Showing papers on "Solar power published in 2013"

Perovskites: The Emergence of a New Era for Low-Cost, High-Efficiency Solar Cells

Abstract: Over the last 12 months, we have witnessed an unexpected breakthrough and rapid evolution in the field of emerging photovoltaics, with the realization of highly efficient solid-state hybrid solar cells based on organometal trihalide perovskite absorbers. In this Perspective, the steps that have led to this discovery are discussed, and the future of this rapidly advancing concept have been considered. It is likely that the next few years of solar research will advance this technology to the very highest efficiencies while retaining the very lowest cost and embodied energy. Provided that the stability of the perovskite-based technology can be proven, we will witness the emergence of a contender for ultimately low-cost solar power.

A review of studies on central receiver solar thermal power plants

Abstract: The use of central receiver system (CRS) for electricity production promises to be one of the most viable options to replace fossil fuel power plants. Indeed, research and development activities on its basic subsystems have been booming rapidly since 1980s. This paper reviews the most important studies on the major components of central receiver solar thermal power plants including the heliostat field, the solar receiver and the power conversion system. After an overview of Concentrating Solar Power (CSP) technology, current status and applications of the CRSs are highlighted. Next, a detailed literature survey of existing design comprising optical, thermal and thermodynamic analysis, and techniques used to assess components have been arranged. This is followed by experimental investigations in which design concepts are established. The last section contains recent subsequent improvement of such key components as heliostat, receiver and hybrid solar gas turbine that are boosting in many R&D activities merging international collaboration during the past 30 years.

MPPT techniques for photovoltaic applications

Abstract: The photovoltaic (PV) system is one of the renewable energies that attract the attention of researchers in the recent decades. The PV generators exhibit nonlinear I–V and P–V characteristics. The maximum power produced varies with both irradiance and temperature. Since the conversion efficiency of PV arrays is very low, it requires maximum power point tracking (MPPT) control techniques. The maximum power point tracking (MPPT) is the automatic control algorithm to adjust the power interfaces and achieve the greatest possible power harvest, during moment to moment variations of light level, shading, temperature, and photovoltaic module characteristics. The purpose of the MPPT is to adjust the solar operating voltage close to the MPP under changing atmospheric conditions. It has become an essential component to evaluate the design performance of PV power systems. This investigation aims to assess different MPPT techniques, provide background knowledge, implementation topology, grid interconnection of PV and solar microinverter requirements presented in the literature, doing depth comparisons between them with a brief discussion. The MPPT merits, demerits and classification, which can be used as a reference for future research related to optimizing the solar power generation, are also discussed. Conventional methods are easy to implement but they suffer from oscillations at MPP and tracking speed is less due to fixed perturb step. Intelligent methods are efficient; oscillations are lesser at MPP in steady state and tracked quickly in comparison to conventional methods.

Analytical model for solar PV and CSP electricity costs: Present LCOE values and their future evolution

Abstract: In this paper we first make a review of the past annual production of electricity and the cumulative installed capacity for photovoltaic (PV) and concentrating solar power (CSP) technologies. This together with the annual costs of PV modules and CSP systems allows us the determination of the experience curves and the corresponding learning rates. Then, we go over a rigorous exposition of the methodology employed for the calculation of the value of the levelized cost of electricity (LCOE) for PV and CSP. Based on this knowledge, we proceed to establish a mathematical model which yields closed-form analytical expressions for the present value of the LCOE, as well as its future evolution (2010–2050) based on the International Energy Agency roadmaps for the cumulative installed capacity. Next, we explain in detail how specific values are assigned to the twelve independent variables which enter the LCOE formula: solar resource, discount and learning rates, initial cost and lifetime of the system, operational and maintenance costs, etc. With all this background, and making use of a simple computer simulation program, we can generate the following: sensitivity analysis curves, graphs on the evolution of the LCOE in the period 2010–2050, and calculations of the years at which grid parities will be reached. These representations prove to be very useful in energy planning policies, like tariff-in schemes, tax exemptions, etc., and in making investment decisions, since they allow, for a given location, to directly compare the costs of PV vs CSP power generation technologies for the period 2010–2050. Among solar technologies, PV seems always more appropriate for areas located in middle to high latitudes of the Earth, while CSP systems, preferably with thermal storage incorporated, yield their best performance in arid areas located at relatively low latitudes.

