Sustainable Renewable Energy Sources Research Articles

Environmentally Friendly Strategies for Recycling Agricultural Waste to Produce Renewable Energy: A Case Study of Durian Fruit

The increasing need for harvests, resources, and facilities is associated with significant biowaste production from agricultural processes. Although the waste is nutrient-rich, it may become refinement lands for ailment-triggering bacteria when not managed correctly. The waste can be transformed into raw materials for valuable crops or sources of environmentally friendly energy. Therefore, this study examined agricultural waste management strategies as Indonesia's sustainable renewable energy source. SWOT and TOPSIS methods were used to identify the optimal approach for advancing renewable energy in Riau Province, while multiple respondents participated in identifying critical criteria and evaluating each option. The results showed that based on SWOT analysis, the Strength–Opportunity (SO) factor favored using agricultural waste for renewable energy in Indonesia. Furthermore, TOPSIS analysis indicated that Alternative A2 (Bioethanol) had the most significant distance among the alternatives, with a weight of 0.825. Future studies are needed to provide more accurate results and improve the current understanding regarding the evolution of renewable energy in Indonesia. Additionally, in-depth investigations should prioritize increased consumer awareness of renewable consumption, higher producer productivity, and strengthened policies.

Effective hydropower renewable energy source selection using fuzzy neutrosophic boundary approximate area

Small hydropower plants in rural areas are contributing to marginal economic growth and social progress, but their social sustainability assessment is under-studied. Previous studies have shown that no single renewable energy source (RES) can fully meet all sustainability criteria, despite their focus on single-user systems. Scaled renewable energy systems have varying impacts across different systems, involving technical, environmental, social, and economic aspects. This paper proposes a Triangular Fuzzy Neutrosophic Numbers (TFNNs) as an extension of the multi-attributive border approximation area comparison (MABAC) method for hybrid multi-criteria decision-making (MCDM). The proposed method is utilized to assess the selection of hydropower as the most efficient and sustainable renewable energy source for society. Pairwise comparison matrices were used to determine priority vectors and weighted averages of indicators for seven criteria. The evaluation framework analyzed five key dimensions of hydropower plants. The most stable renewable energy source, pumped storage hydropower (60.78%), was found to be followed by run-of-river hydropower (56.39%), impoundment hydropower (50.03%), storage hydropower (39.78%), and offshore hydropower (07.95%). The study offers valuable insights for policymakers and implementer on sustainable electricity solutions for hydropower. Pumped storage hydropower (PSH) improves facility efficiency by ensuring optimal operation of coal and nuclear generators without energy loss. The system can provide a stable and reliable power storage solution for renewable energy sources like wind and solar.

Data-driven machine learning models for the prediction of hydrogen solubility in aqueous systems of varying salinity: Implications for underground hydrogen storage

Hydrogen is a clean and sustainable renewable energy source with significant potential for use in energy storage applications because of its high energy density. In particular, underground hydrogen storage via the dissolution of hydrogen gas in an aqueous solution has been identified as a promising strategy to address the difficulties associated with large-scale energy storage. However, this process requires the accurate prediction of the solubility of hydrogen in aqueous solutions, which is affected by a range of factors, including temperature, pressure, and the presence of solutes. The present study thus aimed to effectively predict the solubility of hydrogen in aqueous solutions that vary in their salinity by employing a machine learning approach. Four machine learning models were developed and tested: adaptive gradient boosting (Adaboost), gradient boosting, random forest, and extreme gradient boosting. The performance of each model was quantified in terms of their coefficient of determination (R2), root mean square error (RMSE), and mean absolute error (MAE). The Adaboost algorithm exhibited superior performance across all metrics, with an R2 of 0.994, MAE of 0.006, and RMSE of 0.018. A Williams plot detected only 18 outliers in the Adaboost predictions from a total of 255 data points. These results indicate that machine learning techniques have the potential to serve as a valuable tool in the prediction of hydrogen solubility in aqueous solutions for underground hydrogen storage, facilitating the development of smart, cost-effective, and safe hydrogen storage technologies.

