Distributed Generation Technologies Research Articles

Integration of distributed generation technologies on sustainable buildings

This work addresses the optimal sizing and selection of the most used technologies reported in literature for energy and water supply of sustainable buildings. The addressed technologies includes Combined Heat and Power units, solar collectors, photovoltaic panels, conventional boilers, wind turbines, Organic Rankine Cycles, biogas production and water treatment systems. The selection technology problem is cast as an optimization model which takes into account embedded nonlinear behavior of the addressed equipment, especially the ones associated with operative efficiency, and dynamics of the storage units. The renewable energy generation, total annual cost, emissions generated and water consumption of the system are used as objective functions. Since some of these objective functions are contradictory, a multi-objective and multi-scenario Mixed Integer nonlinear optimization approach was used to reach trade-off solutions. The multi-objective approach presented allows to define the preferences of the designer based on predefined weights for reaching trade-off solutions using a dimensional approach. The environmental and energy profiles of a residential building in the Pacific Coast of Mexico are presented as Case Study. The results show the importance of including the nonlinear behavior of the technologies for defining a suitable operational policy as well as the effect of using different criteria about the design of water-energy systems.

A Comparative Investigation on Optimization Techniques for Optimal Penetration of Distribution Generators in Power System Application

In deregulation of power system, different regulatory units, environmental concerns and economic concerns have lead to the penetration of Distributed Generation (DG) in power system. When DGs are penetrated, various parameters like DG technology, optimal size, optimal location, and its impact on various operating characteristics such electrical losses, voltage profile, stability and reliability of power system are to be monitored. The performance of DG penetration depends largely upon the selection of the optimal parameter values. Special optimizing techniques used to evaluate optimal value of parameter in context of heuristic nature of variable. A literature review has been carried out on different optimal technique used to optimize parameter values. The authors have reviewed various definitions related to DG and conventional and non conventional technologies on which DG are based. Various issues regarding DG integration have been discussed. Exhaustive reviews of many optimization techniques have been done for optimal location and size of DG.

Allocation of Resources Using a Microgrid Formation Approach for Resilient Electric Grids

Microgrid formation is a potential solution in postdisaster electric grid recovery efforts. Recent works propose a distribution level microgrid formation model that applies to radial distribution systems characterized by directed power flows. However, with high renewable penetration levels in future power systems, the flows are expected to be undirected even in distribution grids. In this paper, we develop a model to deal with the restoration process of future power systems, embedding some of the characteristics these systems are likely to have. More specifically, our formulation can deal with radial and meshed topologies, and it requires little preprocessing of the input data. Additionally, we extend the model to allow for possible mobile and fixed distributed generation technologies and distributed energy resources, and explicitly include demand responsive loads with a minimum satisfiability constraint. Thus, this extended formulation can be used as an operation and a short term planning tool for the DG scenario-based location problem. We compare our extended formulation results to those obtained for the radial cases found in the literature. Also, we apply the proposed approach to other instances of the problem based on the IEEE 37-bus, 30-bus, and 118-bus systems.

Small-scale Distributed Power Generation Development in the Siberian Regions: Evaluation of Efficiency

<p>It is shown that topical issue is the solution of problems of enhancement of structure electro and heat generations in regions of Russia, including through synchronization of schemes electro and heat supplies. It causes the necessity of integration to municipal level power engineering into development plans for big power industry that causes gain of a role of the distributed power engineering (including the cogeneration installations). The carried-out serial calculations for comparative assessment of a row of technologies of the small-scale distributed power generation in the Novosibirsk and Kemerovo regions allowed to select the perspective directions of diversification of energetic branch. </p>

Power loss minimisation of rural feeder of Jaipur city by renewable-based DG technologies