Solar energy: Trends and enabling technologies

Abstract: The global demand for energy is currently growing beyond the limits of installable generation capacity. To meet future energy demands efficiently, energy security and reliability must be improved and alternative energy sources must be investigated aggressively. An effective energy solution should be able to address long-term issues by utilizing alternative and renewable energy sources. Of the many available renewable sources of energy, solar energy is clearly a promising option as it is extensively available. Solar power, especially as it reaches more competitive levels with other energy sources in terms of cost, may serve to sustain the lives of millions of underprivileged people in developing countries. Furthermore, solar energy devices can benefit the environment and economy of developing countries. This paper illustrates the need for the utilization of alternative energy sources, evaluates the global scenario of installed generation systems, reviews technologies underlying various solar powered devices, and discusses several applications and challenges in this area. In addition, this paper addresses the costs of deployment, maintenance, and operation, as well as economic policies that promote installation of solar energy systems.

Land-Use Requirements for Solar Power Plants in the United States

Abstract: This report provides data and analysis of the land use associated with utility-scale ground-mounted solar facilities, defined as installations greater than 1 MW. We begin by discussing standard land-use metrics as established in the life-cycle assessment literature and then discuss their applicability to solar power plants. We present total and direct land-use results for various solar technologies and system configurations, on both a capacity and an electricity-generation basis. The total area corresponds to all land enclosed by the site boundary. The direct area comprises land directly occupied by solar arrays, access roads, substations, service buildings, and other infrastructure. As of the third quarter of 2012, the solar projects we analyze represent 72% of installed and under-construction utility-scale PV and CSP capacity in the United States.

State-of-the-art of solar thermal power plants—A review

Abstract: The solar thermal power plant is one of the promising renewable energy options to substitute the increasing demand of conventional energy The cost per kW of solar power is higher and the overall efficiency of the system is lower In the present communication, a comprehensive literature review on the scenario of solar thermal power plants and its up-to-date technologies all over the world is presented Results of the technical and economical feasibility studies by researchers are reported in brief for further reference It is observed that the solar thermal power plants have come out of the experimental stage to commercial applications Case studies of typical 50 MW solar thermal power plants in the Indian climatic conditions at locations such as Jodhpur and Delhi is highlighted with the help of techno-economic model Different solar concentrator technologies (parabolic trough, parabolic dish and central power tower) for solar thermal power plants are compared economically It has been found that the parabolic dish concentrating solar Stirling engine power plant generate electricity at a lower unit cost than the other two solar technologies considering 30 years lifespan and 10% interest rate on investment

Analysis of barriers to implement solar power installations in India using interpretive structural modeling technique

Abstract: India is fast emerging economy in Asia and world. India's manufacturing sector is growing faster and domestic demand is also increasing. India has a severe electricity shortage. It needs massive additions in capacity to meet the demand of its rapidly growing economy. To maintain the pace of economic growth with reduction in emission of greenhouse gases, India must reduce its dependency on fossil fuels for electrification. Hence the requirement of solar power installations in India has increased. In this context, this study aims to develop a structural model of the barriers to implement solar power installations in India. Thirteen relevant barriers to implement solar power installations have been identified from the literature and subsequent discussions with experts from academia and industry. Contextual relationships among these barriers have been identified and interpretive structural modeling (ISM) technique based, a structural model of barriers to implement solar power installations in India has been developed. MICMAC analysis has also been used to carry out the classification of barriers based on dependence and driving power. One barrier has been identified as top level barrier and six bottom level barriers. This paper also suggests the different ways of removal of these barriers. Better understanding of these barriers would help organizations and government bodies to prioritize and manage their resources in an effective and efficient way so that maximum number of solar power projects can be installed in India.

