Alternative Renewable Energy Sources Research Articles

Solar-Powered Multiple-Input Zeta Converter for 48V Applications

To reduce environment pollutants and a current level on high power systems, 48Vpower applications have been studied on uninterruptible power supply, green telecommunication power system, and micro hybrid electric vehicles with renewable energy sources or alternative energy sources. In the electric vehicle field, large numbers of automobile companies are obligated to supply more electrified vehicles. As these more electrified vehicles use high power, a 48V system has been researched to decrease a current level of the vehicle power system. This paper proposes a solar-powered multiple-input zeta dc-dc converter with high reliability and flexibility for 48V applications. The proposed multiple-input zeta converter system was verified by computer-based simulation results.

Bioenergy from Low-Intensity Agricultural Systems: An Energy Efficiency Analysis

In light of possible future restrictions on the use of fossil fuel, due to climate change obligations and continuous depletion of global fossil fuel reserves, the search for alternative renewable energy sources is expected to be an issue of great concern for policy stakeholders. This study assessed the feasibility of bioenergy production under relatively low-intensity conservative, eco-agricultural settings (as opposed to those produced under high-intensity, fossil fuel based industrialized agriculture). Estimates of the net energy gain (NEG) and the energy return on energy invested (EROEI) obtained from a life cycle inventory of the energy inputs and outputs involved reveal that the energy efficiency of bioenergy produced in low-intensity eco-agricultural systems could be as much as much as 448.5–488.3 GJ·ha−1 of NEG and an EROEI of 5.4–5.9 for maize ethanol production systems, and as much as 155.0–283.9 GJ·ha−1 of NEG and an EROEI of 14.7–22.4 for maize biogas production systems. This is substantially higher than for industrialized agriculture with a NEG of 2.8–52.5 GJ·ha−1 and an EROEI of 1.2–1.7 for maize ethanol production systems, as well as a NEG of 59.3–188.7 GJ·ha−1 and an EROEI of 2.2–10.2 for maize biogas production systems. Bioenergy produced in low-intensity eco-agricultural systems could therefore be an important source of energy with immense net benefits for local and regional end-users, provided a more efficient use of the co-products is ensured.

GROWTH AND FATTY ACID COMPOSITION OF MARINE MICROALGA NANNOCHLOROPSIS sp IN MEDIUM ENRICHED WITH MAGNESIUM

Micro-algae are to be an attractive way to produce bio-diesel due to high photosynthetic yields and lipid accumulation in cells. This high productivity combined with possibility to uptake CO2 stimulated its utilization as a biological mitigation method of CO2, at once as an alternative renewable source of energy. Growth characteristics and chemical composition of micro-algae can be altered by culture environment. Nutrient sufficiency,included magnesium element (Mg2+) is important factors on overall biochemical composition. In study, Nannochloropsis sp was cultivated in Erlenmeyer 250 ml containing 200 ml f/2 medium. There are three groups of treatment with different levelof magnesium (Mg2+), i.e. 0 (M0); 0.1mgL-1 (M1); and 1.0 mgL-1 (M2). All treatment was designed triplicate in batch system. Culture was then aerated continuously with sterile atmospheric air (1.5 L.min-1). Cells were harvested on 25th day after inoculation and analyzed. Data showed that Chlorophyll-a increased linearly with time and maximum at 18th days of growth period, i.e. 23.57; 26.44; and 27.74mgL-1, for M0; M1; and M2,respectively. Chlorophyll-a content decreased significantly when pH dropped to 5-6.Enrichment with Mg2+ increased the chlorophyll-a content 12.2-17.7%. Dry cell reached 375-400mgL-1 in all treatment. Lipid content of Nannochloropsis sp in control (M0) is 55.3%, higher than M1 and M2. Saturated fatty acid tends to increase from 80.70 (M0)to 96.70 (M1) and 94.53% (M2). Fatty acid of M0 and M1 was composed dominantly by palmitic acid (C16:0), i.e. 49.19-70.75% total fatty acids. Meanwhile, M2 treatment was dominantly by lauric acid (C12:0), i.e. 32.98%.Keywords: CO2 biological mitigation, chlorophyll-a, fatty acid, lipid, agnesium,microalgae, Nannochloropsis sp, photosynthesis.

