Distributed Energy Production Research Articles

Thermodynamic analysis of a condensing evaporator in an evaporative gas turbine cycle

Low efficiency is the main stumbling block preventing the widespread adoption of small-scale gas turbines in distributed energy production. The evaporative gas turbine cycle has been proposed as a way to improve efficiency, but the large number of components required make the configuration complex and expensive. The condensing evaporator is a component that simplifies the evaporative gas turbine cycle. The heat and mass exchanger device is designed for an externally fired application, which means that the flue gas stream is replaced by moist air. The air-water mixture condenses inside a tube bank, releasing heat to the evaporating water film on the other side of the tubes. Similar inventions include the tubular humidifier and the Maisotsenko compressed air saturator, which also aim to make the evaporative gas turbine cycle more economically feasible. Available theory focuses on either humidification towers or evaporative condensers in HVAC applications. The tubular humidifier has been analyzed in a similar manner as humidification tower since the flow configurations of the two components are similar. However, the theory of humidification towers is not directly applicaple to the condensing evaporator. This study proposes a method of analysis of the condensing evaporator in power generation.

PHIL Test Bench for Online-Identification Methods of Complex Power Grid

Power generation is shifting towards renewable and distributed energy production due to increased awareness of climate change and the recent advancements in renewable technologies. Distributed energy generation typically consists of wind and solar power plants, virtually all of which are connected to power grid by an inverter. As a consequence, the stability issues generated by the active power electronic devices are continuously increasing. The increased requirements for the functionality of the grid-connected inverters require a sophisticated test bench for experimentation. Power hardware-in-the-loop methods allow combining of the simulations to actual hardware, and thus, enable running experiments on real devices in time-varying conditions. This paper presents the use of a power hardware-in-the-loop test bench for stability studies of grid-connected systems. Experimental MIMO measurements based on pseudo-random sequences injected with a three-phase grid-connected inverter are presented and used to demonstrate the effectiveness of the proposed method.

Distributed energy production in a polycentric scenario: policy reforms and community management

Any discussion of distributed energy systems inevitably centres on how they compare with the large energy systems, i.e. the traditional centralised model of energy production, and on the viability of local energy systems as alternatives in terms of efficiency and sustainability. At present, the debate on local energy systems and distributed energy production hinges mainly on questions of technology and engineering; at most, some reflections on economy are thrown in. What we believe is essential is to cast the net wider and include other dimensions. In particular, we also need to consider in greater depth the organisational and institutional issues involved – until now, less considered and discussed. In this perspective, the main question addressed by the present article is if and how new forms of local organisations can provide the crucial catalyst for a new polycentric distributed energy scenario.

Impact for the DSO of integrating storage systems in a low-voltage grid with distributed energy resources

Implementation of solar photovoltaic (PV) systems in low-voltage grids (LVGs) has increased in recent years and future perspectives account for it to keep growing. Technology advancements followed by large commercialisation, led to a fast decrease of PV systems prices which made them a competitive solution for distributed energy production. Such changes require a reformulation of the way electricity distribution is perceived and present new challenges for distribution system operators (DSO) that have to find innovative solutions and might need to invest in new technologies such as batteries to manage energy supply. The considerable improvement in battery systems in the past few years lead to the belief that it will play an important role in future electric grids coupled with PV systems. With this assumptions, it is important first to understand the changes that occur in consumption and production load profiles along the year. As a result of this study, it was observed that, for the analysed LVG, it would be more economically efficient for the electric system, composed by clients and distributors, to introduce batteries at a client's level and that the impact for the DSO will be negligible from a grid losses and grid violations point of view.