ABSTRACTPower systems are becoming more complex day by day due to stressed situation in a distribution system, augmented growth in population and high demands of electrical power. In India, the distribution losses are around 20–25%. Distributed Generation (DG) units are broadly used to reduce the power losses in distribution system. To optimise the benefits of DGs, it is essential to determine its appropriate size and location. A new mathematical expression, power voltage sensitivity constant, has been formulated to determine its size and location. In this paper, two types of DG units (PV module and shunt capacitor) are employed for power loss reduction. The size of DG units (PV module) has been restricted to 50% of total system load in the paper. The proposed approach is tested on standard IEEE 69 bus distribution system and 130 bus real distribution system of Jamwa Ramgarh village, Jaipur, India. The results obtained from standard systems are compared with latest optimisation techniques to show the effectiveness and robustness of the proposed approach. The results of real systems are also encouraging.

PV Hosting Capacity Dependence on Harmonic Voltage Distortion in Low-Voltage Grids: Model Validation with Experimental Data

This paper introduces a brief analysis on hosting capacity and related concepts as applied to distribution network systems. Furthermore, it addresses the applicability of hosting capacity study methodologies to harmonic voltage distortion caused by photovoltaic panels (PV) connected at a low-voltage (LV) side of a university campus grid. The analysis of the penetration of new distributed generation technologies, such as PV panels, in the distribution grid of the campus was carried out via measurement processes, and later by computer simulations analyzing a new concept of the hosting capacity approach in relation to voltage harmonics distortion. The voltage rise due to harmonic injection is analyzed and discussed with the aim of validating the discussed model and also putting forward recommendations for connecting PV generation across other network systems.

Minimization of transmission loss using distributed generation approach

The goal of this work is to calculate the total loss in the system and minimize this loss by implementation of distributed generation (DG) technology. In this paper, load flow analysis method is followed to calculate the loss in the system in conjunction with the line flows. A simple 5 bus system with the main bus of the substation as the slack bus, three Plant generators at the generator bus and three load buses are taken for analysis. For loss minimization two distributed generators at two load buses are connected. One generator is a synchronous type model and the other is asynchronous type model. We searched for the most economical penetration level and the ratings of the distributed generators are decided by the magnitude of penetration power at each load bus. Using software, power system simulation for electrical (PSSE), the system with and without DG technology is modeled and the output from the PSSE is observed.

Smart Net Energy Metering System

With the proliferation of distributed generation technologies and renewable energy electric power system isbecoming more complex. In traditional grid system and current energy metering infrastructure line losses are growingday by day. This project will enable smart net energy metering by using GSM technology, user will not only able to viewreal time usage of energy but also will be able to sell excessive energy to utility which is produced in the vicinity of user.Either Renewable or nonrenewable energy resources can be utilized and controlled remotely through mobileapplication, the energy sold out to utility will be deducted from energy consumed from utility which enables dual waysmart net energy metering system. Net metering makes residential solar energy system ownership even more attractiveand affordable for many families. It can save homeowners hundreds more rupees per year on their utility bills, and itmakes the process of accounting for the energy flowing to and from the utility simpler and easier to administer.

Wind energy potential estimation with prediction of wind speed distribution

Integration of renewable distributed generation technology with radial power distribution system is rapidly growing. Among the number of available renewable energy sources, the role of wind energy in the power sector is very important. In this work, authors have estimated the wind energy potential at Banaras Hindu University (BHU), India. Estimation of wind energy potential depends on statistical analysis of wind speed distribution, which will give us the best-fitted probability density function of the desired location. For statistical analysis of wind speed distribution, authors have taken hourly data of BHU centre from the source of National Renewable Energy Laboratory (NREL), USA for the 12-month period. A statistical R-programming language tool has been used for the computational work. In this work, authors have considered Weibull, Gamma and Lognormal probability distributions for getting best-fitted distribution. After the analysis, result shows for the given wind speed data of BHU area, Weibull distribution is the best-fitted one.

