Co-combustion of biomass and solid fuels from wastes in existing highly efficient power plants is a low-cost solution that can be applied quickly and with low effort to mitigate climate change. Circulating fluidized bed combustion has several advantages when it comes to co-combustion, such as high fuel flexibility. The operational flexibility of circulating fluidized bed (CFB) co-combustion is investigated in a 1 MWth pilot plant. Straw pellets and refuse-derived fuel (RDF) are co-combusted with lignite at full load and part loads. This study focusses on the impact on the hydrodynamic conditions in the fluidized bed, on the heat transfer to the water/steam side of the boiler, and on the flue gas composition. The study demonstrates the flexibility of CFB combustion for three low-rank fuels that differ greatly in their properties. The co-combustion of RDF and straw does not have a negative effect on hydrodynamic stability. How the hydrodynamic conditions determine the temperature and pre... [more]

In this research, the modeling, simulation, and analysis of the energy conversion equations that describe the behavior of a hybrid photovoltaic and wind turbine system that supplies electrical energy to an average organic architecture is performed. Organic constructions have a philosophy that seeks to understand and integrate into the site, taking advantage of the natural potentials and their resources of the surrounding areas so that they form part of a unified and correlated composition. The rooms in these buildings are designed similar to a bean, inspired by the uterus of a mother and her child who are comfortable, at rest, and alive. We are left with the task of spreading this research to integrate its energy potential from the surroundings and transform it into autonomous electrical energy. In this article, a numerical model based on the fundamental equations was developed and coded, and the results compared with experimental data with a real airplane-type system located in a remo... [more]

Electric vehicles (EVs) are one of a prominent solution for the sustainability issues needing dire attention like global warming, depleting fossil fuel reserves, and greenhouse gas (GHG) emissions. Conversely, EVs are shown to emit higher emissions (measured from source to tailpipe) for the fossil fuel-based countries, which necessitates renewable energy sources (RES) for maximizing EV benefits. EVs can also act as a storage system, to mitigate the challenges associated with RES and to provide the grid with ancillary services, such as voltage regulation, frequency regulation, spinning reserve, etc. For extracting maximum benefits from EVs and minimizing the associated impact on the distribution network, modelling optimal integration of EVs in the network is required. This paper focuses on reviewing the state-of-the-art literature on the modelling of grid-connected EV-PV (photovoltaics) system. Further, the paper evaluates the uncertainty modelling methods associated with various parame... [more]

Thermoelectric generation technology is considered to be one of the viable methods to convert waste heat energy directly into electricity. The utilization of this technology has been impeded due to low energy conversion efficiency. This paper aims to improve the energy conversion efficiency of the thermoelectric generator (TEG) model with a novel maximum power point tracking (MPPT) technique. A variable fractional order fuzzy logic controller (VFOFLC)-based MPPT technique is proposed in the present work in which the operating point of the TEG is moved quickly towards an optimal position to increase the energy harvesting. The fraction order term α, introduced in the MPPT algorithm, will expand or contract the input domain of the fuzzy logic controller (FLC to shorten the tracking time and maintain a steady-state output around the maximum power point (MPP). The performance of the proposed MPPT technique was verified with the TEG model by simulation using MATLAB /SIMULINK software. Then,... [more]

In order to combat climate change, many countries have promised to bolster Renewable Energy (RE) production following the Paris Agreement with some countries even setting a goal of 100% by 2025. The reasons are twofold: capitalizing on carbon emissions whilst concomitantly benefiting from reduced fossil fuel dependence and the fluctuations associated with imported fuel prices. However, numerous countries have not yet made preparations to increase RE production and integration. In many instances, this reluctance seems to be predominant in energy-rich countries, which typically provide heavy subsidies on electricity prices. With such subsidies, there is no incentive to invest in RE since the time taken to recoup such investments would be significant. We develop a model using a Neural Network (NN) regression algorithm to quantitatively illustrate this conjecture and also use it to predict the reduction in electricity price subsidies required to achieve a specified RE production target. Th... [more]

