Incorporating voltage security into the planning, operation and monitoring of restructured electric energy markets

As open access market principles are applied to power systems, significant changes are happening in their planning, operation and control. In the emerging marketplace, systems are operating under higher loading conditions as markets focus greater attention to operating costs than stability and security margins. Since operating stability is a basic requirement for any power system, there is need for newer tools to ensure stability and security margins being strictly enforced in the competitive marketplace. This dissertation investigates issues associated with incorporating voltage security into the unbundled operating environment of electricity markets. It includes addressing voltage security in the monitoring, operational and planning horizons of restructured power system. This dissertation presents a new decomposition procedure to estimate voltage security usage by transactions. The procedure follows physical law and uses an index that can be monitored knowing the state of the system. The expression derived is based on composite market coordination models that have both PoolCo and OpCo transactions, in a shared stressed transmission grid. Our procedure is able to equitably distinguish the impacts of individual transactions on voltage stability, at load buses, in a simple and fast manner. This dissertation formulates a new voltage stability constrained optimal power flow (VSCOPF) using a simple voltage security index. In modern planning, composite power system reliability analysis that encompasses both adequacy and security issues is being developed. We have illustrated the applicability of our VSCOPF into composite reliability analysis. This dissertation also delves into the various applications of voltage security index. Increasingly, FACT devices are being used in restructured markets to mitigate a variety of operational problems. Their control effects on voltage security would be demonstrated using our VSCOPF procedure. Further, this dissertation investigates the application of steady state voltage stability index to detect potential dynamic voltage collapse. Finally, this dissertation examines developments in representation, standardization, communication and exchange of power system data. Power system data is the key input to all analytical engines for system operation, monitoring and control. Data exchange and dissemination could impact voltage security evaluation and therefore needs to be critically examined

Cross-border congestion management in the electricity market

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Service identification and allocation in market-based power system operation

In the market-based power system operation environment, ancillary services and other interconnected services are necessary to to maintain the secure and reliable operation of the transmission system. Service identification and allocation, together with congestion management, become important functions in the day- ahead scheduling of the independent system operator (ISO);In this dissertation, a general framework for service identification and congestion management was proposed. Based on a set of market model assumptions and the anticipated behaviors of the market participants, the individual profits of the market participants were analyzed. An overall profit maximization was proposed as the desired objective function. Because of limited information available to the ISO, an upper bound cost minimization, which minimizes the upper bound cost of congestion and services, was applied to identify the necessary reactive support and real power loss services,;As a part of the work, a framework for the economic cost analysis of the reactive support and real power loss services was developed in this research. Economic costs are composed of explicit costs and opportunity costs. According to the difference sources of the two services, the explicit and opportunity costs from generation and transmission sources were discussed separately;Since there are costs associated with each service, an average sensitivity allocation method was proposed in this research to allocate the amount and cost of services to various transmission users. It provides accurate allocation results when the services are second-order functions of the transactions. For higher-order service functions, a piecewise average sensitivity method can reduce the mismatches significantly;Test results showed that the ideas and algorithms proposed in this dissertation will not only be applicable to the deregulated power industry, but also to future researchers in this area

Market based intelligent charging system for electric vehicles

The existing electrical infrastructure is very unlikely to expand overnight. Therefore, a smart solution is certainly needed to integrate the additional load which electric vehicles (EV) bring to the network. The aim of the thesis is to study the electricity market, different intelligences related to electric vehicle charging and establish an algorithm that produces an optimized charging schedule for electric vehicles. The algorithm ensures a cost profit for user and takes part in demand response by shifting the timing of charging loads based on energy prices. The core intelligences integrated to the EV charging system in the thesis are cost optimization, peak shaving and load shifting. The algorithm follows the hourly unit cost related to the energy consumption and distribution fee in order to find the cheapest time slot for charging operation. It allocates as high charging power as possible to the cheapest time slots and then start selecting the expensive time slots until the battery is charged to desired state of charge. Along this process, the algorithm continuously calculates the maximum charging power available after other house-hold usage. The Elspot area price of Finland for 2018 added with 0.3 cents/kWh margin and 24% VAT are used as energy prices. Distribution unit prices include time-of-use pricing for day and nighttime energy use in addition to the fixed fuse-based fee. By following these unit prices, the algorithm shifts the load from high demand to low demand hours in order to minimize the total costs. The algorithm is implemented in MATLAB and tested through a case study on different type of Finnish detached houses. Detached houses with different load profile data are used as input for charging a 75 kWh EV with a 10 kW and 7.5 kW charger in different cases, where the other inputs remain same for all the test cases. The Elspot area price of Finland for 2018 added with 0.3 cents/kWh margin and 24% VAT are used as energy prices. Different day and night-time distribution prices are applied depending on the consumption. The simulation results are compared to regular EV charging, where the charging operation starts right after the EV is plugged in and finishes charging within shortest time. The results from the simulation are investigated from user’s and grid’s point of view. From user’s perspective, all the charging events with intelligent charging have costs savings over regular charging. The monetary profit is higher for higher charger rating (10 kW). In cases where the household usage is low, the proportional profit is high. From grid point of view, over 99% of the load gets shifted to night-time for 10 kW charger cases. For the 7.5kW charger, the amount of shifted load is over 97%, which is a little lower than 10 kW charger cases because of longer charging time. The findings of the case study validate the use of smart charging algorithm in order to ensure cost savings for the user

