Renewable Energy Production Technologies Research Articles

СТАН ВІДНОВЛЮВАЛЬНОЇ ЕНЕРГЕТИКИ УКРАЇНИ ТА ПЕРСПЕКТИВНІ НАПРЯМИ РОЗВИТКУ

Renewable energy has quickly become a global trend and is currently one of the most promising energy industries in the world. Today, all developed countries have focused on the promotion and development of renewable energy and Ukraine is not an exception. Today, Ukraine has significant potential in the field of renewable energy, as evidenced by the main indicators of capacity, production and consumption. It should be noted the significant inflow of investment into the industry. Investment activity is important in the development of alternative energy sources and using existing potential is not only domestic but also significant international importance as a significant factor which we can use to protect global warming. For Ukraine, the development of renewable energy is also a very important area of energy development due to its dependence on energy imports and very attractive conditions for the development of alternative energy. Renewable energy production technologies allow use such devices for energy systems and consumers, which can act as businesses and individuals, which in turn help to increase the number of investors and investment. That is why the assessment of the efficiency of renewable energy in Ukraine is an urgent and important task for all consumers and the energy system of our country as a whole. In 2019, Ukraine entered to the top-20 of the world ranking of countries in terms of investment in renewable energy sources, and the growth of investment flows into the Ukrainian energy sector remains relatively dynamic. However, it was found that the issue of reviving investment activity remains relevant. The article analyzes in detail the role of renewable energy in the energy balance of Ukraine, their segmentation and capacity analysis. Considerable attention is paid to the most powerful and promising sectors, as well as the main areas of renewable energy consumption are analyzed in percentage terms. The main prospects and directions of investment are analyzed, on the example of world experience, and the role of investments for the development of this industry is determined. An analysis of scientific forecasts for future capacity and consumption of renewable energy was also conducted.

ФОРМУВАННЯ ПОЛІТИКИ ЦИФРОВІЗАЦІЇ УПРАВЛІННЯ ПРОЦЕСОМ ЕНЕРГОЗБЕРЕЖЕННЯ ПІДПРИЄМСТВ ВОДОПОСТАЧАННЯ В УКРАЇНІ

The article analyzes the innovative potential of energy saving in the housing and communal services sector, as the ability to develop innovative activities for the implementation of projects to modernize communal infrastructure, in order to reduce energy consumption, which is due to the requirements of ensuring reliability and energy security. Investment projects aimed at introducing renewable energy production technologies have been analyzed. The problem of the quality of wastewater treatment at treatment facilities in Ukraine is considered. The main directions of development and ways of improving the management of energy saving are determined on the example of the modernization of treatment facilities of water supply enterprises. Further directions for the implementation of the proposed projects have been identified, which will ensure efficient processing and disposal of sludge with the involvement of energy-efficient technologies for the production of biofuel. The problem of implementation of energy-saving measures is not new for the authorities, but the implementation of relevant technologies has not acquired a mass character in Ukraine. First of all, this is due to the fact that a few years ago the cost of energy resources was much lower than the market price, which did not create sufficient motivation for frugal energy consumption or investments in energy-saving equipment, technologies or energy-saving projects. In the process of developing a strategy, it is necessary to follow an approach that will contribute to ensuring systematicity in the process of developing the innovative model itself, will create conditions for solving the issues of managing innovations in the energy saving system, and will also make it possible to form a toolkit for its development and implementation. The development and implementation of a strategy for the innovative development of energy saving in housing and communal services should include goals, the choice of means to achieve these goals, and justification of the sources of attraction of the necessary resources. Summarizing what has been said, we note that each industry has its own characteristics that determine the content of innovative and energy policy in this area. For the effective implementation of innovative energysaving technologies in the sphere of housing and communal services of Ukraine, it is necessary to develop a scientifically based strategy for the innovative development of energy saving, which would form the basis for the creation of an integral legal framework for the regulation of the main parameters of the innovative process in the sphere of housing and communal services, the introduction of innovative energy-saving technologies and determine the arsenal of support tools, taking into account scale and social significance. This is an objective necessity of modern existence, since the process should not proceed spontaneously, it should be managed.