Will Florida be saved?

The state of Florida is typical of all the low-lying densely populated coastal areas around the world that are threatened by present and future rising sea level. These coastal areas will become destructively flooded by sea level rise due to melting of the world's glacial ice if fossil fuel consumption and resulting global warming are not strongly limited. Efforts to achieve this limitation in a timely way might not be successful because of cultural inertia, opposition by vested interests, and the difficulties in developing alternative sources of renewable energy on a large scale. However, the rising sea level could be reversed to a more rapidly falling sea level at least temporarily if a previously unrecognized tipping point in the changing climate is reached in coming decades. This tipping point is the onset of rapid new glacial ice sheet growth in northeastern Canada, Greenland, and the Barents Sea. The cause would be an order of magnitude increase in regional precipitation. Much evidence for that event is found in the geological records of the initiation of the last ice age 120,000yrs ago. The precursors for a similar future event are in place and are identified in modern oceanic records. These precursors include the increasing salinity of the Mediterranean Sea and the observed increasing penetration of the Spitsbergen-Atlantic Current into the polar ocean, which suggests that the tipping point may be reached before the end of this century. If so, the flooding may occur on only a small scale. However if so, a sharp 500yr cooling would be expected in eastern Canada and northern Europe, and greenhouse warming elsewhere would continue unless fossil fuel usage is reduced. This paper supports the suggestion by Giff Miller and Anne de Vernal in a 1992 letter to Nature that global warming and an ice age may occur simultaneously.

The Future Expansion of HVDC Power Transmission in Brazil: A Scenario-Based Economic Evaluation

We discuss the expected future needs of the Brazilian electric grid operators for High Voltage Direct Current (HVDC) transmission lines against the background of a changing electricity sector in Brazil. On account of the spatial mismatch between the additional generation potential and the expected future electricity demand, a need for investments in long-distance transmission capacity is postulated. Due to the low losses incurred, HVDC technology is particularly suitable for this. For the analysis, we use different expansion scenarios for the year 2035 that are mainly based on hydropower or alternative renewable energy sources (primarily wind and solar power). Linear optimization is used to determine the optimal HVDC transmission lines to connect regions. The results show that large investments in HVDC transmission are needed, especially in the case of hydropower expansion, and that transmission capacity is a critical factor in the process of expanding the renewable energy generation capacity in Brazil.

To avoid global warming by 2°C—mission impossible

Investigations have been carried out into the basic implications of the decisions taken in December 2015 at the Paris conference of the countries–participants of the UN Framework Convention on Climate Change for the world energy and for the atmosphere and climate. Based on the studied historical record of specific CO2 emissions in the energy production by different countries, it is shown that the implementation of the Paris Agreement will require an unprecedented effort to modernize the global energy sector; in particular, rapid elimination of coal from the global energy mix and a substantially increased share therein of carbon-free energy sources (hydro and nuclear power and alternative renewable energy sources (renewables)) to one third by the middle of this century. We have developed a scenario for the global energy demand mix corresponding to the guidelines of the Paris Agreement and its more conservative variant extending the trend of the last 15 years. It has been established that, under any of the development scenarios, the global mean temperature is to exceed the level of 1.5°C as soon as within a few decades. Using model simulations of the changes in the atmosphere and climate, we show that even the full implementation of the Paris Agreements will not prevent the increase in average global temperature by 2°C as compared to the preindustrial levels. The world community faces a difficult choice between the implementation of more stringent measures for reducing greenhouse gas emissions, which we believe to be almost unreal, and adaptation to utterly new climatic conditions, which will last for centuries to come.

