Alternative Renewable Sources Research Articles

Elicitor-Mediated Enhancement of α-Tocopherol in Cell Suspension Cultures of Nicotiana tabacum

Plant cell and tissue culture have been used as the alternative and potential renewable source for the production of valuable phytochemicals. Elicitation offers a reliable in vitro approach to produce or enhance potential phytochemicals. α-tocopherol, which is an isoform of vitamin E, is a potent fat-soluble phytochemical known in nature. The present study focused on enhancing the production of α-tocopherol in the cell suspension culture through an elicitation approach. Suspension cultures of Nicotiana tabacum were established from the leaf disk-derived callus. The cell suspension cultures were treated with different elicitors (methyl jasmonate, salicylic acid, and yeast extract) at the lag phase of the cell growth cycle. The effects of elicitors on cell cultures were determined in terms of biomass, and α-tocopherol enhancement was determined using high-performance liquid chromatography (HPLC). Different elicitors depending on the concentration exerted different effects on cell growth and α-tocopherol production. Methyl jasmonate treatment showed the significantly highest increase in α-tocopherol on the 6th day of treatment in tobacco suspension cultures. Methyl jasmonate at the concentration of 150 μM enhanced α-tocopherol content to 24-fold over the control. This study clearly shows that the elicitors had the potential to increase the accumulation of α-tocopherol considerably in tobacco cell cultures. The outcomes of this study could be of considerable importance to the nutraceutical and pharmaceutical industries.

Biofuels Production: A Review on Sustainable Alternatives to Traditional Fuels and Energy Sources

With increased worldwide energy demand and carbon dioxide emissions from the use of fossil fuels, severe problems are being experienced in modern times. Energy is one of the most important resources for humankind, and its needs have been drastically increasing due to energy consumption, the rapid depletion of fossil fuels, and environmental crises. Therefore, it is important to identify and search for an alternative to fossil fuels that provides energy in a reliable, constant, and sustainable way that could use available energy sources efficiently for alternative renewable sources of fuel that are clean, non-toxic, and eco-friendly. In this way, there is a dire need to develop technologies for biofuel production with a focus on economic feasibility, sustainability, and renewability. Several technologies, such as biological and thermochemical approaches, are derived from abundant renewable biological sources, such as biomass and agricultural waste, using advanced conversion technologies for biofuel production. Biofuels are non-toxic, biodegradable, and recognized as an important sustainable greener energy source to conventional fossil fuels with lower carbon emissions, combat air pollution, empower rural communities, and increase economic growth and energy supply. The purpose of this review is to explain the basic aspects of biofuels and their sustainability criteria, with a particular focus on conversion technologies for biofuel production, challenges, and future perspectives.

Ziegler-Nichols Based Controller Optimization for DFIG Wind Turbines

Wind power conversion systems are becoming the most preferable alternate renewable energy source. Doubly Fed Induction Generator’s utilization rotating parts in wind turbines is increasing with the wind power penetration to the electric grid. The observation becomes more noticeable when there are abnormal conditions within the electrical power system. In this paper, MPPT Controller is incorporated with DFIG through the MATLAB Simulink program is simulated. A conventional PI controller is tuned with Ziegler-Nichol’s (Z-N) method and was implemented to the DFIG Control Block. The rotor-side converter (RSC) is utilized to regulate the power generated by the doubly-fed induction generator (DFIG), while the direct current (DC) bus voltage is controlled by the grid-side converter (GSC). The DFIG's angular and comparative angular speeds are used to generate the reference torque value in the MPPT controller. This improved the time response, output power, electromotive torque, and other current and voltage characteristics. A comparison was made between the output evaluation of the inbuilt controller and the output evaluation of the proposed controller. The MPPT with tuned PI Controller's results show that the suggested system, which uses DFIG coupled to a rotor, is accurate, dependable, and feasible. DOI: https://doi.org/10.52783/tjjpt.v45.i02.6966