Crop Residue as Sustainable Energy Option: Case of Amritsar District, Punjab, India

Historically, biomass energy is the oldest form of energy, for domestic purposes. Amongst biomass, crop-residue resources are abundant, especially in agriculture-dominated areas. Worldwide, of the total renewable energy potential, one-fourth of total renewable energy is being produced by biomass and waste. Within biomass, co-generation plants using process-based agricultural wastes are used for power generation. However, a major proportion of crop residues, that is, non-processed residues, are burnt in the open fields themselves, resulting in air pollution, greenhouse gases and climate change, deterioration of soil health due to loss of nutrients, moisture, etc. The present article assesses crop-residue generation, utilisation, and surplus-availability for energy generation in Amritsar district. Amritsar district is the second most populated among 22 districts of Punjab state. Agriculture is the main economic activity in the district, covering 82.2% of its geographical area. It has been estimated that a total of 2.5 million tonnes of crop residues are being generated annually within the Amritsar district. Out of the total residues, almost two-thirds of residues remain unutilised. The residues are being burnt, resulting in deteriorating air-quality, which could be used as a sustainable renewable energy source. The total surplus residue has the potential for 721 MW of power generation.

A solar-assisted power-to-hydrogen system based on proton-conducting solid oxide electrolyzer cells

Green hydrogen is anticipated to play a major role in a Net-Zero 2050 scenario since it can be produced using sustainable renewable energy sources, resulting in no greenhouse gas emissions. Furthermore, hydrogen has a high energy density and is readily stored and transferred, making it a versatile and convenient fuel for a broad range of applications. In this regard, an attempt has been made to study a solar-assisted power-to-hydrogen system based on proton-conducting solid oxide electrolyzer cells. The article presents a detailed thermo-economic analysis along with genetic algorithm-based optimization studies of the system. The optimum values of energetic efficiency and the cost of hydrogen are found to be 25.15 % and 1.021 $/kg, respectively. Exergy analysis reveals that the highest exergy destruction occurs in solar photovoltaic thermal (67.83 %) and parabolic trough solar collector (13.31 %), respectively. Furthermore, performance results of the solar-assisted power-to-hydrogen system are compared with other hydrogen production technologies.

Implementation of Nonlinear Controller to Improve DC Microgrid Stability: A Comparative Analysis of Sliding Mode Control Variants

Electricity generation from sustainable renewable energy sources is constantly accelerating due to a rapid increase in demand from consumers. This requires an effective energy management and control system to fulfil the power demand without compromising the system’s performance. For this application, a nonlinear barrier sliding mode controller (BSMC) for a microgrid formed with PV, a fuel cell and an energy storage system comprising a battery and supercapacitor working in grid-connected mode is implemented. The advantages of the BSMC are twofold: The sliding surface oscillates in the close vicinity of zero by adapting an optimal gain value to ensure the smooth tracking of power to its references without overestimating the gains. Secondly, it exhibits a noticeable robustness to variations and disturbance, which is the bottleneck of the problem in a grid-connected mode. The stability of the presented controllers was analyzed with the Lyapunov stability criterion. Moreover, a comparison of the BSMC with sliding mode and supertwisting sliding mode controllers was carried out in MATLAB/Simulink (2020b) with real PV experimental data. The results and the numerical analysis verify the effectiveness of the BSMC in regulating the DC bus voltage in the presence of an external disturbance under varying conventional load and environmental conditions.

Potential of Biomass Briquettes from Tropical Fruit Waste (Study Case: Durian Skin)

The search for alternative and sustainable renewable energy sources has become necessary as the world faces growing concerns over climate change and depleting fossil fuel reserves. Biomass briquettes, derived from various organic materials, present a promising solution to this global energy crisis. This study explores the potential of utilizing tropical fruit, specifically durian (Durio zibethinus), as a renewable energy source by producing biomass briquettes. Durian is a widely cultivated tropical fruit, abundant in certain regions but often underutilized due to its strong aroma and perishability. By converting durian waste into biomass briquettes, we can address environmental challenges while creating a valuable energy resource that aligns with sustainability principles.