A Feasibility Study of Wood Waste to Solid Bio-Coal using Hydrothermal Carbonization(HTC)

As an alternative to a new and renewable energy source, bio-coal is generated through hydrothermal carbonization (HTC) which is a novel renewable energy production technology using waste. Therefore, bio-coal was generated through HTC reaction using wood waste, which is the most used biomass raw material and requires a recycling method and confirmed its possibility as a solid fuel. It can be seen that the higher the reaction temperature and the longer the reaction time, the higher is the fixed carbon content, which affects the heating value. At 300℃ and 4 h, the lowest heating value was 6841.23 Kcal/kg. In addition, the fuel ratio at 300℃ was 1.3 ~ 1.6, which indicates a higher fuel ratio range than that of low-grade coal, and it can be seen from the van krevelen diagram that the biomass region is closer to the lignite region.

An Empirical Approach to Differences in Flexible Electricity Consumption Behaviour of Urban and Rural Populations—Lessons Learned in Germany

This article analyses two major trends of the 21st century. Firstly, the transition from fossil fuel-based energy production to renewable energy sources. Secondly, the inexorable urbanisation which can be witnessed all over the globe. The most promising renewable energy production technologies for the near future, i.e., wind and solar energy, are volatile by nature which makes matching supply and demand essential for a successful transition. Therefore, the aspects that determine the willingness of consumers to flexibilise their demand has gained growing attention. Initial research shows that different settings for (co-)ownership in terms of available prosumption options and used production technologies have a varying impact on demand flexibility. However, existing research has analysed flexibility drivers solely for the general population as an aggregate without any distinction regarding spatial, economic, or social factors. In this article, the authors go one step further and analyse whether those drivers for flexible consumption behaviour differ in rural or urban areas acknowledging differences in day-to-day life in both cases. This study is based on 2074 completed questionnaires from German consumers which were analysed using propensity score matching. The results show that people from rural and urban areas do not significantly differ in their willingness to be demand flexible in general. However, (co-)owners of RE installations from rural areas are generally significantly more demand flexible than (co-)owners of RE installations from urban areas. Further, when looking at different RE technologies, the results show that (co-)owners of solar installations are significantly more demand flexible if they are from rural areas. Lastly, when looking at usage options, people who solely consume produced electricity are more demand flexible if they are from rural areas as well.

Design of Solar Modules for Building Façades at Educational Facilities in Korea

Photovoltaic (PV) panels are the most widely used technology for renewable energy production; however, in urban areas, their installation locations are primarily limited to building rooftops. Here, a PV panel design that allows installation on building façades, particularly in elementary school buildings in South Korea, which are widely distributed throughout the country and have a standardized building design, was developed. Elementary schools in Seoul, Gwangju, and Busan were selected, and the energy production efficiency of the PV panels based on latitude and important influencing factors, including installation position, angle, and incoming solar irradiation, were investigated. Further, each targeted elementary school building and the corresponding PV module design were visualized in three dimensions. Thus, solar irradiation was measured, and the potential energy generated by the PV modules was calculated using the Insight software coupled with the Revit software. The building façade position associated with the highest energy production efficiency for each target elementary school was selected based on the optimal PV module tilt angle, and the total energy production was 307,734 kWh∙year−1. The results of this study can be applied to several other public education facilities and can be readily extended to high-rise residential buildings across Asia.

Comprehensive study on thermochemical putrefaction of Delonix Regia in non-catalytic, catalytic and hydro-catalytic pyrolysis atmospheres