Philippine off-grid islands are mostly electrified by diesel generators, resulting in costly electricity that is interrupted by fuel supply disruptions. The archipelagic nature of the country also impedes off-grid electrification due to the high capital cost of grid extension. Transitioning from diesel-only systems to hybrid renewable energy systems and interconnecting the island microgrids can solve these problems while promoting cleaner energy production. In this work, a comparative study on decentralized and clustered hybrid renewable energy system microgrids in the Polillo group of islands in the Philippines, using HOMER Pro, was performed. Microgrids comprising solar photovoltaics, lithium-ion battery energy storage, and diesel generators were designed on each island. Clustered systems encompassing multiple islands in the island group were simulated by also considering the least-cost interconnection paths. The techno-economics of each decentralized or clustered system and the four... [more]

Data on the thermochemical plants fed by solid biomass in the north-west area of Italy (Liguria, Lombardy, Piedmont and Aosta Valley) have been organised, analysed and discussed. Moreover, the biomass availability and potential has been evaluated. A total of 28,167 plants have been categorised according to their typology and output: thermo-electric power plants for electricity production, thermal plants for heat production, cogeneration plants for combined heat and electricity production and district heating installations for local heating purposes. In general, separate observations for the different provinces may be drawn. Liguria stands out as the most evident case of under-exploited biomass potential, followed by Aosta Valley, which, however, is rich in hydroelectricity. Lombardy and Piedmont are more virtuous and have several plants in their territory. The construction of new plants and the upgrade of existing ones may bring noteworthy benefits, as well as the use of added value su... [more]

In this paper, the development of the wind energy sector in 28 European Union countries in 2017 is described. By means of taxonomic methods—i.e., Ward’s method and the Wroclaw taxonomic methods—clusters of countries similar in terms of their potential and level of development of the wind energy sector in the EU are distinguished. The main purpose of the paper is to separate and cluster EU countries due to the current development potential of the wind energy sector and determinants stimulating the development of this sector. By means of the ranking methods of linear ordering (Technique for Order of Preference by Similarity to Ideal Solution—TOPSIS method), a ranking of EU countries that defines their position in the development of this very important wind energy sector was determined. The results show that the research hypothesis of a great diversity of EU countries considering the development potential of the wind energy sector is justified. The countries of the former European Union,... [more]

The optimal reactive power dispatch (ORPD) problem is an important issue to assign the most efficient and secure operating point of the electrical system. The ORPD became a strenuous task, especially with the high penetration of renewable energy resources due to the intermittent and stochastic nature of wind speed and solar irradiance. In this paper, the ORPD is solved using a new natural inspired algorithm called the marine predators’ algorithm (MPA) considering the uncertainties of the load demand and the output powers of wind and solar generation systems. The scenario-based method is applied to handle the uncertainties of the system by generating deterministic scenarios from the probability density functions of the system parameters. The proposed algorithm is applied to solve the ORPD of the IEEE-30 bus system to minimize the power loss and the system voltage devotions. The result verifies that the proposed method is an efficient method for solving the ORPD compared with the state-o... [more]

This paper reviews and analyses a decarbonization policy called the Tradable Energy Quotas (TEQs) system developed by David Fleming. The TEQs system involves rationing fossil fuel energy use for a nation on the basis of either a contracting carbon emission budget or scarce fuel availability, or both simultaneously, distributing budgets equitably amongst energy-users. Entitlements can be traded to incentivize demand reduction and to maximize efficient use of the limited entitlements. We situate this analysis in the context of Joseph Tainter’s theory about the development and collapse of complex societies. Tainter argues that societies become more socio-politically and technologically ‘complex’ as they solve the problems they face and that such complexification drives increased energy use. For a society to sustain itself, therefore, it must secure the energy needed to solve the range of societal problems that emerge. However, what if, as a result of deep decarbonization, there is less en... [more]