Wind power generation: An impact analysis of incentive strategies for cleaner energy provision in Brazil

Brazil has adopted various strategies to encourage alternative renewable energy sources in pursuit of cleaner and sustainable energy production. To this end, strategies should support the reduction of the financial risk for potential investors in the renewable energy market. Therefore, this study aims to analyze the impact of incentive strategies on the financial risk of wind power generation projects in Brazil in different marketing environments. From a quantitative approach, using Monte Carlo Simulation in three scenarios, we evaluate the impact of funding from the National Development Bank and participation in the Clean Development Mechanism in the financial returns of the investor in a regulated contracting environment and free contracting environment, measured by the Net Present Value. We conduct a statistical analysis to find out if there were statistically significant differences in investor risk in each scenario. The main results of the study are as follows: the wind speed, the selling price of energy, and disbursement for the investment have the most significant impact on the financial return; the project viability probability is greater than 85% in all scenarios, regardless of the marketing environment; the regulated market is less risky for the producer than the free market, since there is a statistically significant difference in Net Present Value variances for all scenarios; in the regulated contracting environment, funding is critical to reducing risk; and carbon credit trading is not a suitable policy for providing financial security to renewable energy producers. Thus, we conclude that in Brazil the contracting of projects from auctions in the regulated contracting environment, with the support of the National Development Bank, has been important for neutralizing the producer's financial risks.

Climate Change and Sustainable Energy in Rural Bangladesh An Innovative Approach

Being a densely populated country with limited natural resources, Bangladesh is severely suffering from the energy crisis since the past few decades. Due to the limitation in fossil fuel reserve, the only way to minimize the supply-demand gaps in the energy sector is switching towards the alternative renewable energy sources. Kazi Shahid Foundation (KSF) has been working in partnership with rural villagers for over 15 years. In order to make rural people’s lives healthier and more productive, KSF has developed “Biogas Program”. The continuous burning of biomass fuels leads to long term health issues, predominantly among women. The amount of wood consumed, also contributes to an increase of green house gas emissions and partly responsible for deforestation. Bangladesh has a long standing tradition of utilizing dung exclusively as the feedstock for biogas plants where as India has focused mainly on food waste. This project has taken mixed approach, using both dung and waste food to produce cooking fuel by allowing the Biogas Plant to operate more efficiently. Attempting another first for Bangladesh, KSF is utilizing the same “no cash” microfinance repayment system, where KSF will be reimbursed the cost of the Biogas Plant through the effluent slurry, as well as, excess cow dung or milk. KSF hopes to continue the Biogas Program by bringing biogas to the rural villages of Panchagarh district. In order to make biogas a viable alternative to the current biomass fuels used in cooking, this multi-purpose approach was developed through careful research into the latest technologies available in Bangladesh. In depth understanding of the needs and concerns of the village people; a comprehensive training program was developed, provided full support structure able to deal quickly with both simple and complex problems and finding innovative methods to use the bio slurry as a regular income generating asset.

SWOT analysis of the renewable energy sources in Romania - case study: solar energy

The evolution of energy sector worldwide triggered intense preoccupation on both finding alternative renewable energy sources and environmental issues. Romania is considered to have technological potential and geographical location suitable to renewable energy usage for electricity generation. But this high potential is not fully exploited in the context of policies and regulations adopted globally, and more specific, European Union (EU) environmental and energy strategies and legislation related to renewable energy sources. This SWOT analysis of solar energy source presents the state of the art, potential and future prospects for development of renewable energy in Romania. The analysis concluded that the development of solar energy sector in Romania depends largely on: viability of legislative framework on renewable energy sources, increased subsidies for solar R&D, simplified methodology of green certificates, and educating the public, investors, developers and decision-makers.

