Virtual power plants with electric vehicles

The benefits of integrating aggregated Electric Vehicles (EV) within the Virtual Power Plant (VPP) concept, are addressed. Two types of EV aggregators are identified: i) Electric Vehicle Residential Aggregator (EVRA), which is responsible for the management of dispersed and clustered EVs in a residential area and ii) Electric Vehicle Commercial Aggregator (EVCA), which is responsible for the management of EVs clustered in a single car park. A case study of a workplace EVCA is presented, providing an insight on its operation and service capabilities

Fuel savings in remote Antarctic microgrids through energy management

Research stations in the Antarctic have their own electrical generation facilities and are not interconnected to any grid. Scarcity of fuel and unavailability of interconnection characterize these Antarctic energy systems as mission-critical isolated microgrids. In this work, an energy management strategy has been proposed for South African Antarctic research station SANAE IV for improving fuel efficiency. The proposed strategy consists of optimal dispatch of generation and installation of a thermal load controller for the supply side, and a novel demand response scheme for the demand side. The system was simulated using HOMER Microgrid Analysis Tool. Results showed an 8.30% decrease in fuel consumption, which corresponds to 21,876 litres of diesel annually. These savings can be achieved without major capital expenditure or difficult engineering work

Automating virtual power plant decision making with fuzzy logic and human psychology

This paper presents a Virtual Power Plant (VPP) decision making approach which uses fuzzy logic and a novel “insecurity” metric, based on human psychology. The VPP approach is modelled as a multi-agent system, which aims to minimize carbon emissions and/or energy cost, using an aggregation structure similar to energy or carbon markets. The “insecurity factor” reflects the operational flexibility of micro-generators, translated to a numerical value through fuzzy logic. The system was able to create a functional internal VPP market, where the micro-generators were trading autonomously according to external price signals and taking into account their own needs and limitations, as well as short-term forecasts

Multiple energy carrier optimisation with intelligent agents

Multiple energy carrier systems stem from the need to evolve traditional electricity, gas and other energy systems to more efficient, integrated energy systems. An approach is presented, for controlling multiple energy carriers, including electricity (AC or DC), heat, natural gas and hydrogen, with the objective to minimise the overall cost and/or emissions, while adhering to technical and commercial constraints, such as network limits and market contracts. The technique of multi-agent systems (MAS) was used. The benefits of this approach are discussed and include a reduction of more than 50% in the balancing costs of a potential deviation. An implementation of this methodology is also presented. In order to validate the operation of the developed system, a number of experiments were performed using both software and hardware. The results validated the efficient operation of the developed system, proving its ability to optimise the operation of multiple energy carrier inputs within the context of an energy hub, using a hierarchical multi-agent system control structure

Decision tree aided planning and energy balancing of planned community microgrids

Planned Communities (PCs) present a unique opportunity for deployment of intelligent control of demand-side distributed energy resources (DER) and storage, which may be organized in Microgrids (MGs). MGs require balancing for maintaining safe and resilient operation. This paper discusses the implications of using MG concepts for planning and control of energy systems within PCs. A novel tool is presented, based on decision trees (DTs), with two potential applications: (i) planning of energy storage systems within such MGs and (ii) controlling energy resources for energy balancing within a PC MG. The energy storage planning and energy balancing methodology is validated through sensitivity case studies, demonstrating its effectiveness. A test implementation is presented, utilizing distributed controller hardware to execute the energy balancing algorithm in real-time

Emissions Of aggregated micro-generators

The key question this thesis aims to address is to what extent can micro-generation sources contribute to the carbon emission reduction targets set by the UK government. The operational emissions of micro-CHP capable micro-generators were examined against the UK grid electricity and gas boiler heat. Fossil and biomass fuels were considered. The life-cycle emissions associated with the manufacturing, transport and disposal of micro-generators were calculated. Case studies were constructed, based on the literature. It was found that emissions associated with domestic electrical and thermal demand would be reduced significantly. A Virtual Power Plant (VPP) was defined for aggregating micro-generators, using micro-generation penetration projections for the year 2030 from the literature. An optimisation problem was described, where the goal was to minimise the VPP carbon emissions. The results show the amount of emissions that would potentially be reduced by managing an existing micro-generation portfolio in a VPP. An Environmental Virtual Power Plant (EVPP) was defined, for controlling micro-generator carbon emissions. A multi-agent system was designed. The principle of operation resembles an Emissions Trading Scheme. Emission allowances are traded by the micro-generators, in order to meet their emissions needs. Three EVPP control policies were identified. Fuzzy logic was utilised for the decision making processes. Simulations were performed to test the EVPP operation. The main benefit for the micro-generators is the ability to participate in markets from which they would normally be excluded due to their small size. The multi-agent system was verified experimentally using micro-generation sources installed in two laboratories, in Athens, Greece. Two days of experiments were performed. Results show that system emissions have been successfully controlled, since only small deviations between desired and actual emissions output were observed. It was found that Environmental Virtual Power Plant controllability increases significantly by increasing the number of participating micro-generators

Additional records on the occurrence of alien fish species in the eastern Mediterranean Sea

Recent records on the occurrence of the species Etrumeus teres, Siganus rivulatus, Stephanolepis diaspros, Sphoeroides pachygaster, Lagocephalus sceleratus, Fistularia commersonii and Siganus luridus are presented for the Aegean, Cretan and Libyan Seas and the new record of Upeneus moluccensis in the Cretan Sea is reported

Containerized compressed natural gas shipping

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (p. 106-108).In the last decades, the demand for energy is increasing. It is necessary to develop new ways to distribute the energy using economically feasible solutions. In this project an Ultra Large Container Ship is used that can carry more than 12,000 TEUs. Inside each TEU, four cylinders are installed that can store compressed natural gas at 250 bar. Two types of cylinders are tested: cylinders made of steel and cylinders made of carbon fiber. Carbon fiber cylinders were chosen because they are lighter. In addition, two types of compressors are used: centrifugal and reciprocating compressors. Centrifugal compressors are used to increase the initial pressure from 10 bar to 50 bar. Reciprocating compressors are used to increase the pressure from 50 bar to 250 bar. A model is developed using thermodynamics and MATLAB, in order to determine the total power required for a compressor to fill the entire vessel in one or more days. Furthermore, by using valuation metrics, a model is created to find the value of the project and to generate sensitivity analyses. It is concluded that leasing the ships is more profitable than buying them.by Georgios V. Skarvelis.S.M

The need for reconfigurable DC electricity networks

A Policy Brie