Exploitation Of Renewable Energy Sources Research Articles

Automating occupant-building interaction via smart zoning of thermostatic loads: A switched self-tuning approach

Load management actions in large buildings are pre-programmed by field engineers/users in the form of if-then-else rules for the set point of the thermostat. This fixed set of actions prevents smart zoning, i.e. to dynamically regulate the set points in every room at different levels according to geometry, orientation and interaction among rooms caused by occupancy patterns. In this work we frame the problem of load management with smart zoning into a multiple-mode feedback-based optimal control problem: multiple-mode refers to embedding multiple behaviors (triggered by building-occupant dynamic interaction) into the optimization problem; feedback-based refers to adopting a Hamilton-Jacobi-Bellman framework, with closed-loop control strategies using information stemming from building and weather states. The framework is solved by parameterizing the candidate control strategies and by searching for the optimal strategy in an adaptive self-tuning way. To demonstrate the proposed approach, we employ an EnergyPlus model of an actual office building in Crete, Greece. Extensive tests show that the proposed solution is able to provide, dynamically and autonomously, dedicated set points levels in every room in such a way to optimize the whole building performance (exploitation of renewable energy sources with improved thermal comfort). As compared to pre-programmed (non-optimal) strategies, we show that smart zoning makes it is possible to save more than 15% energy consumption, with 25% increased thermal comfort. As compared to optimized strategies in which smart zoning is not implemented, smart zoning leads to additional 4% reduced energy and 8% improved comfort, demonstrating improved occupant-building interaction. Such improvements are motivated by the fact that the approach exploits the building dynamics as learned from feedback data. Moreover, the closed-loop feature of the approach makes it robust to variable weather conditions and occupancy schedules.

Maximum Power Point Tracking Charge Controller for Standalone PV System

The depletion of conventional energy sources and global warming has raised worldwide awareness on the usage of renewable energy sources particularly solar photovoltaic (PV). Renewable energy sources are non-polluting sources which can meet energy demands without causing any environmental issues. For standalone PV systems, a low conversion efficiency of the solar panel and high installation cost due to storage elements are the two primary constraints that limit the widespread use of this system. As the size of the system increases, the demand for a highly efficient tracking and charging system is very crucial. Direct charging of battery with PV module will results in loss of capacity or premature battery degradation. Furthermore, most of the available energy generated by the PV module or array will be wasted if proper tracking technique is not employed. As a result, more PV panels need to be installed to provide the same output power capacity. This paper presents selection, design and simulation of maximum power point tracker (MPPT) and battery charge controller for standalone Photovoltaic (PV) system. Contributions are made in several aspects of the whole system, including selection of suitable converter, converter design, system simulation, and MPPT algorithm. The proposed system utilizes direct duty cycle technique thus simplifying its control structure. MPPT algorithm based on scanning approach has been applied by sweeping the duty cycle throughout the I-V curve to ensure continuous tracking of the maximum power irrespective of any environmental circumstances. For energy storage, lead acid battery is employed in this work. MATLAB/Simulink® was utilized for simulation studies. Results show that the propose strategy can track the MPPs and charge the battery effectively.

A holistic approach to assess the exploitation of renewable energy sources for design interventions in the early design phases