Surfactant-mediated sonic hydrolysis of marine macroalgae Ulva fasciata for biohydrogen production

This study investigates the potential utility of Ulva fasciata biomass for biohydrogen production and its disintegration under ultrasonic disintegration (UD), and ultrasonic combined surfactant disintegration (UCSD). SCOD release and specific energy consumption were evaluated for UD and UCSD. In UCSD, optimal surfactant addition was 10 μl, 160 W sonication power, and 30-min sonication time resulted in a maximum release of SCOD of 1030 mg/L and a maximum solubilization of 21.2% to compare the performance of UD and UCSD, biopolymer release was analyzed. The maximum protein and carbohydrate release was 680 mg/L and 224.2 mg/L the disintegrated substrate was evaluated for its biohydrogen production under anaerobic conditions with both UD and UCSD. As compared to UD (90.4 mL), and control (17.3 mL), UCSD (121.6 mL) produced more biohydrogen. According to its energy analysis, UCSD had a positive net energy of 0.012 kW h/kg and an energy ratio of 1.375. This study also reveals that macroalgae U. fasciata could be a sustainable renewable energy source for biohydrogen production.

Bankruptcy problem in energy warehouse: Applications and challenges

Green smart cities that rely completely on sustainable renewable energy sources are being constructed to attract investors, diversify countries’ economies, and move away from dependence on fossil fuels. The main renewable energy sources used in such cities today include solar, wind, and—to a lesser extent—biomass. However, these sources are stochastic in nature, and the amount of energy they produce is not entirely controllable. This results in difficulty maintaining the balance between generation and demand in the power grid. Recent technological advances in smart grids, microgrids, virtual power plants, energy hubs, and energy interconnection technologies offer a wide range of plausible solutions to this problem. Such advances motivated the development of a complementary technology known as the energy warehouse (EW). An EW is a controlled and managed heterogeneous massive modular energy storage and wheeling system. It provides links between microgrids and bulk power systems (BPSs). After describing the structure of an EW and its energy management system and illustrating example EW operating scenarios, this paper uses the concept of bankruptcy to explain the business side of an EW. For the first time, this principle is used to address cases where the EW falls short of its obligations to the connected microgrids and BPSs. This treatment of EW contributes to a better understanding of its operation and opens further opportunities for contributions. Furthermore, our study confirms that a properly sized and located EW promises significant technical and economic benefits. These including load leveling and energy time-shift, as well as the potential to eliminate the typical transmission infrastructure, thereby reducing losses, mitigating congestion, and increasing efficiency.

Hydrogen adsorption and diffusion through two dimensional aluminium : A first-principles investigation

With the exponentially growing global energy demand, green and clean renewable energy has become the need of the hour. To address the impending energy crisis, hydrogen has been proposed as an efficient and sustainable renewable energy source that has potential to replace conventional sources such as fossil fuels. Owing to their large surface-to-volume ratio and unique physiochemical properties, two-dimensional (2D) materials have been more recently explored for their energy storage potential. In this study, we investigate the adsorption of hydrogen molecule on a two-dimensional, free-standing aluminum monolayer using first-principles density functional theory calculations. We examine adsorption at four high symmetry sites in the honeycomb lattice: T (directly above the Al atom on the surface), D (directly above the Al atom in the buckled layer), H (hollow site at the center of the honeycomb lattice), and X (midway between Al bonds). The movement of hydrogen molecule during diffusion through the honeycomb hollow ring center of the aluminum monolayer is also studied using the Nudged Elastic Band (NEB) approach.

Valorisation of Chlorella vulgaris biomass for multi-products synthesis via hydrothermal processing

Microalgal-based biofuel such as hydrochar has gained popularity in recent years owing to the high lipid content and fast growth rate of microalgal cells. However, commercial scale production of microalgal-based biofuel is not feasible due to the high processing cost of microalgal itself. One possible solution to overcome this limitation is to obtain other value-added byproducts to enhance the economic feasibility of the entire process in which such nature of research work is still very limited in the literature. Thus, in the present study, a two-step sequential hydrothermal carbonization (SEQHTC) was used to produce polysaccharides and hydrochar (potential solid fuel) from Chlorella vulgaris biomass. In the first step, whole algal (WA) biomass was subjected to hydrothermal subcritical extraction of polysaccharides whereas in the second step, the solid residue from the first step or identified as treated algal residue (TAR) was subjected to hydrothermal carbonization to produce hydrochar. The yield of hydrochar using WA biomass through SEQHTC process was 39.3 wt% with 12.5 wt% of polysaccharides. Apart from using WA, lipid-extracted algal (LEA) biomass was also used as feedstock for SEQHTC. The total extracted lipid, hydrochar and polysaccharides were 15.2 wt%, 41.5 wt% and 13.4 wt%, respectively. For comparison purposes, the conventional direct hydrothermal carbonization (DHTC) method was also carried out on both biomass. This study successfully demonstrated the realization of microalgal biorefinery concept, in which value-added products (polysaccharides) could be extracted along with the production biofuel such as biodiesel and hydrochar as sustainable renewable energy sources from microalgal biomass.