The need for cleaner energy and faster depleting conventional non-renewable energy resources gave rise to the quest for sustainable sources and their conversion technologies for renewable energy production. The H/C ratio is essential in estimating the fuel potential of any feedstock. In this study, authors have considered a biomass, Delonix Regia (DR), whose H/C ratio is 1.56 which is higher than other competitive biomass such as pinewood sawdust (1.43) and of coal (1–1.4). Thus, selection of DR based on its H/C value formulated the objective of this work as non-catalytic, catalytic and hydro-catalytic pyrolysis of DR at 600 °C in a tubular reactor. Further, the use of zeolite Y, sodium catalyst for the cases of catalytic and hydro-catalytic experiments added novelty to this work because this catalyst is extensively used as cracking catalyst for fractionating the high-boiling petroleum crude into lighter and useful fractions such as gasoline. Accordingly it is expected that this catalyst shall play similar role in the present study for fractionating the high volatile pyrolysis vapours into smaller fractions during the pyrolysis reaction. Thus, the novelty of this work is catalytic and hydro-pyrolysis of a rarely researched biomass using an economical zeolite Y, sodium catalyst. The HHV of bio-oils by non-catalytic, catalytic and hydro-pyrolysis of DR found to be 16.5 MJ/kg, 18.14 MJ/kg and 20.65 MJ/kg, respectively. GC-MS analyses indicated the formation of several value-added chemicals such as benzene, cresol, catechol etc. by hydro-pyrolysis. The fraction of furan in bio-oil by hydro-catalytic pyrolysis decreased substantially whereas the aromatics fraction increased compared to the other two cases.

Surface-Modified Covalent Organic Polymer for Metal-Free Electrocatalytic Hydrogen Evolution Reaction

Rapid global warming forced people to replace conventional energy sources with green renewable solar and wind energies. Consequently, renewable energy production and storage technologies have recen...

Current status of biomethane production using aqueous liquid from pyrolysis and hydrothermal liquefaction of sewage sludge and similar biomass

Pyrolysis and hydrothermal liquefaction (HTL) are potential technologies for renewable energy production and waste valorization using municipal wastewater sewage sludge and other lignocellulosic biomass. However, the organic-rich aqueous pyrolysis liquid (APL) and HTL aqueous phase (HTL-AP) produced currently have no apparent use and are challenging to manage. Furthermore, the toxic organic compounds in them can be harmful to the environment. Anaerobic digestion (AD) may be a viable method to manage the liquids and recover energy in APL and HTL-AP in form of methane-rich biogas. Integrating thermochemical processes with AD could promote a circular economy by recovering resources and reducing environmental pollution. The challenge, however, is the presence of toxic compounds recalcitrant to anaerobic biodegradation such as phenols and nitrogen-containing organics that can inhibit methane-producing microbes. This review presents information on APL and HTL-AP characterization and biodegradability. Feedstock composition and process operational parameters are major factors affecting APL and HTL-AP composition, subsequent toxicity, and degradability. Feedstocks with high nitrogen content as well as increased thermochemical processing temperature and retention time result in a more toxic aqueous liquid and lower methane yield. Dilution and low AD organic loading are required to produce methane. More comprehensive APL and HTL-AP chemical characterization is needed to adopt suitable treatment strategies. Pretreatments such as overliming, air stripping, partial chemical oxidation, adsorption, and solvent extraction of toxic constituents as well as co-digestion and microbial acclimatization successfully reduce toxicity and increase methane yield.

Three-dimensional graphitic mesoporous carbon-doped carbon felt bioanodes enables high electric current production in microbial fuel cells

Microbial fuel cells (MFCs) represent a new approach that can simultaneously enhance the treatment of waste streams and generate electricity. Although MFCs represent a promising technology for renewable energy production, they have not been successfully scaled-up mainly due to the relatively-low electricity generation and high cost associated with MFCs operation. Here, we investigated whether graphitic mesoporous carbon (GMC) decoration of carbon felt would improve the conductivity and biocompatibility of carbon felt anodes, leading to higher biomass attachment and electricity generation in MFCs fed with an organic substrate. To test this hypothesis, we applied 3 different GMC loading (i.e., 2, 5, and 10 mg/cm2 of anode surface area) in MFCs compared to control MFCs (with pristine carbon felt electrodes). We observed that the internal resistances of modified anodes with GMC were 1.2–2.3-order of magnitude less than pristine carbon felt anode, leading to maximum power densities of 70.3, 33.3, and 9.8 mW/m2 for 10, 5, and 2 mg/cm2-doped anode, respectively compared to only 3.8 mW/m2 for the untreated carbon felt. High-throughput sequencing revealed that increasing the GMC loading rate was associated with enriching more robust anode-respiring bacteria (ARB) biofilm community. These results demonstrate that 3-D GMC-doped carbon felt anodes could be a potential alternative to other expensive metal-based electrodes for achieving high electric current densities in MFCs fed with organic substrates, such as wastewater. Most importantly, high electron transfer capability, strong chemical stability, low cost, and excellent mechanical strength of 3-D GMC-doped carbon felt open up new opportunities for scaling-up of MFCs using cheap and high-performance anodes.