This study presents a holistic approach applied to assess the exploitation of renewable energy sources for design interventions in the early design phases in a consolidated urban environment. Concerning the cooling season, the approach implies set of environmental analyses focused on twofold assessments: (i) the use of renewable energy sources for active and passive strategies, (ii) the impact on outdoor thermal comfort of the technological solutions and cool materials installed on the buildings’ facades. From the definition of the local boundary conditions, preliminary climate analyses were conducted with dynamic simulation tools such as Ladybug and DIVA-for-Rhino, while numerical and computational fluid dynamic models, such as ENVI-met and OpenFOAM, were used to carry out microclimate and wind flow analyses. The approach is tested on two existing residential building blocks in a case study district in Bolzano (Italy). The assessment of several design interventions and building technological solutions have been studied: from the (i) addition of one-story volume on the existing buildings, to the (ii) creation of new green areas, and the (iii) installation of building integrated photovoltaic (BIPV), vertical greenery and double skin façade (DSF) systems on the building's façades. The results, divided into practice and policy implications, demonstrate that preliminary analyses play a relevant role to assess the exploitation of renewable energy sources to optimize the use of urban and building surfaces since the early design phases. High-albedo materials on the façades can counterbalance the loss of solar potential due to the overshadowing effect of the additional story. The combination of cool materials (e.g., white reflective plaster) and the increment of the buildings’ height could reduce by about 1°C the thermal discomfort registered during the high thermal peak during the day. Solar and urban airflow analyses allow optimizing the integration of BIPV in a DSF system; while the installation of green façade can reduce the air temperature locally by up to about 0.5°C.

World Decarbonization through Global Electricity Interconnections

The challenge of worldwide energy decarbonization is crucial to ensure sustainable development. The achievement of decarbonization encompasses not only a considerable exploitation of renewable energy sources, but also a paradigm shift in final energy uses towards their massive electrification. Electrification based on Global Energy Interconnections (GEI) is one of the possible pathways towards decarbonization in energy systems. In this paper, we critically discuss the idea of decarbonization through global interconnections in an ‘electricity based’ world, contrasting it against the typically desirable attributes for energy in terms of security, efficiency, sustainability, and affordability. We provide a comparative analysis of global interconnection with other internationally proposed visions of future energy scenarios. The analysis shows that the GEI option could be particularly beneficial from an environmental point of view; however, it requests deep and relevant modifications in the energy markets and regulations, in which a common framework based on the cooperation among different countries is needed.

The Analysis of Satisfaction Level from Renewable Energy Sources Usage Co-Financed from European Funds in the Rossosz Commune

Abstract Subject and purpose of work: the purpose of this article is to present the opportunities for rural development and the benefits of participation in the Regional Operational Program of the Lublin Province for the years 2007-2013, as well as the estimation of the level of satisfaction of the inhabitants of the Rossosz Commune in the Bialski Poviat, Lublin Province, using renewable energy sources co-financed by EU funds. Materials and methods: this work was created with the use of author’s interview questionnaire as the basic research tool. The survey was carried out among the inhabitants of the Rossosz Commune. Results and conclusions: participation in the “Clean Energy in the Zielawy Valley” project contributed to the development of rural areas in the Biała Podlaska Poviat of the Lubelskie Province and it was a fundamental factor enabling the installation of devices using renewable energy. The research shows that the vast majority of respondents appreciated the benefits of renewable energy installations and many of them envisage to make use of the possibility of installing renewable energy devices in the near future.

Algal biophotovoltaic (BPV) device for generation of bioelectricity using Synechococcus elongatus (Cyanophyta)

The exploitation of renewable energy sources for delivering carbon neutral or carbon negative solutions has become challenging in the current era because conventional fuel sources are of finite origins. Algae are being used in the development of biophotovoltaic (BPV) platforms which are used to harvest solar energy for bioelectricity generation. Fast-growing algae have a high potential for converting CO2 from the atmosphere into biomass and valuable products. In photosynthesis light-driven splitting of water occurs, releasing a pair of electrons and generating O2. The electrons can be harvested and converted to bioelectricity. In this study, algal biofilms of a tropical cyanobacterial strain Synechococcus elongatus (UMACC 105) were formed on two types of electrodes, indium tin oxide (ITO) and reduced graphene oxide (rGO), and investigated for use in the algal biophotovoltaic (BPV) device. The highest maximum power density was registered in the rGO-based BPV device (0.538 ± 0.014 mW m−2). This illustrates the potential of this local algal strain for use in BPV devices to generate bioelectricity in both the light and dark conditions.

