All content in this area was uploaded by Thomas B. Johansson on Sep 08, 2014
Content may be subject to copyright.
A preview of the PDF is not available
... Hence, there is a need to redirect and shift the focus of the power supplies and energy sources from oil, coal, and natural gas to wind, solar, geothermal, and other renewable energy sources (Boyle 2004;Panwar, Kaushik, and Kothari 2011). Solar energy is a wide, unlimited, clean, and renewable energy source that can be used to substitute nonrenewable energy sources (Johansson et al. 1993). A lot of research is currently targeted at developing photovoltaic systems using solar cells with high thermal, optical, and electrical properties that help address the technological and energy crisis (Bialasiewicz 2008). ...
There has been an increasing demand for green energy due to the negative impact of global warming on the environment and life. This has necessitated the fabrication of different semiconductor materials using various methods for solar cell and photovoltaic applications. Cadmium telluride (CdTe) is a polycrystalline thin film and has emerged as a leading material for the development of cost-effective and reliable photovoltaic systems because of its near-ideal bandgap for high photovoltaic conversion efficiency and optical absorption coefficient. The CdTe has excellent resistivities of 10⁷-10⁹ Ω cm, carrier densities of 10⁹-10¹¹ cm⁻³, and mobility ca. cm² V⁻¹ s⁻¹. Development has been made in terms of optimizing the fabricating of CdTe thin films with efficiencies increasing above 22%. The addition of copper (Cu) doping has been used to increase the Cdte efficiency through a controlled amount of Cu employed in the annealing process. The characterization tools used to understand the structures of the fabricated CdTe solar cells are discussed and it was revealed from the Atomic Force Microscope that increasing the grain size reduces the non-radiative recombination for higher performance of the solar cell. Finally, the achievements and prospects of CdTe solar cells for future development are presented.
... PV panels are vulnerable to degradation due to internal factors such as their age, failure in wiring and adhesion failure, or external (on-site) factors such as deposition of dust, bird-droppings, waterstains (salts), snow, temperature/moisture and others which can significantly degrade their efficiency over time (Johansson and Burnham 1993, King, Quintana et al. 2000, Asl-Soleimani, Farhangi et al. 2001, Tian, Wang et al. 2007. A study by the National Renewable Energy Laboratory (NREL) on 2000 solar panels made it clear that the performance of a PV module will decrease over time and the degradation rate is typically higher in the first year upon initial exposure to light and then stabilizes. ...
... Another alternative has been studied to investigate the direct production of water and steam in absorber tubes . Currently, the largest solar thermal facility has been constructed, located in the Mojave Desert with 354 MW capacity . A 2 MW capacity solar plant has been established in Spain to investigate steadystate and transient flow behavior into a direct steam generation with PTCs . ...
This paper focuses on the technological development of solar thermal technologies through the analysis of patent records and search traffic. First, various solar thermal technologies are reviewed and discussed. Then, the related published patents are analysed. To improve the accuracy of patents retrieval, a new framework is proposed and employed based on the combination of keywords and keycodes. In this new framework, the proposed methodology can enhance the retrieved patent pool resolution by eliminating the patent with the relevant title but irrelevant technology scopes. Furthermore, new technological features such as technology attractiveness and acceleration are introduced and applied to solar thermal technologies. These two introduced features help to recognize interested areas by industrial players in the technological field. The pace of technology being developed and becoming matured could be identified by how fast the industry invests in technology by protecting its intellectual properties. The logistic S-curve is employed for assessing the current state of solar technologies on the technology life cycle. The market diffusion of each solar thermal technology is assessed by developing adoption curves using search traffic. Finally, the hype cycle of solar thermal technologies is demonstrated by combining the two technological assessment graphs. Through the proposed methodology, 8740 related patents are retrieved and screened. The analysis shows that Photovoltaic-thermal has the highest share in published patents and the parabolic trough and evacuated tube collectors are in their maturity phase. The parabolic dish collector is identified as one of the highest accelerated technologies and also located near the maturity phase. Therefore, it can be predicted that the next technology reaching the maturity phase would be the parabolic dish collector. Overall, all solar-heat driver cycles are in their growth stage, but the Rankine cycle is more developed. Text analysis determines the main challenge with cycles is the operation and maintenance that should be overcome to meet the maturity phase.