Defect Detection in Solar Modules Using ICA Basis Images

Abstract: Solar power has become an attractive alternative of electricity energy. Solar cells that form the basis of a solar power system are mainly based on multicrystalline silicon. A set of solar cells are assembled and interconnected into a large solar module to offer a large amount of electricity power for commercial applications. Many defects in a solar module cannot be visually observed with the conventional CCD imaging system. This paper aims at defect inspection of solar modules in electroluminescence (EL) images. The solar module charged with electrical current will emit infrared light whose intensity will be darker for intrinsic crystal grain boundaries and extrinsic defects including micro-cracks, breaks and finger interruptions. The EL image can distinctly highlight the invisible defects but also create a random inhomogeneous background, which makes the inspection task extremely difficult. The proposed method is based on independent component analysis (ICA), and involves a learning and a detection stage. The large solar module image is first divided into small solar cell subimages. In the training stage, a set of defect-free solar cell subimages are used to find a set of independent basis images using ICA. In the inspection stage, each solar cell subimage under inspection is reconstructed as a linear combination of the learned basis images. The coefficients of the linear combination are used as the feature vector for classification. Also, the reconstruction error between the test image and its reconstructed image from the ICA basis images is also evaluated for detecting the presence of defects. Experimental results have shown that the image reconstruction with basis images distinctly outperforms the ICA feature extraction approach. It can achieve a mean recognition rate of 93.4% for a set of 80 test samples.

Technical Challenges and Opportunities for Concentrating Solar Power With Thermal Energy Storage

Abstract: Concentrating solar power (CSP) provides the ability to incorporate simple, efficient, and cost-effective thermal energy storage (TES) by virtue of converting sunlight to heat as an intermediate step to generating electricity Thermal energy storage for use in CSP systems can be one of sensible heat storage, latent heat storage using phase change materials (PCMs) or thermochemical storage Commercially deployed CSP TES systems have been achieved in recent years, with two-tank TES using molten salt as a storage medium and steam accumulators being the system configurations deployed to date Sensible energy thermocline systems and PCM systems have been deployed on a pilot-scale level and considerable research effort continues to be funded, by the United States Department of Energy (DOE) and others, in developing TES systems utilizing any one of the three categories of TES This paper discusses technoeconomic challenges associated with the various TES technologies and opportunities for advancing the scientific knowledge relating to the critical questions still remaining for each technology

Design, Analysis, and Implementation of Solar Power Optimizer for DC Distribution System

Abstract: This paper proposes a high step-up solar power optimizer (SPO) that efficiently harvests maximum energy from a photovoltaic (PV) panel then outputs energy to a dc-microgrid. Its structure integrates coupled inductor and switched capacitor technologies to realize high step-up voltage gain. The leakage inductance energy of the coupled inductor can be recycled to reduce voltage stress and power losses. A low voltage rating and low-conduction resistance switch improves system efficiency by employing the incremental conductance method for the maximum power point tracking (MPPT) algorithm. Because of its high tracking accuracy, the method is widely used in the energy harvesting of PV systems. laboratory prototypes of the proposed SPO that have an input voltage range of 20 to 40 V and a maximum PV output power of 400 V/300 W are applied. The highest PV power conversion efficiency is 96.7%. The maximum MPPT accuracy is 99.9%, and the full load average MPPT accuracy is 97.8%.

The green game changer: An empirical assessment of the effects of wind and solar power on the merit order

Abstract: We estimate the impact of renewable energy sources on the merit order and the wholesale price in Spain. We use a structural vectorautoregressive model for the merit order of production and argue that wind and solar production are exogenous to the system. As expected the overall effect is negative for the wholesale price and the produced quantities of most generation technologies. The estimated impact, however, is biggest for mid-merit plants. This finding sheds light on the theoretical discussion about which power plants are affected most by renewable energy sources. The effect is also mainly driven by wind power. Solar energy increases wholesale prices as peak plants enlarge their production with more solar power.

Pool solar power generator

Abstract: Solar panels located on residential roofs can be unsightly in some cases. A swimming pool solar power generator can locate solar panels in or around the sides and/or bottoms of a swimming pool in a manner so as to create electricity from the sun without creating an eyesore. In an embodiment, a pool solar power generator includes a solar cell module disposed in a portion of a swimming pool. The solar cell module can include solar cells and be submerged under water held by the swimming pool. The solar cell module can convert sunlight incident on the solar cells to electricity and transmit the electricity for use at a location external to the swimming pool.