Investments in renewable energy sources are an important direction in the development of modern economies. Motivating organizations to include appropriate investments in their development strategies becomes an essential issue. It seems clear that organizations need to see the long-term benefits of such investments in order to follow this trend. This article presents a thesis that assumes that from the microeconomic perspective, such investments are conducive to the implementation of various goals of the organization, causing the phenomenon of resonance in spheres such as the implementation of the sustainable development strategy, the level of innovation in the organization, brand image, and brand equity. The survey method was carried out on a sample of 143 industrial companies in the food industry in order to verify the hypotheses based on previous examples. Among the most important findings, it should be noted that investments in renewable energy sources make a significant contributio... [more]

Emerging photovoltaic (PV) technologies have a potential to address the shortcomings of today’s energy market which heavily depends on the use of fossil fuels for electricity generation. We created inventories that offer insights into the environmental impacts and cost of all the materials used in emerging PV technologies, including perovskites, polymers, Cu2ZnSnS4 (CZTS), carbon nanotubes (CNT), and quantum dots. The results show that the CO2 emissions associated with the absorber layers are much less than the CO2 emissions associated with the contact and charge selective layers. The CdS (charge selective layer) and ITO (contact layer) have the highest environmental impacts compared to Al2O3, CuI, CuSCN, MoO3, NiO, poly (3-hexylthiophene-2,5-diyl (P3HT)), phenyl-C61-butyric acid methyl ester (PCBM), poly polystyrene sulfonate (PEDOT:PSS), SnO2, spiro-OMeTAD, and TiO2 (charge selective layers) and Al, Ag, Cu, FTO, Mo, ZnO:In, and ZnO/ZnO:Al (contact layers). The cost assessments show t... [more]

We developed an inflatable solar dryer for mushroom drying, which was adapted from the Solar Bubble DryerTM originally designed for paddy drying. The improved dryer with an added perforated elevated floor ensured the quality without any requirement of mixing or turning of the mushrooms during drying. Its drying performance and economic feasibility were evaluated through determination of the drying parameters including moisture content (MC) reduction, mushroom quality, energy efficiency, greenhouse gas emissions, and cost-benefits ratio. Mushroom MC was reduced from 90% down to 40−60% within 2−4 h, corresponding to the drying rate at this stage of 10−20% h−1. At the next stage, it took about 4−6 h corresponding to a drying rate of 2−10% h−1 to reach the required product MC of 8−10%. The color of the dried mushrooms still remained white-cream. The drying process required 4.57 MJ, emitted 0.33 kg CO2e, and required an input cost of 1.86 $US kg of dry product. For the specific case in the... [more]

Following the recent development trend in the struggle for cleaning the earth’s environment, solar is the one of most promising area that can partially be used as a replaceable energy from non-renewable fuel sources. As such, it plays a significant role in protecting the environment from global warming. As solar power does not emit harmful gases into the atmosphere, its production, distribution, setup, and operation are vital should the production remain constant. Even solar energy waste emissions are small; when compared to current energy sources, the amount of harmful gases is negligible. This paper presented an integrated approach for site of solar plants by using data envelopment analysis (DEA) and Fuzzy Analytical Network Process (FANP). Furthermore, these integrated methodologies, incorporated with the most relevant parameters of requirements for solar plants, are introduced. First, the paper considers an integrated hierarchical DEA and FANP model for the optimal geographical loc... [more]

This study proposes a building energy simulation (BES) model of an air-to-water heat pump (AWHP) system integrated with a multi-span greenhouse using the TRNSYS-18 program. The proposed BES model was validated using an experimental AWHP and a multi-span greenhouse installed in Kyungpook National University, Daegu, South Korea (latitude 35.53° N, longitude 128.36° E, elevation 48 m). Three AWHPs and a water storage tank were used to fulfill the heat energy requirement of the three-span greenhouse with 391.6 m2 of floor area. The model was validated by comparing the following experimental and simulated results, namely, the internal greenhouse temperature, the heating load of the greenhouse, heat supply from the water storage tank to the greenhouse, heat pumps’ output water temperature, power used by the heat pumps, coefficient of performance (COP) of the heat pump, and water storage tank temperature. The BES model’s performance was evaluated by calculating the root mean square error (RMS... [more]