Contingency Management in Power Systems and Demand Response Market for Ancillary Services in Smart Grids with High Renewable Energy Penetration.

Ph.D. Thesis. University of Hawaiʻi at Mānoa 2017

A World-Class University-Industry Consortium for Wind Energy Research, Education, and Workforce Development: Final Technical Report

During the two-year project period, the consortium members have developed control algorithms for enhancing the reliability of wind turbine components. The consortium members have developed advanced operation and planning tools for accommodating the high penetration of variable wind energy. The consortium members have developed extensive education and research programs for educating the stakeholders on critical issues related to the wind energy research and development. In summary, The Consortium procured one utility-grade wind unit and two small wind units. Specifically, the Consortium procured a 1.5MW GE wind unit by working with the world leading wind energy developer, Invenergy, which is headquartered in Chicago, in September 2010. The Consortium also installed advanced instrumentation on the turbine and performed relevant turbine reliability studies. The site for the wind unit is InvenergyÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs Grand Ridge wind farmin Illinois. The Consortium, by working with Viryd Technologies, installed an 8kW Viryd wind unit (the Lab Unit) at an engineering lab at IIT in September 2010 and an 8kW Viryd wind unit (the Field Unit) at the Stuart Field on IITÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs main campus in July 2011, and performed relevant turbine reliability studies. The operation of the Field Unit is also monitored by the Phasor Measurement Unit (PMU) in the nearby Stuart Building. The Consortium commemorated the installations at the July 20, 2011 ribbon-cutting ceremony. The ConsortiumÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs researches on turbine reliability included (1) Predictive Analytics to Improve Wind Turbine Reliability; (2) Improve Wind Turbine Power Output and Reduce Dynamic Stress Loading Through Advanced Wind Sensing Technology; (3) Use High Magnetic Density Turbine Generator as Non-rare Earth Power Dense Alternative; (4) Survivable Operation of Three Phase AC Drives in Wind Generator Systems; (5) Localization of Wind Turbine Noise Sources Using a Compact Microphone Array; (6) Wind Turbine Acoustics - Numerical Studies; and (7) Performance of Wind Turbines in Rainy Conditions. The ConsortiumÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs researches on wind integration included (1) Analysis of 2030 Large-Scale Wind Energy Integration in the Eastern Interconnection; (2) Large-scale Analysis of 2018 Wind Energy Integration in the Eastern U.S. Interconnection; (3) Integration of Non-dispatchable Resources in Electricity Markets; (4) Integration of Wind Unit with Microgrid. The ConsortiumÃÂÃÂÃÂâÃÂÃÂÃÂÃÂÃÂÃÂÃÂÃÂs education and outreach activities on wind energy included (1) Wind Energy Training Facility Development; (2) Wind Energy Course Development; (3) Wind Energy Outreach

