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A smart adaptive load for power-frequency support applicationsCarmona Sanchez, Jesus January 2016 (has links)
At present, one of the main issues in electric power networks is the reduction in conventional generation and its replacement by low inertia renewable energy generation. The balance between generation and demand has a direct impact on the system frequency and system inertia limits the frequency rate of change until compensation action can be undertaken. Traditionally generation managed frequency. In future, loads may be required to do more than just be able to be switched off during severe under frequency events. This thesis focuses on the development and practical implementation of the control structure of a smart adaptive load for network power-frequency support applications. The control structure developed makes use of advanced demand side management of fan loads (powered by AC drives) used in heating, ventilation, and air conditioning systems; where a change in power at rated load has little effect on their speed due to the cubic relationship between speed and power. The AC drive implemented in this thesis is based on an induction motor and a two level voltage source converter. To achieve the smart adaptive load functionality, first a power-frequency multi-slope droop control structure (feedforward control) is developed; relating the frequency limits imposed by the network supplier and the fan power-speed profile (Chapter 2, Fig 2.19). Secondly, this control structure is combined with the control developed, in Chapter 3, for the AC drive powering the fan load. The full development of the control structure of the AC drive, its tuning process and its practical implementation is given; an equation is developed to find suitable tuning parameters for the speed control of the nonlinear load (fan load), i.e. Eq. (3.59).The analysis and simulation results provided in Chapter 4 conclude that a fast control of the active power drawn by the AC drive is possible by controlling the electromagnetic torque (hence current) of the induction motor without disturbing the fan load overly. To achieve this, changes between closed loop speed control and open loop torque control (power control) are performed when needed. Two main issues were addressed before the hardware implementation of the smart adaptive load: the estimation of the network frequency under distorted voltage conditions, and the recovery period of the network frequency. In this thesis two slew rate limiters were implemented to deal with such situations. Other possible solutions are also outlined. Finally, experimental results in Chapter 5 support results given in Chapter 4. A full power-frequency response is achieved by the smart adaptive load within 3s.
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Online prediction of the post-disturbance frequency behaviour of a power systemWall, Peter Richard January 2013 (has links)
The radical changes that are currently occurring in the nature of power systems means that in the future it may no longer be possible to guarantee security of supply using offline security assessment and planning. The increased uncertainty, particularly the reduction and variation in system inertia that will be faced in the future must be overcome through the use of adaptive online solutions for ensuring system security. The introduction of synchronised measurement technology means that the wide area real time measurements that are necessary to implement these online actions are now available.The objective of the research presented in this thesis was to create methods for predicting the post-disturbance frequency behaviour of a power system with the intent of contributing to the development of real time adaptive corrective control for future power systems. Such a prediction method would generate an online prediction based on wide area measurements of frequency and active power that are recorded within the period of approximately one second after a disturbance to the active power balance of the system. Predictions would allow frequency control to respond more quickly and efficiently as it would no longer be necessary to wait for the system frequency behaviour to violate pre-determined thresholds.The research presented in this thesis includes the creation of an online method for the simultaneous detection of the time at which a disturbance occurred in a power system, or area of a power system, and the estimation of the inertia of that system, or area. An existing prediction method based on approximate models has been redesigned to eliminate its dependence on offline information. Furthermore, the thesis presents the novel application of pattern classification theory to frequency prediction and a five class example of pattern classification is implemented.
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Smart Microgrid Energy Management Using a Wireless Sensor NetworkDarden, Kelvin S 12 1900 (has links)
Modern power generation aims to utilize renewable energy sources such as solar power and wind to supply customers with power. This approach avoids exhaustion of fossil fuels as well as provides clean energy. Microgrids have become popular over the years, as they contain multiple renewable power sources and battery storage systems to supply power to the entities within the network. These microgrids can share power with the main grid or operate islanded from the grid. During an islanded scenario, self-sustainability is crucial to ensure balance between supply and demand within the microgrid. This can be accomplished by a smart microgrid that can monitor system conditions and respond to power imbalance by shedding loads based on priority. Such a method ensures security of the most important loads in the system and manages energy by automatically disconnecting lower priority loads until system conditions have improved. This thesis introduces a prioritized load shedding algorithm for the microgrid at the University of North Texas Discovery Park and highlight how such an energy management algorithm can add reliability to an islanded microgrid.
