Future Renewable Energy Sources Research Articles

Sustainable production of biodiesel from waste cooking oil using magnesium oxide nano catalyst: An optimization study

Biodiesel is rapidly becoming an efficient substitute for fuel and a potentially significant future renewable energy source. In recent years, used cooking oil has been used as a feedstock for biofuel to reduce production costs. Due to its high catalytic activity, low cost, and eco-friendliness, Nano magnesium oxide (MgO) has attracted attention as a catalyst for biodiesel production. Our work presents the preparation of nanomagnesium oxide (MgO) by the sol–gel method, and its characterization. Optimum conditions and the productive combination of waste cooking oil, methanol, and the synthesized nanocatalyst were predicted using response surface methodology. The optimum conditions were methanol to oil ratio of 7:1, temperature of 50 °C and time of 60 min. The expected values for the yield of biodiesel production responses are quite like the actual values, demonstrating the consistency of the models used for establishing a relationship between the independent process variables and the responses. The predicted model's F-value was 9.09 indicating that the model is significant. The model's pure error had a poor correlation, as the "Lack of Fit F-values” 4.16. The quadratic model fits the data well because the R-squared value for the model equation 92%. The expected values for the yield of biodiesel production responses are quite like the actual values, demonstrating the consistency of the models used for establishing a relationship between the independent process variables and the responses. Biodiesel was characterized using gas chromatography–mass spectrometry and Fourier transform infrared spectroscopy.

Electrocatalytic performance of Shape-Controlled synthesized PdNi-rGO nano Cube on sodium borohydride and methanol electrooxidation

In recent years, increasing climate change, environmental pollution and water problems have increased the need for sustainable and environmentally friendly solutions in energy production. In this context, renewable energy sources, especially fuel cells, have become an important focus. In this study, the synthesis and characterization of the shape-controlled synthesized PdNi-rGO Cube electrocatalyst was carried out. X-ray diffraction (XRD), scanning electron microscopy with energy dispersive x-ray (SEM-EDX), and transmission electron microscope (TEM) characterization experiments were performed to examine the shape of the particles. TEM analysis revealed the formation of nanostructures with a size of 19.18 nm in the cubic structure of the PdNi-rGO. Furthermore, cyclic voltammetry (CV) measurements evaluated the usability of this electrocatalyst in the electrooxidation of sodium borohydride (NaBH4), and methanol (CH3OH). In this context, the anodic peak current density values were 77.34 mA/cm2 and 13.47 mA/cm2, for electrooxidation of sodium borohydride (NaBH4), and methanol (CH3OH), respectively. This study demonstrates that PdNi-rGO cube contains shape-controlled nanostructure, and these structures can play an important role in future renewable energy sources. It can also be considered an important step forward in the development of nanomaterial-based electrocatalysts capable of efficient energy conversion.

Grain boundary passivation by alkylammonium salt for highly stable perovskite solar cells

Perovskite solar cells (PSCs) are a strong candidate for next-generation photovoltaics, but their long-term stability poses challenges for use as a future renewable energy source. In particular, ambient moisture causes detrimental effects on not only the stability but also performance of PSCs. Herein, alkylammonium salts with perfluorinated long alkyl chains are introduced to passivate the grain boundaries and form hydrophobic surfaces. The perfluorinated alkyl chain moiety introduced into the perovskite layer reduces defect density and suppresses nonradiative recombination, thereby enhancing carrier transport capability and achieving a power conversion efficiency (PCE) of 20.31 %. Given the hydrophobic effects of fluorinated compounds on PSCs, about 90 % of the initial PCE can be retained after 1,000 h of continuous operation under a relative humidity of ∼ 40 % without encapsulation. The proposed additive strategy thus enables long-term operational stability of PSCs under humid conditions.

Iraqi Economy and Renewable Energy Projects Between Economic Necessity and Investment Challenges

Purpose: Given Iraq's current excessive fossil fuel output, this article seeks to investigate the country's potential for future renewable energy sources. The report also endeavors to foresee Iraq's future position in clean energy production in Iraq and throughout the globe and the rate at which the global energy market will shift towards renewable energy sources.
 
