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Special Issue "Selected Papers from ICEER 2017: 2017 the 4th International Conference on Energy and Environment Research"

A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (15 November 2017)

Special Issue Editors

Guest Editor
Dr. Nídia Caetano

LEPABE/FEUP, Porto, Portugal
Website | E-Mail
Interests: biodiesel; bioethanol; biorefinery; energy storage systems; microalgae biorefineries; sustainable energy systems; waste valorization; wastewater treatment
Guest Editor
Dr. Carlos Felgueiras

CIETI/ISEP, Porto, Portugal
Website | E-Mail
Interests: energy quality; energy and buildings; energy and environmental Indicators; renewable energy systems; sustainable energy systems
Guest Editor
Dr. Zita Vale

Polytechnic of Porto, Portugal
Website | E-Mail
Interests: demand response; electric vehicles; electricity markets; power systems; smart grids
Guest Editor
Dr. Moustafa Eissa

Faculty of Engineering/Helwan University, Cairo, Egypt
Website | E-Mail
Interests: digital relaying; power system; protection; smart grids

Special Issue Information

Dear Colleagues,

Nations’ development has been based on energy consumption, and developing countries aim to reach a state of development that demands massive amounts of energy. Fossil-derived energy is becoming scarce in order to fulfil these needs, and the associated emissions and impacts on the environment are driving scientists and decision makers towards the development of renewable energy systems, as well as of more efficient energy systems. This paradigm calls for a new class of energy, and environment professionals, who are able to relate their own particular expertise with all the other areas involved, and understand the impacts of such systems, are thus able to plan truly sustainable energy systems. Problems, such as the storage of surplus renewable energy produced for later use, or its immediate distribution to where it is needed by using smart grids, the mobility and transportation in modern mega cities, or even the construction of zero net energy buildings (ZEB), demand the intensive use of life cycle assessment tools and the work in multidisciplinary teams.

Now is the time to explore emerging technologies and concepts in a collaborative way, bringing together engineers, researchers, and professionals from different areas. In fact, we can perceive that new and tighter targets towards sustainable development have been set by several countries, such as the Paris Agreement in December 2015. However, how to reach them is a sensitive matter for each country.

This Special Issue, therefore, aims to contribute to the Sustainable Energy agenda through advanced scientific and multi-disciplinary knowledge, combined to improve energy security and performance. We therefore invite papers on innovative technical developments, reviews, case studies, analytical, as well as assessment, from different disciplines, which are relevant to sustainable energy systems.

Dr. Nídia Caetano
Dr. Carlos Felgueiras
Dr. Zita Vale
Dr. Moustafa Eissa
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • biofuels
  • combustion
  • energy efficiency
  • energy quality
  • energy storage
  • life cycle assessment
  • renewable energy
  • waste-to-energy
  • zero energy buildings

Published Papers (13 papers)

