into distribution grids will bring about the effective deployment of advances in information and communication technologies (ICT) to improvements in the reliability, resiliency, flexibility and efficiency of such grids. Under the resulting new paradigm, it is possible to identify new roles that the distribution network operator (DNO) can play as well as additional activities and services that the DNO can provide to bring out marked improvements in the distribution grid management arena. The rapid changes in the distribution grid need to be accompanied by associated changes in their operations and provide the flexibility for the operators to evolve from the conventional DNO who manages passive networks to that of the distribution system operator (DSO) to run the new bidirectional flow distribution grid. This thesis is presented within the context of the newly evolving distribution grids managed by their DSOs. The aim of the work is to investigate the feasibility and implementation of the provision of ancillary services able to support current and future DSOs to facilitate improvements in the harnessing of the energy produced by deeper penetrations of RESs into the distribution grids. To this end, specific services must be provided by resources in the distribution network (DN) to provide congestion relief, as well as various ancillary services (AS), such as frequency control, voltage regulation, spinning and non spinning reserves and in some cases energy services from distributed energy resources or DERs. A key contribution of the thesis is to address the potential of three DER types – distributed generations (DGs), demand response and energy storage resources – to provide such services in DNs. Proposed strategies and approaches are tested and validated on real-world DN test systems. In detail, the thesis discusses two proposed decentralised approaches to provide voltage support from DG resources. These approaches’ objective is to avoid active power curtailments or the disconnection of RESs due to rises in voltage that usually occur in periods of high generation and low demand. We take advantage of the inverter that usually interfaces a DG to the DN into which it is integrated to implement a practical control strategy to provide reactive power support, be it either via injection or absorption of vars. Capability curves define the actual operational area that defines the amount of reactive power that is possible to absorb or inject into the grid, making curtailments/disconnections the least frequent solution performed by DSO when contingencies occur. To extend the approach of this control technique, it is possible to coordinate reactive power flows coming from different DG units of an independent power producer (IPP). The idea is to maximise active power production (and, then, reduce curtailments/disconnections) of PV and wind generators by optimising reactive power injections/absorption of DG units connected to different point of the DNs. The first decentralised but coordinated approach calculates the set points of each DG units by using the coefficients of the mixed sensitivity matrix of the network. This method results to be very fast to perform but it requires the calculation of the mixed sensitivity matrix; moreover, in some conditions, it could not give the best solution in terms of reactive power. The second method is based on the solution of a non-linear optimisation problem in order to calculate the active power-reactive power set points. By solving a global problem, the method points out an optimal solution even if the number DG units involved in the control is nontrivial; anyway, a communication framework must be developed for the exchange of information between DSO and IPP. We illustrate each scheme with applications to an actual Italian distribution network and provide a comparative analysis of their performance. To provide ancillary services by demand response resources in the DN, it is necessary to develop new load models. Two alternative formulations of the well-known ZIP model to explicitly represent the dependence of the demand on voltage changes under steady state conditions are presented. These model representations are able to provide acceptable estimates of the impacts of schemes, such as conservation voltage reduction (CVR), on the energy consumption by these loads. More in detail, the study wants to estimate how much demand it is possible to unlock by changing voltage values along the lines. To this end, an experimental study on a next-generation home appliance (a washing machine with digital control and motor drive fed by inverter) is conducted. The time-varying behaviour of domestic appliances is represented by using a discrete-time ZIP model to describe each phase of the appliance operations. The proposed model is capable of modelling the active power absorption of thermostatic loads, which exhibit periodic behaviour that depends on the applied voltage as well as equipment settings and the surrounding environment. To reduce the number of loads to be modelled during a time-series simulation, a time-varying formulation of the ZIP model is presented. It allows the aggregation of ZIP parameters at a given instant in time by using a polynomial structure. This model is tested on a real UK distribution network in order to estimate the amount of demand subject to change when the voltage at the primary substation is modified via an on load tap changer (OLTC). The deployment of energy storage resources (ESRs) for the provision of certain ancillary services is investigated. The focus of the work is specifically on battery energy storage system integrated into PV systems. Two specific situations, under which the battery energy storage system (BESS) provides voltage support at the DN level, are proposed. The BESS is integrated into a PV solar farm. In detail, two