 Theoretical framework: Iraq's reliance on oil earnings and the country's overburdened public sector poses serious economic issues. There is a domination of state-owned firms, stringent laws, a need for more access to finance, a shortage of competent labor, and poor infrastructure that limits the expansion of numerous industries. Growth in recent years has not led to decreased poverty since the economy has changed greatly since 2014.
 
 Design/Methodology/Approach: The study included both retrospective and prospective approaches. The most pressing problems in implementing and making use of renewable energy sources were described and analyzed descriptively. Future outcomes for the Iraqi economy were envisioned using a prospective approach in the form of development scenarios.
 
 Findings: A significant source of international capital flows and a key source of funding for economic growth, foreign direct investment (FDI) has mostly focused on the oil industry and certain tourism projects. As a result of the country's outdated energy grid, investors are interested in something other than investing in Iraq's electrical industry.
 
 Research, practical & social implications: We describe the current issues confronting Iraqi economic development, including the need for more diversity in the economy, structural imbalances between the main sectors, and the near-total dependence on crude oil export revenues, resulting in a decline in industrial production.
 
 Originality/Value: We describe the reality of the Iraqi economy, analyze the structure of Iraq's energy sector based on conventional energy, and then find out about the progress made in renewable energy and existing and future projects under fossil fuels.

Microstructure Investigation of Activated Carbon Prepared by Carbon Dioxide-Physical Activation

Abstract. in this Study, Activated Carbon was Created by Physically Activating Potato Peel Waste (PPW) with Carbon Dioxide. the Potential of this Approach, which Uses Carbon Dioxide to Produce Actuation Carbon (AC) from Precursor Potato Peel Waste, has been Investigated. Utilizing x-Ray Diffraction Analysis, Scanning Electron Microscopy, and Atomic Force Microscopy, the Microstructure of the Activated Carbon was Examined. the Average Crystallite Size was Affected by Employing Varied Periods for the Activation Process, as Seen by the Crystallite Size of the High-Intensity Peaks of the Precursor Potato Peel Waste at Various Drying Times and the Activated Products. after 60 Minutes of Drying, the Activation Stage was under Ideal Conditions, and in Comparison to the other Times, a Size of 325 Nm was Also Attained with the Rest of the Periods, as well as a High Adhesion Elevation Surface Region for the Carbon. the Activated Carbon Produced Using Physical Activation Showed a Surface Area as High as 1733 m2/g with a Pore Volume of 0.45 cm3/g, whereas the Precursor Showed a Surface Area of < 4 m2/g. this Investigation Aims to Modify the Surface of Activated Carbon without Significantly Altering its Structural Parameters for Use in Future Renewable Energy Sources and to Make the Synthesis of such Materials more Potent, more Eco-Friendly, and Less Expensive.

Cost-Optimal Sector Integration and Energy Balancing Strategies for Reaching Carbon Neutrality

Sectoral integration will play a major role in the clean energy transition to increase the utilisation rates of available renewable energy sources (RES). Preliminary studies have shown that the decarbonisation of power generation can be reached through well-developed technical solutions such as the integration of hydro, wind, and solar energy. However, emissions in the buildings, transport, and industrial sectors remain stubbornly high. Therefore, the electrification of these sectors and interconnection through smart grids have been identified as promising future development trends to avoid the usage of fossil fuels. The TIMES optimisation model is used to evaluate the future cost-effective pathways for reaching carbon neutrality in the Latvian energy sector. The model includes both the end-use sectors such as transport, buildings, industry and agriculture and the energy sector with a well-developed database of existing and future RES and storage technologies. The modelling framework allows for identifying the cost-optimal future energy mix by considering the electrification potential of each sector. Therefore, it allows analysing of the impact of different policy strategies at sectoral integration levels and the necessity for additional energy storage capacities. The preliminary results show that one of regret-free solutions for reaching the energy efficiency targets in 2030 is the wide expanse of heat pump utilisation in residential buildings instead of inefficient biomass boilers. The building heat supply transformation also brings higher power consumption and interacts with the wider utilisation of wind power. In addition, sensitivity analyses have been performed to evaluate the impact of high uncertainties related to fuel costs, resource availability and other conditions.

