Energies

Research

45 pages, 4743 KiB

Open AccessFeature PaperArticle

Intelligence Techniques in Sustainable Energy: Analysis of a Decade of Advances

by Juan D. Velásquez, Lorena Cadavid and Carlos J. Franco

Energies 2023, 16(19), 6974; https://doi.org/10.3390/en16196974 - 6 Oct 2023

Cited by 2 | Viewed by 2049

In the last decade, many artificial intelligence (AI) techniques have been used to solve various problems in sustainable energy (SE). Consequently, an increasing volume of research has been devoted to this topic, making it difficult for researchers to keep abreast of its developments. [...] Read more.

In the last decade, many artificial intelligence (AI) techniques have been used to solve various problems in sustainable energy (SE). Consequently, an increasing volume of research has been devoted to this topic, making it difficult for researchers to keep abreast of its developments. This paper analyzes 18,715 articles—about AI techniques used for SE—indexed in Scopus and published from 2013 to 2022, which were retrieved and selected following a novel iterative methodology. Besides calculating basic bibliometric indicators, we used clustering techniques and a co-occurrence analysis of author keywords to discover and characterize dominant themes in the literature. As a result, we found eight dominant themes in SE (solar energy, smart grids and microgrids, fuel cells, hydrogen, electric vehicles, biofuels, wind energy, and energy planning) and nine dominant techniques in AI (genetic algorithms, support vector machines, particle swarm optimization, differential evolution, classical neural networks, fuzzy logic controllers, reinforcement learning, deep learning, and multi-objective optimization). Each dominant theme is discussed in detail, highlighting the most relevant work and contributions. Finally, we identified the AI techniques most widely used in each SE area to solve its specific problems. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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24 pages, 807 KiB

Open AccessArticle

Realistic Nudging through ICT Pipelines to Help Improve Energy Self-Consumption for Management in Energy Communities

by Haicheng Ling, Pierre-Yves Massé, Thibault Rihet and Frédéric Wurtz

Energies 2023, 16(13), 5105; https://doi.org/10.3390/en16135105 - 1 Jul 2023

Cited by 1 | Viewed by 1279

Abstract

Taking full advantage of the potentialities of renewable energies implies overcoming several specific challenges. Here, we address matching an intermittent energy supply with household demand through a nudging approach. Indeed, for households endowed with solar panels, aligning energy consumption with production may be [...] Read more.

Taking full advantage of the potentialities of renewable energies implies overcoming several specific challenges. Here, we address matching an intermittent energy supply with household demand through a nudging approach. Indeed, for households endowed with solar panels, aligning energy consumption with production may be challenging. Therefore, the aim of this study is to introduce two information and communication technology (ICT) nudging pipelines aimed at helping households integrated in energy communities with solar panels to improve their self-consumption rates, and to evaluate their efficiency on semi-real data. Our pipelines use information available in real-world settings for efficient management. They identify “green periods”, where households are encouraged to consume energy with incitation through nudging signals. We evaluate the efficiency of our pipelines on a simulation environment using semi-real data, based on well-known consumption datasets. Results show that they are efficient, compared to an optimal but unrealistic pipeline with access to complete information. They also show that there is a sweet spot for production, for which nudging is most efficient, and that a few green periods are enough to obtain significant improvements. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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14 pages, 1506 KiB

Open AccessFeature PaperArticle

Energy Aspects of Flavonoid Extraction from Rowanberry Fruits Using Pulsed Ultrasound-Assisted Extraction

by Zbigniew Kobus and Monika Krzywicka

Energies 2023, 16(13), 4966; https://doi.org/10.3390/en16134966 - 26 Jun 2023

Viewed by 742

Abstract

The aim of the study was to analyze the influence of the dimensions of extraction cells on the energy aspects and extraction efficiency of flavonoids from rowanberry fruits (S. aucuparia L.). The total flavonoid content was determined using the spectrophotometric method. Response [...] Read more.