Topological Considerations on the Use of Batteries to Enhance the Reliability of HV-Grids

Abstract The large amount of renewable energy sources (RESs) recently integrated within the electric power systems across the world poses new challenges for their operation. Among several viable solutions, energy storage systems are the most promising to increase reliability and flexibility. This paper proposes a novel topological and probabilistic approach to find the optimal capacity and siting of energy storage devices, in order to increase the system reliability and the hosting capacity of renewables. Wind and solar productions, generators availability, and real-time demand are modeled with proper distribution functions, and the yearly expected energy not supplied is estimated using a sequential Monte Carlo technique. Four siting policies are applied and compared to place the optimal storage capacity on eight grids with different topological characteristics. Power flows are linearized and the optimization of resources is formulated as a linear programming problem. The results show that large-scale batteries operated by the Transmission System Operator can significantly improve system reliability and exploitation of RESs. The presence of energy-hubs and small-world properties strongly increase the transmission effectiveness of weakly- and well-meshed grids. A siting policy based on the Power Transfer Distribution Factors matrix of the grid turns out to be particularly successful.

Analysis of some renewable energy uses and demand side measures for hotels on small Mediterranean islands: A case study

Tourist activity strongly influences the energy consumption and the overall load profile of communities with isolated energy systems. One example is hotel sectors on small islands that are not connected to mainland energy distribution grids. The use of solar energy systems could be a smart option for reducing energy consumption and tackling seasonal fluctuation. The operation of a weak and isolated electric grid requires attention to the management of power profiles in very short time frames. Energy storage (thermal or electric), as well as building automation control technologies, can be utilised for these aims. In this context, the present paper illustrates a study conducted at a hotel located on Lampedusa Island (Italy) that was considering some energy-retrofit scenarios dealing with the exploitation of renewable energy sources and building automation control technologies. The hotel is equipped with an air-to-water heat pump able to fulfil air conditioning and domestic hot water demands. Data concerning the hotel's energy consumption was measured during summer months while yearly data was provided by the local electric utility company. Detailed simulation models have been validated by this data and used to assess the efficacy of retrofit scenarios and their effects on the average daily electric profile.

A compact nanogrid for home applications with a behaviour-tree-based central controller

This paper proposes a nanogrid for home applications. Compactness, rapid installation and minor changes to the existing equipment are among the basic concepts behind the proposed nanogrid. With this in mind, the authors designed the proposed nanogrid as a compact object. To this aim, the power electronic converters of a typical nanogrid are no longer distributed and placed close to peripherals; they now are grouped together. The electric wires of the local power distribution system connect the grouped converters to the distributed peripherals (e.g. photovoltaic panels, batteries storage systems, loads). As a benefit, when the proposed nanogrid is installed between the meter and the switchboard of an existing dwelling, no significant changes to local equipment, devices and electrical system are required.A central controller governs the proposed nanogrid. Such a controller ensures the power balancing, implementing the continuous controllers of all the power converters belonging to the proposed nanogrid. In addition, such a controller optimizes generation and demand, implementing a decisional process based on behavioural rules.In this paper, a behaviour tree models the behavioural rules. The behaviour tree serves the discrete controller to decide the operation point of the nanogrid. The behaviour tree drives the central controller to pursue strategic targets so as to ensure power supply continuity to critical loads, maximize the exploitation of renewable energy sources and minimize power flow at the point of delivery.This paper also illustrates a single-phase 1 kW prototype of the proposed nanogrid; the prototype is subject to four tests and conditions: black start, utility failure, utility restore and over generation. Besides the capability to pursue the strategic targets mentioned above, the experimental results also demonstrate the proposed nanogrid’s capability to adjust the current imported from the utility grid, to change from grid-connected mode to stand-alone mode and vice versa, to compensate for a surge of the DC bus voltage.