controls, in which BESSs are co-located with PV units in order to provide voltage support in DNs, are presented. The former is a sensitivity-based decentralized control approach described above reduces the reactive power needed to maintain the voltage within a specified interval when compared to the case of the same solar PV unit farm without the integrated BESS. The latter ancillary service envisages the possibility to coordinate charging/discharging periods of BESSs co-located with PV units with DSO needs. Assuming that the DSO is able to estimate generation and demand peaks during the day (when the possibility of having voltage rises and voltage drops increases), then it is possible to identify the periods of the day in which the possibility that voltage issues occur is higher. Thus, DSO can require BESSs to provide voltage support in these periods by charging/discharging according to the possibility of having voltage rises/drops. The proposed method is compared with the case in which PV/BESS are operated without supporting network operation. Energy selfconsumption resulted to be comparable; moreover, the opportunity cost is estimated to associate a cost to the proposed ancillary service. The initial design of an analytic framework to assess the deployment of ESRs within a market environment and their performance in terms of reliability, environmental and economic impacts is presented. The rather comprehensive framework provides the capability to represent all the interactions among the embedding environment of the deployed ESR with all other players/stakeholders in the grid and in the markets. The framework has the flexibility to incorporate relevant and appropriate policy issues and policy alternatives as well as to represent new market products to effectively harness ESR capabilities. The framework is able to represent the physical grid, the ESR embedding environment, if any; all resources and loads; the communication of control signals; the broadcast of market information/forecasts/data; submission of ESR offers for provision of various services; the evaluation of all reliability, environmental and economic/financial metrics of interest; attributes and sensor measurements; the physical/financial/information flows between physical resources, market players, asset owners and resource and grid operators. The design of the framework provides an interconnected four-layer framework structure consisting of a separate layer for the physical, information, market and environmental flows with the various interactions among the layers. The four- layer structure can accommodate the consideration of all issues in the operations of ESR deployment. Despite the number of studies available in the literature, there is limited activity in the provision of services in DNs by RESs. Technical issues as well as economic considerations has been addressed in the Thesis that gives significant contributions in the field of voltage regulation by using dispersed resources for reducing the risk of curtailments and maximizing the hosting capacity. This work also contributed to the understanding that decentralised approaches can, in certain case, have similar performance of centralised ones. In addition, the role of load as an active resource in the grid has been investigated. Load models that correlate consumption and voltage have been improved and reformulated. Finally, the role of BESSs in providing ASs in DNs has been demonstrated and a preliminary framework for the assessment of their economics has been presented. [edited by Author]
XIV n.s.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2015.
From the electric power generation perspective, the last three decades have been characterized by sustained growth in the amount of Distributed Power Generation (DPG) systems integrated into the electric grid. This trend is anticipated to continue, especially in light of the widespread acceptance of the many benefits envisaged in the increase of renewable-based power generation. The potential for grid-integrated DPG systems to significantly contribute to electric power supply reliability has consistently attracted extensive research in recent times, although concerns continue to be raised over their adverse impact on the normal grid operation at high penetration levels. These concerns largely stem from the limited controllability of most DPG systems, which tend to exhibit large output impedance variation, and non-deterministic power output characteristics. There has therefore also been a growing need to develop effective control strategies that can enhance the overall impact of the DPG systems on the grid operation, thus improving their synergistic properties, and probably also enabling an even higher penetration level into the utility grid. In line with this identified need, this thesis discusses the modeling and controller design for an inverter-based DPG system with the capability to effectively operate both in grid-connected and autonomous (i.e. independent of the utility grid) operational modes. The dual-mode operation of the DPG is made possible by incorporating into the inverter interface control scheme the means to ensure seamless transition of the DPG between the grid-connected and autonomous modes of operation. The intention is to have a grid-integrated inverter-based DPG system whose operation approximates that of an online Uninterruptible Power Supply (UPS) system, in that it is able to sustain power supply to the local load in the absence of the grid supply, which would be desirable for critical loads, for which the level of power supply reliability guaranteed by the grid often falls short of the requirements. The work developed in this thesis considers three of the aspects associated with grid-integrated DPG systems that are equipped with autonomous-mode operation capability.