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Tekniskt potentiell efterfrågeflexibilitet hos industriella elkonsumenter : En fallstudie av SSAB:s produktionsanläggning i Borlänge / Demand Response Potential for Industrial Energy ConsumersBengtson, Måns January 2022 (has links)
The power grid faces major and escalating challenges in maintaining the power balance whilst society transitions towards increased sustainability. One promising solution to this challenge is found in the concept of demand response, where consumers adapt their energy demand due to some incentive in order to help balance the power grid. This study analyses the technical potential for industrial energy consumers to provide demand response by combining theory on demand response with theory on operations management and puts this to the test through a case study of a Swedish industrial sheet metal plant. In the study relevant factors such as energy and productivity parameters as well as planning and business models are shown to restrict the demand response potential. Different kinds of load shape objectives are analyzed, where peak clipping is shown to be simple but costly whilst load shifting is shown to be more complex but with the potential of offering demand response without affecting the overall productivity of the plant. These results help expand the picture of industrial consumer demand reponse from a static value depending on the economical incentive into a more complex concept that requires further research and optimization.
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The Development of a DC Micro-grid model with Maximum Power Point Tracking for Waste Heat Recovery SystemsElrakaybi, Ahmed 06 1900 (has links)
Research in sustainable energy sources has become the interest of many studies due to the increasing energy demand and the amount of wasted energy released from existing methods, along with their effect on climate change and environment sustainability. Thermo-Electric Generators (TEGs) are a potential solution that is being studied and implemented as they can convert low grade thermal energy to useful electrical energy at various operating conditions.
The integration of a TEG within a heat exchanger (TEG/HX) system connected to an electrical DC micro-grid, using a Maximum Power Point Tracking (MPPT) system is the focus of this study. Using a numerical TEG/HX model from a previous study and a developed DC micro-grid model the interaction between the thermal and electrical aspects were investigated with the focus on the electrical performance of the system.
The main concern of this study is to investigate the effect of the sub components of the DC micro-grid on the overall available energy. An analytic model was developed to estimate the power loss in the electrical circuit of the micro-grid, the model utilizes the equations for switching and conduction losses which have been used by several studies. Other variables such as the battery characteristics and electrical load profiles were also investigated by simulating several case studies including changing operating conditions.
This study shows the effect of a TEG configuration on the power loss in an electrical system using power loss curves in comparison with the Open Circuit Voltage (OCV) of such configuration. It also covers important modes of operation for the battery, loads and MPPT for a stable and reliable operation of an isolated DC micro-grid system were TEGs are the only source of power.
The result of the study presented is a system design that is able to maximize the electrical energy harvested from the TEGs to extend the operation of the dc-micro-grid first by applying a suitable TEG configuration and consequently a suitable electrical circuit. Secondly, by adapting to the changing operating conditions of the TEGs and the loads; and compensating for these changes using the battery storage system. / Thesis / Master of Applied Science (MASc)
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Power Systems Frequency Dynamic Monitoring System Design and ApplicationsZhong, Zhian 25 August 2005 (has links)
Recent large-scale blackouts revealed that power systems around the world are far from the stability and reliability requirement as they suppose to be. The post-event analysis clarifies that one major reason of the interconnection blackout is lack of wide area information. Frequency dynamics is one of the most important parameters of an electrical power system. In order to understand power system dynamics effectively, accurately measured wide-area frequency is needed. The idea of building an Internet based real-time GPS synchronized wide area Frequency Monitoring Network (FNET) was proposed to provide the imperative dynamic information for the large-scale power grids and the implementation of FNET has made the synchronized observations of the entire US power network possible for the first time. The FNET system consists of Frequency Disturbance Recorders (FDR), which work as the sensor devices to measure the real-time frequency at 110V single-phase power outlets, and an Information Management System (IMS) to work as a central server to process the frequency data. The device comparison between FDR and commercial PMU (Phasor Measurement Unit) demonstrate the advantage of FNET. The web visualization tools make the frequency data available for the authorized users to browse through Internet.