Socio-ecological challenges of hydroelectric dams among ethnic minorities in northern Laos

Globally, hydroelectric dams are increasingly considered to be a sustainable source of renewable energy. Many countries have invested in hydroelectric projects to boost the local and national economies. The findings of recent hydroelectric projects are mixed. Even though the construction of these dams has provided immediate benefits to surrounding communities, long-term negative implications of hydroelectric development have called into question the true sustainability of hydroelectric projects. These negative impacts of hydroelectric dams include the resettlement of marginalized communities, in addition to significant alterations to the local environment and economy. Taking both the positive and negative impacts of hydroelectric development into consideration, this paper examines how such hydroelectric dam development projects have led to the extreme marginalization of already vulnerable ethnic groups in Laos. Particularly, it focuses on the effects of hydroelectric dams on one of the largest ethnic groups in northern Laos, the Khmou. The findings suggest that the construction of hydroelectric dams act as a double-edged sword for the local environment, people, and economy. This study is an attempt to synthesize the existing knowledge to shed light on the negative implications that hydroelectric developments have had on ethnic minorities, particularly Khmou in northern Laos. Even though this paper has a geographical focus on northern Laos, the findings are relevant for understanding the impacts of hydroelectric dams on various historically marginalized populations in other parts of the Global South.

Daily Solar Radiation Forecasting for Northwest Nigeria Using Long Short-Term Memory

In order to ensure energy security and environmental sustainability, transition to renewable energy sources is required. One of the most viable and sustainable renewable energy sources is solar. However, developing solar energy systems requires solar radiation data which is scarce for most locations including Northwest Nigeria. In order to address this challenge, solar radiation is usually estimated from the available meteorological parameters. Several previous studies have used various methods including geospatial techniques and machine learning to predict monthly and yearly solar radiation, while few studies have focused on the estimation of daily solar radiation. Meanwhile, providing daily solar radiation data is necessary for the development of solar energy systems. Deep learning has been shown to be effective in solar radiation forecasting. To evaluate the performance of the deep learning method for daily solar radiation prediction, a Long Short-Term Memory (LSTM) based deep learning model was developed in this study. The forecasting model was created using daily solar radiation data collected over a 21-year period by the Nigerian Meteorological Agency in three major towns in North West Nigeria: Kano, Kaduna, and Katsina. The model was evaluated using two statistical indicators: coefficient of determination (R2) and Root Mean Square Error (RMSE). Results showed that R2 of 0.79 and 0.78 were obtained for the training and testing datasets respectively, while RMSE of 0.46 and 0.47 were obtained for the training and testing datasets respectively. Overall, the LSTM deep learning model has been proven to be effective in forecasting daily solar radiation.

Recent Developments and Perspectives of Cobalt Sulfide-Based Composite Materials in Photocatalysis

Photocatalysis, as an inexpensive and safe technology to convert solar energy, is essential for the efficient utilization of sustainable renewable energy sources. Earth-abundant cobalt sulfide-based composites have generated great interest in the field of solar fuel conversion because of their cheap, diverse structures and facile preparation. Over the past 10 years, the number of reports on cobalt sulfide-based photocatalysts has increased year by year, and more than 500 publications on the application of cobalt sulfide groups in photocatalysis can be found in the last three years. In this review, we initially summarize the four common strategies for preparing cobalt sulfide-based composite materials. Then, the multiple roles of cobalt sulfide-based cocatalysts in photocatalysis have been discussed. After that, we present the latest progress of cobalt sulfide in four fields of photocatalysis application, including photocatalytic hydrogen production, carbon dioxide reduction, nitrogen fixation, and photocatalytic degradation of pollutants. Finally, the development prospects and challenges of cobalt sulfide-based photocatalysts are discussed. This review is expected to provide useful reference for the construction of high-performance cobalt sulfide-based composite photocatalytic materials for sustainable solar-chemical energy conversion.