On the hydrodynamics of membrane assisted fluidized bed reactors using X-ray analysis

The application of membrane assisted fluidized bed reactors for distributed energy production has generated considerable research interest during the past few years. It is widely accepted that, due to better heat and mass transfer characteristics inside fluidized bed reactors, the reactor efficiency can outperform other reactor configurations such as packed bed units. Although many experimental studies have been performed to demonstrate and monitor the long term performance of membrane assisted fluidized bed reactors, the hydrodynamics of membrane-assisted fluidized bed reactors has thus far only been studied in pseudo-2D geometries. In this work the solids concentration inside a real 3D fluidized bed reactor geometry was measured using a fast X-ray analysis technique. Experiments were conducted in absence and presence of two different membrane modules with different configurations and number of membranes (porous Al2O3 tubes) for two types of particles, viz. 400–600μm polystyrene (Geldart B type) and 80–200μm Al2O3 (Geldart A/B type). Results from the experiments with Geldart B type particles revealed that the membrane modules (both the membranes and the spacers) can significantly reduce bubble growth along the fluidized bed resulting in a smaller average bubble diameter, expected to improve the bubble-to-emulsion mass transfer, whereas for the experiments with fine Geldart A/B particles, and at a very high extraction values (40% of the inlet flow), a densified layer with high solids concentration was formed near the membrane, which may impose an additional mass transfer resistance for gas components to reach the surface of the membranes (concentration polarization). The results from this study help designing and optimizing the positioning of the membranes and membrane spacers for optimal performance of fluidized bed membrane reactors.

A life cycle assessment of distributed energy production from organic waste: Two case studies in Europe

By means of the life cycle assessment methodology, the purpose of this study is to assess the environmental impact when biomethane from organic waste produced at residential level is used to supply energy to a group of dwellings in the distributed generation paradigm. Three different Combined Heat and Power systems, such as fuel cells, Stirling engine and micro gas turbine, installed at household level are assessed in two different settings: one in Northern Europe (UK) and one in Southern Europe (Italy). Different operating strategies are investigated for each technology. Moreover, marginal electricity production technologies are analysed to assess their influence on the results. This study has demonstrated that the type of bio-methane fed micro-CHP technology employed has a significantly different environmental impact: fuel cells are the most environmentally friendly solution in every category analysed; Stirling engines, although can supply heat to the largest number of dwellings are the least environmentally friendly technology. However, key factors investigated in the model presented in this paper influence the decision making on the type of technology adopted and the operating strategy to be implemented.

Futures of distributed small-scale renewable energy in Finland — A Delphi study of the opportunities and obstacles up to 2025

Distributed small-scale renewable energy (RE) production and markets expand globally. Policies play a major role in the growth. Distributed systems can help in achieving official targets, as well as offer economic opportunities for small-scale energy producers and the producers, retailers and installers of energy devices. However, small-scale energy production in households, farms or small enterprise has received relatively little attention in Finland to date. The opportunities and challenges of distributed small-scale RE sector in Finland were assessed in this study. Data was gathered using a Delphi-based method. 26 experts within the RE technology chain participated. Results were discussed and further elaborated in an expert workshop. Five scenarios representing views of the expert panel were produced for the development up to 2025: 1) Stagnation, 2) Stable slow growth, 3) Multifaceted reform, 4) Solar business prosperity, and 5) Electricity expansion at the grass root level. In no scenario was significant RE growth combined with little governmental support. Underdeveloped business concepts, insufficient information and availability of professional services, lacking profitability of small-scale energy sales, and the price of production systems were identified as key obstacles for distributed energy production in Finland. Removing barriers in domestic markets would also support exports.

Chemical Energy Conversion as Enabling Factor to Move to a Renewable Energy Economy

Abstract The role of chemical energy storage and solar fuels as key elements for the sustainable chemical and energy production is discussed in this concept paper. It is shown how chemical energy storage, with the development of drop-in carbon-based solar fuels, will play a central role in the future low-carbon economy, but it is necessary to consider its out-of-the-grid use, rather than being limited to be a tool for smart grids. Related aspects discussed are the possibility to: (i) enable a system of trading renewable energy on a world scale (out-of-the-grid), including the possibility to exploit actually unused remote resources, (ii) develop a solar-driven and low-carbon chemical production, which reduces the use of fossil fuels and (iii) create a distributed energy production, going beyond the actual limitations and dependence on the grid.