Molten Salt Power Tower Cost Model for the System Advisor Model (SAM)

Abstract: This report describes a component-based cost model developed for molten-salt power tower solar power plants. The cost model was developed by the National Renewable Energy Laboratory (NREL), using data from several prior studies, including a contracted analysis from WorleyParsons Group, which is included herein as an Appendix. The WorleyParsons' analysis also estimated material composition and mass for the plant to facilitate a life cycle analysis of the molten salt power tower technology. Details of the life cycle assessment have been published elsewhere. The cost model provides a reference plant that interfaces with NREL's System Advisor Model or SAM. The reference plant assumes a nominal 100-MWe (net) power tower running with a nitrate salt heat transfer fluid (HTF). Thermal energy storage is provided by direct storage of the HTF in a two-tank system. The design assumes dry-cooling. The model includes a spreadsheet that interfaces with SAM via the Excel Exchange option in SAM. The spreadsheet allows users to estimate the costs of different-size plants and to take into account changes in commodity prices. This report and the accompanying Excel spreadsheet can be downloaded at https://sam.nrel.gov/cost.

Towards zero grid electricity networking: Powering BSs with renewable energy sources

Abstract: In this paper we study cellular access networks which solely rely on renewable energy. We consider a cellular network in which a mesh of base stations (BSs) that are powered with renewable sources, and interconnected with wireless backhaul links, cover the service area, and provide connection to few, typically remote, wired network accesses to the national and international backbone. In particular, we study how to dimension BS power generators and energy storage. We start by discussing the BS energy need, that depends on both the BS consumption model and the BS traffic profiles. Focusing then on some specific locations, we consider the use of photovoltaic (PV) panels, and dimension them based on the daily energy need of the BS and on typical radiative power of sun in the considered locations. Once the PV system has been dimensioned, we also evaluate the energy storage capacity that is needed to absorb energy production variability due to both daily and seasonal radiative power variations. Finally, we investigate the effectiveness of integrating the PV system with wind turbines, as well as the benefit induced on the system by base station sleep modes.