The research work addresses some preliminary observations and analyses with the field-measured frequency information from FNET. The original algorithms based on the frequency response characteristic are designed to process event detection, localization and unbalanced power estimation during frequency disturbances. The analysis of historical cases illustrate that these algorithms can be employed in real-time level to provide early alarm of abnormal frequency change to the system operator. The further application is to develop an adaptive under frequency load shedding scheme with the processed information feed in to prevent further frequency decline in power systems after disturbances causing dangerous imbalance between the load and generation. / Ph. D.
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Um novo esquema para rejeição de cargas baseado em um sistema multiagentes / A new scheme for load shedding based on a multiagent systemSantos, Athila Quaresma 13 July 2016 (has links)
Esquemas de Rejeição de Cargas (RC) por subfrequência, utilizados para manter a frequência de operação de um Sistema Elétrico de Potência (SEP) próxima ao seu valor nominal, precisam ser criteriosamente projetados a fim de diminuir os riscos de colapso generalizado do sistema. Entretanto, pelos métodos convencionais, a quantidade de carga a ser rejeitada não leva em consideração a dinamicidade intrínseca do sistema, sendo baseada em conjecturas estáticas sobre porções do SEP. Como resultado, a redução da carga geralmente não é eficiente, gerando rejeição insuficiente ou excessiva. Neste cenário, este trabalho propõe um novo esquema para o controle da frequência em comparação aos processos de RC usualmente empregados. Com o propósito de superar as limitações e melhorar as principais funções desses processos é proposto um Sistema Multi Agentes (SMA) centralizado que irá coordenar as diversas etapas de monitoramento, processamento e tomada de decisão nos barramentos disponíveis para corte em situações de subfrequência. Busca-se dessa forma, desconectar o menor montante de cargas do sistema, por um curto espaço de tempo e com menor perturbação da frequência. Neste sentido, uma malha de controle fechada foi desenvolvida a partir da simulação de um sistema elétrico de potência completo via o Real Time Digital Simulator (RTDS). O SMA foi embarcado em um sistema integrado de hardware e software em tempo real para teste e validação da metodologia proposta. No contexto delineado, uma métrica de avaliação foi proposta para comparar o método proposto com outras duas filosofias convencionais de RC. Os resultados obtidos permitem evidenciar o bom desempenho do SMA frente às duas filosofias convencionais, principalmente no que se refere ao montante de carga a ser rejeitado, com boa aproximação do valor esperado. / Automatic Under Frequency Load Shedding (AUFLS) schemes, used to maintain the frequency of an electric power system close to the nominal value, need to be carefully designed in order to reduce the risk of a widespread system collapse. However, the conventional methods do not take into account the inherent dynamics of an electric system and they are based on static assumptions. As a result, the shedding is generally not efficient, causing insufficient or excessive load discontinuity. In this scenario, this work proposes a new scheme for controlling the frequency compared to the AUFLS processes usually employed. In order to overcome the limitations of the methods usually employed and to improve the main functions of the AUFLS schemes, this work proposes a centralized MultiAgent System (MAS) that will coordinate the various stages of the monitoring and decision making process. The MAS seeks to disconnect a minimum amount of loads, in a short period of time and with less disturbance of the system frequency. A Hardware in Loop (HIL) configuration was developed from the simulation of a full electric system using the Real Time Digital Simulator (RTDS). The MAS was embedded in a real time system, consisting of hardware and software to test and validate the proposed methodology. In addition, a scoring metric evaluation is defined in order to compare other two conventional AUFLS philosophies. The results show good performance of the proposed MAS. The shedding was carried out in a single step and the amount of load shed was very close to the expected value.