Future energy services: empowering local communities and citizens

Purpose– The purpose of this paper is to examine the future prospects of innovative services linked to sustainable energy systems.Design/methodology/approach– Service perspective is examined in the context of socio-technical transition and linked to the bottom-up and top-down social processes that foster sustainability. The foresight method applied is trend analysis.Findings– Two groups of trends were identified: the trends driven by technological development and the trends focussing on societal, managerial and consumer issues. The former consists of renewable energy sources, hybrid solutions, smart grids and smart energy markets. The latter involves distributed energy production, demand response, optimisation of sustainability and the role of energy as an opportunity and as service. The study reveals that energy is increasingly understood as a comprehensive and tailor-made service solution for communities and individual households. Consumers will enter the energy market as active participants; it raises the need for many types of services.Research limitations/implications– Deepening of understanding is required in several topics of this study, and more formal methods of foresight are needed to test the generalisability of its qualitative results.Practical implications– More effective policy measures are needed for fostering new services and social and system innovations in the area of sustainable energy. Innovation management practices should be developed in these areas.Originality/value– The paper aims to narrow the research gap linked to foresight in services by examining services in the area of sustainable energy systems – one of the “grand challenges” today.

Project appraisal for small and medium size wind energy installation: The Italian wind energy policy effects

In the last few years, the distributed energy production from small wind turbines (i.e.<200kWp) has developed into a relevant business opportunity for different investors in Italy. The market, especially in Italy, has rapidly grown, achieving 9MWp only in 2011, with an increase from 1.5MW in 2009 to 13.3MW at the end of 2011. This paper reports the results of a case study on the installation of several small wind turbines. It aims to provide an analysis of the conditions in Italy that make it possible to install these machines and offer a reliable reference for designing, planning, and controlling small wind turbine projects while focusing on the strategic variables of time, cost, and quality used by typical enterprises in the investment projects. The results are relevant to investors as well as engineering, procurement, and construction companies involved in this new sector, which must understand Italy’s renewable energy policy and its effects in practice. Moreover, certain national energy policy conclusions are reported and discussed in this paper. To properly study the sector, the data on time, cost and quality are analysed using typical project management tools.

A Management Application for the Small Distributed Generation Systems of Electric Power Based on Renewable Energy

A multitude of factors, from the technological ones to the availability of primary resources and not least the current trend of electricity production at small capacities, led to a significant development of distributed generation. The problems they bring requires a special attention provided by supervisory control and data acquisition (SCADA) solutions. These systems can include or can be extended with new facilities such as the one proposed in this paper.The present paper aims to implement a management solution for isolated or connected to local grid systems of energy production from renewable sources, with small production capacity. The idea at the basis of the proposed solution focuses on using the existing energy management principles for distributed energy production facilities and on the accessible existing communication infrastructure. The proposed system allows the management of multiple energy production systems based on renewable energy including the using of mobile devices.

Top ten most cited papers published in IJABE according to google scholar

1. Overview of biomass pretreatment for cellulosic ethanol production Yi Zheng, Zhongli Pan, Ruihong Zhang Int J Agric & Biol Eng, 2009; 2(3) Cited times: 106 2. Current status of adoption of no-till farming in the world and some of its main benefits Rolf Derpsch, Theodor Friedrich, Amir Kassam, Li Hongwen Int J Agric & Biol Eng, 2010; 3(1) Cited times: 49 3. Effect of nitrogen and extraction method on algae lipid yield Ying Shen, Zhijian Pei, Wenqiao Yuan, Enrong Mao Int J Agric & Biol Eng, 2009; 2(1) Cited times: 25 4. Size matters: small distributed biomass energy production systems for economic viability Roger Ruan, Paul Chen, Richard Hemmingsen, Vance Morey, Doug Tiffany Int J Agric & Biol Eng, 2008; 1(1) Cited times: 12 5. Mathematical modeling of microwave- assisted convective heating and drying of grapes Gokhan Bingol, Zhongli Pan, John S.Robert, Y. Onur Devres, Murat O.Balaban Int J Agric & Biol Eng, 2008; 1(2) Cited times: 10 6. Nondestructive assessment of quality of Nanfeng mandarin fruit by a portable near infrared spectroscopy Sun Xudong, Zhang Hailiang, Liu Yande Int J Agric & Biol Eng, 2009; 2(1) Cited times: 10 7. Optimization of Japanese beech hydrolysis treated with batch hot-compressed water by response surface methodology L

