Online Energy Generation Scheduling for Microgrids with Intermittent Energy Sources and Co-Generation

Microgrids represent an emerging paradigm of future electric power systems that can utilize both distributed and centralized generations. Two recent trends in microgrids are the integration of local renewable energy sources (such as wind farms) and the use of co-generation (i.e., to supply both electricity and heat). However, these trends also bring unprecedented challenges to the design of intelligent control strategies for microgrids. Traditional generation scheduling paradigms rely on perfect prediction of future electricity supply and demand. They are no longer applicable to microgrids with unpredictable renewable energy supply and with co-generation (that needs to consider both electricity and heat demand). In this paper, we study online algorithms for the microgrid generation scheduling problem with intermittent renewable energy sources and co-generation, with the goal of maximizing the cost-savings with local generation. Based on the insights from the structure of the offline optimal solution, we propose a class of competitive online algorithms, called CHASE (Competitive Heuristic Algorithm for Scheduling Energy-generation), that track the offline optimal in an online fashion. Under typical settings, we show that CHASE achieves the best competitive ratio among all deterministic online algorithms, and the ratio is no larger than a small constant 3.Comment: 26 pages, 13 figures. It will appear in Proc. of ACM SIGMETRICS, 201

Catalytic-Dielectric Barrier Discharge Plasma Reactor For Methane and Carbon Dioxide Conversion

A catalytic - DBD plasma reactor was designed and developed for co-generation of synthesis gas and C2+ hydrocarbons from methane. A hybrid Artificial Neural Network - Genetic Algorithm (ANN-GA) was developed to model, simulate and optimize the reactor. Effects of CH4/CO2 feed ratio, total feed flow rate, discharge voltage and reactor wall temperature on the performance of catalytic DBD plasma reactor was explored. The Pareto optimal solutions and corresponding optimal operating parameters ranges based on multi-objectives can be suggested for catalytic DBD plasma reactor owing to two cases, i.e. simultaneous maximization of CH4 conversion and C2+ selectivity, and H2 selectivity and H2/CO ratio. It can be concluded that the hybrid catalytic DBD plasma reactor is potential for co-generation of synthesis gas and higher hydrocarbons from methane and carbon dioxide and showed better than the conventional fixed bed reactor with respect to CH4 conversion, C2+ yield and H2 selectivity for CO2 OCM process

Review of existing electricity quality label systems in the European Union

Green electricity quality labels have been utilised in the European Union since 1990. Of the seventeen European countries analysed here1, at the time of writing nine had no countryspecific quality label, although all electricity tariffs within Europe were able to apply for accreditation under the EUGENE labelling scheme. Germany had several quality labels, each with slightly different criteria. All of the eighteen labels identified in the report applied to electricity from renewable sources. Of these, seven also allowed co-generation to be a part of the fuel mix and one had a requirement for eligible companies to fulfil some demand side management activities. No existing labelling scheme set an overall requirement for CO2 emissions, although some did set emissions limits for co-generation components. Seven labels required some contribution from new renewable energy plant2. Only three of the labels did not allow publicly funded plant to contribute to a labelled green tariff. A review of labels clearly indicates that: · there are several schemes with varying levels of “greenness”, operating in some countries, which may be confusing for customers; · very few labels are clearly requiring some additionality for the products. It is therefore recommended that the European Union and member states continue to use other support mechanisms to increase the generation of electricity from renewable sources

Studi Alih–fungsi Cfb Boiler Sebagai Pembangkit Co–generation

Demo–plant CFB boiler 30 ton steam/hour is a granted equipments of cooperation program between BPPT and NEDO Japan in technological study area of CFB Boiler to utilize low–rank coal which functioned as steam consumption supply as well as electricity at production process system in Paper Mill of Basuki Rachmat – Banyuwangi. But outside calculation in the year of 1998, Indonesia occured economic crisis which result activity of construction which have 90% perforced to be discontinued, because PKBR as area owner and construction funder expressed have national debt, so that the asset taken over by BPPN. Since the project activities discontinued, various effort of project solving have been conducted, one of them, BPPT propose study of CFB Boiler displace function as steam and electricity generation (co–generation). In this paper, writer try to elaborate result of study giving 5 option, that is (1) Stand–alone power station, (2) Co–generation 1 (new steam turbine), (3) Co–generation 2 (new steam turbine+cooling tower), (4) Co–generation 3 (existing steam turbine) and (5) Co–generation 4 (existing steam turbine+cooling tower)

CO-GENERATION AND OPERATING NETWORK CELLS

In Denmark several thousands of generators are connected to the distribution system (10 kV and 0.4 kV). The production from these generators many times exceeds the load. The generators can be divided into two types, Wind turbines and CHP generators. These generators have one thing in common, the power system they are connected to, has never been designed to accommodate so many generators. In Denmark we now expect a third type of generators: the microgenerators. This time we want to be prepared. Denmark therefore now participates in a lot of research and full scale demonstration projects. A key concept in along these lines is the “Network Cell”