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Um novo esquema para rejeição de cargas baseado em um sistema multiagentes / A new scheme for load shedding based on a multiagent systemAthila Quaresma Santos 13 July 2016 (has links)
Esquemas de Rejeição de Cargas (RC) por subfrequência, utilizados para manter a frequência de operação de um Sistema Elétrico de Potência (SEP) próxima ao seu valor nominal, precisam ser criteriosamente projetados a fim de diminuir os riscos de colapso generalizado do sistema. Entretanto, pelos métodos convencionais, a quantidade de carga a ser rejeitada não leva em consideração a dinamicidade intrínseca do sistema, sendo baseada em conjecturas estáticas sobre porções do SEP. Como resultado, a redução da carga geralmente não é eficiente, gerando rejeição insuficiente ou excessiva. Neste cenário, este trabalho propõe um novo esquema para o controle da frequência em comparação aos processos de RC usualmente empregados. Com o propósito de superar as limitações e melhorar as principais funções desses processos é proposto um Sistema Multi Agentes (SMA) centralizado que irá coordenar as diversas etapas de monitoramento, processamento e tomada de decisão nos barramentos disponíveis para corte em situações de subfrequência. Busca-se dessa forma, desconectar o menor montante de cargas do sistema, por um curto espaço de tempo e com menor perturbação da frequência. Neste sentido, uma malha de controle fechada foi desenvolvida a partir da simulação de um sistema elétrico de potência completo via o Real Time Digital Simulator (RTDS). O SMA foi embarcado em um sistema integrado de hardware e software em tempo real para teste e validação da metodologia proposta. No contexto delineado, uma métrica de avaliação foi proposta para comparar o método proposto com outras duas filosofias convencionais de RC. Os resultados obtidos permitem evidenciar o bom desempenho do SMA frente às duas filosofias convencionais, principalmente no que se refere ao montante de carga a ser rejeitado, com boa aproximação do valor esperado. / Automatic Under Frequency Load Shedding (AUFLS) schemes, used to maintain the frequency of an electric power system close to the nominal value, need to be carefully designed in order to reduce the risk of a widespread system collapse. However, the conventional methods do not take into account the inherent dynamics of an electric system and they are based on static assumptions. As a result, the shedding is generally not efficient, causing insufficient or excessive load discontinuity. In this scenario, this work proposes a new scheme for controlling the frequency compared to the AUFLS processes usually employed. In order to overcome the limitations of the methods usually employed and to improve the main functions of the AUFLS schemes, this work proposes a centralized MultiAgent System (MAS) that will coordinate the various stages of the monitoring and decision making process. The MAS seeks to disconnect a minimum amount of loads, in a short period of time and with less disturbance of the system frequency. A Hardware in Loop (HIL) configuration was developed from the simulation of a full electric system using the Real Time Digital Simulator (RTDS). The MAS was embedded in a real time system, consisting of hardware and software to test and validate the proposed methodology. In addition, a scoring metric evaluation is defined in order to compare other two conventional AUFLS philosophies. The results show good performance of the proposed MAS. The shedding was carried out in a single step and the amount of load shed was very close to the expected value.
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Coordination de GEDs pour la fourniture de services systèmes temps réel / Distributed Energy Resources coordination toward the supply of ancillary services in real-timeLebel, Gaspard 26 April 2016 (has links)
Les politiques entreprises dans le domaine de la production d’électricité pour lutter contre le changement climatique reposent communément sur le remplacement des moyens de production fossiles et centralisés par de nouveaux moyens de type renouvelables. Ces énergies renouvelables sont en grande partie distribuées dans les réseaux moyenne et basse tension et sont le plus souvent intermittentes (énergies éolienne et photovoltaïque principalement). Les gestionnaires de réseaux s’attentent à ce que ce changement de paradigme induise des difficultés conséquences dans leurs opérations. Les mondes de la recherche et de l’industrie se sont ainsi structurés depuis le milieu des années 2000 afin d’apporter une réponse aux problèmes anticipés. Cette réponse passe notamment par le déploiement de technologies de l’information et de la communication (TIC) dans les réseaux électriques, des centres de contrôle jusqu’au sein même des moyens de production distribués. C’est ce que l’on appelle le Smart Grid. Parmi le champ des possibles du Smart Grid, ces travaux de thèses se sont en particulier attachés à apporter une réponse aux enjeux de stabilité en fréquence du système électrique, mise en danger par la réduction anticipée de l’inertie des systèmes électriques et la raréfaction des moyens de fourniture de réserve primaire (FCR), auxquels incombent le maintien de la fréquence en temps réel. En vue de suppléer les moyens de fourniture de réserve conventionnels et centralisés, il a ainsi été élaboré un concept de coordination de charges électriques délestables distribuées, qui se déconnectent et se reconnectent de manière autonome sur le réseau au gré des variations de fréquence mesurées sur site. Ces modulations de puissance répondent à un schéma préétabli qui dépend de la consommation électrique effective de chacune des charges. Ces travaux ont été complétés d’une étude