Potential of <i>Mikania micrantha</i> for biogas production

Invasive weeds are one of the major ecosystem-degrading elements and also a threat to crop production. The conventional approaches of weed control appear ineffective for Mikania micrantha which is one of the notorious invasive weeds having vigorous propagation characteristics. The manual method of control is otherwise effective provided the manpower cost involved in the collection is recovered. This study attempts an innovative approach to energy recovery from Mikania micrantha biomass. The suitability of Mikania biomass as a source of biogas production is investigated using a commercially available biogas reactor. The study primarily aims to understand the techno-economic feasibility of achieving the benefits of weed control and the generation of clean cooking fuel taking into consideration of collection, and handling of Mikania biomass and its subsequent conversion into biogas for a typical rural situation. In general biogas production potential of hydrolyzed Mikania is comparable with several weed biomasses and even more than cow dung. The time spent to remove Mikania micrantha to protect crops and the ecosystem is justified by its fuel value as biogas. Outcomes of the current study concerning the benign control of invasive weed, will be useful to materialize the multifaceted benefits of biogas technology such as clean fuel (an alternative renewable source of energy) and nutrient recycling from the large-scale conversion of Mikania biomass into biogas and organic fertilizer.

Small-angle neutron scattering from cellulose solutions in phosphoric acid at different water content

Cellulose from biomass is an abundant and renewable alternative source for chemicals and fuels, yet its utilization by chemical or biological process requires pre-treatment in order to release the macromolecules from their tightly packed crystal structure. Phosphoric acid (PA) has been known for many years to be an efficient solvent for crystalline cellulose. It is also established that a certain quantity of water content in PA is required for efficient pretreatment. This study uses small-angle neutron scattering (SANS) measurements to evaluate cellulose dissolution in deuterated phosphoric acid (dPA), at different wt% dPA between 78 and 97 % (different D2O content). The SANS method is useful for this purpose due to the availability of deuterated dPA, its contrast in scattering length density towards cellulose, and its low incoherent scattering cross-section. The results indicate that most of the cellulose in 2 wt% solution is dissolved in PA as individual chains, at acid content of 81–94 wt% PA. Structural differences of the dissolved cellulose in PA of the various water compositions in this range are insignificant. At 78 % dPA the cellulose crystal still seem to be disrupted, yet the structure can be modeled as mass-surface fractals of small fibrils with irregular surface, possibly due to dissolved chain segments, which are aggregated as mass fractals of rods. At 97 % dPA evidence for a small content of undissolved fibrils is noted.

Chemical and rheological analysis of unaged and aged bio-extended binders containing lignin

The use of alternative renewable sources to totally or partially replace bitumen is one of the most current challenges in the road pavement sector. The growing energy cost and environmental concerns lead to the necessity to find alternative solutions, by supporting at the same time sustainability and circular economy principles. Within this framework, this paper presents the application of a powder lignin, a natural bio-polymer deriving from by-products of wood pulp and paper industry, to replace part of bitumen. The bituminous blend consisting in 70% of bitumen and 30% of powder lignin (by weight) was made in laboratory through the use of a high shear stirring mixer, and a reference plain bitumen characterized by a similar consistency (i.e., same penetration grade) was used as comparison. Then, an extensive investigation on chemical and rheological properties of the bio-binder is presented. Fourier transform infrared spectroscopy (FTIR), saturates, aromatics, resins and asphaltenes (SARA), bending beam rheometer (BBR), frequency sweep tests and multiple stress creep recovery tests (MSCR) with a dynamic shear rheometer (DSR) were performed. Moreover, unaged, short- and long-term aging conditions were considered. Results indicated that powder lignin dominates the rheological behavior of the bio-binder and, from chemical analysis, it seems that it partially acts as a filler and partially as a binder. This would result in improved performances at both low and high temperatures, leading to a wider temperature range of performance grade (PG). Moreover, despite a stiffening effect is recognized, lignin also offers an antioxidant potentiality, reducing the aging susceptibility of the investigated bio-binder.