A Social Assessment of the Usage of Renewable Energy Sources and Its Contribution to Life Quality: The Case of an Attica Urban Area in Greece

The aim of this paper is to analyze and evaluate the use of Renewable Energy Sources (RES) and their contribution to citizens’ life quality. For this purpose, a survey was conducted using a sample of 400 residents in an urban area of the Attica region in Greece. The methods of Principal Components Analysis and Logit Regression were used on a dataset containing the respondents’ views on various aspects of RES. Two statistical models were constructed for the identification of the main variables that are associated with the RES’ usage and respondents’ opinion on their contribution to life quality. The conclusions that can be drawn show that the respondents are adequately informed about some of the RES’ types while most of them use at least one of the examined types of RES. The benefits that RES offer, were the most crucial variable in determining both respondents’ perceptions on their usage and on their contribution to life quality.

A Novel Multicriteria Evaluation of Small-Scale LNG Supply Alternatives: The Case of Greece

Natural gas as fuel for electricity production has significant advantages, such as the reduction of environmental emissions and the lower operational cost. Due to the flexibility of gas engines, the exploitation of renewable energy sources in an area, can be maximized. The main objective of the present study is to investigate the possibility of LNG supply for sustainable electricity production in insular small-scale electricity systems. A novel multicriteria evaluation model has been developed, based on the methods of Additive Value Model, PROMETHEE and Simos approach. A set of coherent criteria has been selected, that fits perfectly with the demands of this type of problem. The proposed methodology has been implemented in four Greek islands (as they are the most indicative examples and with future perspectives to use natural gas for electricity production) and in one power plant in the mainland (as another typical example of small-scale electricity production). The evaluation process included four supply alternatives that cover the annual fuel demands of the examined regions. The obtaining ranking showed that the development of a network supplying individual small-scale terminals in a roundtrip is preferable, compared to the separate supply of each terminal.

On-site LNG production at filling stations

In the next decades fossil fuels are expected to still play a fundamental role within the energy market, contemporarily to the increased exploitation of renewable energy sources. Among all fossil fuels, natural gas is predicted to be the key source to achieve the satisfaction of the forecasted increase in energy demand, due to its lower environmental impact. In particular, great attention is being paid on the transport sector where liquefied natural gas can be seen as an interesting opportunity. In this context, this paper aims to elaborate a novel solution for liquefied natural gas production directly at filling stations. With this purpose, in this work four different liquefaction process layouts will be proposed and analyzed, considering natural gas supply grid operating at middle pressure or at low pressure. The developed configurations will be analyzed by applying an in-house developed calculation model, which enables to define the physical conditions in each section of the process and the energy fluxes of the plant.In order to define a configuration which allows to minimize the process’ energy consumption, a parametric analysis has been carried out to evaluate and compare the performance of the proposed processes. With this purpose, several performance indicators have been defined and applied to the considered scenarios.

Life Cycle Assessment of Flat Plate Solar Thermal Collectors

The environmental assessment of facilities and equipment used for the exploitation of renewable energy sources constitutes a major challenge of the environmental scientific community. Studies conducted in this field aim to define manufacturing alternatives which could mitigate the negative environmental impacts. The purpose of this study is the implementation of a comprehensive life cycle assessment for the definition of the environmental performance of flat plate solar thermal collectors. In terms of this study four alternative manufacturing scenarios are examined and a comparative assessment of the findings of the individual analyses is performed. The interpretation of the LCA findings leads to some useful conclusions concerning the improvement of the environmental performance of flat plate solar thermal collectors manufacturing. DOI: http://dx.doi.org/10.5755/j01.sace.21.4.18299

Addressing Climate Change through Sustainable Agriculture Practices in India with Reference to Biogas Programme: A Review of State of Punjab

Punjab is an agrarian state and faces a critical problem of burning of crop residues to eliminate waste from agricultural fields. This emits large amount of particulate matters and green house gases, which adversely affect human health as well as the environment. In order to address this problem, biogas can be used as it is one of the renewable sources to supply clean energy and green manure and is an excellent solution for mitigation of climate change. The National Biogas and Manure Management Programme (NBMMP) initiated in 2005 aims to reduce usage of conventional fuels in houses and in agriculture to encourage usage of renewable energy sources. The main objective of the paper is to explore the development of NBMMP scheme in Punjab while assessing the perspective of beneficiaries towards use of biogas plant from three districts of Punjab. The analytical study shows that beneficiaries are satisfied with working and performance of biogas plants and this has reduced the carbon emission through use of unprocessed biomass and has also decreased the use of synthetic chemical fertilizers in farms. The results of study highlight the gaps in promoting awareness regarding biogas plants in rural areas in Punjab.