Distributed generation technologies, cost analysis and power quality issues in India

Distributed generation technologies, cost analysis and power quality issues in India

Life Cycle Energy Consumption and Greenhouse Gas Emissions Analysis of Natural Gas-Based Distributed Generation Projects in China

In this paper, we used the life-cycle analysis (LCA) method to evaluate the energy consumption and greenhouse gas (GHG) emissions of natural gas (NG) distributed generation (DG) projects in China. We took the China Resources Snow Breweries (CRSB) NG DG project in Sichuan province of China as a base scenario and compared its life cycle energy consumption and GHG emissions performance against five further scenarios. We found the CRSB DG project (all energy input is NG) can reduce GHG emissions by 22%, but increase energy consumption by 12% relative to the scenario, using coal combined with grid electricity as an energy input. The LCA also indicated that the CRSB project can save 24% of energy and reduce GHG emissions by 48% relative to the all-coal scenario. The studied NG-based DG project presents major GHG emissions reduction advantages over the traditional centralized energy system. Moreover, this reduction of energy consumption and GHG emissions can be expanded if the extra electricity from the DG project can be supplied to the public grid. The action of combining renewable energy into the NG DG system can also strengthen the dual merit of energy conservation and GHG emissions reduction. The marginal CO2 abatement cost of the studied project is about 51 USD/ton CO2 equivalent, which is relatively low. Policymakers are recommended to support NG DG technology development and application in China and globally to boost NG utilization and control GHG emissions.

Voltage stability control method of electric springs based on adaptive PI controller

With the continuous development of distributed generation technology, the permeability of wind, solar and other renewable energy continues to increase. As a new kind of voltage control device, electric spring can suppress the voltage fluctuation caused by the power change of distributed generation effectively. In this paper, based on the analysis of the principle of voltage stability control for the electric spring, the optimization of control effect and non-critical load change are taken into consideration. Combined with advanced particle swarm optimization algorithm and fuzzy control algorithm, a method of voltage control for electric spring based on adaptive PI control is proposed, and the digital simulation is carried out. The simulation results show that the adaptive PI control has better voltage regulation effect than the traditional PI control, and can solve the adverse effect of the load variation on the electric spring.

Reliability and economic assessment of a microgrid power system with the integration of renewable energy resources

The reliability assessment of a power system has become a significant subject in the power sector for both utilities and customers due to sudden increase in demand of a reliable power supply at minimal frequency and duration of power outages. This has prompted the utilities to use the accessible renewable energy resources (RERs) as measures to increase the reliability of a power system as well as reduction of over dependence on fossil fuels. The incorporation of renewable energy technologies into a radial distribution system has changed the single power source to bidirectional and multiple power sources. This improves the reliability of the system as well as reducing the power outages that associated with the radial distribution networks. In this work, wind turbine generator (WTG), photovoltaic (PV) and battery storage system (BSS) are utilized with the aim of improving the reliability of the existing microgrid power system and reducing the cost of energy (COE) and annualised cost of the system (ACS). The objective of the research work is accomplished by using the total outage cost (TOC), COE, ACS, annualized capital cost (ACC), annualized maintenance cost (AMC), annualized fuel cost (AFC), annualized emission cost (AEC), annualized replacement cost (ARC) and net present cost (NPC) of the power system. An fmincon optimization tool is utilized in this paper to investigate the effects of RERs in a microgrid system. The stochastic characteristics of the major components of RERs and their influences on the reliability of a power system are studied by using a Markov model. The proposed method is applied on the modified Roy Billinton Test System (RBTS)to establish the fact that RERs can be used to enhance the reliability and reduce the COE and ACS of the system. A comparative analysis of RERs is also carried out by studying the effects of interest rates on the COE, NPC and ACS of a power system. The results obtained from the research work demonstrate that the application of renewable energy distributed generation technologies has achieved better results.

Optimal policies to promote efficient distributed generation of electricity

We analyze the design of policies to promote efficient distributed generation (DG) of electricity. The optimal policy varies with the set of instruments available to the regulator and with the prevailing DG production technology. DG capacity charges often play a valuable role in inducing optimal investment in DG capacity, allowing payments for DG production to induce the optimal production of electricity using non-intermittent DG technologies. Net metering can be optimal in certain settings, but often is not optimal, especially for non-intermittent DG technologies.