The increasing number of prosumers and the accompanying greater use of decentralised energy resources (DERs) bring new opportunities and challenges for the traditional electricity systems and the electricity markets. Microgrids, virtual power plants (VPPs), peer-to-peer (P2P) trading and federated power plants (FPPs) propose different schemes for prosumer coordination and have the potential of becoming the new paradigm of electricity market and power system operation. This paper proposes a P2P trading scheme for energy communities that negotiates power flows between participating prosumers with insufficient renewable power supply and prosumers with surplus supply in such a way that the community welfare is maximized while avoiding critical grid conditions. For this purpose, the proposed scheme is based on an Optimal Power Flow (OPF) problem with a Multi-Bilateral Economic Dispatch (MBED) formulation as an objective function. The solution is realized in a fully decentralized manner on t... [more]

The deteriorating condition of the environment and the increasing emission of pollutants into the atmosphere intensify the greenhouse effect. Energy production in power plants results in emissions that affect the increase of global temperatures. According to the Research Institute for Global Climate Change in Berlin there are just over 7 years to cross the critical point, which will start chain reactions associated with irreversible changes in the climate. In order to reduce the climate changes, exhaust emissions must be reduced. One of the steps is to reduce electricity consumption. In the case of roads, electricity is most related to the technical infrastructure. First steps has been taken to reduce the demand for electricity by using lighting systems equipped in the energy saving solutions. The next step should be to use renewable energy sources. There are many solutions to generate electricity that can be used directly on roads or nearby. There are many sides in the area of the roa... [more]

Renewable energy (RE) is one of the most popular public policy orientations worldwide. Compared to some other countries and continents, Europe has gained an early awareness of energy and environmental problems in general. At the theoretical level, free-market environmentalism indicates that based on the principle of private property rights, with fewer state interventionist and regulation policies, entrepreneurs, as the driving force of the market economy, can provide better services to meet the necessity of offering RE to protect the environment more effectively. Previous studies have revealed that Germany, Denmark, and the United Kingdom have made some progress in using the market to develop RE. However, this research did not analyze the three countries’ RE conditions from the perspective of free-market environmentalism. Based on our review of the principles of free-market environmentalism, this paper originally provides an empirical study of how Germany, Denmark, and the United Kingd... [more]

This review paper provides a critical interpretation and analysis of almost 150 dedicated optimization research papers in the field of droop-controlled islanded microgrids. The significance of optimal microgrid allocation and operation studies comes from their importance for further deployment of renewable energy, reliable and stable autonomous operation on a larger scale, and the electrification of rural and isolated communities. Additionally, a comprehensive overview of islanded microgrids in terms of structure, type, and hierarchical control strategy was presented. Furthermore, a larger emphasis was given to the main optimization problems faced by droop-controlled islanded microgrids such as allocation, scheduling and dispatch, reconfiguration, control, and energy management systems. The main outcome of this review in relation to optimization problem components is the classification of objective functions, constraints, and decision variables into 10, 9 and 6 distinctive categories,... [more]

In recent years, the investment in the wind energy sector has increased in the context of producing green electricity and saving the environment. The installation of small wind turbines (SWTs) represents an actual strategy for meeting energy needs for off-grid systems and certain specialized applications. SWTs are more expensive per kilowatt installed as compared to large-scale wind turbines. Therefore, the main objective of this study is to produce an economical technology for the wind power market offering low-cost SWTs. The idea consists of considering a simple structure of the wind turbine using direct-drive permanent magnet synchronous generator (DDPMSG). DDPMSGs are the most useful machines in the wind energy field thanks to several advantages, such as elimination of noise and maintenance cost due to suppression of the gearbox and absence of the rotor circuit excitation barriers by the presence of the permanent magnets (PMs). Their major downside is the high cost of active materi... [more]