Designing Vertical Axis Wind Turbine Prototype as Future Renewable EnergySource in STEAM Learning

Vertical Axis Wind Turbine (VAWT) is a wind power plant with many advantages, especially as a renewable energy source. Through the pocket of Science–Technology–Engineering–Art–Mathematics (STEAM) learning, this study designs a VAWT and explores the potential of this tool for learning. This study used a mixed-method embedded design with an experimental and interview type. The research results show that the influence of the number of blades and wind speed on voltage, current strength, and power is directly proportional. Therefore, VAWT can also be used as one of the projects for STEAM-based learning.

In Situ Grown CoMn-Based Metal–Organic Framework on Nickel Foam as Efficient and Robust Electrodes for Electrochemical Oxygen Evolution Reaction

Abstract It is of great significance to develop efficient and robust oxygen evolution reaction (OER) electrocatalysts based on inexpensive and earth-abundant materials to enable water splitting as a future renewable energy source. Herein, the in situ grown CoMn-MOF-74 on nickel foam and their use as active electrodes for high-performance water-oxidation catalysis are reported. In alkaline media, the binder-free three-dimensional (3D) electrode shows superior OER activity with a current density of 10 mA cm−2 at a small overpotential of 260 mV, a Tafel slope of 58.2 mV dec−1, as well as excellent stability, making it one of the most active OER catalyst. Such high performance is attributed to increased electrochemically active areas, accelerated electron transport capability and the synergy between metal–organic framework (MOFs) and Ni substrate. This work elucidates a promising electrode for electrochemical water oxidation and enriches the direct application of MOF materials for future clean energy conversion and storage systems.

Assessment of Tomato Peels Suitable for Producing Biomethane within the Context of Circular Economy: A GIS-Based Model Analysis

Biomass is seen as one of the most dominant future renewable energy sources. In detail, agro-industrial by-products represent a cheap, renewable, and abundant feedstock useful for several new products, including biochemical, biomaterials, and above all biogas, which are taking on an ever-increasing role in Italy. In this context, the tomato chain was analysed aiming at estimating the amount of processed tomato and the related waste production as a new suitable resource for producing biofuel as a new frontier within the context of a circular economy. Due the importance of the tomato industry, this research aims at filling gaps in the knowledge of the production and yield of the by-products that are useful as biomass for energy use in those territorial areas where the biomethane sector is still developing. This aim could be relevant for planning the sustainable development of the biomethane sector by reducing both soil consumption for dedicated energy crops and GHG emissions coming from the biomass logistic supply. The achieved results show the localization of territorial areas highly characterized by this kind of biomass. Therefore, it would be desirable that the future policies of development in the biomethane sector consider the availability and the distribution of these suitable biomasses within the territory.

Pipeline for Annual Averaged Wind Power Output Generation Prediction of Wind Turbines Based on Large Wind Speed Data Sets and Power Curve Data

In this article, an abstract framework for annual averaged wind power output generation prediction of wind turbines is presented which is heavily based on large wind speed data sets and power curve data of wind turbines due to the rising interest in wind energy as one main future renewable energy source. As combinations of arbitrary power curve modeling techniques and arbitrary wind speed distributions based on wind speed data are seldom combined, the abstract combination of these two aspects in wind power output generation prediction in one pipeline is thoroughly described here. Conclusively, one detailed example wind speed data set from a weather station situation in Bremen, Germany illustrates applicability of the presented framework.

