Residential energy resources management by a SCADA system in case of excess wind generation

The end consumers in a smart grid context are seen as active players. The distributed generation resources applied in smart home system as a micro and small-scale systems can be wind generation, photovoltaic and combine heat and power facility. The paper addresses the management of domestic consumer resources, i.e. wind generation, solar photovoltaic, combined heat and power, electric vehicle with gridable capability and loads, in a SCADA system with intelligent methodology to support the user decision in real time. The main goal is to obtain the better management of excess wind generation that may arise in consumer’s distributed generation resources. The optimization methodology is performed in a SCADA House Intelligent Management context and the results are analyzed to validate the SCADA system.

Residential property loans and performance during property price booms: evidence from European banks

Understanding the performance of banks is of the utmost relevance, because of the impact of this sector on economic growth and financial stability. Of all the different assets that make up a bank portfolio, the residential mortgage loans constitute one of its main. Using the dynamic panel data method, we analyse the influence of residential mortgage loans on bank profitability and risk, using a sample of 555 banks in the European Union (EU-15), over the period from 1995 to 2008. We find that banks with larger weights of residential mortgage loans show lower credit risk in good times. This result explains why banks rush to lend on property during booms due to the positive effects it has on credit risk. The results show further that credit risk and profitability are lower during the upturn in the residential property price cycle. The results also reveal the existence of a non-linear relationship (U-shaped marginal effect), as a function of bank’s risk, between profitability and the residential mortgage loans exposure. For those banks that have high credit risk, a large exposure of residential mortgage loans is associated with higher risk-adjusted profitability, through lower risk. For banks with a moderate/low credit risk, the effects of higher residential mortgage loan exposure on its risk-adjusted profitability are also positive or marginally positive.

Residential property loans and performance during property price booms: evidence from European

Understanding the performance of banks is of the u tmost importance due to the impact the sector may have on economic growth and financial stability. Residential mortgage loans constitute a large proportion of the portfolio of many banks and are one of the key assets in the determination of performance. Using a dynamic panel model , we analyse the impact of res idential mortgage loans on bank profitability and risk , based on a sample of 555 banks in the European Union ( EU - 15 ) , over the period from 1995 to 2008. We find that banks with larger weight s in residential mortgage loans display lower credit risk in good market conditions . This result may explain why banks rush to lend on property during b ooms due to the positive effect it has on credit risk . The results also show that credit risk and profitability are lower during the upturn in the residential property cy cle. Furthermore, t he results reveal the existence of a non - linear relationship ( U - shaped marginal effect), as a function of bank’s risk, between profitability and residential mortgage exposure . For those banks that have high er credit risk, a large exposur e to residential loans is associated with increased risk - adjusted profitability, through a reduction in risk. For banks with a moderate to low credit risk, the impact of higher exposure are also positive on risk - adjusted profitability.

O papel dos sistemas de Non-Intrusive Load Monitoring para a eficiência energética do setor residencial

A sustentabilidade energética do planeta é uma preocupação corrente e, neste sentido, a eficiência energética afigura-se como sendo essencial para a redução do consumo em todos os setores de atividade. No que diz respeito ao setor residencial, o indevido comportamento dos utilizadores aliado ao desconhecimento do consumo dos diversos aparelhos, são factores impeditivos para a redução do consumo energético. Uma ferramenta importante, neste sentido, é a monitorização de consumos nomeadamente a monitorização não intrusiva, que apresenta vantagens económicas relativamente à monitorização intrusiva, embora levante alguns desafios na desagregação de cargas. Abordou-se então, neste documento, a temática da monitorização não intrusiva onde se desenvolveu uma ferramenta de desagregação de cargas residenciais, sobretudo de aparelhos que apresentavam elevados consumos. Para isso, monitorizaram-se os consumos agregados de energia elétrica, água e gás de seis habitações do município de Vila Nova de Gaia. Através da incorporação dos vetores de água e gás, a acrescentar ao da energia elétrica, provou-se que a performance do algoritmo de desagregação de aparelhos poderá aumentar, no caso de aparelhos que utilizem simultaneamente energia elétrica e água ou energia elétrica e gás. A eficiência energética é também parte constituinte deste trabalho e, para tal, implementaram-se medidas de eficiência energética para uma das habitações em estudo, de forma a concluir as que exibiam maior potencial de poupança, assim como rápidos períodos de retorno de investimento. De um modo geral, os objetivos propostos foram alcançados e espera-se que num futuro próximo, a monitorização de consumos não intrusiva se apresente como uma solução de referência no que respeita à sustentabilidade energética do setor residencial.