... The rapid mechanization of living activities created a disbalance in utilizing natural resources and its harmful impact on climate. By judicious and efficient use of renewable energy and supporting technologies, it is expected to achieve the target of 75% lesser CO 2 emission by the year 2050 than the year 1985 level ). The biggest challenge of conventional PV systems is their low efficiency due to inherent weakness in utilizing the whole solar energy spectrum ). ...
The aim of the presented review is based on recent past research and ongoing practices in the area of Photovoltaic Thermal (PVT) technology and thereby to explore the challenges and suggest practical solutions leading to the development of an efficient working system.
Current development in technologies and its engineering applications are based on further development in materials, process parameters and modelling and simulations based solutions. These issues well addressed in review process. Investigative review intends to explore progressive advances in materials and their applications in PV/T devices, process parameters and optimizations models to reach optimum working efficiencies. Integration of PV/T systems with buildings given focused attention.
Synergistic correlation among three subdomains can lead to the dynamic working system based on optimized utilization of thermal and photosensitive spectrum of solar radiation. The study elucidates the inception of PVT technology as a non-concentrating type of system, incubating the idea of utilizing it as a process enhancing system. Besides these, it is further extended to the concentrated type of PVT systems using varying material intervention with an essential milestone of attaining an efficient built environment system by conceptualizing multifaceted utilization of PVT as Building Integrated Photovoltaic Thermal (BIPVT).
... These include harvesting light as well as charge separation and production of electrochemical potential on the two sides of the photosynthetic membrane . The most important reasons underlying this approach, include (1) extremely high quantum efficiency of the energy conversion (close to 100%, i.e., nearly each photon absorbed by PSI results in charge separation); (2) operation not limited to the production of photoinduced voltage-similarly as in the photosynthetic apparatus, bioinspired catalytic systems may produce solar fuels and chemicals, such as hydrogen, formate, carbon monoxide, or alcohols . These products are not only easier to store and transport than electric energy, but such a functionality may also improve CO 2 neutral final balance. ...
One of the crucial challenges for science is the development of alternative pollution-free and renewable energy sources. One of the most promising inexhaustible sources of energy is solar energy, and in this field, solar fuel cells employing naturally evolved solar energy converting biocomplexes—photosynthetic reaction centers, such as photosystem I—are of growing interest due to their highly efficient photo-powered operation, resulting in the production of chemical potential, enabling synthesis of simple fuels. However, application of the biomolecules in such a context is strongly limited by the progressing photobleaching thereof during illumination. In the current work, we investigated the excitation wavelength dependence of the photosystem I photodamage dynamics. Moreover, we aimed to correlate the PSI–LHCI photostability dependence on the excitation wavelength with significant (ca. 50-fold) plasmonic enhancement of fluorescence due to the utilization of planar metallic nanostructure as a substrate. Finally, we present a rational approach for the significant improvement in the photostability of PSI in anoxic conditions. We find that photobleaching rates for 5 min long blue excitation are reduced from nearly 100% to 20% and 70% for substrates of bare glass and plasmonically active substrate, respectively. Our results pave promising ways for optimization of the biomimetic solar fuel cells due to synergy of the plasmon-induced absorption enhancement together with improved photostability of the molecular machinery of the solar-to-fuel conversion.
... Syngas can be used as an intermediate to create other attractive clean fuels such as ammonia (NH 3 ), dimethyl ether (DME), and methanol (CH 3 OH) . Another use of syngas is as a primary chemical building block in petrochemical and refining processes . ...