Benchmarking renewable energy sources carbon savings and economic effectiveness

Over the last decade, the levelised cost of energy (LCOE) of many renewable technologies has sharply declined. As a result, direct cost comparisons of LCOE figures have made renewables to be perceived as economically very competitive options to decarbonise energy systems when compared to other low-carbon technologies such as Nuclear and Carbon Capture and Storage. We identify several theoretical shortcomings in relation to using LCOE or similar life-cycle economic metrics to make inferences about the relative economic effectiveness of using renewable technologies to decarbonise energy systems. We outline several circumstances in which the sole reliance on these metrics can lead to suboptimal or misguided investment and policymaking decisions. The thesis proposes a new theoretical framework to measure and benchmark the cost- effectiveness of decarbonising electric systems using renewables. The new framework is generic, technology-neutral, and enables consolidation of the results of decarbonisation studies that consider various renewable technologies and low carbon technologies. It also enables measuring and tracking the cost-effectiveness of the renewable decarbonisation process at a country or a system level. As a result, it also allows the direct comparison of the economic implications of different decarbonisation scenarios and various policy proposals in a very intuitive graphical way. In addition, the thesis proposes a new, unit-free metric, tentatively called Carbon Economic Effectiveness Credit (CEEC), to benchmark the relative cost-effectiveness of using different renewable technologies to achieve long-term carbon emission savings. Theoretically, CEEC represents the elasticity of the system total cost with respect to the carbon reduction savings attributable to renewables. In contrast to stand-alone, life-cycle metrics such as the LCOE, the proposed metric considers the economic and technical parameters of the renewable technologies and characteristic of the system under study. It also allows expressing the cost- effectiveness of the renewable decarbonisation process as a function of the system-wide decarbonisation level. Using historical load profiles, high-resolution solar radiation data and long-term meteorological data for a relatively small Gulf country, we investigate the deep decarbonisation of the electric system through the large-scale deployment of different renewables technologies. In particular, we use two well-established optimisation methodologies that have been used extensively in the literature to study the decarbonisation of power systems, namely: the screening curve (SC) method and the unit commitment (UC) method. In analysing the results of the two methodologies, we find that the choice of the modelling methodology, in some cases, can greatly influence the perceived carbon cost- effectiveness of renewables and subsequently their carbon abatement cost estimates. In particular, our results suggest that under deep decarbonisation scenarios, the estimate of the long-term carbon savings of renewables is strongly influenced by (1) the choice of the modelling method and (2) the technical specifications of the simulation models. Our results suggest that under deep decarbonisation scenarios, using simpler optimisation models may change the perceived economic effectiveness of renewables to decarbonise some electric systems. More importantly, our research sheds light on potential shortcomings in the current modelling practices and help identify patterns of possible inaccuracies or biases in renewable decarbonisation results. Moreover, our research suggests that the variations in the technical characteristics of renewable technologies can have a large influence on the economics of the decarbonisation process. We show that not all renewable technology types can have a suppressing effect on the variable costs of the systems due to their “zero marginal costs.” In particular, we identify certain technologies and circumstances in which an increase in renewable penetration can significantly inflate the variable energy costs of the system. More specifically, we find that under deep decarbonisation scenarios, renewable technologies with a highly volatile production profiles can act as an amplifier for the variable cost of the systems through (1) reducing the effectiveness of thermal generation units due the increased start-up and shutting downing activities, and (2) increasing the energy output levels from more flexible and yet more expensive thermal technologies. In addition, we identify circumstances in which an increased renewable penetration can materially affect the capacity adequacy of electric systems, leading to an increase in capacity investment in thermal flexibility assets. Perhaps more importantly, we find that these additional flexibility assets will not be commercially viable on an energy-output basis. We believe that this might have specific implications for the energy-only markets. Finally, we discuss the policy implications of our findings and propose several important recommendations. Altogether, we hope that our work will advance the understanding of the economics of climate change and integrating renewables into energy systems.Open Acces

Current legal and institutional issues in the commercialization of phosphoric acid fuel cells

Legal and institutional factors affecting the development and commercial diffusion of phosphoric acid fuel cells are assessed. Issues for future research and action are suggested. Perceived barriers and potential opportunities for fuel cells in central and dispersed utility operations and on-site applications are reviewed, as well as the general concept of commercialization as applied to emerging energy technologies