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Research

Open AccessArticle Optimal Control Algorithms with Adaptive Time-Mesh Refinement for Kite Power Systems
Energies 2018, 11(3), 475; https://doi.org/10.3390/en11030475
Received: 31 October 2017 / Revised: 6 February 2018 / Accepted: 11 February 2018 / Published: 25 February 2018
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Abstract
This article addresses the problem of optimizing electrical power generation using kite power systems (KPSs). KPSs are airborne wind energy systems that aim to harvest the power of strong and steady high-altitude winds. With the aim of maximizing the total energy produced in
[...] Read more.
This article addresses the problem of optimizing electrical power generation using kite power systems (KPSs). KPSs are airborne wind energy systems that aim to harvest the power of strong and steady high-altitude winds. With the aim of maximizing the total energy produced in a given time interval, we numerically solve an optimal control problem and thereby obtain trajectories and controls for kites. Efficiently solving these optimal control problems is crucial when the results are used in real-time control schemes, such as model predictive control. For this highly nonlinear problem, we derive continuous-time models—in 2D and 3D—and implement an adaptive time-mesh refinement algorithm. By solving the optimal control problem with such an adaptive refinement strategy, we generate a block-structured adapted mesh which gives results as accurate as those computed using fine mesh, yet with much less computing effort and high savings in memory and computing time. Full article
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Open AccessArticle CAES Systems Integrated into a Gas-Steam Combined Plant: Design Point Performance Assessment
Energies 2018, 11(2), 415; https://doi.org/10.3390/en11020415
Received: 31 October 2017 / Revised: 22 January 2018 / Accepted: 6 February 2018 / Published: 11 February 2018
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Abstract
In the present paper, the performance of an energy storage concept based on the integration of a compressed air energy storage (CAES) system into a gas–steam combined cycle (GSCC) plant is investigated. CAES systems featured by different design specifications have been coupled with
[...] Read more.
In the present paper, the performance of an energy storage concept based on the integration of a compressed air energy storage (CAES) system into a gas–steam combined cycle (GSCC) plant is investigated. CAES systems featured by different design specifications have been coupled with a commercially available small size GSCC plant. Storage efficiencies up to 65% have been evaluated for CAES design power output ranging from 5 to 10 MW. A techno-economic analysis aimed at assessing plant performance and investment costs has been performed. Despite the relatively high investment costs and the storage efficiency being less than those featuring alternative storage approaches, the proposed system may be considered of interest due to the long-life duration and the established technologies available for the key plant components. Full article
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Open AccessArticle Potential of Phaeodactylum tricornutum for Biodiesel Production under Natural Conditions in Chile
Energies 2018, 11(1), 54; https://doi.org/10.3390/en11010054
Received: 10 November 2017 / Revised: 22 December 2017 / Accepted: 25 December 2017 / Published: 28 December 2017
Cited by 2 | PDF Full-text (1871 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Diatoms are very diverse and highly productive organisms, found in a wide variety of environments. This study aims to analyze the growth and lipid composition of Phaeodactylum tricornutum, cultured in an outdoor pilot-scale bubble column photobioreactor under natural conditions in Chile for biodiesel
[...] Read more.
Diatoms are very diverse and highly productive organisms, found in a wide variety of environments. This study aims to analyze the growth and lipid composition of Phaeodactylum tricornutum, cultured in an outdoor pilot-scale bubble column photobioreactor under natural conditions in Chile for biodiesel production. Results showed that P. tricornutum cultures reached their highest biomass concentration (0.96 ± 0.04 kg m−3) after 14 days of culturing, at the stationary phase, with a volumetric productivity of 0.13 kg m−3 d−1. Biomass samples showed a total lipid content of 9.08 ± 0.38 wt %. The fatty acid methyl ester analysis revealed a composition of 24.39% C16-C18 fatty acids, 42.34% saturated fatty acids, 21.91% monounsaturated fatty acids and 31.41% polyunsaturated fatty acids. These findings suggest that P. tricornutum oil can be used as an alternative raw material for the production of biodiesel capable of meeting international quality standards. Full article
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Open AccessArticle A Probabilistically Constrained Approach for the Energy Procurement Problem
Energies 2017, 10(12), 2179; https://doi.org/10.3390/en10122179
Received: 13 November 2017 / Revised: 10 December 2017 / Accepted: 15 December 2017 / Published: 19 December 2017
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Abstract
The definition of the electric energy procurement plan represents a fundamental problem that any consumer has to deal with. Bilateral contracts, electricity market and self-production are the main supply sources that should be properly combined to satisfy the energy demand over a given
[...] Read more.