Application of central composite design for optimization of bio‐oil production using peat moss

AbstractMost nations have concentrated on reducing greenhouse gas emissions since global warming is such a serious problem. Due to land use changes, the harvesting of peat for use as fuel in homes, and the gardening industry, peat moss from peat bogs or peat fields may cause smoldering fires and release quantities of carbon dioxide. Bio‐fuel is one of the alternative renewable sources created from organic materials. Pyrolysis, a thermochemical process that converts organic materials into substitutes for fossil fuels and used to create biofuel because it is readily available, straightforward, and inexpensive to implement. The feedstock utilized in this experiment was peat moss. Proximate and ultimate analyses were performed using thermogravimetric analysis and elemental analyzer to determine thermal breakdown and elemental characteristics. Pyrolysis was carried out in this work using a prototype lab scale fixed‐bed pyrolysis. Based on prior study, the parameters used are pyrolysis temperature, nitrogen flow rate and reaction time to create the central composite design model. According to the analysis of variance results, pyrolysis temperature and flow rate were significant, however reaction time was not. The effect of flow rate and reaction time on response was explored. The actual bio‐oil yield achieved utilizing the optimal parameters was 10.02 %. The presence of chemical compounds in bio‐oil was measured.

The nexus between global carbon and renewable energy sources: A step towards sustainability

The energy transition is at the core of sustainable development as it helps to combat global warming and climate change. Similarly, carbon markets also support the climate change mitigation. Therefore, by realizing the potential role of clean energy and carbon markets in ensuring environmental sustainability, this study analyzes the spillovers and connectedness between the environment (global carbon) and renewable energy sources (wind, solar, geothermal, biofuel, and fuel cell). The empirical analysis is conducted by applying the novel “TVP-VAR” connectedness framework of Balcilar et al. (2021) on the daily data over the period from August 1, 2014, to February 4, 2022. The findings show that solar and biofuel appear as the highest net shock transmitter among alternative renewable sources while global carbon is shown as the net receiver of shocks. The largest transmission of shocks to global carbon is observed from wind followed by solar. Although these findings support the connectedness between renewable energy and the environment, however this connectedness is influenced by economic crises such as the oil crisis and pandemic crisis. During COVID-19, the fuel cell was the highest transmitter of shocks. The results are important for policy formulation, investment, and portfolio management as they provide insights into the interconnectedness and help in boosting climate actions.

A simplified methodology for estimating the Carbon Footprint of heat generation by forest woodchips as a support tool for sustainability assessment in decision-making

Energy production from biomass is very strategic for the achievement of global sustainability goals and the use of biofuels for decentralized energy production in medium-small size plants, which conforms to global fossil energy and GHG reduction targets, is expected to increase in the short-medium term. This paper proposes a simplified methodology for estimating the Carbon Footprint associated with heat generation by forest woodchips. The methodology includes all the relevant life cycle phases and is based on the specific fuel and plant characteristics, so it can effectively support sustainability assessment in decision-making regarding biomass projects through proper Carbon Footprint estimates. The application of the methodology showed results in the range of about 6–12 gCO2eq/MJ, depending on the case study characteristics, that agree with the impact values range observed from previous literature. The basic idea that the use of forest woodchips is particularly strategic for sustainable energy production within a “local” wood-energy supply chain (short transport distance) was confirmed. Furthermore, the methodology allowed to estimate indicative transportation distances for which forest woodchips can be considered environmentally competitive compared to alternative renewable sources such as, for instance, wood pellets.

Performance, combustion, and emission of a diesel engine fueled with an eco‐friendly mixture of two biodiesel blends