Optimal Design and Techno-economic Analysis of Off-grid Hybrid Renewable Energy System for Remote Rural Electrification: A Case Study of Southwest China

Demand for electricity in remote areas is a key bottleneck for development of these areas. Challenges of grid extension to remote areas have been identified, such as difficult terrain for construction and vast investment. Fast development of decentralized renewable energy production technologies provides opportunity for tackling the challenges. The study aims to demonstrate the techno-economic feasibility of off-grid hybrid renewable energy system for sustainable remote rural electrification via a case study of a village in Southwest China. In order to determine the most cost competitive configuration whilst ensuring a reliable power supply for residential, community and agricultural demand of the village, different combinations of PV panels, wind turbine and biogas generator are modelled and optimized in HOMER. Daily and seasonal characteristics of energy supply and demand sizes and patterns of remote rural areas are considered. Comparison of grid extension and an off-grid hybrid power system has been carried out. Results show that a hybrid power system comprising solar, wind and biomass is a reliable and cost-effective option for remote rural electrification whilst achieving environmental benefits.

Optimal design and techno-economic analysis of a solar-wind-biomass off-grid hybrid power system for remote rural electrification: A case study of west China

Demand for electricity is a key bottleneck for the development of remote areas. Grid extension to remote areas has previously been constrained due to difficult terrain for construction and vast investment. Fast development of decentralized renewable energy production technologies provides opportunity for tackling the challenges. The study aims to demonstrate the techno-economic feasibility of off-grid hybrid renewable energy system for remote rural electrification, via a case study of a village in West China by performing simulation, optimization and sensitivity analysis. Daily and seasonal characteristics of energy supply as well as demand sizes and patterns of remote rural areas are considered. Different combinations of PV panels, wind turbine and biogas generator are modeled and optimized in Hybrid Optimization Model for Electric Renewables (HOMER). The most cost competitive configuration is determined whilst ensuring a reliable power supply featuring residential, community, commercial and agricultural demand of the village. Comparison of the off-grid hybrid power system and grid extension has been carried out. Results show that a hybrid power system comprising solar, wind and biomass is a reliable and cost-effective option for sustainable remote rural electrification whilst achieving environmental benefits.

Hybrid nanostructures for solar-energy-conversion applications

Solar energy harvesting through photovoltaic conversion is the most promising technology for renewable energy production. Nanoscience and nanotechnology have enabled the development of hybrid and multifunctional materials for harnessing solar energy. Hybrid nanomaterials consist of more than two nanomaterials to improve the individual performance of the components. In this paper, the authors explain and review two approaches to solar energy harvesting – namely, photovoltaic and photosynthetic. Natural photosynthetic biomaterials such as photosystem I, photosystem II, proteins and bacteria extracted from various leaves, plants or fruits can be used with inorganic nanomaterials to enhance the efficiencies of hybrid solar cells. The authors review biohybrid solar cells based on various natural dyes and nanostructures such as quantum dots, nanotubes, thin films and bulk nanoparticles. Biohybrid nanostructures have the potential to absorb almost 100% light, and hence, they can exhibit an extraordinary efficiency of up to 100%. Artificial photosynthetic systems such as photoelectrochemical cells may be built using biohybrid materials for solar energy conversion at a low cost and in an eco-friendly manner. Biohybrid nanostructured light-harvesting devices are desirable for high efficiency with a wide spectral response. Hybrid solar cells can change the path of next-generation hybrid solar cell technology.