The definition of the electric energy procurement plan represents a fundamental problem that any consumer has to deal with. Bilateral contracts, electricity market and self-production are the main supply sources that should be properly combined to satisfy the energy demand over a given time horizon at the minimum cost. The problem is made more complex by the presence of uncertainty, mainly related to the energy requirements and electricity market prices. Ignoring the uncertain nature of these elements can lead to the definition of procurement plans which are infeasible or overly expensive in a real setting. In this paper, we deal with the procurement problem under uncertainty by adopting the paradigm of joint chance constraints to define reliable plans that are feasible with a high probability level. Moreover, the proposed model includes in the objective function a risk measure to control undesirable effects caused by the random variations of the electricity market prices. The proposed model is applied to a real test case. The results show the benefit deriving from the stochastic optimization approach and the effect of considering different levels of risk aversion. Full article
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Open AccessArticle The Effect of Wind Forcing on Modeling Coastal Circulation at a Marine Renewable Test Site
Energies 2017, 10(12), 2114; https://doi.org/10.3390/en10122114
Received: 15 November 2017 / Revised: 6 December 2017 / Accepted: 7 December 2017 / Published: 12 December 2017
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Abstract
The hydrodynamic circulation in estuaries is primarily driven by tides, river inflows and surface winds. While tidal and river data can be quite easily obtained for input to hydrodynamic models, sourcing accurate surface wind data is problematic. Inaccurate wind data can lead to
[...] Read more.
The hydrodynamic circulation in estuaries is primarily driven by tides, river inflows and surface winds. While tidal and river data can be quite easily obtained for input to hydrodynamic models, sourcing accurate surface wind data is problematic. Inaccurate wind data can lead to inaccuracies in the surface currents computed by three-dimensional hydrodynamic models. In this research, a high-resolution wind model was coupled with a three-dimensional hydrodynamic model of Galway Bay, a semi-enclosed estuary on the west coast of Ireland, to investigate the effect of wind forcing on model accuracy. Two wind-forcing conditions were investigated: (1) using wind data measured onshore on the NUI Galway campus (NUIG) and (2) using offshore wind data provided by a high resolution wind model (HR). A scenario with no wind forcing (NW) was also assessed. The onshore wind data varied with time but the speed and direction were applied across the full model domain. The modeled offshore wind fields varied with both time and space. The effect of wind forcing on modeled hydrodynamics was assessed via comparison of modeled surface currents with surface current measurements obtained from a High-Frequency (HF) radar Coastal Ocean Dynamics Applications Radar (CODAR) observation system. Results indicated that winds were most significant in simulating the north-south surface velocity component. The model using high resolution temporally- and spatially-varying wind data achieved better agreement with the CODAR surface currents than the model using the onshore wind measurements and the model without any wind forcing. Full article
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Open AccessArticle A Multicriteria GIS-Based Assessment to Optimize Biomass Facility Sites with Parallel Environment—A Case Study in Spain
Energies 2017, 10(12), 2095; https://doi.org/10.3390/en10122095
Received: 18 October 2017 / Revised: 8 December 2017 / Accepted: 10 December 2017 / Published: 11 December 2017
Cited by 2 | PDF Full-text (5138 KB) | HTML Full-text | XML Full-text
Abstract
Optimizing a biomass facility site is a critical concern that is currently receiving an increased attention because of geographically spread biomass feedstock. This research presents a multicriteria GIS assessment with Weighted Linear Combination (WLC) (most suitable areas) and a sensitivity analysis (implementation strategies)
[...] Read more.
Optimizing a biomass facility site is a critical concern that is currently receiving an increased attention because of geographically spread biomass feedstock. This research presents a multicriteria GIS assessment with Weighted Linear Combination (WLC) (most suitable areas) and a sensitivity analysis (implementation strategies) applied to various disciplines using suitable criteria to optimize a biomass facility location in the context of renewable energies respecting the environment. The analyses of results with twelve criteria show the most suitable areas (9.25%) and constraints in a case study in Extremadura (Spain), where forest and agriculture are typical for land uses. Thus, the sensitivity analysis demonstrates the insight of the most influential criteria for supporting energy planning decisions. Therefore, this assessment could be used in studies to verify suitable biomass plants sites with corresponding geographical and spatial circumstances and available spatial data necessary in various governmental and industrial sectors. Full article
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Open AccessArticle Numerical Simulation about Reconstruction of the Boundary Layer
Energies 2017, 10(12), 2074; https://doi.org/10.3390/en10122074
Received: 31 October 2017 / Revised: 23 November 2017 / Accepted: 4 December 2017 / Published: 6 December 2017
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Abstract
In this paper, the reconstruction mechanism of the boundary layer in the channel is studied using the lattice Boltzmann method (LBM). By comparing the distribution of velocity in the channel, the conclusion that LBM has feasibility and superiority is obtained. Based on this,
[...] Read more.
In this paper, the reconstruction mechanism of the boundary layer in the channel is studied using the lattice Boltzmann method (LBM). By comparing the distribution of velocity in the channel, the conclusion that LBM has feasibility and superiority is obtained. Based on this, a physical model of square cylinders is set up to simulate the velocity distribution and the effect on the thickness of boundary layer. When the square cylinder moves at a certain speed, the velocity distribution in the flow field changes drastically. As well, it is found that the thickness of the boundary layer decreases with the cylinders’ height increasing in the given range. Furthermore, double cylinders model is also set up, and the results show that the optimal interval distance of the cylinders is between 90 and 140 lattice units. It is found that the moving cylinders have a significant effect on the thickness of the boundary layer, which will change the fluid flow and enhance the heat transfer. Full article