Comparing the Expected Stack Cost of Next Generation Intermediate Temperature Protonic Ceramic Fuel Cells with Solid Oxide Fuel Cell Technology

Lowering the operating temperature of high-temperature fuel cells has historically been motivated by stack and system cost reduction and durability considerations towards making fuel cells a more attractive distributed generation technology. Protonic ceramic fuel cells (PCFCs) operating beneath 600oC have emerged as a promising technology candidate for developing power generation systems. Recent progress in PCFC development has solved the challenges of poor cathodes and cell fabrication thereby, enabling them to achieve high power density at intermediate temperatures (450-600oC) while demonstrating remarkable fuel flexibility (hydrogen, hydrocarbon gases, alcohols, ammonia) without external fuel processing measures [1]. This ARPA-E funded project focuses on PCFC cells made by solid-state reactive sintering (SSRS) fabrication processes for cells comprised of a thin BaZr0.8Y0.2O3-δ (BZY20) electrolyte screen-printed onto a BZY20/Ni porous anode support, with a triple conducting cathode material based on BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY0.1). In this paper, we present an economic manufacturing model that was developed to estimate the overall expected cost of a PCFC stack and compare the results with solid oxide fuel cell (SOFC) technology for hydrogen and methane fuels. The comparative analysis is based on similar cell and stack SOFC manufacturing processes and cost data for small-scale stacks (5-10 kW) at production volumes of about 10,000 units/year. Relying on previous SOFC stack cost manufacturing studies [2, 3] a competitive stack capital cost for PCFCs operating at intermediate temperature is projected. Specifically, operating on methane fuel, the costs of PCFC stacks at 500oC (0.155 W/cm2) and 550oC (0.240 W/cm2) are estimated to be 5-10% lower and ~35% lower, respectively, than SOFC stacks running at 800oC (~0.300 W/cm2). To eliminate any uncertainties using methane fuel gas supply (such as extent of reforming, fuel utilization, steam content, etc.), the PCFC and SOFC stack cost estimates were also benchmarked on 97% hydrogen / 3% water vapor fuel gas where an impressive 29% lower stack cost was estimated for PCFC technology (at 500oC). This potential cost advantage of PCFC vs. SOFC stacks is found despite the 20-50% lower power density of PCFCs and is driven by fewer firing steps and the use of lower lower-grade materials. Improvements to further decrease PCFC stack cost consist of replacing nickel oxide precursor, reducing the anode thickness and merging the two-firing steps into a one-firing step SSRS. Overall, as PCFC power density performance is expected to increase with further development, this work demonstrates that if PCFC technology scale-up to larger platforms is successful, they have excellent potential for filling the technology gap of low-cost, high efficiency distributed generation for small- and intermediate-scale commercial combined heat and power systems.

Comparing the Expected Stack Cost of Next Generation Intermediate Temperature Protonic Ceramic Fuel Cells with Solid Oxide Fuel Cell Technology

Lowering the operating temperature of high-temperature fuel cells has historically been motivated by stack and system cost reduction and durability considerations towards making fuel cells a more attractive distributed generation technology. Protonic ceramic fuel cells (PCFCs) operating beneath 600oC have emerged as a promising technology candidate for developing power generation systems. In this paper, we present an economic manufacturing model that was developed to estimate the overall expected cost of a PCFC stack and compare the results with solid oxide fuel cell (SOFC) technology for hydrogen and methane fuels. The costs of PCFC stacks operating on methane at 500oC (0.155 W/cm2) and 550oC (0.240 W/cm2) are estimated to be 4% to 38% lower, respectively, than SOFC stacks operating at 800oC (~0.300 W/cm2).