Superconductivity and the environment: a Roadmap

Abstract: There is universal agreement between the United Nations and governments from the richest to the poorest nations that humanity faces unprecedented global challenges relating to sustainable energy, clean water, low-emission transportation, coping with climate change and natural disasters, and reclaiming use of land. We have invited researchers from a range of eclectic research areas to provide a Roadmap of how superconducting technologies could address these major challenges confronting humanity.Superconductivity has, over the century since its discovery by Kamerlingh Onnes in 1911, promised to provide solutions to many challenges. So far, most superconducting technologies are esoteric systems that are used in laboratories and hospitals. Large science projects have long appreciated the ability of superconductivity to efficiently create high magnetic fields that are otherwise very costly to achieve with ordinary materials. The most successful applications outside of large science are high-field magnets for magnetic resonance imaging, laboratory magnetometers for mineral and materials characterization, filters for mobile communications, and magnetoencephalography for understanding the human brain.The stage is now set for superconductivity to make more general contributions. Humanity uses practically unthinkable amounts of energy to drive our modern way of life. Overall, global power usage has been predicted to almost double from 16.5 to 30?TW in the next four decades (2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources).The economy with which electrons carry energy compels the continued quest for efficient superconducting power generation, energy storage, and power transmission. The growing global population requires new arable land and treatment of water, especially in remote areas, and superconductivity offers unique solutions to these problems. Exquisite detectors give warning of changes that are otherwise invisible. Prediction of climate and disasters will be helped by future supercomputer technologies that support huge amounts of data and sophisticated modeling, and with the aid of superconductivity these systems might not require the energy of a large city.We present different sections on applications that could address (or are addressing) a range of environmental issues. The Roadmap covers water purification, power distribution and storage, low-environmental impact transport, environmental sensing (particularly for the removal of unexploded munitions), monitoring the Earth?s magnetic fields for earthquakes and major solar activity, and, finally, developing a petaflop supercomputer that only requires 3% of the current supercomputer power provision while being 50 times faster.Access to fresh water. With only 2.5% of the water on Earth being fresh and climate change modeling forecasting that many areas will become drier, the ability to recycle water and achieve compact water recycling systems for sewage or ground water treatment is critical. The first section (by Nishijima) points to the potential of superconducting magnetic separation to enable water recycling and reuse.Energy. The Equinox Summit held in Waterloo Canada 2011?(2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources) identified electricity use as humanity?s largest contributor to greenhouse gas emissions. Our appetite for electricity is growing faster than for any other form of energy. The communiqu? from the summit said ?Transforming the ways we generate, distribute and store electricity is among the most pressing challenges facing society today?. If we want to stabilize CO2 levels in our atmosphere at 550 parts per million, all of that growth needs to be met by non-carbon forms of energy? (2011 Equinox Summit: Energy 2030 http://wgsi.org/publications-resources). Superconducting technologies can provide the energy efficiencies to achieve, in the European Union alone, 33?65% of the required reduction in greenhouse gas emissions according to the Kyoto Protocol (Hartikainen et?al 2003 Supercond. Sci. Technol. 16 963). New technologies would include superconducting energy storage systems to effectively store power generation from renewable sources as well as high-temperature superconducting systems used in generators, transformers and synchronous motors in power stations and heavy-industry facilities. However, to be effective, these systems must be superior to conventional systems and, in reality, market penetration will occur as existing electrical machinery is written off. At current write-off rates, to achieve a 50% transfer to superconducting systems will take 20?years (Hartikainen et?al 2003 Supercond. Sci. Technol. 16 963).The Roadmap next considers dc transmission of green power with a section by Eckroad and Marian who provide an update on the development of superconducting power transmission lines in view of recent sustainability studies. The potential of magnetic energy storage is then presented by Coi and Kim, who argue that a successful transition to wind and solar power generation must be harmonized with the conventional electrical network, which requires a storage technology with a fast response and long backup times.Transport. Superconducting Maglev trains and motors for international shipping have the potential to considerably reduce the emissions that contribute to greenhouse gases while improving their economic viability by reducing losses and improving efficiencies. International shipping, alone, contributes 3% of the greenhouse gas emissions. Three sections of the Roadmap identify how high-speed rail can be a major solution to providing fast, low energy, environmentally-friendly transport enabling reduction in automobile and aircraft travel by offering an alternative that is very competitive. With maritime international environmental regulations tightening, HTS motors with the characteristics of high torque and compactness will become important devices for high-performance and low-emission electric ship propulsion systems. A section on the development of a megawatt-class superconducting motor for ship propulsion is presented by Umemoto.Monitoring in manufacturing for waste reduction. Environmental impact from the waste created by the manufacturing sector and the need to make manufacturing efficient can be addressed by terahertz imaging. This technology has great potential in non-destructive testing, industrial process monitoring and control to greatly improve the industry process efficiency and reliability by reducing waste materials and toxic by-products. The section by Du shows how terahertz imaging can provide process and property information such as rust levels under paint that can assist with the reduction of waste in manufacturing and maintenance.Monitoring for naturally occurring disturbances. The environmental and social impact of natural disasters is mounting. Febvre provides the Roadmap for the use of ultra-sensitive magnetometry to understand geomagnetic phenomena and Earth?ionosphere couplings through the study of very small variations of the magnetic field. This magnetic monitoring has many implications for understanding our environment and providing new tools for early warning of natural hazards, either on Earth or in space which will enable us to be better prepared for natural disasters.Restoring environments after military use. Throughout the world, there are many areas confirmed or suspected of being contaminated by unexploded munitions known as unexploded ordnance (UXO). Its presence is the result of wars and training of military forces. Areas affected by UXO contamination are hazardous to the public and have a major influence on the nature of land use. UXO has impact in developed as well as developing nations. For example, the USA has UXO dating back to the American Civil War and countries such as Cambodia are living with landmines as a daily issue due to more recent wars. Underwater UXO has caused severe impacts such as the explosion in 1969 in the waters of Kent in the UK that caused a reading of 4.5 on the Richter scale for earthquake monitors. Another example was a land-based detonation of a 500?kg World War II bomb in Germany killing three people in 2010. There is countless UXO from recent conflicts worldwide. Detection and accurate location with 100% reliability is required to return land to safe civilian use. Keenan provides details of a prototype magnetic gradiometer developed for this purpose.Reducing power needs for high-end IT. Supercomputers are so large that they are close to requiring their own small power plant to support the energy needed to run the computer. For example, in 2011 Facebook data centers and operations used 532 million kW hours of energy. Mukhanov explores the potential of reducing the power dissipation for future supercomputers from more than 500?MW for Exascale systems to 0.2?MW by using superconducting-ferromagnetic Josephson junctions for magnetic memory and programmable logic.Clearly superconductivity is an ultimate energy-saving technology, and its practical implementation will contribute to the reduction of CO2 emissions, improved water purification, reduction of waste and timely preparedness for natural disasters or significant events. This Roadmap shows how the application of superconducting technologies will have a significant impact when they are adopted.