Short term solar irradiance forecasting via a novel evolutionary multi-model framework and performance assessment for sites with no solar irradiance data

Accurate forecasting of solar irradiance is a key issue for planning and management of renewable solar energy production technologies. The present paper aims to propose new machine learning forecasting models based on optimized ANNs in order to accurately predict solar irradiance. For this purpose, an evolutionary framework is suggested to generate multiple models for different time horizons up to 6 h ahead by the evolution of the forecasting history and ANN architecture. A dataset of 28 Moroccan cities is used in our experiments in order to explore the performances of the proposed models against different climatic conditions. The proposed framework is then evaluated through a zoning scenario giving the ability to our models to accurately forecast solar irradiance in sites where no such data is available. Two other scenarios are used to assess and compare the resulting performances. For all studied scenarios obtained results show good generalization abilities with NRMSE varying from 7.59% to 12.49% and NMAE from 4.41% to 8.12% as best performances for solar irradiance forecasting from 1 to 6 h ahead respectively. A comparative study is then conducted with three other models (smart persistence, regression trees and random forest), showing better performances of our proposed HAEANN models.

Multi-Criteria Decision-Making (MCDM) for the Assessment of Renewable Energy Technologies in a Household: A Review

Different power generation technologies have different advantages and disadvantages. However, if compared to traditional energy sources, renewable energy sources provide a possibility to solve the climate change and economic decarbonization issues that are so relevant today. Therefore, the analysis and evaluation of renewable energy technologies has been receiving increasing attention in the politics of different countries and the scientific literature. The household sector consumes almost one third of all energy produced, thus studies on the evaluation of renewable energy production technologies in households are very important. This article reviews the scientific literature that have used multiple-criteria decision-making (MCDM) methods as a key tool to evaluate renewable energy technologies in households. The findings of the conducted research are categorized according to the objectives pursued and the criteria on which the evaluation was based are discussed. The article also provides an overview and in-depth analysis of MCDM methods and distinguishes the main advantages and disadvantages of using them to evaluate technologies in households.

Special Issue on Cutting-Edge Technologies for Renewable Energy Production and Storage

Anthropogenic greenhouse gas emissions are dramatically influencing the environment, and research is strongly committed in proposing alternatives, mainly based on renewable energy sources [...]

Design of Monovalent Ion Selective Membranes for Reducing the Impacts of Multivalent Ions in Reverse Electrodialysis.

Reverse electrodialysis (RED) represents one of the most promising membrane-based technologies for clean and renewable energy production from mixing water solutions. However, the presence of multivalent ions in natural water drastically reduces system performance, in particular, the open-circuit voltage (OCV) and the output power. This effect is largely described by the “uphill transport” phenomenon, in which multivalent ions are transported against the concentration gradient. In this work, recent advances in the investigation of the impact of multivalent ions on power generation by RED are systematically reviewed along with possible strategies to overcome this challenge. In particular, the use of monovalent ion-selective membranes represents a promising alternative to reduce the negative impact of multivalent ions given the availability of low-cost materials and an easy route of membrane synthesis. A thorough assessment of the materials and methodologies used to prepare monovalent selective ion exchange membranes (both cation and anion exchange membranes) for applications in (reverse) electrodialysis is performed. Moreover, transport mechanisms under conditions of extreme salinity gradient are analyzed and compared for a better understanding of the design criteria. The ultimate goal of the present work is to propose a prospective research direction on the development of new membrane materials for effective implementation of RED under natural feed conditions.

Bimetallic Iron–Cobalt Catalysts and Their Applications in Energy-Related Electrochemical Reactions

Since the persistently increasing trend of energy consumption, technologies for renewable energy production and conversion have drawn great attention worldwide. The performance and the cost of electrocatalysts play two crucial roles in the globalization of advanced energy conversion devices. Among the developed technics involving metal catalysts, transition-metal catalysts (TMC) are recognized as the most promising materials due to the excellent properties and stability. Particularly, the iron–cobalt bimetal catalysts exhibit exciting electrochemical properties because of the interior cooperative effects. Herein, we summarize recent advances in iron–cobalt bimetal catalysts for electrochemical applications, especially hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR). Moreover, the components and synergetic effects of the composites and catalytic mechanism during reaction processes are highlighted. On the basis of extant catalysts and mechanism, the current issues and prospective outlook of the field are also discussed.