Resource Scheduling in Residential Microgrids Considering Energy Selling to External Players

The operation of distribution networks has been facing changes with the implementation of smart grids and microgrids, and the increasing use of distributed generation. The specific case of distribution networks that accommodate residential buildings, small commerce, and distributed generation as the case of storage and PV generation lead to the concept of microgrids, in the cases that the network is able to operate in islanding mode. The microgrid operator in this context is able to manage the consumption and generation resources, also including demand response programs, obtaining profits from selling electricity to the main network. The present paper proposes a methodology for the energy resource scheduling considering power flow issues and the energy buying and selling from/to the main network in each bus of the microgrid. The case study uses a real distribution network with 25 bus, residential and commercial consumers, PV generation, and storage.

Sectors and routes in solid waste collection

Collecting and transporting solid waste is a constant problem for municipalities and populations in general. Waste management should take into account the preservation of the environment and the reduction of costs. The goal with this paper is to address a real-life solid waste problem. The case reveals some general and specific characteristics which are not rare, but are not widely addressed in the literature. Furthermore, new methods and models to deal with sectorization and routing are introduced, which can be extended to other applications. Sectorization and routing are tackled following a two-phase approach. In the first phase, a new method is described for sectorization based on electromagnetism and Coulomb’s Law. The second phase addresses the routing problems in each sector. The paper addresses not only territorial division, but also the frequency with which waste is collected, which is a critical issue in these types of applications. Special characteristics related to the number and type of deposition points were also a motivation for this work. A new model for a Mixed Capacitated Arc Routing Problem with Limited Multi-Landfills is proposed and tested in real instances. The computational results achieved confirm the effectiveness of the entire approach.

Influência dos equipamentos de aquecimento, arrefecimento e AQS na certificação energética de edifícios

Na União Europeia os sectores dos transportes e da indústria são ambos grandes consumidores de energia, mas são os edifícios residenciais e de serviços onde o consumo energético é maior, e em 2005, segundo a EnerBuilding, representavam cerca de 17% dos consumos de energia primária em termos nacionais. A energia gasta com a iluminação, o aquecimento, o arrefecimento e AQS das habitações, locais de trabalho e locais de lazer é superior à consumida pelos sectores dos transportes e da indústria. As habitações representam dois terços do consumo total de energia dos edifícios europeus, o qual aumenta todos os anos com a melhoria da qualidade de vida, traduzindo-se numa maior utilização dos sistemas de climatização. Neste sentido, e de acordo com o decreto-lei que transpõe para a legislação portuguesa a diretiva comunitária relativa ao desempenho energético dos edifícios, todos os Estados da União Europeia devem ter um sistema de certificação energética para informar o cidadão sobre a qualidade térmica dos edifícios, aquando da construção, da venda ou do arrendamento. Assim, entrou em vigor em Portugal, desde 1 de Janeiro de 2009, a obrigatoriedade de apresentação de um certificado de eficiência energética, no ato de compra, venda ou aluguer de edifícios novos e existentes. A certificação energética permite assim aos futuros utilizadores dos edifícios obter informação sobre os potenciais consumos de energia, no caso dos novos edifícios ou no caso de edifícios existentes sujeitos a grandes intervenções de reabilitação, dos seus consumos reais ou aferidos para padrões de utilização típicos, passando o consumo energético a integrar um conjunto dos aspetos importantes para a caracterização de qualquer edifício. Em edifícios de serviços, o certificado energético assegura aos utentes do edifício ou da fração que este reúne condições para garantir a eficiência energética e a adequada qualidade do ar interior. Uma vez que passamos 80% do nosso tempo em edifícios, e que isto se reflete num consumo cada vez mais elevado do sector residencial e dos serviços no consumo total energético do país, este trabalho pretende fazer a comparação dos vários equipamentos de aquecimento, de arrefecimento e de AQS e qual a influência dos mesmos na certificação energética de edifícios, e consequentemente na eficiência dos mesmos, sendo que a eficiência e a certificação energética de um edifício deve ser um aspeto relevante a levar em consideração no momento do planeamento ou da construção, bem como na aquisição de uma nova habitação. Um projeto concebido de modo a tirar proveito das condições climáticas, da orientação solar, dos ventos dominantes e utilizadas técnicas construtivas e os materiais adequados, é possível reduzir os gastos energéticos com a iluminação ou os sistemas de climatização.