The aim of the study was to analyze the influence of the dimensions of extraction cells on the energy aspects and extraction efficiency of flavonoids from rowanberry fruits (S. aucuparia L.). The total flavonoid content was determined using the spectrophotometric method. Response surface methodology (RSM) was used to optimize the variables under investigation. The flavonoid content in the obtained extracts ranged from 0.17 to 0.66 mg QE/g dry matter for cells with a diameter of 3.5 cm, and from 0.19 to 0.7 mg QE/g dry matter for cells with a diameter of 2.5 cm, depending on the other experimental conditions. The energy consumption during extraction in the 3.5 cm diameter cell ranged from 0.451 kJ to 26.120 kJ, while for the 2.5 cm diameter cell, it ranged from 0.637 kJ to 25.677 kJ. The unit energy consumption for the 3.5 cm diameter cell ranged from 1.47 kJ/mg QE/g to 48.92 kJ/mg QE/g. For the 2.5 cm diameter cell, these values ranged from 2.17 kJ/mg QE/g to 40.64 kJ/mg QE/g. Significant effects of the dimensions of the extraction cells on flavonoid yield and unit energy consumption were observed, while there was no impact on electricity consumption. The dimensions of the extraction cells were also found to influence the form of the obtained empirical models. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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26 pages, 1292 KiB

Open AccessArticle

The Role of State in Managing the Wind Energy Projects: Risk Assessment and Justification of the Economic Efficiency

by Galina Chebotareva, Inna Čábelková, Wadim Strielkowski, Luboš Smutka, Anna Zielińska-Chmielewska and Stanislaw Bielski

Energies 2023, 16(12), 4807; https://doi.org/10.3390/en16124807 - 19 Jun 2023

Cited by 1 | Viewed by 1078

Abstract

Our paper focuses on assessing the role of state funding in supporting wind energy projects with a focus on economic efficiency and risk assessment. In particular, we analyze the new program aimed at supporting Russian renewable energy (RE) projects envisaged for the period [...] Read more.

Our paper focuses on assessing the role of state funding in supporting wind energy projects with a focus on economic efficiency and risk assessment. In particular, we analyze the new program aimed at supporting Russian renewable energy (RE) projects envisaged for the period from 2024–2035 that involves a reduction in investments in such projects and the introduction of large fines for non-compliance with regulatory requirements for localization and export. These strict rules imposed by the regulatory authorities, as well as the withdrawal by foreign manufacturers of equipment for renewable energy from the domestic energy market, put into doubt the economic feasibility of the participation of sector players in state-supported programs. Our paper assesses the economic justification for the practicality of the Russian energy market to implement renewable energy projects under the influence of negative environmental factors and the reduction of state support programs. We employ a case study of wind energy projects carried out in 2018–2020 as a part of the first sector support program. Our methodology is based on the calculations of the classical indicators of economic efficiency of projects (NPV, IRR, and DPP). Our own approach reveals that these indicators are supplemented by taking into account the cost of specific political, environmental, and economic risks of wind energy projects. Our results reveal that, at the moment, Russian wind energy projects in various scenarios retain a sufficient margin of financial strength and are able to withstand a reduction in the amount of financial support from the state. Our findings allow the formulation of some practical recommendations for reducing the share of governmental support for wind energy projects on the local energy market as a measure of cutting costs and increasing overall economic efficiency. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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23 pages, 4406 KiB

Open AccessEditor’s ChoiceArticle

Grass from Road Verges as a Substrate for Biogas Production

by Robert Czubaszek, Agnieszka Wysocka-Czubaszek, Piotr Banaszuk, Grzegorz Zając and Martin J. Wassen

Energies 2023, 16(11), 4488; https://doi.org/10.3390/en16114488 - 2 Jun 2023

Cited by 1 | Viewed by 1127

Abstract

Maintenance of urban green infrastructure generates a large amount of biomass that can be considered a valuable feedstock for biogas production. This study aims to determine the effect of the cutting time and method of substrate preservation on the specific methane yield (SMY) [...] Read more.