The adverse environmental impact of fossil fuel combustion in engines has motivated research towards using alternative low-carbon fuels. In recent years, there has been an increased interest in studying the combustion of fuel mixtures consisting mainly of hydrogen and carbon monoxide, referred to as syngas, which can be considered as a promising fuel toward cleaner combustion technologies for power generation. This paper provides an extensive review of syngas production and application in internal combustion (IC) engines as the primary or secondary fuel. First, a brief overview of syngas as a fuel is presented, introducing the various methods for its production, focusing on its historical use and summarizing the merits and drawbacks of using syngas as a fuel. Then its physicochemical properties relevant to IC engines are reviewed, highlighting studies on the fundamental combustion characteristics, such as ignition delay time and laminar and turbulent flame speeds. The main body of the paper is devoted to reviewing the effect of syngas utilization on performance and emissions characteristics of spark ignition (SI), compression ignition (CI), homogeneous charge compression ignition (HCCI), and advanced dual-fuel engines such as reactivity-controlled compression ignition (RCCI) engines. Finally, various on-board fuel reforming techniques for syngas production and use in vehicles are reviewed as a potential route towards further increases in efficiency and decreases in emissions of IC engines. These are then related to the research reported on the behavior of syngas and its blends in IC engines. It was found that the selection of the syngas production method, choice of the base fuel for reforming, its physicochemical properties, combustion strategy, and engine combustion system and operating conditions play critical roles in dictating the potential advantages of syngas use in IC engines. The discussion of the present review paper provides valuable insights for future research on syngas as a possible fuel for IC engines for transport.
... In the last few decades, renewable energies have gained great importance around the world, their development increases exponentially to the detriment of conventional energy sources such as: oil, coal, lignite and natural gas which are the original source of climate change phenomenon, environmental pollution, human health degradation and the growth of the greenhouse effect . Furthermore, renewable energies, in particular photovoltaic energy is safe and clean, with no carbon di-oxide emission, widely available and environment-friendly. ...
The present work brings a new intelligent algorithm for PV system's diagnosis and fault detection (IFD). At this stage of the study, this algorithm can detect and identify three recurrent cases between healthy and short circuit faults, as well as string disconnection in PV array using artificial neural networks (ANN). Both, detection and isolation are simple and fast. The developed model requires small training period and is based on only four inputs: the maximum power current and voltage from the output current-voltage (I eV) characteristic, the solar irradiation and the cell temperature. Experimental validation of the proposed IFD has been carried on small grid connected PV generator (PVG). The obtained results demonstrate that this approach can precisely detect and classify the existing faults with high accuracy (98.6%).
... In the charter of the United Nations, proper forest management was considered the main obligation of governments at all levels: local, regional, and global . In view of the United Nations policies regarding forest management, different countries are trying to protect the livelihood of the forest with some solid steps such as formulating policies for cutting timber and using the forest for commercial purposes such as renewable energy projects, etc. [43,44]. ...
Community participation for forest sustainability and use of forest resources for community development is considered a vital way in all societies. This study was conducted to assess the public views toward sustainable forest management in the area of Gilgit–Baltistan, Pakistan, through collecting data from 255 respondents. Views about forest management techniques at different levels were discussed. Three main areas of focus to manage forest resources were: strategic-level management, local-level management, and communication-level management. To provide confidence and to measure factors affecting sustainable forest management, this study applied the structural equation modeling approach and built a model that explained and identified the critical factors affecting sustainable forest management. A quantitative approach via Smart Partial Least Squares version 3.2.8 was used for analysis. The findings of the study show that the R2 value of the model was 0.653, which means that the three exogenous latent constructs collectively explained 65.3% of the variance in sustainable forest management. In this study, the goodness of fit of the model was 0.431, which is considered valid for further analysis. Among the three proposed levels for forest management, the strategic-level-management factor was found the most important of the three variables. This study concluded that for better and sustainable forest management, policies should flow from the strategic level to the local and also focus on communication-level management because all these factors appear to be significant in measuring sustainable forest management. Community engagement and awareness are also found to be an important way for forest resource management.
... If generalized measures are not implemented and effective to meet the demand for energy such as efficient production, technological developments and environmental awareness, according to studies registered in  the demand for primary energy is likely to expand 2 to 2.5 times by 2050; And 3.5 to 4.5 times for the year 2100. Renewable energies generate different benefits, as mentioned by the authors  where they state that demand growth and decline in prices they can be better than those predicted by conventional energy sources. ...
The demand for energy has been increasing and with this the need to find new sources of electricity generation for the system. In Colombia, different investigations have been developed in which different sources of generation are considered. In this article, we will be based on the study done in de Atlas of the wind of Colombia considering wind power as a source of generation. This article presents a case study in the LCOE analysis in generation projects of renewable energy through wind technology. Crystal Ball is used for this analysis as a simulation tool for different scenarios in order to determine the cost kilowatt hour in a wind farm in Colombia. In addition, in this article evaluates the financial feasibility of installing a wind farm in Colombia by comparing the cost kilowatt hour of energy generated in different regions of the country with the energy costs presented in the last year in Colombia and contemplating the energy policies of Colombia that generate economic benefits in the installation of renewable energy generation sources.