Design and Performance Analysis of Tandem Organic Solar Cells: Effect of Cell Parameter

An organic solar cell (OSC), competitive with traditional one (Si-based), draws attention to future renewable energy sources due to its low-cost and continually rising efficiency. The tandem or multijunction structure undoubtedly offers an efficient way to boost the performance of OSCs. This work has explored the optical modeling of different organic photoactive materials to identify the potential materials for efficient tandem structure. The performance of double, triple, and quadruple junction tandem OSCs with suitable bandgaps has been analyzed with photoactive materials. The absorption efficiency enhances considerably using the thickness optimization of each subcell in tandem structures. Current matching in all subcells, an essential factor for efficient device operation, is taken into account while optimizing tandem structures. The quadruple design can achieve better photovoltaic performance than double or triple junction devices. The efficiency predicted from our proposed quadruple structure is ~15.45%, with a short-circuit current density, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{J}_{\mathrm {SC}}$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 9$ </tex-math></inline-formula> mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and an open-circuit voltage, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\mathrm {OC}}$ </tex-math></inline-formula> of ~2.64 V. These results are one of the high-performance in terms of organic photovoltaic (OPV). Therefore, the above findings indicate that OSCs are very potential for future photovoltaic applications.

Utilization of Ecoenzyme Citrus reticulata in a microbial fuel cell as a new potential of renewable energy

The world's energy needs generally come from non-renewable sources. In other circumstances, some research on renewable energy is being developed from a variety of different sources, one of which is biomass. Biomass changes the energy system towards the modernization of the bioenergy system by utilizing the concept of biochemical systems (BESs). A microbial fuel cell is known as one of the renewable technologies that convert biomass with the help of microbes to produce electricity. This research is based on a microbial fuel cell based on ecoenzyme Citrus reticulata known as Ecoenzyme fuel cell to determine the electrical value (voltage, current, and power density). Ecoenzyme was made from orange peel waste, molasses, and water with a ratio of 3: 1: 10 and fermented for a month. Meanwhile, the electrode device used was a pencil graphite. Some treatments were carried out to optimize the performance of the system based on the number of electrodes (one pair and three pairs), and the stirring conditions, stirring at 200 rpm and without stirring (0 rpm). The EFC system was run for four weeks (600 hours) with the highest voltage obtained at 650 mV and current at 29.55 mA. The ecoenzyme produced the most significant power density of 750 W/m2 in the treatment of 3 electrode pairs with a stirring speed of 200 rpm. The influence of electrodes and stirring in the MFC system upsurged the electrical value output by 53.7% for a pair of electrodes and 142% for three electrode pairs. Further development will continue to be done to improve the performance and output of the Ecoenzyme fuel cell system as a future renewable energy source in Indonesia.

Model-based control for a demand-driven biogas production to cover residual load rises.

The development of systems for energy storage and demand-driven energy production will be essential to enable the switch from fossil to renewable energy sources in future. To cover the residual load rises, a rigorous dynamic process model based on the Anaerobic Digestion Model No. 1 (ADM1) was applied to analyse the flexible operation of biogas plants. For this, the model was optimised and an operational concept for a demand-driven energy production was worked out. Different substrates were analysed, both by batch fermentation and Weende analysis with van Soest method, to determine the input data of the model. The lab results show that the substrates have got different degradation kinetics and biogas potentials. Finally, the ADM1 was extended with a feeding algorithm which is based on a PI controller. Essential feeding times and quantities of available substrates were calculated so that a biogas plant can cover a defined energy demand. The results prove that a flexible operation of biogas plants with a feeding strategy is possible.

Cobalt/Molybdenum Phosphide and Oxide Heterostructures Encapsulated in N-Doped Carbon Nanocomposite for Overall Water Splitting in Alkaline Media.

The development of designing and searching inexpensive electrocatalysts with high activity for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is significant to enable water splitting as a future renewable energy source. Herein, we synthesize a new CoP(MoP)-CoMoO3 heterostructure coated by a N-doped carbon shell [CoP(MoP)-CoMoO3@CN] via thermal decomposition and phosphatizing of the CoMoO4·0.9H2O nanowires encapsulated in N-doped carbon. At 10 mA·cm-2, this CoP(MoP)-CoMoO3@CN nanocomposite exhibits superior electrocatalytic activity at low overpotentials of 296 mV for OER and 198 mV for HER in alkaline media. More importantly, we achieve a current density of 10 mA·cm-2 at 1.55 V by using this CoP(MoP)-CoMoO3@CN as both cathode and anode for overall water splitting. This promising performance could be due to the high activity of CoP(MoP)-CoMoO3 and the good conductivity of the external mesoporous N-carbon shell, which makes the CoP(MoP)-CoMoO3@CN nanowires a competitive alternative to noble-metal-based catalysts for water splitting.