Transition Metal‐based Perovskite Oxides: Emerging Electrocatalysts for Oxygen Evolution Reaction

AbstractDevelopment of clean and sustainable renewable energy sources is imperative to deal with the future energy crises. Various technologies have been developed in this context, for example, water electrolysis, reversible fuel cell and metal‐air batteries etc. However, the sluggish kinetics of oxygen evolution reaction (OER) occurring at the anode of these energy storage/conversion systems becomes a significant hurdle. Recently, researchers utilized noble metals as electrocatalysts to enhance their efficiency still the high cost and scarcity of these materials draw the attention of researchers towards the cost‐effective Perovskite oxide nanomaterials due to their extraordinary flexibility. In this review, the importance of perovskite oxide nanomaterials as electrocatalysts for OER is discussed, followed by related reaction mechanisms and series of activity descriptors. Fundamental understanding about the instrumentation, parameters and protocols for the experimental measurements including concerned issues are also summarized. Moreover, various activation strategies adopted in recent years to enhance the electrocatalytic performance of perovskite oxides are also underlined. The article concludes with an outlook of existing challenges and future scope of these materials as electrocatalysts. The challenges and prospects discussed herein may pave the ways to rationally design the highly active and stable perovskites to outperform noble metal‐based OER electrocatalysts.

Asta-Ja and Energy Security in Nepal

Energy independence and sustainable renewable energy sources are the two main components of energy security for Nepal. More than 2/3rd of energy consumed in Nepal comes from biofuels and waste and about 1/4th of energy consumed comes from coal and petroleum products. With increasing number of motor vehicles and rising demand for cooking gas, Nepal’s coal and petroleum import bills in recent years have reached over Rs. 200 billion. With its vast water resources, Nepal has a great potential for energy independence and sustainability and achieve energy security. Nepal’s current 1,689 MW hydroelectricity capacity is expected to reach over 5,000 MW in next three to five years, which means Nepal will have a large amount of clean energy in the market. This increased hydropower production will also require an increased domestic consumption by making hydroelectricity affordable, reliable, and high-quality energy by improving its distribution system. Nepal also has a very high potential for solar power, which need to be harnessed and brought to the national grid. Nepal needs to harness all energy sources, which consist of hydropower, solar power, wind power, biofuels, and biogas, in a sustainable way for its energy independence and security. Because Nepal is in a geologically active and natural disasters prone area, it is critical to ensure ecological balance of Asta-Ja elements, Nepali letter, Jal (water), Jamin (land), Jungle (forest), Jadibuti (medicinal and aromatic plants), Janashakti (manpower), Janawar (animal), Jarajuri (crop plants) and Jalabayu (climate) while developing energy resources. Asta-Ja Framework serves as the connecting bridge between the energy resources and the end users. Strategic planning for comprehensive energy development considering ecological balance of Asta-Ja resources, decarbonization and electrification of energy end uses, improvement of energy infrastructures, continuous monitoring and evaluation of energy sector, and development of hydropower plants and alternative energy sources such as solar and wind is suggested for energy security in Nepal.

Investigation and Study of Ammonium Hydroxide and Biodiesel Blend as an IC Engine Fuel

The use of conventional fossil fuel has resulted in global warming. Biodiesel is a substitute fuel obtained from vegetable oil by transesterification process which can replace conventional diesel. Good alternative to traditional hydrocarbon-based fuel is ammonia combined with a biofuel. Ammonia is free of Carbon and can be extracted from sustainable renewable energy sources. It can be used with slight modifications on current IC engines. However running the engine on pure ammonia poses a lot of challenges which needs to be tackled. Running the engine on Biodiesel results in slightly more NOx emission, compared with traditional fuel. In the present study an experimentation has been carried out to examine the effect of biodiesel and ammonium hydroxide blend on ICE performance, emission and combustion aspects, in terms of specific fuel consumption, brake thermal efficiency, Nitrogen oxides (NOx) and Hydrocarbon (HC), Carbon monoxide (CO) and Carbon dioxide emissions. Biodiesel blends are examined using a single cylinder four stroke Kirloskar ICE. Experiments have been performed with varying percentages of ammonium hydroxide (3%, 6%, 9%) and B50 (50% diesel and 50% Karanja biodiesel) blended with Diesel and then compared with base line conventional diesel. This paper will help in understanding how percentage variation in ammonium hydroxide and biodiesel blend will effect emission and performance.