Maintenance of urban green infrastructure generates a large amount of biomass that can be considered a valuable feedstock for biogas production. This study aims to determine the effect of the cutting time and method of substrate preservation on the specific methane yield (SMY) of urban grass collected from road verges and median strips between roadways in wet (WF) and dry fermentation (DF) technology. The grass was collected three times in a growing season, including in spring, summer, and autumn. The biochemical methane potential (BMP) test was performed on fresh grass, grass ensiled without additives, and grass ensiled with microbiological additives. In addition, the energy potentially produced from biogas and the avoided CO₂ emissions were calculated. The highest SMY (274.18 ± 22.59 NL kg_VS⁻¹) was observed for the fresh grass collected in spring and subjected to WF. At the same time, the lowest CH₄ production (182.63 ± 0.48 NL kg_VS⁻¹) was found in the grass ensiled without additives, collected in summer, and digested in DF technology. A comparison of the SMY obtained from the same grass samples in the WF and DF technologies revealed that higher CH₄ yields were produced in WF. The electricity and heat production were affected by the time of grass cutting, ensilage method, and AD technology. Generally, less electricity but more heat was produced in DF technology. The least electricity (469–548 kWh t_DM⁻¹) was produced from the grass cut in spring and subjected to DF, while the most electricity (621–698 kWh t_DM⁻¹) was obtained from the grass collected in autumn and subjected to WF. In the case of heat production, the situation was reversed. The least heat (1.4–1.9 GJ t_DM⁻¹) was produced by the grass collected in spring and subjected to WF, while the most heat (2.2–2.7 GJ t_DM⁻¹) was produced by the grass collected in autumn and subjected to DF. Ensilage decreased the electricity and heat production in almost all the cuttings. The total reduction in CO₂ emissions may amount to 2400 kg CO₂ per 1 hectare of road verges. This significant reduction demonstrates that the use of grass from roadside verges in biogas plants should be considered a feasible option. Even though urban grass should be considered a co-substrate only, it can be a valuable feedstock that may partially substitute energy crops and reduce the area needed for energy purposes. Our results reveal that biogas production from the grass waste in WF technology is a stable process. The cutting time and preservation method do not affect the AD process. In DF technology, fresh grass, especially from the late growing season used as feedstock, extends the time of biomass decomposition and, therefore, should be avoided in a real-life biogas plant. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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14 pages, 4642 KiB

Open AccessArticle

Evaluation of an Energy Separation Device for the Efficiency Improvement of a Planar Solid Oxide Fuel Cell System with an External Reformer

by Jinwon Yun, Eun-Jung Choi, Sangmin Lee, Younghyeon Kim and Sangseok Yu

Energies 2023, 16(9), 3947; https://doi.org/10.3390/en16093947 - 8 May 2023

Viewed by 1036

Abstract

Due to the high operating temperature of solid oxide fuel cells (SOFC), the system efficiency depends on efficient thermal integration and the effective construction of system configuration. In this study, nine configurations of system integration design were investigated to evaluate the possible improvement [...] Read more.

Due to the high operating temperature of solid oxide fuel cells (SOFC), the system efficiency depends on efficient thermal integration and the effective construction of system configuration. In this study, nine configurations of system integration design were investigated to evaluate the possible improvement of system efficiency with energy separation devices. The models were developed under the Matlab/Simulink^® platform with Thermolib^® module. The reference layout of the simulation included an SOFC stack, a compressor, an external reformer with a burner, a three-way valve, a heat exchanger, and a water pump. From the reference case, eight cases extended layouts for the capability of thermal energy utilization with a catalytic converter, SOFC hybridization, and an energy separation device. Since the energy separation device was beneficial to thermal energy utilization via a boost to the gas temperature, electric efficiency, and combined heat and power (CHP) efficiency was improved with the thermal integration of the energy separation device with a turbo generator. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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15 pages, 1582 KiB

Open AccessFeature PaperArticle

Analysis of Specific Greenhouse Gas Emissions Savings from Biogas Production Based on Agricultural Residues and Industrial By-Products

by Ana Kodba, Tomislav Pukšec and Neven Duić

Energies 2023, 16(9), 3721; https://doi.org/10.3390/en16093721 - 26 Apr 2023

Cited by 4 | Viewed by 1273

Abstract

The aim of this study was to analyse specific greenhouse gas emissions savings for a variety of agricultural residues, industrial by-products, and municipal biowaste. One of the most viable alternatives to fossil fuels is bioenergy, particularly biogas produced by the anaerobic digestion of [...] Read more.