Evaluation of Biodiesel Production, Engine Performance, and Emissions

Nowadays, to decrease environmental pollution and dependence on fossil-based fuels, research on alternative renewable energy sources has been increasing. One such renewable energy source is biodiesel, which is used as an alternative fuel for diesel engines. Biodiesel is renewable, nontoxic, biodegradable, and environmentally friendly. Biodiesel is domestically produced from vegetable␣oil (edible or nonedible), animal fat, and used cooking oils. In the biodiesel production process, oil or fat undergoes transesterification reaction through use of simple alcohols such as methanol, ethanol, propanol, butanol, etc. Use of methanol is most feasible because of its low cost, and physical and chemical advantages. Acid catalysis, alkali catalysis, and enzyme catalysis are usually used to improve the reaction rate and yield. Glycerol is a byproduct of the reaction and can be used as an industrial raw material. In this study, biodiesel production methods (direct use, pyrolysis, microemulsion, transesterification, supercritical processes, ultrasound- assisted, and microwave-assisted) and types of catalyst (homogeneous, heterogeneous, and enzyme) have been evaluated and compared. In addition, the effects of biodiesel and its blends on diesel engine performance and exhaust emissions are described and reviewed.

A Terrestrial Microbial Fuel Cell for Powering a Single-Hop Wireless Sensor Network.

Microbial fuel cells (MFCs) are envisioned as one of the most promising alternative renewable energy sources because they can generate electric current continuously while treating waste. Terrestrial Microbial Fuel Cells (TMFCs) can be inoculated and work on the use of soil, which further extends the application areas of MFCs. Energy supply, as a primary influential factor determining the lifetime of Wireless Sensor Network (WSN) nodes, remains an open challenge in sensor networks. In theory, sensor nodes powered by MFCs have an eternal life. However, low power density and high internal resistance of MFCs are two pronounced problems in their operation. A single-hop WSN powered by a TMFC experimental setup was designed and experimented with. Power generation performance of the proposed TMFC, the relationships between the performance of the power generation and the environment temperature, the water content of the soil by weight were measured by experiments. Results show that the TMFC can achieve good power generation performance under special environmental conditions. Furthermore, the experiments with sensor data acquisition and wireless transmission of the TMFC powering WSN were carried out. We demonstrate that the obtained experimental results validate the feasibility of TMFCs powering WSNs.

Downregulation of liver HSP70 in zebrafish exposed toJatropha curcasseed cake extract

AbstractThe use of Jatropha curcas in biodiesel production is one of the emerging alternative sources of renewable energy. However, the extraction process leaves a seed cake waste and the lack of disposal protocols poses serious threat to ecosystems. This study aims to determine the toxicity of the seed cake extract to Danio rerio (zebrafish) through the analysis of heat shock protein 70 expression. The median lethal concentration (LC50) was first determined through an acute toxicity test coupled with probit analysis. For the HSP70 induction test, fishes were subjected to a non-exposed setup and sublethal concentration (50% of LC50) of detoxified, washed, and untreated seed cake. Total RNA from liver samples was isolated and reverse transcribed followed by amplification through polymerase chain reaction (PCR) and gel profiling. Results indicate an LC50 of 0.172% (w/v) or 1.72 g/L. The heat shock induction test showed a significant downregulation of HSP70 expression in fishes exposed to washed and untreate...

The Concept of Mechanical Part of the Model Micro-Energy Sources for Electrical Laboratories

The use of renewable (alternative) energy sources of energy is still a hot topic. In the electrical engineering laboratories of the Department of technical subjects created a model of micro energy sources that can be operated in various operating modes to simulate in various operating conditions. The machine set is dedicated for laboratory of electric engeneering. Goal is to show students in the subject Renewable energy sources and their application, practical use and parameters an the asynchronous generator. The article deals with the mechanical concept and mechanical construction of laboratory machine set.