The Key to A Sustainable Future- Algal Biofuel

The depletion of fossil fuel reserves is posing a significant challenge in meeting the increasing energy demands. In response to concerns related to pollution, global warming, and rising oil costs, the exploration for alternative energy sources has gained momentum. Among these alternatives, macroalgae has emerged as a promising renewable energy option. Furthermore, various alternative fuels, such as hydrogen, natural gas, propane, ethanol, methanol, butanol, vegetable and waste-derived oils, and electricity, can be utilized either in a standalone fuel system or in combination with conventional fuels like gasoline, diesel, and petrol within hybrid-electric or flexible fuel systems. A particularly noteworthy advancement in next-generation biofuels is the production of biofuels derived from microalgae. Although further research is required to optimize algae production methods, equal attention must be given to downstream processing, particularly the generation of biofuels. In the face of the severe global consequences associated with the fossil fuel energy crisis, biofuels are progressively establishing themselves as a potent and sustainable source of renewable energy.

Artificial photosynthesis a novel and sustainable renewable energy source: In the perspective of Saudi Arabia

Artificial photosynthesis a novel and sustainable renewable energy source: In the perspective of Saudi Arabia

Bioinspired Three-Dimensional Nanoporous Membranes for Salinity-Gradient Energy Harvesting

ConspectusSalinity-gradient energy represents a widespread, clean, environmentally friendly, and sustainable source of renewable energy, which has attracted great attention in the past years. To harness this energy, interdisciplinary efforts from chemistry, materials science, environmental science, and nanotechnology have been made to develop efficient and low-cost approaches and materials for energy conversion. Conventional reverse electrodialysis (RED) systems are generally based on ion-exchange membranes, which usually suffer from ineffective mass transport, high membrane resistance, limited pore size, and concentration polarization, resulting in low output power density and poor energy-conversion efficiency. As one promising material, nanofluidic channels with their unique transport properties, which can be attributed to nanoconfinement effect, enable high-performance reverse electrodialysis to efficiently harvest salinity-gradient energy. Due to the unique porous architectures, three-dimensional (3D) nanoporous membranes demonstrate great potential for harvesting salinity-gradient power. It is generally known that the porous membranes can be prepared by many methods; however, there are some shortcomings such as high costs, poor ion conductance, and fragility limiting the practical application. Several simple and versatile approaches to low-cost fabrication of 3D nanoporous membranes have been developed in recent years. For example, self-assembly provides an effective route of constructing functional materials and organizing them into 3D architectures. In this Account, we mainly review our recent progress in the design and fabrication of bioinspired 3D nanoporous membranes for salinity-gradient energy harvesting. First, we give a brief introduction to bioinspired nanochannel membranes (BNMs) with diverse structural dimensions, and nanofluidic channel membranes may lead to technological breakthroughs and thus act as an emerging platform for harvesting salinity-gradient energy. Subsequently, we discuss the typical preparation approaches for bioinspired 3D nanoporous membranes. To tackle the bottlenecks of the conventional membrane-based power generator and extrapolate single-channel devices to macroscopic materials, our group have developed a series of 3D nanoporous membranes for power generation via various simple and versatile methods. We highlight the design and fabrication of several types of 3D nanoporous membranes, i.e., heterogeneous and homogeneous membranes, with tunable surface charge and porosity. The proof-of-concept demonstration of bioinspired 3D porous membranes shows that these nanofluidic platforms have the potential to overcome the selectivity-permeability trade-off and have impressive osmotic-energy-harvesting performance. Specifically, the scale-up Janus 3D porous membranes maintained high selectivity and rectified current in a hypersaline environment, which benefitted effective energy conversion and high output power density when seawater and river water were mixed. Finally, we give an outlook for future challenges and perspectives on the development of 3D nanofluidics for salinity-gradient energy conversion. We expect that this Account will spark further efforts on the development of bioinspired 3D nanoporous membranes for large-scale (typical side length of more than 10 cm) energy conversion and new opportunities for the applications in water desalination, dialysis, and ionic circuitries.