Thesis (M.S.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 8, 2008) Includes bibliographical references.

With the new challenges brought by the high penetration of Renewable Energy Resources (RESs) into the modern grid, developing new solutions and concepts are necessary. Microgrid (MG) is one of the new concepts introduced to overcome upcoming issues in the modern electricity grids. MGs and Multi-Microgrids (MMGs) are defined as the building blocks of smart grids. MGs are the small units, where power generation and consumption happen at the same location and MG makes the decisions by itself. MGs can operate grid-connected or island mode depending on the functionality of the MG. Energy Management System (EMS) is the decision making centre of the MG. The data from the devices is received by the EMS and after processing, the commands are sent to the controllable components. Management of voltage, active and reactive power, neutral current, unit commitment and economic dispatch are of the tasks of EMS. In this PhD thesis, an optimal EMS for MGs and MMGs is developed. The main objective of this project by developing the EMS is to optimize the energy flow in the MGs and MMGs to obtain peak load shaving in a cost beneficial system. In order to achieve an efficient EMS, communication system, forecasting system, scheduling system, and optimization system are modelled and developed. Different types of EMS operation, centralized, decentralized and distributed, are investigated in this work to achieve the best combination for MMG EMS operation. The communication system is mainly utilizing Modbus TCP/IP protocol for data transmission at local level and Internet of Things (IoT) protocols (MQTT) for the global communication level. A communication operation algorithm is proposed to manage the MMG EMS under different communication operation modes and communication failure conditions. Furthermore, a monitoring system is developed to collect the data from different devices in the MG. The data is processed in the MG EMS and the commands are sent to components through the communication infrastructure. The link between MGs and MMGs is through the proposed two-level communication system, where the expansion of MGs to a MMG is investigated. In the MMG, MGs are functioning as a unit while having different priorities and operating under different policies. Each MG has its own MG EMS and the EMSs transfer information through the communication system between each other in either centralized, decentralized, distributed, or no communication modes under the MMG EMS. The forecasting system is required in the EMS to predict the future MG characteristics such as power generation and consumption. The forecasted data is the input to the optimization and scheduling system of EMS. Employing the forecasting system in the EMS would increase the accuracy of the optimization and scheduling systems. In this thesis, the timeseries-based forecasting algorithms are employed to predict next day’s active power using the load data, generation data, weather data and temperature data as the inputs. The heart of EMS is the scheduling and optimization system. The purpose of the scheduling system is to define the amount and the time of energy flow in the MG for different generation sources and consumption loads. Furthermore, scheduling system is responsible for peak load shaving and valley filling. On the other hand, the optimization system has the task of minimizing the operation costs of the MGs. The role of market in the scheduling and optimization is important. Time of Use (ToU) tariff is the pricing system, which determines the peak and off peak hours for energy usage pricing. In order to apply the optimization system, a model of the system, an objective function and systems constraints are defined, where aging of battery energy storage system (BESS), operational cost of components and MG cost benefits are considered. To operate the EMS scheduling and optimization system, IBM CPLEX Optimization Studio solver conducts the optimization while for the scheduling system, objective function and constraints are defined in MATLAB. In this thesis, a rule-based, MILP and MIQP optimization system for commercial MGs including electric vehicles (EVs) are proposed to investigate performance of MG EMS for different case studies. In this thesis, the literature for different scheduling and forecasting systems is investigated and different optimization algorithms are analysed. The communication protocols utilized in this research are described and compared to other protocols in the literature. In different chapters of this thesis, the modelling of MGs and MMG EMS, different modules of EMS, forecasting, optimization, scheduling and communication systems are described and analysed. A novel communication system for MMG EMS operation is proposed for commercial buildings. The performance of MG EMS and MMG EMS is examined for power and neutral current sharing, operation cost optimization, and demand peak shaving applications and results are compared to investigate the performance of proposed algorithms.