On the Effect of Aqueous Ammonia Soaking Pre-Treatment on Continuous Anaerobic Digestion of Digested Swine Manure Fibers.

(1) Background: The continuously increasing demand for renewable energy sources renders anaerobic digestion as one of the most promising technologies for renewable energy production. Due to the animal production intensification, manure is being used as the primary feedstock for most biogas plants. Their economical profitable operation, however, relies on increasing the methane yield from the solid fraction of manure, which is not so easily degradable. The solid fraction after anaerobic digestion, the so-called digested fibers, consists mainly of hardly biodegradable material and comes at a lower mass per unit volume of manure compared to the solid fraction before anaerobic digestion. Therefore, investigation on how to increase the biodegradability of digested fibers is very relevant. So far, Aqueous Ammonia Soaking (AAS), has been successfully applied on digested fibers separated from the effluent of a manure-fed, full-scale anaerobic digester to enhance their methane productivity in batch experiments. (2) Methods: In the present study, continuous experiments at a mesophilic (38 °C) CSTR-type anaerobic digester fed with swine manure first and a mixture of manure with AAS-treated digested fibers in the sequel, were performed. Anaerobic Digestion Model 1 (ADM1) previously fitted on manure fed digester was used in order to assess the effect of the addition of AAS-pre-treated digested manure fibers on the kinetics of anaerobic digestion process. (3) Results and Conclusions: The methane yield of AAS-treated digested fibers under continuous operation was 49–68% higher than that calculated in batch experiments in the past. It was found that AAS treatment had a profound effect mainly on the disintegration/hydrolysis rate of particulate carbohydrates. Comparison of the data obtained in the present study with the data obtained with AAS-pre-treated raw manure fibers in the past revealed that hydrolysis kinetics after AAS pre-treatment were similar for both types of biomasses.

Exploitation of Algal-Bacterial Consortia in Combined Biohydrogen Generation and Wastewater Treatment

Microalgae cultivation in municipal, industrial and agricultural wastewater is an emerging, highly effective approach for resource recovery and concomitant bioenergy generation. Wastewater effluents represent ideal sources of nutrients for eukaryotic green algal species. However, the performance of photosynthetic green algae is strongly dependent on the associated bacterial partners present in the effluents. Our combined wastewater treatment and biohydrogen evolution approach applied green microalgae-based photoheterotrophic degradation using dark fermentation wastewater effluent as substrate. The results showed that condition-dependent mutualistic relationships between the microbial and Chlorella algae populations had direct impact on the biodegradation efficiency and also on algal biohydrogen production. Metagenome analysis of the novel hybrid biodegradation system together with total nitrogen and phosphorous analytics provided important clues for the primary importance of the green algae partner in nitrogen and phosphorous removal. Bacterial bin genome data also indicated algal growth promotion by bacterial partners. With further development and optimization this new approach can lead to a highly efficient simultaneous organic waste mitigation and renewable energy production technology.

Fast anaerobic digestion of complex substrates via immobilized biofilms in a novel compartmentalized reactor design

Anaerobic digestion of municipal waste is a promising technology for renewable energy production, notably for methane (CH4) production. Existing reactor designs have limitations that prevent efficient conversion and high throughput, especially of substrates high in suspended solids. Here, we introduce a novel compartmentalized reactor design encompassing controlled feed flow over fixed microbial biofilms for high rate CH4 production from enzymatically pre-hydrolyzed municipal solid waste. In a 240 L working volume reactor, the biofilm generation was completed in less than 60 days and CH4 production was minimum ∼700 L day−1 in the ensuing months with a Hydraulic Retention Time (HRT) of 10 days or lower. When the organic load was gradually increased, a reactor productivity of 6 LCH4 Lreactor−1 day−1 was achieved. At this point, the reactor processed 20.8 gCOD Lreactor-1 day−1 at a HRT below 5 days, maintaining above 70% of the maximal Chemical Oxygen Demand (COD) conversion rate. Such fast conversion rates and high yields are far beyond what has been reported for other reactor designs, and are a crucial prerequisite for industrial realization of renewable biogas production from municipal solid waste and other organic waste streams.