Conversion banana and orange peel waste into electricity using microbial fuel cell

Microbial Fuel Cell (MFC) is one of green technologies widely developed for future renewable energy sources. The MFC is a bio-electrochemical system that uses the bacterial growth to transform organic substrates, via oxidation-reduction reactions, from chemical energy into electricity. Two different organic substrates include banana peel waste (BPW) and orange peel waste (OPW) are investigated for their potency as a feedstock for MFCs. In this study, single chamber MFC was used in all experiment, without chemical pre-treatment or the addition of extra mediators. Both electricity current and potential values were measured for 10 days. The characterisation study indicated that OPW contains higher organics materials than that of BPW, as indicated by the VS values of 87.06% total solids/TS (OPW) and 75.32% TS (BPW). Furthermore, the results also showed that both wastes produced electricity with a slightly different amount. In average, BPW has a voltage rating of 0.492 V and electric current rating of 0.101 mA. While, OPW has in average values of 0.563 V and 0.017 mA, respectively. The study confirmed that the organic content of substrates and the microbial activity influenced the electricity produced from the MFCs

Acid Pretreatment of Sago Wastewater for Biohydrogen Production

Biohydrogen has been recognized to be one of the future renewable energy sources and has the potential in solving the greenhouse effects. In this study, Enterobacter aerogenes (E. aerogenes) was used as the biohydrogen producer via dark fermentation process using sago wastewater as the substrate. However, pretreatment of sago wastewater is required since it consists of complex sugars that cannot be utilized directly by the bacteria. This study aimed to use acid pretreatment method to produce high amount of glucose from sago wastewater. Three different types of acid: sulfuric acid (H2SO4); hydrochloric acid (HCl) and nitric acid (HNO3) were screened for the best acid in producing a maximum amount of glucose. H2SO4 gave the highest amount of glucose which was 9.406 g/L. Design of experiment was done using Face-centred Central Composite Design (FCCCD) tool under Response Surface Methodology (RSM) in Design Expert 9 software. The maximum glucose (9.138 g/L) was recorded using 1 M H2SO4 at 100 °C for 60 min. A batch dark fermentation using E. aerogenes was carried out and it was found that pretreated sago wastewater gave a higher hydrogen concentration (1700 ppm) compared to the raw wastewater (410 ppm).

Highly Efficient and Stable Water-Oxidation Electrocatalysis with a Very Low Overpotential using FeNiP Substitutional-Solid-Solution Nanoplate Arrays.

The development of efficient water-oxidation electrocatalysts based on inexpensive and earth-abundant materials is significant to enable water splitting as a future renewable energy source. Herein, the synthesis of novel FeNiP solid-solution nanoplate (FeNiP-NP) arrays and their use as an active catalyst for high-performance water-oxidation catalysis are reported. The as-prepared FeNiP-NP catalyst on a 3D nickel foam substrate exhibits excellent electrochemical performance with a very low overpotential of only 180 mV to reach a current density of 10 mA cm-2 and an onset overpotential of 120 mV in 1.0 m KOH for the oxygen evolution reaction (OER). The slope of the Tafel plot is as low as 76.0 mV dec-1 . Furthermore, the long-term electrochemical stability of the FeNiP-NP electrode is investigated by cyclic voltammetry (CV) at 1.10-1.55 V versus reversible hydrogen electrode (RHE), demonstrating very stable performance with negligible loss in activity after 1000 CV cycles. This present FeNiP-NP solid solution is thought to represent the best OER catalytic activity among the non-noble metal catalysts reported so far.