Optimal Operating Strategies and Management for Smart Microgrid Systems

AbstractSmart microgrid systems are distributed energy production systems intended to increase local renewable energy use and power supply reliability and lower transmission loss and carbon dioxide...

Top ten most cited papers published in IJABE according to google scholar

1. Overview of biomass pretreatment for cellulosic ethanol production Yi Zheng, Zhongli Pan, Ruihong Zhang Int J Agric & Biol Eng, 2009; 2(3) Cited times: 106 2. Current status of adoption of no-till farming in the world and some of its main benefits Rolf Derpsch, Theodor Friedrich, Amir Kassam, Li Hongwen Int J Agric & Biol Eng, 2010; 3(1) Cited times: 49 3. Effect of nitrogen and extraction method on algae lipid yield Ying Shen, Zhijian Pei, Wenqiao Yuan, Enrong Mao Int J Agric & Biol Eng, 2009; 2(1) Cited times: 25 4. Size matters: small distributed biomass energy production systems for economic viability Roger Ruan, Paul Chen, Richard Hemmingsen, Vance Morey, Doug Tiffany Int J Agric & Biol Eng, 2008; 1(1) Cited times: 12 5. Mathematical modeling of microwave- assisted convective heating and drying of grapes Gokhan Bingol, Zhongli Pan, John S.Robert, Y. Onur Devres, Murat O.Balaban Int J Agric & Biol Eng, 2008; 1(2) Cited times: 10 6. Nondestructive assessment of quality of Nanfeng mandarin fruit by a portable near infrared spectroscopy Sun Xudong, Zhang Hailiang, Liu Yande Int J Agric & Biol Eng, 2009; 2(1) Cited times: 10 7. Optimization of Japanese beech hydrolysis treated with batch hot-compressed water by response surface methodology L

Feasibility study of a spouted bed gasification plant

We have studied the feasibility of building a biomass gasification plant with an innovative spouted bed reactor for distributed energy production. The process was simulated using a thermodynamic approach (concentrated parameter model) using LIBPF, a C++ process modelling library. A nominal size of about 100kW total thermal power was chosen.Fifteen chemical species were taken into account (dry and ash-free (daf) biomass, C, CH4, CO, CO2, H2, H2O, N2, NH3, O2, methanol, ethylene, phenol, naphthalene and ash).After preliminary simulation trials and unit operation sizing, a proper plant configuration was developed.The air ER (equivalent ratio), syngas condensate recycling and biomass moisture fraction were studied in compliance with the constraint of the gas flow required for a stable spouting regime (120m3/h) and optimal gasification temperature (930°C).A working condition map was obtained in terms of air ER and syngas condensate recycling for different biomass moisture fractions and the main plant performance parameters were studied.The net electrical yield was found to vary from the ideal maximum of 25% to a minimum of about 17% and the heat cogeneration yield was found to vary in the range 45–48% for all the process conditions studied.

Ready or not, here comes the smart grid!