AbstractFast depletion and higher emissions of fossil fuels are posing problems to scientists across the globe. To overcome this, thorough research is needed to find out alternate renewable sources. Biodiesel is such a renewable, biodegradable, and innocuous fuel to meet this global need. Oil extracted from vegetable oil seeds is processed into biodiesel by the transesterification process. The experimental work is carried out to study the performance and emission characteristics of a single‐cylinder, air‐cooled diesel engine by using a mixture of two diverse biodiesels namely Pongamia and Mahua. The results indicate that at higher loads there is a reduction of smoke emission for the 100PM blend (50% Pongamia biodiesel and 50% Mahua biodiesel) along with a 4.4% reduction in brake thermal efficiency when compared to diesel. The smoke is reduced for 100PM by 78.4% and 70.8% and for 50D50PM (50% diesel and 25% each biodiesel) by 71% and 61% at higher loads. From the combustion analysis, it is found that peak cylinder pressure for 100PM and 50D50PM blends are higher when compared with diesel which may be due to the advanced start of injection and ignition of blends. Injection and ignition advance of the blends may be attributed to higher bulk modulus and higher cetane number of biodiesels.

Environmental Assessment of Hydrogen Utilization in Various Applications and Alternative Renewable Sources for Hydrogen Production: A Review

Rapid industrialization is consuming too much energy, and non-renewable energy resources are currently supplying the world’s majority of energy requirements. As a result, the global energy mix is being pushed towards renewable and sustainable energy sources by the world’s future energy plan and climate change. Thus, hydrogen has been suggested as a potential energy source for sustainable development. Currently, the production of hydrogen from fossil fuels is dominant in the world and its utilization is increasing daily. As discussed in the paper, a large amount of hydrogen is used in rocket engines, oil refining, ammonia production, and many other processes. This paper also analyzes the environmental impacts of hydrogen utilization in various applications such as iron and steel production, rocket engines, ammonia production, and hydrogenation. It is predicted that all of our fossil fuels will run out soon if we continue to consume them at our current pace of consumption. Hydrogen is only ecologically friendly when it is produced from renewable energy. Therefore, a transition towards hydrogen production from renewable energy resources such as solar, geothermal, and wind is necessary. However, many things need to be achieved before we can transition from a fossil-fuel-driven economy to one based on renewable energy.

Fish biodiversity declines with dam development in the Lower Mekong Basin

Hydropower dams are a source of renewable energy, but dam development and hydropower generation negatively affect freshwater ecosystems, biodiversity, and food security. We assess the effects of hydropower dam development on spatial–temporal changes in fish biodiversity from 2007 to 2014 in the Sekong, Sesan, and Srepok Basins—major tributaries to the Mekong River. By analyzing a 7-year fish monitoring dataset, and regressing fish abundance and biodiversity trends against cumulative number of upstream dams, we found that hydropower dams reduced fish biodiversity, including migratory, IUCN threatened and indicator species in the Sesan and Srepok Basins where most dams have been constructed. Meanwhile, fish biodiversity increased in the Sekong, the basin with the fewest dams. Fish fauna in the Sesan and Srepok Basins decreased from 60 and 29 species in 2007 to 42 and 25 species in 2014, respectively; while they increased from 33 in 2007 to 56 species in 2014 in the Sekong Basin. This is one of the first empirical studies to show reduced diversity following dam construction and fragmentation, and increased diversity in less regulated rivers in the Mekong River. Our results underscore the importance of the Sekong Basin to fish biodiversity and highlight the likely significance of all remaining free-flowing sections of the Lower Mekong Basin, including the Sekong, Cambodian Mekong, and Tonle Sap Rivers to migratory and threatened fish species. To preserve biodiversity, developing alternative renewable sources of energy or re-operating existing dams to increase power generation are recommended over constructing new hydropower dams.

Production and Kinetic Study of Biogas Formation from Cow Dung and Utilization of Biogas Effluent as Bio-Fertilizer

Biogas is an alternative and eco-friendly renewable power source and biogas effluent is used as a bio-fertilizer. In this research, the kinetic of biogas formation was studied and also the acceptance of biogas effluent as a bio-fertilizer was evaluated. 8000 g of cow dung and 600 ml of inoculum were fed to the digester. The volume of biogas production was observed for 50 days by using Orsat Apparatus and gas chromatography was used to analyze the gas. From the data, it was found that the formation of methane gas didn’t depend upon the concentration of cow-dung hydrocarbon and it followed the mechanism of the zero-order reaction. On the other hand, the elementary analysis of biogas effluent by AAS ensured the property of effluent as a bio-fertilizer. Utilization of Miscanthus fuscus with E. coli and S. aureus ensured a higher degree of biodegradation.