Spatial modeling framework for bioethanol plant siting and biofuel production potential in the U.S

Because of rising fuel prices and increasing energy demand, bioethanol has been recognized as an important future renewable energy source. The goals and mandates developed for renewable fuel production will require construction of several bioethanol plants throughout the U.S. Using high-resolution geospatial data from Geographic Information Systems-Multi Criteria Evaluation (GIS-MCE) a biorefinery suitability model has been developed for identifying feasible sites and appropriate biofuel production capacity in the U.S. The biomass feedstocks considered for analysis were switchgrass, miscanthus and corn stover. We conducted a spatial exclusion and preference GIS analysis subjected to environmental and infrastructure criteria combined with biomass yield estimates and identified 164 basic sites and 17 co-location scenarios. Biorefineries using miscanthus feedstock could produce biofuel satisfying a significant portion of the U.S. mandate. This national-scale assessment enhances strategic decision-making capabilities and understanding of spatial distribution of biorefineries.

Experimental Validation of Surface Coverage Model for Li-Air Battery

The Lithium-air battery has captured so much interest and been considered as a promising candidate for the future renewable energy sources because of its high specific energy density comparable to gasoline. But unfortunately, the maximum amount of the lithium metal utilized is limited because of the tunnel blockage and surface coverage inside cathode, which are caused by insoluble lithium composite generated at cathode. In other words, the total energy capacity is restricted by the cathode under adequate lithium. So if we can fully understand how the deposits work on the cathode, we are supposed to develop a better cathode, which can hold more products per unit volume, with immensely higher energy capacity per unit cathode volume. This paper describes a surface coverage model and two relative dominating effects, electrode passivation and transport resistance. By using the electron conservation combined with experimental formula from previous works, we could investigate how much the insoluble there is and the coverage coefficient used to evaluate what degree deposits damage the effectivity of cathode to. We could use the coverage coefficient to describe the effective surface area under different stage of precipitation. We may go further to obtain the oxygen profile by taking the oxygen transport equation into account. Then we have a chance to use the above model to formulate the loss of effective voltage and total energy capacity. We could eventually split the voltage loss into 2 pieces, one caused by electrode passivation and another caused by oxygen transport resistance. We can compare them to find out which one is the prime force to kill the battery, or that they cooperate together. We can also know how much deposits the cathode can be filled with before exhausted. Then the total energy capacity is ready to come out by integrating the voltage along the time under constant current. By looking into the integral, there are actually three parts, which are the capacity without considering voltage loss effect, and two capacity losses solely considering the voltage loss from the electrode passivation or oxygen transport resistance respectively. If we compare these different part, we could have a knowledge of whether the capacity loss is immense enough to be cared about, or which kind of loss costs more. To validate our model, we will also perform the experiments by using our sandwich cell to get the discharging curve, which will be used to validate our model by comparing the voltage loss and energy capacity loss. The sandwich cell structure from bottom to top is: bottom frame, aluminum foil, lithium metal, separator, rubble sealing ring, top frame with air window and electrolyte pool on top, and cathode. The whole cell is assembled by using screws. We could get open circuit voltage and discharging curves under different current. The data will be used to validate and improve our model mentioned above.

Assessment of Environmental Stresses for Enhanced Microalgal Biofuel Production – An Overview

Microalgal biofuels are currently considered to be the most promising alternative to future renewable energy source. Microalgae have great potential to produce various biofuels, including biodiesel, bioethanol, biomethane, and biohydrogen. Cultivation of biofuel-producing microalgae demands favorable environmental conditions, such as suitable light, temperature, nutrients, salinity, and pH. However, these conditions are not always compatible with the conditions beneficial to biofuel production, because biofuel-related compounds (such as lipids and carbohydrates) tend to accumulate under environmental-stress conditions of light, temperature, nutrient, and salt. This paper presents a brief overview of the effects of environmental conditions on production of microalgal biomass and biofuel, with specific emphasis on how to utilize environmental stresses to improve biofuel productivity. The potential avenues of reaping the benefits of enhanced biofuel production by environmental stresses while maintaining high yields of biomass production have been discussed.