Potential of Solar Energy in Kota Kinabalu, Sabah: An Estimate Using a Photovoltaic System Model

Solar energy is becoming popular as an alternative renewable energy to conventional energy source, particularly in the tropics, where duration and intensity of solar radiation are longer. This study is to assess the potential of solar energy generated from solar for Kota Kinabalu, a rapidly developing city in the State of Sabah, Malaysia. A year data of solar radiation was obtained using pyranometer, which was located at Universiti Malaysia Sabah (6.0367° N, 116.1186° E). It was concluded that the annual average solar radiation received in Kota Kinabalu was 182 W/m2. In estimating the potential energy generated from solar for Kota Kinabalu city area, a photovoltaic (PV) system model was used. The results showed that, Kota Kinabalu is estimated to produce 29,794 kWh/m2 of electricity from the solar radiation received in a year. This is equivalent to 0.014 MW of electricity produced just by using one solar panel. Considering the power demand in Sabah by 2020 is 1,331 MW, this model showed that the solar energy can contribute around 4% of energy for power demand, with 1 MW capacity of the PV system. 1 MW of PV system installation will require about 0.0328% from total area of the city. This assessment could suggest that, exploration for solar power energy as an alternative source of renewable energy in the city can be optimised and designed to attain significant higher percentage of contribution to the energy demand in the state.

Use of Biomass and Waste for Energy Purposes

This article focuses on the use of alternative renewable energy sources (waste and biomass) as a full replacement for traditional non-renewable resources. We focus on ways to increase the heating value of the raw materials by drying and pyrolysis, and the possibilities of influencing low heating value of fuels by using pyrolysis products. Pyrolysis generates heat and products, which may be used directly as fuel or after modification as additives for fuels. Pyrolysis is a suitable process for recovery of municipal, biological or contaminated waste. It contributes to a sustainable way of energy production and waste management. Moreover, the production in local conditions from local resources, increases land use, employment in the regions and energy self-sufficiency in the state. With combined production of fuels (pellets, briquettes) from biomass, wastes and pyrolysis products we expect to increase the heating value of well over 20 MJ.kg-1.

Development of Energy-Efficient Thermal Management System for Proton Exchange Membrane Fuel Cell and Reformer

The rising energy cost and limited supply of fossil fuel make it important for an alternative renewable energy source. Of all the alternatives, proton exchange membrane (PEM) fuel cell is very promising due to its high efficiency and zero emission characteristics. A fuel cell converts chemical energy to electricity by combining hydrogen with air. However, hydrogen storage poses a lot of practical challenges. Hence, alcohol based steam reforming systems are widely used for on-site hydrogen generation instead. During operation, a fuel reformer needs heating to maintain its temperature. At the same time, the fuel cell stack needs cooling to maintain its temperature. Currently, separate heating and cooling systems are used, resulting in an inefficient thermal management system. In this study, a more efficient thermal management system is proposed. It incorporates a vapor compression refrigeration (VCR) system to a reformer - PEM fuel cell unit. A VCR system can be seen as a device that transports heat from one place to another with a very high efficiency. In this application, heat is removed from the stack and is transferred to the reformer. This method will save around 38% of energy as compared to the conventional thermal management system.

Optical diagnostics of early flame development in a DISI (direct injection spark ignition) engine fueled with n-butanol and gasoline

Given the instability in supply and finite nature of fossil fuels, alternative renewable energy sources are continuously investigated throughout the production–distribution-use chain. Within this context, the research presented in this work is focused on using butanol as gasoline replacement in a Direct Injection Spark Ignition engine. The impact of this fuel on the combustion processes was investigated using optical diagnostics and conventional methods in a transparent single cylinder engine. Three different load settings were investigated at fixed engine speed, with combined throttling and mixture strength control. The engine was operated in homogenous charge mode, with commercial gasoline and pure n-butanol fueling. High spatial and temporal resolution visualization was applied in the first phase of the combustion process in order to follow the early flame development for the two fuels. The optical data were completed with conventional measurements of thermodynamic data and pollutants emission at the exhaust. Improved performance was obtained in throttled stoichiometric mode when using the alternative fuel, while at wide open throttle, gasoline featured higher indicated mean effective pressure at both air–fuel ratio settings. These overall findings were correlated to flame characteristics; the alcohol was found to feature more distorted flame contour compared to gasoline, especially in lean conditions. Differences were reduced during throttled stoichiometric operation, confirming that mass transfer processes, along with fuel chemistry and physical properties, exert a significant influence on local phenomena during combustion.