The present research aims to conduct a systemic review on Renewable Energy, Economic Growth and Economic Development and look for links between the papers published between 2008 and May 2021. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, it was possible to reach a sample of 111 articles selected by Web of Science and a sample of 199 academic articles selected by Scopus in that specific period. The analysis of the group of Renewable and Non-renewable Energy Consumption, Economic Growth and Economic Development shows that most of the articles published in this subsample use the quantitative methodology in economic sciences. The results indicate that research on the subject has a growing trend and that most of the articles are post-2015 publications. In addition, China has been the leading nation in published works. The journal Renewable and Sustainable Energy Reviews is considered the most relevant in this category, and Sustainability... [more]

Today, the power system operation represents a challenge given the security and reliability requirements. Mathematical models are used to represent and solve operational and planning issues related with electric systems. Specifically, the AC optimal power flow (ACOPF) and the DC optimal power flow (DCOPF) are tools used for operational and planning purposes. The DCOPF versions correspond to lineal versions of the ACOPF. This is due to the fact that the power flow solution is often hard to obtain with the ACOPF considering all constraints. However, the simplifications use only active power without considering reactive power, voltage values and losses on transmission lines, which are crucial factors for power system operation, potentially leading to inaccurate results. This paper develops a detailed formulation for both DCOPF and ACOPF with multiple generation sources to provide a 24-h dispatching in order to compare the differences between the solutions with different scenarios under hi... [more]

In recent years, the urgent necessity and tremendous opportunity to accelerate the transition to a low-carbon competitive economy has resulted in growth of long-term targets for renewable energy and energy efficiency, which are coming from policy bodies worldwide. The inherent distributed nature of renewable energies, together with the modularity of those technologies, brings opportunities for consumer empowerment in terms of participation. Nevertheless, there is still the need for increasing global awareness and enabling policies, to strengthen the citizen role in the energy system, facilitating their proactive participation as renewable energy purchasers, investors, and clean energy producers. Drawing from research interviews and the academic literature, this article conceptualizes the understanding of the need for improving public attitudes and explores the factors influencing the acceptance in terms of misconceptions, best communication practices, activities addressing public conce... [more]

Reversible solid oxide cells (rSOC) enable the efficient cyclic conversion between electrical and chemical energy in the form of fuels and chemicals, thereby providing a pathway for long-term and high-capacity energy storage. Amongst the different fuels under investigation, hydrogen, methane, and ammonia have gained immense attention as carbon-neutral energy vectors. Here we have compared the energy efficiency and the energy demand of rSOC based on these three fuels. In the fuel cell mode of operation (energy generation), two different routes have been considered for both methane and ammonia; Routes 1 and 2 involve internal reforming (in the case of methane) or cracking (in the case of ammonia) and external reforming or cracking, respectively. The use of hydrogen as fuel provides the highest round-trip efficiency (62.1%) followed by methane by Route 1 (43.4%), ammonia by Route 2 (41.1%), methane by Route 2 (40.4%), and ammonia by Route 1 (39.2%). The lower efficiency of internal ammoni... [more]

We add to the emerging body of literature highlighting cracks in the foundation of the mainstream energy transition narrative. We offer a tripartite analysis that re-characterizes the climate crisis within its broader context of ecological overshoot, highlights numerous collectively fatal problems with so-called renewable energy technologies, and suggests alternative solutions that entail a contraction of the human enterprise. This analysis makes clear that the pat notion of “affordable clean energy” views the world through a narrow keyhole that is blind to innumerable economic, ecological, and social costs. These undesirable “externalities” can no longer be ignored. To achieve sustainability and salvage civilization, society must embark on a planned, cooperative descent from an extreme state of overshoot in just a decade or two. While it might be easier for the proverbial camel to pass through the eye of a needle than for global society to succeed in this endeavor, history is replete... [more]