technico-économique visant à réutiliser cette infrastructure de coordination de charges délestables pour la fourniture de services systèmes ou de produits de gros complémentaires. Ce travail de thèse réalisée au sein des équipes innovation de Schneider Electric et du laboratoire de Génie Electrique de Grenoble (G2Elab), est en lien avec les projets Européens EvolvDSO et Dream, financés dans le cadre du programme FP7 de la Commission Européenne. / Climate change mitigation policies in the power generation industry lead commonly on the replacement of bulk generation assets by Renewable Energy Resources (RES-E). Such RES-E are largely distributed among the medium and low voltage grids and most of them are intermittent like photovoltaic and wind power. System Operators expect that such new power system paradigm induces significant complications in their operations. The communities of research and industry started thus to structure themselves in the mid-2000s in order to respond to these coming issues, notably through the deployment of Information and Communication Technology (ICT) in power systems assets, from the Network Operations Centers (NOCs) down to Distributed Energy Resources (DERs) units. This is the Smart Grid. Among the range of possibilities of the Smart Grid, this Ph.D work aims in priority to provide a solution to handle the issue of frequency stability of the power system that are endangered by the combined loss of inertia of the power system and the phasing-out of conventional assets which used to be in charge of the maintain of the frequency in real time through the supply of Frequency Containment Reserve (FCR). The concept developed lead on a process of coordinated modulation of the level of loads of DERs, whose evolve depending on the system frequency measured in real time on-site. The strategy of modulation of each DER follows a pattern which is determined at the scale of the portfolio of aggregation of the DER, depending on the effective level of load of the DER at normal frequency (i.e. 50Hz in Europe). This work is completed by a cost benefit analysis that assesses the opportunity of sharing of the previous infrastructure of coordinated modulation of DERs for the supply of ancillary services and wholesale products. This thesis conducted within Schneider Electric’s Innovation teams and Grenoble Electrical Engineering Laboratory (G2Elab) is linked with the European projects Dream and EvolvDSO, and funded under European Commission’s FP7 program.
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Community Microgrids for Decentralized Energy Demand-Supply Matching : An Inregrated Decision FrameworkRavindra, Kumudhini January 2011 (has links) (PDF)
Energy forms a vital input and critical infrastructure for the economic development of countries and for improving the quality of life of people. Energy is utilized in society through the operation of large socio-technical systems called energy systems. In a growing world, as the focus shifts to better access and use of modern energy sources, there is a rising demand for energy. However, certain externalities result in this demand not being met adequately, especially in developing countries. This constitutes the energy demand – supply matching problem.
Load shedding is a response used by distribution utilities in developing countries, to deal with the energy demand – supply problem in the short term and to secure the grid. This response impacts the activities of consumers and entails economic losses. Given this scenario, demand – supply matching becomes a crucial decision making activity. Traditionally demand – supply matching has been carried out by increasing supply centrally in the long term or reducing demand centrally in the short term. Literature shows that these options have not been very effective in solving the demand-supply problem. Gaps in literature also show that the need of the hour is the design of alternate solutions which are tailored to a nation's specific energy service needs in a sustainable way. Microgrids using renewable and clean energy resources and demand side management can be suitable decentralized alternatives to augment the centralized grid based systems and enable demand – supply matching at a local community level.
The central research question posed by this thesis is:
“How can we reduce the demand – supply gap existing in a community, due to grid insufficiency, using locally available resources and the grid in an optimal way; and thereby facilitate microgrid implementation?”
The overall aim of this dissertation is to solve the energy demand – supply matching problem at the community level. It is known that decisions for the creation of energy systems are influenced by several factors. This study focuses on those factors which policy-makers and stakeholders can influence. It proposes an integrated decision framework for the creation of community microgrids. The study looks at several different dimensions of the existing demand – supply problem in a holistic way. The research objectives of this study are:
1. To develop an integrated decision framework that solves the demand – supply matching problem at a community level.
2. To decompose the consumption patterns of the community into end-uses.
solar thermal, solar lighting and solar pumps and a combination of these at different capacities. The options feasible for medium income consumers are solar thermal, solar pumps, municipal waste based systems and a combination of these. The options for high income consumers are municipal waste based CHP systems, solar thermal and solar pumps. Residential consumers living in multi-storied buildings also have the options of CHP, micro wind and solar. For cooking, LPG is the single most effective alternative.