Impact of Distributed Generation on the Reliability of Local Distribution System

With the growth of distributed generation (DG) and renewable energy resources the power sector is becoming more sophisticated, distributed generation technologies with its diverse impacts on power system is becoming attractive area for researchers. Reliability is one of the vital area in electric power system which defines continuous supply of power and customer satisfaction. Around the world many power generation and distribution companies conduct reliability tests to ensure continues supply of power to its customers. Uttermost reliability problems in power system are due to distribution network. In this research reliability analysis of distribution system is done. The interruption frequency and interruption duration increases as the distance of load points increase from feeder. Injection of single DG unit into distribution system increase reliability of distribution system, injecting multiple DG at different locations and near to load points in distribution network further increases reliability of distribution system, while introducing multiple DG at single location improves reliability of distribution system. The reliability of distribution system remains unchanged while varying the size of DG unit. Different reliability tests were done to find the optimum location to plant DG in distribution system. For these analyses distribution feeder bus 2 of RBTS is selected as case study. The distribution feeder is modeled in ETAP, ETAP is software tool used for electrical power system modeling, analysis, design, optimization, operation, control, and automation. These results can be helpful for power utilities and power producer companies to conduct reliability tests and to properly utilize the distributed generation sources for future expansion of power systems.

Generalized Analytical Approach to Assess Reliability of Renewable-Based Energy Hubs

This paper proposes a generalized analytical approach to evaluate the reliability of active distribution networks. The studies are implemented in the context of renewable-based energy hubs. The reliability of energy demands is determined as a function of reliability characteristics of energy hub input resources and converters as well as hub operating strategies. The framework proposed in this paper involves the main attributes of different distributed generation technologies as well as vehicle-to-grid (V2G)-capable vehicles in the reliability studies. Dealing with the uncertainty in energy services provided by the wind turbine output generation and V2G programs, efficient probabilistic methods are presented to attain the reliability models of these energy resources for the studies. The fluctuations in energy demands are also represented through multistate analytical models. Convolving the probabilistic models of energy hub resources by the load profiles’ models, different reliability indices are calculated taking into consideration possible operating strategies of the energy hubs. Effectiveness of the proposed methodology is validated using extensive numerical studies on an energy hub and the obtained results demonstrate its applicability in adequacy studies of active energy networks.

Designing a regulatory framework for efficient integration of distributed generation technologies

This paper focuses on the designing procedure of a regulatory framework in distribution networks with the main goal being to facilitate the integration of distributed generation (DG) units. The proposed framework is based on the concept of the reward penalty scheme (RPS) and creates effective financial incentives for distribution companies (DISCOs) in improving the quality of their services by applying DG units. To achieve this goal, reliability indices and annual energy losses of a distribution network are considered as two significant measures used in designing the structure of several RPSs. Employing these schemes, the regulators can quantify the quality of services provided by DISCOs. In order to examine the abilities of the proposed method, a case study on a test distribution system connected to bus 6 of the RBTS is performed. The obtained results show that a well-designed regulatory scheme can motivate DISCOs to adopt higher penetration of DG in such a way that their technical criteria can be improved.

Biogas-an Alternative Fuel for Distributed Generation

The electric energy sector is facing problems of fuel scarcity such as coal shortage, average losses of power transmission, distribution rise, insufficient or poor infrastructure and connectivity in distribution lines etc. Renewable energy sources are considered as clean sources of energy and when use optimally, these resources minimize environmental hazards, produce minimum secondary wastes and are sustainable based on future energy demands. Since Internal combustion engines are developed more than a century ago, IC engines are the most common of all distributed generation technologies. In this paper a review has been done on use of biogas as an alternative sustainable fuel to be used in internal combustion engine for distributed generation. The main objective of this paper is to investigate bio-gas generation, its properties, desired characteristics and factors affecting the biogas generation from organic wastes by the anaerobic digestion. The biogas primarily comprises of methane, which is used for combustion. Use of methane reduces harmful engine emissions, and keeps the environment clean. It is economical and slurry can be used as organic manure. The main aspect of stationary internal combustion engines for electrical generators use is for isolated farms and rural areas.