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Open AccessArticle Multiscale Modeling of a Packed Bed Chemical Looping Reforming (PBCLR) Reactor
Energies 2017, 10(12), 2056; https://doi.org/10.3390/en10122056
Received: 31 October 2017 / Revised: 29 November 2017 / Accepted: 1 December 2017 / Published: 5 December 2017
Cited by 1 | PDF Full-text (2011 KB) | HTML Full-text | XML Full-text
Abstract
Packed bed reactors are broadly used in industry and are under consideration for novel reactor concepts such as packed bed chemical looping reforming (PBCLR). Mass and heat transfer limitations in and around the particles in packed bed reactors strongly affect the behavior of
[...] Read more.
Packed bed reactors are broadly used in industry and are under consideration for novel reactor concepts such as packed bed chemical looping reforming (PBCLR). Mass and heat transfer limitations in and around the particles in packed bed reactors strongly affect the behavior of these units. This study employs a multiscale modeling methodology to simulate a PBCLR reactor. Specifically, small-scale particle-resolved direct numerical simulation is utilized to improve large-scale mass transfer models for use in an industrial scale 1D model. Existing intra-particle mass transfer models perform well for simple first order reactions, but several model enhancements were required to model the more complex steam methane reforming reaction system. Three specific aspects required enhanced modeling: the generation of additional gas volume by the reforming reactions, the lack of clear reaction orders in the equilibrium reactions, and the diffusion of multiple reactant species into the particle. Large-scale simulations of the PBCLR reactor with the enhanced 1D model showed that the highly reactive Ni-based catalyst/oxygen carrier employed allows for the use of large particle sizes and high gas flowrates, offering potential for process intensification. Full article
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Open AccessArticle A Metaheuristic Approach to the Multi-Objective Unit Commitment Problem Combining Economic and Environmental Criteria
Energies 2017, 10(12), 2029; https://doi.org/10.3390/en10122029
Received: 31 October 2017 / Revised: 24 November 2017 / Accepted: 29 November 2017 / Published: 1 December 2017
Cited by 1 | PDF Full-text (529 KB) | HTML Full-text | XML Full-text
Abstract
We consider a Unit Commitment Problem (UCP) addressing not only the economic objective of minimizing the total production costs—as is done in the standard UCP—but also addressing environmental concerns. Our approach utilizes a multi-objective formulation and includes in the objective function a criterion
[...] Read more.
We consider a Unit Commitment Problem (UCP) addressing not only the economic objective of minimizing the total production costs—as is done in the standard UCP—but also addressing environmental concerns. Our approach utilizes a multi-objective formulation and includes in the objective function a criterion to minimize the emission of pollutants. Environmental concerns are having a significant impact on the operation of power systems related to the emissions from fossil-fuelled power plants. However, the standard UCP, which minimizes just the total production costs, is inadequate to address environmental concerns. We propose to address the UCP with environmental concerns as a multi-objective problem and use a metaheuristic approach combined with a non-dominated sorting procedure to solve it. The metaheuristic developed is a variant of an evolutionary algorithm, known as Biased Random Key Genetic Algorithm. Computational experiments have been carried out on benchmark problems with up to 100 generation units for a 24 h scheduling horizon. The performance of the method, as well as the quality, diversity and the distribution characteristics of the solutions obtained are analysed. It is shown that the method proposed compares favourably against alternative approaches in most cases analysed. Full article
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Open AccessArticle Study of a Coil Heat Exchanger with an Ice Storage System
Energies 2017, 10(12), 1982; https://doi.org/10.3390/en10121982
Received: 31 October 2017 / Revised: 23 November 2017 / Accepted: 28 November 2017 / Published: 1 December 2017
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Abstract
In this study, a coil heat exchanger with an ice storage system is analyzed by theoretical analysis, numerical analysis, and experimental analysis. The dynamic characteristics of ice thickness variation is studied by means of unstable heat conduction theory in cylindrical coordinates, and the
[...] Read more.
In this study, a coil heat exchanger with an ice storage system is analyzed by theoretical analysis, numerical analysis, and experimental analysis. The dynamic characteristics of ice thickness variation is studied by means of unstable heat conduction theory in cylindrical coordinates, and the change rule of the ice layer thickness is obtained. The computational fluid dynamics method is employed to simulate the flow field and ice melting process of the coil heat exchanger. The effect of the agitator height on the flow characteristics and heat transfer characteristics is investigated. The numerical results show that the turbulence intensity of the fluid near the wall of the heat exchanger is the largest with an agitator height of 80 mm. Furthermore, the process of ice melting is analyzed. The ice on the outer side of the evaporator tube close to the container wall melts faster than the inner side and this agrees well with the experimental result. The experimental study on the process of the operational period and deicing of the coil heat exchanger is conducted and the temperature variation curves are obtained by the arrangement of thermocouples. It is found that the temperature of the evaporating tube increases with increasing height in the process of ice storage. Full article