3. To identify the ‗best fitting‘ distributed energy system (microgrid), based on the end-use consumption patterns of the community and locally available clean and renewable energy resources, for matching demand – supply at the community level.
4. To facilitate the implementation of microgrids by
* Contextualizing the demand – supply matching problem to consider the local social and political environment or landscape,
* Studying the economic impact of load shedding and incorporating it into the demand-supply matching problem, and
* Presenting multiple decision scenarios, addressing the needs of different stakeholders, to enable dialogue and participative decision making.
A multi-stage Integrated Decision Framework (IDF) is developed to solve the demand - supply matching problem in a sequential manner. The first stage in the IDF towards solving the problem is the identification and estimation of the energy needs / end-uses of consumers in a community. This process is called End-use Demand Decomposition (EUDD) and is accomplished by an empirical estimation of consumer electricity demand based on structural and socio-economic factors. An algorithm/ heuristic is also presented to decompose this demand into its constituent end-uses at the community level for the purpose of identifying suitable and optimal alternatives/ augments to grid based electricity.
The second stage in the framework is Best Fit DES. This stage involves identifying the “best-fit‘ distributed energy system (microgrid) for the community that optimally matches the energy demand with available forms of supply and provides a schedule for the operation of these various supply options to maximize stakeholder utility. It provides the decision makers with a methodology for identifying the optimal distributed energy resource (DER) mix, capacity and annual operational schedule that “best fits” the given end-use demand profile of consumers in a community and under the constraints of that community such that it meets the needs of the stakeholders. The optimization technique developed is a Mixed Integer Linear Program and is a modification of the DER-CAM™ (Distributed Energy Resources Customer Adoption Model), which is developed by the Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory using the GAMS platform.
The third stage is the Community Microgrid Implementation (CMI) stage. The CMI stage of IDF includes three steps. The first one is to contextualize the energy demand and supply for a specific region and the communities within it. This is done by the Energy Landscape Analysis (ELA). The energy landscape analysis attempts to understand the current scenario and develop a baseline for the study. It identifies the potential solutions for the demand - supply problem from a stakeholder perspective. The next step provides a rationale for the creation of community level decentralized energy systems and microgrids from a sustainability perspective. This is done by presenting a theoretical model for outage costs (or load shedding), empirically substantiating it and providing a simulation model to demonstrate the viability for distributed energy systems. Outage cost or the cost of non supply is a variable that can be used to determine the need for alternate systems in the absence/ unavailability of the grid. The final step in the CMI stage is to provide a scenario analysis for the implementation of community microgrids. The scenario analysis step in the framework enlightens decision makers about the baselines and thresholds for the solutions obtained in the “best fit‘ analysis.
The first two stages of IDF, EUDD and Best Fit DES, address the problem from a bottom-up perspective. The solution obtained from these stages constitutes the optimal solution from a technical perspective. The third stage CMI is a top-down approach to the problem, which assesses the social and policy parameters. This stage provides a set of satisficing solutions/ scenarios to enable a dialogue between stakeholders to facilitate implementation of microgrids. Thus, IDF follows a hybrid approach to problem solving.
The proposed IDF is then used to demonstrate the choice of microgrids for residential communities. In particular, the framework is demonstrated for a typical residential community, Vijayanagar, situated in Bangalore and the findings presented.
The End-use Demand Decomposition (EUDD) stage provides the decision makers with a methodology for estimating consumer demand given their socio-economic status, fuel choice and appliance profiles. This is done by the means of a statistical analysis. For this a primary survey of 375 residential households belonging to the LT2a category of BESCOM (Bangalore Electricity Supply Company) was conducted in the Bangalore metropolitan area. The results of the current study show that consumer demand is a function of the variables family income, refrigeration, entertainment, water heating, family size, space cooling, gas use, wood use, kerosene use and space heating. The final regression model (with these variables) can effectively predict up to 60% of the variation in the electricity consumption of a household
ln(ElecConsumption) = 0.2880.396*ln(Income)+0.2 66*Refri geration+
0.708*Entertainment+0.334*WaterHeating+0.047*FamSize+
0243*SpaceCooling.+580*GasUse+0.421*WoodUse–0.159*KeroseneUse+
0.568*SpaceHeating
ln(ElecConsumption) = 0.406*ln(Income)0.168*Ref rigeration+0.139*Entertainment+
0.213*WaterHeating+0.114*FamSize+0.121*SpacCooling+0.171*GasUse+
0.115*WoodUse–0.094*KeroseneUse+0.075*SpaceHeating
The next step of EUDD is to break up the demand into its constituent end-uses. The third step involves aggregating the end-uses at the community level. These two steps are to be performed using a heuristic.