The “smart grid” represents one of the greatest potential advances in electricity delivery infrastructure in the past century. While the technologies that collectively comprise the smart grid have existed for decades, the potential for changing the way that electricity is generated, delivered, utilized and priced is revolutionary. Not surprisingly, many countries have undertaken initiatives to rollout smart grid infrastructure at an aggressive pace. Understanding the fundamental changes that the smart grid is likely to introduce is important for the development of future energy scenarios and the environmental, social and economic implications of these scenarios. Here we present an overview of the emerging smart grid and outline a few implications for the energy modeling community. Specifically, we discuss the potential for the smart grid to act as an enabling technology for renewable energy integration, price-responsive electricity demand, electrified transportation and distributed energy production as examples of how the smart grid may fundamentally change future energy system scenario development. The smart grid is being deployed and implemented much faster than we are able to fully consider its implications, and in some cases public policy has a long way to go before it catches up with the pace of smart grid technology deployment.

How internet concepts and technologies can help green and smarten the electrical grid

Several powerful forces are gathering to make fundamental and irrevocable changes to the century-old grid. The next-generation grid, often called the 'smart grid,' will feature distributed energy production, vastly more storage, tens of millions of stochastic renewable-energy sources, and the use of communication technologies both to allow precise matching of supply to demand and to incentivize appropriate consumer behaviour. These changes will have the effect of reducing energy waste and reducing the carbon footprint of the grid, making it 'smarter' and 'greener.' In this position paper, we discuss how the concepts and techniques pioneered by the Internet, the fruit of four decades of research in this area, are directly applicable to the design of a smart, green grid. This is because both the Internet and the electrical grid are designed to meet fundamental needs, for information and for energy, respectively, by connecting geographically dispersed suppliers with geographically dispersed consumers. Keeping this and other similarities (and fundamental differences, as well) in mind, we propose several specific areas where Internet concepts and technologies can contribute to the development of a smart, green grid. We also describe some areas where the Internet operations can be improved based on the experience gained in the electrical grid. We hope that our work will initiate a dialogue between the Internet and the smart grid communities.

Dynamic optimization for distributed energy production

AbstractEnergy is essential for human beings and activities. Renewable resources can be considered a challenge to provide energy for future mankind. However, technological improvements are needed as well as tools to support decisions about the mix of energies to adopt and their integration in the electrical network. In this work, a distributed energy production and storage system (involving technologies to use energy from sun, wind and biomass) is formalized. A general optimal control problem to select the energy flows to be sent to the different storages and demands from the production plants is also defined. The dynamic model is tested with Savona Province (Italy) data.

Model-Based Method for Combustion Power Stabilisation in Grate-Fired Boilers

Abstract A model-based control strategy for the compensation of combustion power fluctuations in small-scale biomass fired boilers is presented. Delay-free heat output model is obtained by utilising combustion temperature measurements. Local principal component regression models are constructed to cope with changing combustion conditions and redundant input variables found by data analysis. The modelling approach was validated using data from 30 kW and 300 kW boilers. Usability of the discussed monitoring method for compensating fuel power disturbances by the primary air control was tested in practice. The results imply that modelling information can be utilised as a part of the control structure, enabling the cost-effective way to reduce emissions and maintain optimal combustion conditions in the distributed energy production with solid biomass fuels.

Low Cost Embedded Controlled Full Bridge LC Parallel Resonant Converter

Low Cost Embedded Controlled Full Bridge LC Parallel Resonant ConverterIn this paper the converter requirements for an optimum control of an electrolyser linked with a DC bus are analyzed and discussed. An electrolyser is a part of renewable energy system which generates hydrogen from water electrolysis. The hydrogen generating device is part of a complex system constituted by a supplying photovoltaic plant, the grid and a fuel cell battery. The characterization in several operative conditions of an actual industrial electrolyser is carried out in order to design and optimize the DC/DC converter. A dedicated zero voltage switching DC/DC converter is presented and simulated inside the context of the distributed energy production and storage system. The proposed supplying converter gives a stable output voltage and high circuit efficiency in all the proposed simulated scenarios. The adopted DC/DC converter is realized in a full-bridge topology technique in order to achieve zero voltage switching for the power switches and to regulate the output voltage. This converter has advantages like high power density, low EMI and reduced switching stresses. The simulation results are verified with the experimental results.