Methodical approaches to energy supply with usage of renewable energy sources on objects of transport infrastructure of federal importance

In this article we consider the potential possibility of using renewable energy sources for the construction of transport infrastructure facilities of the Federal importance. We analyzed major promising projects for the construction of roads and bridges for the period until 2030 year, considered a step-by-step scheme for energy supply of a large facility, using the example of the Kerch bridge, and made an analysis of the potential usage of hybrid power plants based on renewable energy sources for the implementation of projects. We developed methodological approaches to the implementation of large-scale projects that would allow one to take into account not only economic efficiency, but all the positive effects that can be achieved from the project.

Small hydropower plants optimization for equipping and exploitation software application

Presently, the exploitation of renewable energy sources has exceeded the stage of unconditioned completion of as many plants as possible to provide. The amount of the electrical energy produced using renewable sources becomes notable and it is the time of economic investments in this field, which should be self-sustainable. The paper presents an effective method for small hydro-power plants (SPPs) exploitation and equipping optimization. If the installed power of the plants is P≤10MW it is considered as renewable energy source systems utilizations, and the greater, are not. Presently, there are many solutions for efficiency growth of the SPPs, but without making a consistent adaptation of the working regimes, to the affluent debts regimes, offered by the rivers on which the plants are built. Generally, it is accepted to be installed an ensemble of two turbines, of the same type, identical or of different sizes, in a current SPP. The turbine could be of classical types (Francis or Kaplan), with high efficiency near the nominal exploitation regime, or other types, with a more flexible efficiency characteristic, but with a much lower efficiency. The paper proposes an algorithm for an automatically flow distributor, which will split the affluent flow between the turbines, in order to obtain a maximum of output power of the plant. According to this solution, the plants can be equipped with classical efficient turbines (Francis or Kaplan), which have higher efficiencies but a sharp feature of efficiency, then the special types of turbines (example, Banki), recommended by flat efficiency characteristics. These last types of turbines are suitable for SPPs because they are working at acceptable efficiencies for a large range of affluent debts. Another important advantage of the proposed solution is the low level of the investment in the distributor mechanism and its accessories, and the opportunity to equip with this distributor small hydropower plants already built and equipped with two turbines, even they are identical or of different sizes.

A heat pump coupled with photovoltaic thermal hybrid solar collectors: A case study of a multi-source energy system

The development of heat pump technology in the residential sector can lead, and has led to a reduction in greenhouse emissions and enhanced exploitation of renewable energy sources, including solar energy which represents the renewable source for excellence. The current study examines a multi-source energy system equipped with photovoltaic thermal hybrid solar collectors, two storage tanks for the heat source and the domestic hot water respectively and heat pumps for the space heating and domestic hot water production of a single-family dwelling located in North East Italy. Air, solar, and ground source heat pumps were analysed. Some configurations were investigated utilizing computer simulations based on a mathematical model developed to evaluate the electrical and thermal performances of hybrid solar collectors. A smart control unit capable of identifying the best heat source for the heat pump and of considering the possibility of injecting heat harvested by solar collectors into the ground during the summer period was analysed. The investigation uncovered that the multi-energy source systems were responsible for increasing the energy efficiency by 16–25% with respect to an ordinary air to water heat pump system. The simulations also revealed that the energy efficiency of the air-solar source system was slightly lower than that linked to the other configurations including a ground source heat pump.