Impact of using solar heat pumps for domestic hot water in Portuguese residential buildings

In recent years, we have seen an improvement of existing facilities in dwellings in Portugal. Within the heat pumps systems, there is a special type known as direct expansion heat pump assisted by Solar Collector (DX-SAHP). It was calculate the SPF indicator for 30 regions of Portugal. It was analyses the potential of reductions of CO2 and primary energy use for the retrofitting of DHW preparation systems. It was found that the performances of this type of equipment are benefiting from the Portuguese climate conditions, especially in the South and in the Autonomous Regions. Best SPF was obtained for Beja. It was found in all regions of the high potential for reducing CO2 emissions and verifying a potential significant reduction of primary energy consumption.

Performance Energética no contexto do sistema LEED

Com o aumento constante de procura de recursos naturais por parte dos vários setores da sociedade é urgente encontrar soluções para reduzir o seu consumo sem se travar a expansão demográfica que se tem vindo a sentir nos grandes centros urbanos. É através da implementação de medidas de sustentabilidade e pelo aumento da eficiência de utilização desses recursos que se tem vindo a combater esta tendência cada vez maior de consumismo global, sendo isto apenas possível com a implementação de ferramentas tecnológicas avançadas que permitem estabelecer limites ao considerado eficiente e premiando, em termos financeiros e de imagem de marketing, as entidades que o alcancem. O LEED é um sistema de certificação de sustentabilidade voluntário de edifícios residenciais e comerciais que estabelece métricas de comparação de parâmetros indicadores de consumos energéticos, hídricos e de materiais em todo o ciclo de vida do edifício e que tem vindo a ganhar destaque em crescendo a nível mundial. Esta dissertação teve como objetivo comparar a performance de consumo energético no âmbito do sistema LEED com a do sistema de certificação energética de edifícios nacional (SCE) de um grande edifício de serviços, estabelecendo um paralelismo de semelhanças e diferenças entre os dois e de avaliar os efeitos de potenciais medidas de eficiência energética e seus efeitos nas classificações de mérito obtidas em cada sistema. Os resultados obtidos na simulação que permitiu avaliar a performance foi muito satisfatório, tendo sido aproveitado pela empresa para efeitos de certificação LEED do edifício em estudo.