The Best Fit DES stage of IDF is demonstrated with data from an urban community in Bangalore. This community is located in an area called Vijayanagar in Bangalore city. Vijayanagar is a mainly a residential area with some pockets of mixed use. Since grid availability is the constraining parameter that yields varying energy availability, this constraint is taken as the criteria for evaluation of the model. The Best Fit DES model is run for different values of the grid availability parameter to study the changes in outputs obtained in DER mix, schedules and overall cost of the system and the results are tabulated. Sensitivity analysis is also performed to study the effect of changing load, price options, fuel costs and technology parameters.
The results obtained from the BEST Fit DES model for Vijayanagar illustrate that microgrids and DERs can be a suitable alternative for meeting the demand – supply gap locally. The cost of implementing DERs is the optimal solution. The savings obtained from this option however is less than 1% than the base case due to the subsidized price of grid based electricity. The corresponding costs for different hours of grid availability are higher than the base case, but this is offset by the increased efficiency of the overall system and improved reliability that is obtained in the community due to availability of power 24/7 regardless of the availability of grid based power. If the price of grid power is changed to reflect the true price of electricity, it is shown that DERs continue to be the optimal solution. Also the combination of DERs chosen change with the different levels of non-supply from the grid. For the study community, Vijayanagar, Bangalore, the DERs chosen on the basis of resource availability are mainly discrete DERs. The DERs chosen are the LPG based CHP systems which run as base and intermediate generating systems. The capacity of the discrete DERs selected, depend on the end-use load of the community. Biomass based CHP systems are not chosen by the model as this technology has not reached maturity in an urban setup. Wind and hydro based systems are not selected as these resources are not available in Vijayanagar.
The CMI stage of IDF demonstrates the top-down approach to the demand-supply matching problem. For the Energy Landscape Analysis (ELA), Bangalore metropolis was chosen in the study for the purpose of demonstration of the IDF framework. Bangalore consumes 25% of the state electricity supply and its per capita consumption at 1560kWh is higher than the state average of 1230kWh and is 250% more than the Indian average of 612kWh. A stakeholder workshop was conducted to ascertain the business value for clean and renewable energy technologies. From the workshop it was established that significant peak power savings could be obtained with even low penetrations of distributed energy technologies in Bangalore. The feasible options chosen by stakeholders for low income consumers are The second step of CMI is finding an economic rationale for the implementation of community microgrids. It is hypothesized that the ‘The cost of non-supply follows an s-shaped curve similar to a growth curve.’ It is moderated by the consumer income, consumer utility, and time duration of the load shedding. A pre and post event primary survey was conducted to analyze the difference in the pattern of consumer behaviour before and after the implementation of a severe load shedding program by BESCOM during 2009-10. Data was collected from 113 households during February 2009 and July 2010. The analysis proves that there is indeed a significant difference in the number of uninterrupted power systems (inverters) possessed by households. This could be attributed mainly to the power situation in Karnataka during the same period. The data also confirms the nature of the cost of non-supply curve.
The third step in CMI is scenario analysis. Four categories of scenarios are developed based on potential interventions. These are business-as-usual, demand side, supply side and demand-supply side. About 21 scenarios are identified and their results compared. Comparing the four categories of scenarios, it is shown that business-as-usual scenarios may result in exacerbation of the demand-supply gap. Demand side interventions result in savings in the total costs for the community, but cannot aid communities with load shedding. Supply side interventions increase the reliability of the energy system for a small additional cost and communities have the opportunity to even meet their energy needs independent of the grid. The combination of both demand and supply side interventions are the best solution alternative for communities, as they enable communities to meet their energy needs 24/7 in a reliable manner and also do it at a lower cost. With an interactive microgrid implementation, communities have the added opportunity to sell back power to the grid for a profit.
The thesis concludes with a discussion of the potential use of IDF in policy making, the potential barriers to implementation and minimization strategies. It presents policy recommendations based on the framework developed and the results obtained.
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