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Open AccessArticle Study and Optimization of Design Parameters in Water Loop Heat Pump Systems for Office Buildings in the Iberian Peninsula
Energies 2017, 10(12), 1958; https://doi.org/10.3390/en10121958
Received: 24 October 2017 / Revised: 8 November 2017 / Accepted: 20 November 2017 / Published: 24 November 2017
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Abstract
Water loop heat pump (WLHP) air conditioning systems use heat pumps connected to a common water circuit to fulfill the energy demands of different thermal zones in a building. In this study, the energy consumption was analyzed for the air conditioning of an
[...] Read more.
Water loop heat pump (WLHP) air conditioning systems use heat pumps connected to a common water circuit to fulfill the energy demands of different thermal zones in a building. In this study, the energy consumption was analyzed for the air conditioning of an office building in the typical climate of four important cities of the Iberian Peninsula. The energy consumption of one water loop heat pump system was compared with a conventional water system. Two design parameters, the range in the control temperatures and the water loop thermal storage size, were tested. Energy redistribution is an important advantage of the WLHP system, but significant savings came from high efficiency parameters in the heat pumps and minor air flow rates in the cooling tower. The low thermal level in the water loop makes this technology appropriate to combine with renewable sources. Using natural gas as the thermal energy source, a mean decrease in CO2 emissions of 8.1% was reached. Simulations showed that the installation of big thermal storage tanks generated small energy savings. Besides, the total annual consumption in buildings with high internal loads can be reduced by keeping the water loop as cool as possible. Full article
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Open AccessArticle Charge and Discharge Analyses of a PCM Storage System Integrated in a High-Temperature Solar Receiver
Energies 2017, 10(12), 1943; https://doi.org/10.3390/en10121943
Received: 31 October 2017 / Revised: 15 November 2017 / Accepted: 20 November 2017 / Published: 23 November 2017
Cited by 2 | PDF Full-text (4770 KB) | HTML Full-text | XML Full-text
Abstract
Solar Dish Micro Gas Turbine (MGT) systems have the potential to become interesting small-scale power plants in off-grid or mini-grid contexts for electricity or poly-generation production. The main challenging component of such systems is the solar receiver which should operate at high temperatures
[...] Read more.
Solar Dish Micro Gas Turbine (MGT) systems have the potential to become interesting small-scale power plants in off-grid or mini-grid contexts for electricity or poly-generation production. The main challenging component of such systems is the solar receiver which should operate at high temperatures with concentrated solar radiations, which strongly vary with time. This paper deals with the design and the analysis of a novel solar receiver integrated with a short-term storage system based on Phase Change Materials to prevent sudden variations in the maximum temperature of the MGT working fluid. Particularly, the charge and discharge behavior of the storage system was analyzed by means of Computational Fluid Dynamic methods to evaluate the potentiality of the concept and the component capabilities. Achieved results were highly satisfactory: the novel solar receiver has a good thermal inertia and can prevent relevant fluctuations in the working fluid temperature for 20–30 min. Full article
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Open AccessArticle Evaluation of Economic, Social and Environmental Effects of Low-Emission Energy Technologies Development in Poland: A Multi-Criteria Analysis with Application of a Fuzzy Analytic Hierarchy Process (FAHP)
Energies 2017, 10(10), 1550; https://doi.org/10.3390/en10101550
Received: 10 July 2017 / Revised: 29 September 2017 / Accepted: 30 September 2017 / Published: 9 October 2017
Cited by 1 | PDF Full-text (979 KB) | HTML Full-text | XML Full-text
Abstract
The European Commission as well as the Polish government are promoting sustainable use of energy sources as a part of the dominating sustainable development paradigm. The development of low-emission energy sources engages the challenges of gradual depletion of coal, oil and natural gas
[...] Read more.
The European Commission as well as the Polish government are promoting sustainable use of energy sources as a part of the dominating sustainable development paradigm. The development of low-emission energy sources engages the challenges of gradual depletion of coal, oil and natural gas reserves, as well as the intensification of the greenhouse effect. The energy policy should take into account development of low-emission energy technologies that contribute mostly to meeting the goals of sustainable development in three dimensions: economic, social and environmental. This study aims to assess the extent to which five low-emission energy technologies contribute to social welfare in the scope of the concept of sustainable development. Heuristic methods, including fuzzy analytic hierarchy process (FAHP) are used to resolve the multi-goal problem in order to achieve the aim of this research. Research results show that economic goal is still the most important to the development of various low-emission energy technologies in Poland, followed by the social and environmental goals. Secondly, renewable energy technologies should be utilized instead of nuclear energy to meet sustainable development policy goals. Photovoltaics, followed by biomass and biogas are perceived as the most suitable renewable energy sources. Wind on-shore and wind of-shore are on third and fourth place, respectively. Full article
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