Análise crítica ao processo de auditoria da qualidade

Dissertação apresentada ao Instituto Superior de Contabilidade para a obtenção do Grau deMestre em Auditoria Orientada por Alcina Augusta de Sena Portugal Dias

Norma contabilística e de relato financeiro 10 – custos de empréstimos obtidos

Dissertação de Mestrado submetida ao Instituto Superior de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Auditoria Trabalho efetuado sob a orientação do Mestre Carlos Martins

Economia social, pilar de um novo modelo de desenvolvimento económico sustentável

Dissertação apresentada ao Instituto Superior de Contabilidade para a obtenção do Grau de Mestre em Auditoria Orientada por Dr.ª Alcina Portugal Dias

Genetic algorithm methodology applied to intelligent house control

In recent years the use of several new resources in power systems, such as distributed generation, demand response and more recently electric vehicles, has significantly increased. Power systems aim at lowering operational costs, requiring an adequate energy resources management. In this context, load consumption management plays an important role, being necessary to use optimization strategies to adjust the consumption to the supply profile. These optimization strategies can be integrated in demand response programs. The control of the energy consumption of an intelligent house has the objective of optimizing the load consumption. This paper presents a genetic algorithm approach to manage the consumption of a residential house making use of a SCADA system developed by the authors. Consumption management is done reducing or curtailing loads to keep the power consumption in, or below, a specified energy consumption limit. This limit is determined according to the consumer strategy and taking into account the renewable based micro generation, energy price, supplier solicitations, and consumers’ preferences. The proposed approach is compared with a mixed integer non-linear approach.

A data-mining-based methodology for transmission expansion planning

In recent decades, all over the world, competition in the electric power sector has deeply changed the way this sector’s agents play their roles. In most countries, electric process deregulation was conducted in stages, beginning with the clients of higher voltage levels and with larger electricity consumption, and later extended to all electrical consumers. The sector liberalization and the operation of competitive electricity markets were expected to lower prices and improve quality of service, leading to greater consumer satisfaction. Transmission and distribution remain noncompetitive business areas, due to the large infrastructure investments required. However, the industry has yet to clearly establish the best business model for transmission in a competitive environment. After generation, the electricity needs to be delivered to the electrical system nodes where demand requires it, taking into consideration transmission constraints and electrical losses. If the amount of power flowing through a certain line is close to or surpasses the safety limits, then cheap but distant generation might have to be replaced by more expensive closer generation to reduce the exceeded power flows. In a congested area, the optimal price of electricity rises to the marginal cost of the local generation or to the level needed to ration demand to the amount of available electricity. Even without congestion, some power will be lost in the transmission system through heat dissipation, so prices reflect that it is more expensive to supply electricity at the far end of a heavily loaded line than close to an electric power generation. Locational marginal pricing (LMP), resulting from bidding competition, represents electrical and economical values at nodes or in areas that may provide economical indicator signals to the market agents. This article proposes a data-mining-based methodology that helps characterize zonal prices in real power transmission networks. To test our methodology, we used an LMP database from the California Independent System Operator for 2009 to identify economical zones. (CAISO is a nonprofit public benefit corporation charged with operating the majority of California’s high-voltage wholesale power grid.) To group the buses into typical classes that represent a set of buses with the approximate LMP value, we used two-step and k-means clustering algorithms. By analyzing the various LMP components, our goal was to extract knowledge to support the ISO in investment and network-expansion planning.

Multi-agent negotiation for coalition formation and management in electricity markets

Negotiation is a fundamental tool for reaching understandings that allow each involved party to gain an advantage for themselves by the end of the process. In recent years, with the increasing of compe-titiveness in most sectors, negotiation procedures become present in practically all of them. One particular environment in which the competitiveness has been increasing exponentially is the electricity markets sector. This work is directed to the study of electricity markets’ partici-pating entities interaction, namely in what concerns the formation, management and operation of aggregating entities – Virtual Power Players (VPPs). VPPs are responsible for managing coalitions of market players with small market negotiating influence, which take strategic advantage in entering such aggregations, to increase their negotiating power. This chapter presents a negotiation methodology for the creation and management of coalitions in Electricity Markets. This approach is tested using MASCEM, taking advantage of its ability to provide the means to model and simulate VPPs. VPPs are represented as coalitions of agents, with the capability of negotiating both in the market, and internally, with their members, in order to combine and manage their individual specific characteristics and goals, with the strategy and objectives of the VPP itself.