... Renewable energy sources began to grow in the early seventies due to the fossil energy crisis that hit the energy market at that time . As the global demand for energy is growing rapidly, it is time to look for new and renewable energy sources to replace the dwindling fossil fuel supply , . ...
Medan is the capital city of North Sumatra Province, consisting of various tribes and a dense population that requires a large amount of electrical power. Energy demand continues to increase along with population and business growth, so that additional energy sources are needed; one of which is wind. An evaluation of the potential of wind energy sources is needed to determine the feasability of its use as an environmentally-friendly, renewable energy source without emissions.This paper aims to evaluate the potential wind speed in the city of Medan using the correlation coefficient (R 2) model. The four application models proposed for the probability density function used are Normal Distribution, Lognormal, Weibull 2-parameters and Weibull 3-parameters. The analysis results show that the four models used are all potentially feasible options that can be used to evaluate the potential sources of wind energy in Medan. The potential of these models for use, ranked from most to least, are the Weibull 3-parameter Model, followed by the Lognormal, Normal Distribution and Weibull2-parameter. In addition to the analysis, the results of the Normal, Lognormal and Weibull Distribution tests are also presented.
Hock and Don R. Smith 4 Wind Energy: Resources, Systems and Regional Strategies Michael J. Grubb and Niels 1. Meyer 5 Solar-thermal Electric Technology Pascal De Laquill III
Its Constraints Jose Roberto Moreira
Alfred J Cavallo
Z Hydropower and Its Constraints
Jose Roberto Moreira and Alan Douglas Poole
3 Wind Energy: Technology and Economics
Alfred J. Cavallo, Susan M. Hock and Don R. Smith
4 Wind Energy: Resources, Systems and Regional Strategies
Michael J. Grubb and Niels 1. Meyer
5 Solar-thermal Electric Technology
Pascal De Laquill III, David Kearney, Michael Geyer and Richard Diver
6 Introduction to Photovoltaic Technology
7 Crystalline-and Polycrystalline-silicon Solar Cells
Martin A. Green
Price 13 Geothermal Energy Civis G. Palmerini 14 Biomass for Energy. Supply Prospects David O. Hall, Frank Rosillo-Calle, Robert H. Williams and Jeremy Woods 15 Bioenergy Direct Applications in
Photovoltaic Concentrator Technology Eldon
Antonio Luque David
Photovoltaic Concentrator Technology
Eldon C. Boes and Antonio Luque
David E. Carlson and Sigurd Wagner
10 Polycrystalline Thin-film Photovoltaics
Ken Zweibel and Allen M. Barnett
11 Utility Field Experience with Photovoltaic Systems
Kay Firor, Roberto Vigotti and Joseph J. Iannucci
12 Ocean Energy Systems
James E. Cavanagh, John H. Clarke and Roger Price
13 Geothermal Energy
Civis G. Palmerini
14 Biomass for Energy. Supply Prospects
David O. Hall, Frank Rosillo-Calle, Robert H. Williams and Jeremy Woods
15 Bioenergy. Direct Applications in Cooking
Gautam S. Dutt and N.H. Ravindranath
16 Open-top Wood Gasifiers
H.S. Mukunda, S. Dasappa and U. Shrinivasa
17 Advanced Gasification-based Biomass Power Generation
Robert H. Williams and Eric D. Larson
18 Biogas Electricity-the Pura Village Case Study
P. Rajabapaiah, S. Jayakumar and Amulya K.N. Reddy
19 Anaerobic Digestion for Energy Production and Environmental Protection
Gatze Lettinga and Adrian C. van Haandel
20 The Brazilian Fuel-alcohol Program
Jose Goldemberg, Lourival C. Monaco and Isaias C. Macedo
21 Ethanol and Methanol from Cellulosic Biomass
Charles E. Wyman, Richard L. Bain, Norman D. Hinman and Don. J. Stevens
22 Solar Hydrogen
Joan M. Ogden and Joachim Nitsch
23 Utility Strategies for Using Renewables
Henry Kelly and Carl J. Weinberg