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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An increased penetration of renewable energy into the electric power grid is desirable from an environmental standpoint as well as an economical one. However, renewable sources such as wind and solar energy are often variable and intermittent, and additionally, are non-dispatchable. Also, the locations with the highest amount of available wind or solar may be located in areas that are far from areas with high levels of demand, and these areas may be under the control of separate, individual entities. In this dissertation, a method that coordinates these areas, accounts for the variability and intermittency, reduces the impact of renewable energy forecast errors, and increases the overall social benefit in the system is developed. The approach for the purpose of integrating intermittent energy sources into the electric power grid is considered from both the planning and operations stages. In the planning stage, two-stage stochastic optimization is employed to find the optimal size and location for a storage device in a transmission system with the goal of reducing generation costs, increasing the penetration of wind energy, alleviating line congestions, and decreasing the impact of errors in wind forecasts. The size of this problem grows dramatically with respect to the number of variables and constraints considered. Thus, a scenario reduction approach is developed which makes this stochastic problem computationally feasible. This scenario reduction technique is derived from observations about the relationship between the variance of locational marginal prices corresponding to the power balance equations and the optimal storage size. Additionally, a probabilistic, or chance, constrained model predictive control (MPC) problem is formulated to take into account wind forecast errors in the optimal storage sizing problem. A probability distribution of wind forecast errors is formed and incorporated into the original storage sizing problem. An analytical form of this constraint is derived to directly solve the optimization problem without having to use Monte-Carlo simulations or other techniques that sample the probability distribution of forecast errors. In the operations stage, a MPC AC Optimal Power Flow problem is decomposed with respect to physical control areas. Each area performs an independent optimization and variable values on the border buses between areas are exchanged at each Newton-Raphson iteration. Two modifications to the Approximate Newton Directions (AND) method are presented and used to solve the distributed MPC optimization problem, both with the intention of improving the original AND method by improving upon the convergence rate. Methods are developed to account for numerical difficulties encountered by these formula- tions, specifically with regards to Jacobian singularities introduced due to the intertemporal constraints. Simulation results show convergence of the decomposed optimization problem to the centralized result, demonstrating the benefits of coordinating control areas in the IEEE 57- bus test system. The benefit of energy storage in MPC formulations is also demonstrated in the simulations, reducing the impact of the fluctuations in the power supply introduced by intermittent sources by coordinating resources across control areas. An overall reduction of generation costs and increase in renewable penetration in the system is observed, with promising results to effectively and efficiently integrate renewable resources into the electric power grid on a large scale.

Can rural renewable energy projects simultaneously meet the multiple goals of sustainable development, climate change mitigation and climate change adaptation? If so, under what conditions? Rural communities throughout Latin America have increasingly suffered the impacts of climate change and few policies exist to help them adapt to these impacts. The basic infrastructure and services that they frequently lack can be provided by low carbon technologies, potentially funded by international carbon finance flows that could enable the Millennium Development Goals of economic growth and poverty alleviation to be met while minimizing carbon emissions. This research will focus on this interrelationship among development, climate change mitigation and climate change adaptation policies and practices using political ecology to analyse community renewable energy projects in rural Central America. I assess fifteen community-owned renewable energy projects in Guatemala and Nicaragua to analyse whether current renewable energy projects are achieving these goals in an integrated way. The projects were established primarily as development, emissions reductions, climate change adaptation and disaster relief. The projects are evaluated on economic, development and climate change indicators that include sustainable development, poverty alleviation, emissions reductions, and climate vulnerability. I examine how the type of common property governance, local historical and environmental background and project implementation process influence the project success in meeting multiple objectives of climate adaptation, mitigation and development. Research methods include participatory poverty assessment techniques, semi-structured interviews, stakeholder analysis, and a combination of rapid and participatory methods. The analysis of sustainable development and vulnerability used the Sustainable Livelihoods Approach methodologies and emissions reductions were calculated using standard carbon reduction methodologies. The results show that, under certain conditions, renewable energy projects can simultaneously meet these three objectives, and thus that responses to climate change can be integrated with poverty alleviation and sustainable development. Small scale hydroelectric and solar systems can reduce emissions, enable adaptation and help local livelihoods although there are numerous problems that limit the success of projects including poor design, inequitable distribution of benefits, and poorly designed governance and maintenance structures.