Optimization of bioethanol production from nigerian sugarcane juice using factorial design

The quest to reduce the level of overdependence on fossil fuel product and to provide all required information on proven existing alternatives for renewable energy has resulted into rapid growth of research globally to identify efficient alternative renewable energy sources and the process technologies that are sustainable and environmentally friendly. The present study is aimed at production and characterization of bioethanol produced from sugarcane juice using a 24 factorial design investigating the effect of four parameters (reaction temperature, time, concentration of bacteria used and amount of substrate). The optimum bioethanol yield of 19.3% was achieved at a reaction temperature of 30oC, time of 72 hours, yeast concentration of 2 g and 300 g concentration of substrate (sugarcane juice). The result of statistical analysis of variance shows that the concentration of yeast had the highest effect of 7.325 and % contribution of 82.72% while the substrate concentration had the lowest effect and % contribution of -0.25 and 0.096% respectively. The bioethanol produced was then characterized for some fuel properties such as flash point, specific gravity, cloud point, pour point, sulphur content, acidity, density and kinematic viscosity. The results of bioethanol characterization conform to American society for testing and materials (ASTM) standard. Hence, sugarcane juice is a good and sustainable feedstock for bioethanol production in Nigeria owing relative abundance, cheap source of supply and available land for large scale production.

Reducing the Volume of Garbage and Production of Biogas through Anaerobic Decomposition

Biogas is one of the most eco-friendly alternative renewable energy sources, to meet future energy requirement. In order to carry out this research, two experiments were set up taking cow dung, cow dung with wasted flour and cultured Bacteria with waste flour. In Experiment 1, only cow dung was used in build biogas plant and decomposed periodically for 28 days. After that cow dung slurry (as inoculum) with waste flour were decomposed for 28 days. In Experiment 2, same waste flour with cultured anaerobic bacterial colony (as inoculum) was used as the feed stocks and the experiment was completed in 28 days. Result of the Study revealed that production of biogas was higher and consuming less time when cultured bacterial colony was used as inoculum with feed stock, compared to that of cow dung. In this experiment, garbage is decomposed with approximately all type of anaerobic bacteria. If methanogens, facultative anaerobes and other bacteria which are responsible for anaerobic digestion and biogas formation, are separately cultured and these garbage’s are separately decomposed with this bacteria. Anaerobic decomposition has a number of environmental benefits including production of ‘green’ energy and natural fertilizers. The process of converting organic feed stock into biogas can serve as a substitute for fossil fuels and artificial fertilizers, reducing the amount of greenhouse gases released into the atmosphere.J. Environ. Sci. & Natural Resources, 8(2): 33-36 2015

Utilization of energy from waste potential in Turkey as distributed secondary renewable energy source

Running out of fossil fuels and rising of environmental issues pressurize energy policies in the direction of increasing renewable energy utilization. As a part of full-recycling scheme, Municipal Solid Waste (MSW) can be accounted as an alternative and prevalent source of renewable energy for smart grid applications. This study presents a case study investigating the future of dry combustion in Turkey and gives some projections on Energy from Waste (EfW) utilization potentials as secondary local generators. EfW potential of MSW incineration plants is modeled depending on MSW mass function. An empirical formula for prediction of EfW potential of Turkey is derived by curve fitting to yearly MSW data. Dependence of EfW potential on human population is modeled and thus spread of EfW potential over the territory of Anatolia landscape is illustrated. Analyses reveal that EfW has a potential to be local source of renewable energy for future smart grids due to the fact that EfW exhibits energy generation distribution correlated with city population. We concluded that EfW incineration plants can act on sustainable development of Turkey by serving as a consistent, distributed, near-field generators integrated to waste management systems of cities.