Design and fabrication of solar powered wheelchair

As per the census, 2011 in 2016 disabled population of India was around 2.66 Cr and currently, it is about 3 Cr, talking about the physically disabled the count is 54,36,826. Around 70–75% are above 15 years of age. Conventional manual wheelchairs need to be handled by the other person ultimately they have to rely on others for their movement and daily activities which may cause mental depression among them and sometimes they hesitate to ask for help so electric wheelchair is the best option in this situation. But due to the continuous decline of fossil fuels, there is a need to find alternative renewable sources; here solar energy is a good solution. In this paper, study shows conventional wheelchairs and their conversion into an electric wheelchair which is semi-automated using sensors and controllers. This paper studies power consumption and shows that by using renewable sources of energy we can save 60–70% of the energy and once the battery is charged it will give 3–4 h of runtime. From the following research study, it can be concluded that designed wheelchair is having good features and would be very convenient and friendly to the aged people and handicapped. The device will be very useful to people suffering from disabilities and physical problems that they can take advantage of, as well as an eco-friendly device that works on renewable sources of energy. The frequency of charging is acceptable, improving the present scenario in said area of research.

Catalytic Graphitization of Biomass as a Potential Method Produce Graphite In The Future : A Review

The traditional graphitization process involves the use of non-renewable carbon sources and high temperatures, which are time-consuming and expensive. Biomass has been proposed as an alternative renewable source of carbon, which can be graphitized at lower temperatures using transition metal catalysts. The article highlights successful research on graphitization of various biomass carbon sources, such as coconut coir, whey protein, pine wood sawdust, mangosteen peel, miscanthus grass, and palm kernel shell waste, using metals as a catalyst. The graphitization process using catalysts derived from transition metals has been shown to reduce the graphitization temperature, shorten the graphitization time and improve the physicochemical properties of the resulting graphite material.

Analysis of varying ETL/HTL material for an effective perovskite solar cell by numerical simulation

The rapid development in the industrial sector as well as an increasing population worldwide during the past few decades have led to the increase in demand for the energy. We all are familiar that the major source of energy mainly constitutes the fossil fuels which are predicted to get exhausted in near future. Therefore, to serve the increasing demands of energy, researchers were urged to find an alternate renewable source of energy which would be able to replace fossil fuels. This work reports the simulation of an inorganic/organic perovskite solar cell and to study the variation in the conversion efficiency by varying the ETL (electron transport layer), and the HTL (hole transport layer). We note here that the perovskite / absorber layer is kept the same for all combinations of HTL and ETL. The absorber layer taken into consideration in this particular paper is CH3NH3PbI3. Therefore, we compare the results of various cell combinations to obtain the one with the highest conversion efficiency. All the simulation work is done in SCAPS-1D software.

Efficiency Analysis of Hydrogen Fuel Cell Power Systems for Off-Grid Applications

The escalating environmental hazards associated with the use of fossil fuels call for eco-friendly alternative renewable energy conversion sources. One of these renewable energy measures is the development of a hydrogen fuel cell, a device which directly converts the potential of chemical fuel into electrical power without combustion. This study evaluates the efficiency of a hydrogen fuel cell power system for off-grid applications with an aim to show how much energy can be generated from a locally produced hydrogen powered device, and for how long an electrical load (1Ω resistor) in the form of bulbs of varying loading sizes is carried. For the power and performance evaluation of the cell, multimeters equipped with integrated voltmeters and ammeters were employed for their accuracy, with a power generator, functioning through a rectifier, supplying a direct current of 3.45A at a known voltage of 18.2V, providing the means to calculate the energy input into the developed fuel cell. The results assessments, revealed that power levels steadily fall as time progresses, an occurrence caused by the depletion of reactants and the continuous accumulation of reaction products, which ultimately lead to decreasing electrochemical activity and subsequently decreased power generation. The graph readings show the dynamic behaviour of the fuel cell's performance depicted by the distinct pattern followed in the relationship between time and power output.