Electricity power planning in Portugal: the role of wind energy

Tese de Doutoramento em Engenharia Económica - Engenharia Produção e SistemasEnergy decisions play a major role in the achievement of sustainable development and consequently on the economic, environmental and social welfare of future generations. Combining energy efficiency with renewable energy resources constitutes a key strategy for a sustainable future, emphasised in the European and Portuguese policy guidelines. The wind power sector stands out as a fundamental element for the achievement of the European renewable objectives. Currently, most of the energy planning models focus predominantly on the economic and environmental dimensions of the problem. Although recognised as important, the social aspects of energy decisions are not fully integrated into the available decision aids for planners. The main contribution of this thesis is to provide a new integrated tool for decision makers engaged in long term electricity planning. An Integrated Electricity Planning Model (IEPM) was developed accommodating environmental, economic and social issues. The proposed approach involves complex optimisation models for cost, and emissions objective functions based on the mathematical description of the electricity system. Linear and non-linear optimisation models were developed establishing the link between the cost of generation and CO2 emissions. In addition, a value judgment assessment of each of the possible generation technologies was obtained by a combination of Delphi and Analytic Hierarchy Process to develop Social Indices for the proposed technologies. From these models possible generation plans are developed for a 10 year planning period, and their financial, CO2 emissions and social impacts are assessed and fully integrated into the final optimising decision tool. For the implementation of the IEPM, details of the Portuguese electricity system were obtained from official sources and from experts’ collaboration. According to the official reports, the increasing demand for electricity in Portugal over the next ten years will be mainly supported by new investments in coal, natural gas, wind and hydro power technologies. The rising trend of the installed wind power is analysed resulting in new insights that demonstrate the need to address the impact that energy sources with variable output may have, not only on the short-term dispatching process, but especially on the medium to long range planning activities. The study of the Portuguese case concludes that while wind power influences significantly the power system operation and it is not free of negative social impacts, it has a fundamental role in future electricity plans, particularly in regard to meeting the renewable and Kyoto protocol commitments. Although it was applied to Portugal, the proposed methodology may be used in other regions or countries if adapted to the specific features of each individual energy system under analysis. On the whole, the proposed methodology gives the decision maker a better understanding of the system characteristics and of the full impact of possible decisions, and in doing so, makes a valuable contribution to the selection of long term sustainable energy plans.As decisões no sector energético têm um papel fundamental na consecução de um desenvolvimento sustentado, influenciando decisivamente o bem estar económico, ambiental e social das gerações futuras. A combinação da eficiência energética com fontes de energia renováveis representa uma estratégia chave para um futuro sustentado, enfatizada nas políticas orientadoras Europeias e Portuguesas. O sector eólico destaca-se como um elemento essencial na concretização dos objectivos traçados para as energias renováveis ao nível da União Europeia. Actualmente a maioria dos modelos de planeamento energético centram-se predominantemente nas dimensões económica e ambiental. Apesar de reconhecidamente importantes, os aspectos sociais não estão ainda totalmente integrados nos sistemas de apoio à decisão aplicados ao sector da energia. A principal contribuição desta tese é a de dotar os decisores de uma nova ferramenta para apoio ao planeamento eléctrico de longo prazo, integrando variáveis ambientais, económicas e sociais. A abordagem apresentada envolve modelos complexos de optimização de funções objectivo custo e emissões, baseadas na descrição matemática do sistema eléctrico. Foram desenvolvidos modelos de optimização linear e não linear, estabelecendo-se a relação entre os custos de produção de energia eléctrica e emissões de dioxido de carbono associadas. Adicionalmente, a combinação do método Delphi com o Processo de Análise Hierárquica permitiu estimar e analisar julgamentos de valor relativamente aos impactos das possíveis tecnologias de geração de electricidade, resultando em Índices Sociais associados a cada uma destas tecnologias. A partir destes modelos são desenvolvidos possíveis planos para geração de electricidade para um período de 10 anos, sendo os respectivos impactos sociais analisados e integrados na decisão final. A implementação do Sistema Integrado para Planeamento Eléctrico, implicou uma recolha detalhada de informação relativa ao sistema eléctrico Português recorrendo a fontes oficiais e a especialistas na matéria. De acordo com os relatórios oficiais, o aumento de consumo de electricidade em Portugal durante os próximos 10 anos, será essencialmente suportado por novos investimentos em centrais a carvão, gás natural, energia eólica e hídrica. O esperado aumento da potência eólica instalada é analisado, demonstrando-se a necessidade de considerar o impacto que as fontes energéticas de produção variável terão, não apenas na gestão de curto prazo do sistema eléctrico, mas especialmente no planeamento a médio e longo prazo. Do estudo do caso Português conclui-se que a energia eólica tem um impacto significativo ao nível da gestão das operações do sistema eléctrico e não pode ser considerada livre de impactos sociais adversos. No entanto, a energia eólica tem também um papel fundamental no futuro sistema eléctrico Nacional, particularmente para atingir as metas traçadas pelo protocolo de Kyoto e pela Directiva Europeia das energias renováveis. Apesar da metodologia proposta ter sido aplicada ao caso Português, poderá ser aplicada a outras regiões ou países tomando em linha de conta as particularidades de cada sistema energético em análise. Na globalidade, a metodologia proposta permite que o decisor reconheça e entenda de forma clara as características do sistema e os impactos que as possíveis decisões acarretarão, contribuindo assim para a selecção de planos energéticos de longo prazo consistentes com os princípios do desenvolvimento sustentado

Telecommunication Economics

This book constitutes a collaborative and selected documentation of the scientific outcome of the European COST Action IS0605 Econ@Tel "A Telecommunications Economics COST Network" which run from October 2007 to October 2011. Involving experts from around 20 European countries, the goal of Econ@Tel was to develop a strategic research and training network among key people and organizations in order to enhance Europe's competence in the field of telecommunications economics. Reflecting the organization of the COST Action IS0605 Econ@Tel in working groups the following four major research areas are addressed: - evolution and regulation of communication ecosystems; - social and policy implications of communication technologies; - economics and governance of future networks; - future networks management architectures and mechanisms