Economical analysis of combined fuel cell generators and absorption chillers

AbstractThis paper presents a co-generation system based on combined heat and power for commercial units. For installation of a co-generation system, certain estimates for this site should be performed through making assessments of electrical loads, domestic water, and thermal demand. This includes domestic hot water, selection of the type of power generator, fuel cell, and the type of air conditioning system, and absorption chillers. As a matter of fact, the co-generation system has demonstrated good results for both major aspects, economic and environmental. From the environmental point of view, this can be considered as an ideal solution for problems concerned with the usage of Chlorofluoro carbons. On the other hand, from the economic point of view, the cost analysis has revealed that the proposed system saves 4% of total cost through using the co-generation system

Co-Generation of C2 Hydrocarbons and Synthesis Gases from Methane and Carbon Dioxide: a Thermodynamic Analysis

This paper deals with thermodynamic chemical equilibrium analysis using the method of direct minimization of Gibbs free energy for all possible CH4 and CO2 reactions. The effects of CO2/CH4 feed ratio, reaction temperature, and system pressure on equilibrium composition, conversion, selectivity and yield were studied. In addition, carbon and no carbon formation regions were also considered at various reaction temperatures and CO2/CH4 feed ratios in the reaction system at equilibrium. It was found that the reaction temperature above 1100 K and CO2/CH4 ratio=1 were favourable for synthesis gas production with H2/CO ratio unity, while carbon dioxide oxidative coupling of methane (CO2 OCM) reaction to produce ethane and ethylene is less favourable thermodynamically. Numerical results indicated that the no carbon formation region was at temperatures above 1000 K and CO2/CH4 ratio larger than

Co-generation at CERN: Beneficial or not?

A co-generation plant for the combined production of electricity and heat has recently been installed on the CERN Meyrin site. This plant consists of: a gas turbine generator set (GT-set), a heat recovery boiler for the connection to the CERN primary heating network, as well as various components for the integration on site. A feasibility study was carried out and based on the argument that the combined use of natural gas -available anyhow for heating purposes- gives an attractively high total efficiency, which will, in a period of time, pay off the investment. This report will explain and update the calculation model, thereby confirming the benefits of the project. The results from the commissioning tests will be taken into account, as well as the benefits to be realized under the condition that the plant can operate undisturbed by technical setbacks which, incidentally, has not been entirely avoided during the first year of test-run and operation

Reviews on Fuel Cell Technology for Valuable Chemicals and Energy Co-Generation

This paper provides a review of co-generation process in fuel cell type reactor to produce valuable chemical compounds along with electricity. The chemicals and energy co-generation processes have been shown to be a promising alternative to conventional reactors and conventional fuel cells with pure water as a byproduct. This paper reviews researches on chemicals and energy co-generation technologies of three types of promising fuel cell i.e. solid oxide fuel cell (SOFC), alkaline fuel cell (AFC), and proton exchange membrane fuel cell (PEMFC). In addition, the research studies on applications of SOFCs, AFCs, and PEMFCs with chemical production (i.e. nitric oxide, formaldehyde, sulfur oxide, C2 hydrocarbons, alcohols, syngas and hydrogen peroxide) were also given. Although, it appears that chemicals and energy co-generation processes have potential to succeed in commercial applications, the development of cheaper catalyst materials with longer stability ,and understanding in thermodynamic are still challenging to improve the overall system performance and enable to use in commercial market

Conceptual design and development of an automated co-generation system

Co-generation or Combined Heat and Power (CHP) is the simultaneous generation of both electricity and heat from the same fuel for useful purposes. The fuel varies greatly and can include coal, biomass, natural gas, nuclear material, the sun or heat stored in the earth. Co-generation (as a vector of energy efficiency) and renewable sources of energy possess their own set of low carbon benefits. Coupling co-generation and renewable sources contribute to a very strong proposition since it leads to the supply of both low-carbon electricity and low-carbon heat. In the case of co-generation plants fuelled by renewable energy sources, the low-carbon benefits of the heat are obvious since they derive from the renewable nature of the fuel. However, this also apply in the case of plants feed by other types of fuel. Such plants produce excess heat alongside electricity. When this heat, which is an unavoidable by-product, is used to satisfy an existing heat demand carbon dioxide (CO2) emissions are reduced overall, through a more efficient use of the fuel. The distributed generation systems produce energy close to the point of use, which typically doubles the efficiency in terms of fuel input‐to‐energy output ratio compared to conventional power generation in central plants. This means that the same amount of energy can be produced with half the amount of fuel, making distributed generation an effective approach to reducing greenhouse gas emissions. According to official government reports, the creation of distributed generation systems will account for at least 5% of gas reduction. In this paper the conceptual design and development of an automated co-generation system to apply in collective residences is presented. After concluding the definition of the demanded specifications and requirements for the co-generation system it is presented and discussed the developed solution with the identification of the main components, including the selection and prototype implementation of the necessary sensors and actuators that integrate the system. It is also shown a systematized approach that consists in using the GEMMA and the SFC formalisms for the structure and specification of all the system behaviour, considering all the stop states and functioning modes of the co-generation system.(undefined