Time Series Analysis of Fossil Fuels Consumption in Slovakia by Arima Model

Abstract According to the Green Deal, the carbon neutrality of the European Union (EU) should be reached partly by the transition from fossil fuels to alternative renewable sources. However, fossil fuels still play an essential role in energy production, and are widely used in the world with no alternative to be completely replaced with, so far. In recent years, we have observed the rapidly growing prices of commodities such as oil or gas. The analysis of past fossil fuels consumption might contribute significantly to the responsible formulation of the energy policy of each country, reflected in policies of related organisations and the industrial sector. Over the years, a number of papers have been published on modelling production and consumption of fossil and renewable energy sources on the level of national economics, industrial sectors and households, exploiting and comparing a variety of approaches. In this paper, we model the consumption of fossil fuels (gas and coal) in Slovakia based on the annual data during the years 1965–2020. To our knowledge, no such model, which analyses historical data and provides forecasts for future consumption of gas and coal, respectively, in Slovakia, is currently available in the literature. For building the model, we have used the Box–Jenkins methodology. Because of the presence of trend in the data, we have considered the autoregressive integrated moving average (ARIMA (p,d,q)) model. By fitting models with various combinations of parameters p, d, q, the best fitting model has been chosen based on the value of Akaike’s information criterion. According to this, the model for coal consumption is ARIMA(0, 2, 1) and for gas consumption it is ARIMA(2, 2, 2).

Factors Affecting Rooftop Solar Photovoltaic System Adoption Intention: With Special Reference to Middle-Income Households in Kaduwela Municipal Council Area, Sri Lanka

The generation and supply of electricity is a prominent contemporary topic in Sri Lanka. Due to high dependency on non-renewable imported energy sources and due to various economic instabilities, a number of challenges have emerged leading to disruption of continuous electricity supply at affordable prices. Thus, it is high time to consider alternative renewable sources of energy and most specialists consider solar energy as one of the most promising technologies. Despite of benefits of solar energy and all the initiatives taken by different parties, Sri Lanka is still at a lower level of producing electricity using solar systems. This study aims to identify the factors affecting rooftop solar photovoltaic system adoption intention of middle-income households in Sri Lanka. The data was collected through a structured questionnaire targeting 75 middle-income residents in Kaduwela area selected using simple random sampling technique. The collected data were analysed using descriptive and inferential analyses. The study findings revealed that both motivating factors and barriers make an impact on rooftop solar photovoltaic system adoption intention. However, situations prevail where not all components of those factors impact adoption intention similarly. The study findings lead to a better understanding of the complex relationships between motivating factors, barriers and rooftop solar photovoltaic system adoption. These insights may be used to evaluate motivating factors and barriers to find relevant interventions in encouraging motivating aspects more while mitigating the barriers, as immense number of benefits can be gained from rooftop solar photovoltaic systems to the country.

Impact of natural resource rents and economic growth on environmental degradation in the context of COP-26: Evidence from low-income, middle-income, and high-income Asian countries

This study investigates the influence of natural resource rents and economic growth on environmental degradation by using the three classifications of the Asian countries based on per capita income. A panel data from 1990 to 2018 is analyzed to determine the cointegration relationship through Mean Group (MG) regression. The calculations indicate that there is a strong positive correlation between natural resource rents and carbon emissions, particularly in the group of low-income countries. The results indicate a positive correlation between economic growth and carbon emissions for the middle and low-income groups while there is a negative relationship found in the group of high-income countries. The study suggests that to achieve the targets of COP-26, joint efforts of high, middle, and low-income countries are required on urgent basis to reduce carbon emissions. The group of high-income countries is required to improve the resource rents policies such as the search for alternative renewable sources, plantation of trees on a large scale, judicious way of energy preservation, and use of biofuels at the household level. The group of middle and low-income countries needs to adopt environment-friendly economic growth along with the aforementioned policies to preserve natural resources.