The aim of this study was to analyse specific greenhouse gas emissions savings for a variety of agricultural residues, industrial by-products, and municipal biowaste. One of the most viable alternatives to fossil fuels is bioenergy, particularly biogas produced by the anaerobic digestion of renewable feedstocks. The revised Renewable Energy Directive (D 2018/2001) recognizes that biogas production from agricultural residues, livestock production, and industrial by-products is an acknowledged greenhouse gas mitigation technology in cases where their use results in a certain level of specific greenhouse gas savings. This study delivered values for the maximum transport distance of agricultural residues and industrial by-products to achieve the greenhouse gas (GHG) emissions-saving requirement defined by Directive 2018/2001. It analysed the greenhouse gas emissions reduction for numerous feedstocks for which Directive 2018/2001 has not defined the default and typical values but which could be used as sustainable substitutes for currently dominantly used maize silage in biogas production. The results obtained in this work define the maximum transport and distribution distance for which biogas produced from considered feedstocks achieved required specific greenhouse gas emissions savings (80%), compared with fossil fuel comparator. The obtained results can be used as the constraints in the optimisation of the biomass supply chains for the feedstocks considered in this work. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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14 pages, 290 KiB

Open AccessArticle

Knowledge Discovery to Support WTI Crude Oil Price Risk Management

by Radosław Puka, Bartosz Łamasz, Iwona Skalna, Beata Basiura and Jerzy Duda

Energies 2023, 16(8), 3486; https://doi.org/10.3390/en16083486 - 17 Apr 2023

Cited by 1 | Viewed by 1283

Abstract

The high volatility of commodity prices and various problems that the energy sector has to deal with in the era of COVID-19 have significantly increased the risk of oil price changes. These changes are of the main concern of companies for which oil [...] Read more.

The high volatility of commodity prices and various problems that the energy sector has to deal with in the era of COVID-19 have significantly increased the risk of oil price changes. These changes are of the main concern of companies for which oil is the main input in the production process, and therefore oil price determines the production costs. The main goal of this paper is to discover decision rules for a buyer of American WTI (West Texas Intermediate) crude oil call options. The presented research uses factors characterizing the option price, such as implied volatility and option sensitivity factors (delta, gamma, vega, and theta, known as “Greeks”). The performed analysis covers the years 2008–2022 and options with an exercise period up to three months. The decision rules are discovered using association analysis and are evaluated in terms of the three investment efficiency indicators: total payoff, average payoff, and return on investment. The results show the existence of certain ranges of the analyzed parameters for which the mentioned efficiency indicators reached particularly high values. The relationships discovered and recorded in the form of decision rules can be effectively used or adapted by practitioners to support their decisions in oil price risk management. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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33 pages, 41489 KiB

Open AccessArticle

Exploitation of Mediterranean Cooperation Projects’ Tools for the Development of Public Buildings’ Energy Efficiency Plans at Local Level: A Case Study in Greece

by George M. Stavrakakis, Panagiotis L. Zervas, Konstantinos Terzis, Panagiotis Langouranis, Panagiota Saranti and Yorgos J. Stephanedes

Energies 2023, 16(8), 3352; https://doi.org/10.3390/en16083352 - 10 Apr 2023

Cited by 3 | Viewed by 1342

Abstract

Ever since European Directive 2012/27/EU, particular attention has been focused on the improvement of the energy efficiency of the public building stock. According to the directive, local public authorities, regions and municipalities, are expected to develop and implement energy efficiency retrofitting plans for [...] Read more.

Ever since European Directive 2012/27/EU, particular attention has been focused on the improvement of the energy efficiency of the public building stock. According to the directive, local public authorities, regions and municipalities, are expected to develop and implement energy efficiency retrofitting plans for their public building stocks. While conducting such plans, important challenges are raised mainly related to data collection and the manipulation of key performance indicators (KPIs) for many buildings. The present paper deals with the aforementioned challenges through (a) the evaluation of freely available tools developed in the framework of Mediterranean territorial cooperation projects, with respect to the main pillars of energy efficiency planning, and (b) the introduction of a stepwise methodology using selected tools toward a reliable energy efficiency plan extending from the classification of the building stock to the prioritization of projects in terms of a gradual renovation plan based on energy and cost criteria. The methodology is applied for a case study in Greece, which refers to 10 public buildings of the Municipality of Aigialeia in Greece. A reliable renovation plan is developed, taking into account the municipal authority’s directions in a specialized decision-making scheme. It is concluded that the suggested methodology is very practical for planning purposes, while for the case studied, a 6-year gradual renovation plan is emerged until a deep retrofit of all buildings, associated with an estimated primary energy saving and CO₂ emissions avoidance of more than 1850 MWh and 400 tns, respectively, with a total investment of about EUR 3 million. Full article

(This article belongs to the Special Issue Effective and Efficient Management Practices in Energy Sources and Energy Consumption)

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