Load Disturbance Rejection Based PID Controller for Frequency Regulation of a Microgrid

<p>Today’s world is very much concerned to reduce green house gas emission from the conventional thermal power plants as cutting down emissions from transport and heating sector may not be realistic in the near future. To reduce pollution from electrical power sources, the world is now marching towards usage of renewable energy sources (RESs). These sources being small in capacity are mostly connected at the distribution voltage level. This indirectly reduces transmission and distribution losses as the sources are around the load. This distribution system having small scale energy sources is called as a microgrid or active distribution network. Microgrid operates generally in a grid connected mode. However, circumstances such as fault, voltage sag and large frequency oscillations in the main grid may force the active distribution network to be disconnected from the main grid and operate as an isolated microgrid . During this isolation there will be change in power output from the controllable microsources which are to be regulated properly to have a stable operation in regard to power balance and frequency of operation within the isolated microgrid. An autonomous isolated microgrid comprising both controllable & uncontrollable sources. Like solar, wind, diesel generator(DG), aqua electrolyzer(AE), fuel cell(FC), a battery energy storage system(BESS), and fly wheel(FW) are considered. Solar, wind, DG and FC are power generating source & BESS, FW, AE as energy storage element. The generated hydrogen by an AE is used as fuel for a FC. The power system frequency deviates for the sudden change in load demand and the real power generation. The output power of DG, FC, BESS, FW and power absorbed by AE is regulated by using controller such that frequency of the system is controlled. Controller used is proportional plus integral plus derivative (PID). Load Disturbance Rejection(LDR) is used for tuning of controller gains of the proposed hybrid system. This uses the chien-hornes-resnick(CHR) setting with 20% overshoot. Design of p-f droop(frequency regulation parameter) for different controllable source in microgrid using bode plot stability criterion. The system response with Modified LDR based controller, LDR based controller and classical controller are compared. Investigation shows that Modified LDR based controller gives best response amongst these three methods.</p>

Architectural and energy refurbishment of the headquarter of the University of Teramo

The recent seismic events, which distressed the population of the Central Italy, have caused the incompliance with national safety standards of several historical buildings. In particular, the headquarter of the University of Teramo revealed some structural damages which make necessary to operate a restoration of the buildings. It represents a rare opportunity for investigating possible applications of a cluster of technologies and approaches largely recognized as efficient and high-performing to such particular buildings in order to achieve an upgrading in terms of energy efficiency. The proposal includes the improvement of the exploitation of renewable energy sources through adequate systems, which do not modify the visual perception of the pavilions. In that regards, the required electricity could be produced by a PV roofing installed on the parking area, while a biomass boiler and an absorption chiller could allow supplying the thermal and cooling needs. Furthermore, the rain water recovery system permits to reduce the exploitation of potable water for uses which do not require a high quality, such as irrigation. On the other hand, the envelope energy efficiency could be enhanced by applying passive strategies for reducing the heat losses (winter conditions) and gains (summer conditions) through façades and roof. The results confirmed the reliability of those interventions and the consequent advantages from an economical and energy point of view.

Linking the Power and Transport Sectors—Part 1: The Principle of Sector Coupling

The usage of renewable energy sources (RESs) to achieve greenhouse gas (GHG) emission reduction goals requires a holistic transformation across all sectors. Due to the fluctuating nature of RESs, it is necessary to install more wind and photovoltaics (PVs) generation in terms of nominal power than would otherwise be required in order to ensure that the power demand can always be met. In a near fully RES-based energy system, there will be times when there is an inadequate conventional load to meet the overcapacity of RESs, which will lead to demand regularly being exceeded and thereby a surplus. One approach to making productive use of this surplus, which would lead to a holistic transformation of all sectors, is “sector coupling” (SC). This paper describes the general principles behind this concept and develops a working definition intended to be of utility to the international scientific community. Furthermore, a literature review provides an overview of relevant scientific papers on the topic. Due to the challenge of distinguishing between papers with or without SC, the approach adopted here takes the German context as a case study that can be applied to future reviews with an international focus. Finally, to evaluate the potential of SC, an analysis of the linking of the power and transport sectors on a worldwide, EU and German level has been conducted and is outlined here.