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Showing papers on "Solar power published in 2002"


Journal ArticleDOI
TL;DR: In this article, the authors present the current state of the art of parabolic trough solar power technology and describe the R&D efforts that are in progress to enhance this technology.
Abstract: Parabolic trough solar technology is the most proven and lowest cost large-scale solar power technology available today, primarily because of the nine large commercial-scale solar power plants that are operating in the California Mojave Desert. These plants, developed by Luz International Limited and referred to as Solar Electric Generating Systems (SEGS), range in size from 14-80 MW and represent 354 MW of installed electric generating capacity. More than 2,000,000 m 2 of parabolic trough collector technology has been operating daily for up to 18 years, and as the year 2001 ended, these plants had accumulated 127 years of operational experience. The Luz collector technology has demonstrated its ability to operate in a commercial power plant environment like no other solar technology in the world. Although no new plants have been built since 1990, significant advancements in collector and plant design have been made possible by the efforts of the SEGS plants operators, the parabolic trough industry, and solar research laboratories around the world. This paper reviews the current state of the art of parabolic trough solar power technology and describes the R&D efforts that are in progress to enhance this technology. The paper also shows how the economics of future parabolic trough solar power plants are expected to improve.

762 citations


Journal ArticleDOI
TL;DR: In this article, a 2nd-law analysis performed on the closed cyclic process indicates a maximum exergy conversion efficiency of 29% (ratio of Δ G 298 K °| H 2 + 0.5 O 2 → H 2 O for the H 2 produced to the solar power input), when using a solar cavity-receiver operated at 2300 K and subjected to a solar flux concentration ratio of 5000.

669 citations


ReportDOI
01 Jul 2002
TL;DR: In this article, the authors describe the concentrating solar power (CSP) systems using solar absorbers to convert concentrated sunlight to thermal electric power, and achieve solar absorber surfaces for efficient photothermal conversion having high solar absorptance (a) for solar radiation and low thermal emittance (e) at the operational temperature.
Abstract: This report describes the concentrating solar power (CSP) systems using solar absorbers to convert concentrated sunlight to thermal electric power. It is possible to achieve solar absorber surfaces for efficient photothermal conversion having high solar absorptance (a) for solar radiation and a low thermal emittance (e) at the operational temperature. A low reflectance (?'' 0) at wavelengths (?) 3 mm and a high reflectance (?'' 1) at l 3 mm characterize spectrally selective surfaces. The operational temperature ranges of these materials for solar applications can be categorized as low temperature (T 400 C). High- and mid-temperature applications are needed for CSP applications. For CSP applications, the ideal spectrally selective surface would be low-cost and easy to manufacture, chemically and thermally stable in air at elevated operating temperatures (T= 500 C), and have a solar absorptance= 0.98 and a thermal emittance= 0.05 at 500 C.

571 citations


Journal ArticleDOI
TL;DR: In this article, a literature review was carried out to evaluate the state of the art of thermal energy storage applied to parabolic trough power plants, where the heat transfer fluid (HTF) also serves as storage medium.
Abstract: A literature review was carried out to critically evaluate the state of the art of thermal energy storage applied to parabolic trough power plants. This survey briefly describes the work done before 1990 followed by a more detailed discussion of later efforts. The most advanced system is a 2-tank-storage system where the heat transfer fluid (HTF) also serves as storage medium. This concept was successfully demonstrated in a commercial trough plant (13.8 MW e SEGS I plant; 120 MWh t storage capacity) and a demonstration tower plant (10 MW e Solar Two; 105 MWh t storage capacity). However, the HTF used in state-of-the-art parabolic trough power plants (30-80 MW e ) is expensive, dramatically increasing the cost of larger HTF storage systems. Other promising storage concepts are under development, such as concrete storage, phase change material storage, and chemical storage. These concepts promise a considerable cost reduction compared to the direct 2-tank system, but some additional R&D is required before those systems can be used in commercial solar power plants. An interesting and likely cost-effective near-term option for thermal energy storage for parabolic trough power plants is the use of an indirect 2-tank-storage, where another (less expensive) liquid medium such as molten salt is utilized rather than the HTF itself.

380 citations


Journal ArticleDOI
TL;DR: In this article, the authors provide an overview of the current state of our scientific understanding and technological development of copper chalcogenide devices and materials, and provide a comparison between the two materials.
Abstract: Solar cells based on copper ternary chalcogenide compounds and alloys have emerged over the last 20 years as a promising solution to the problem of high-cost solar cells. Solar power conversion efficiencies exceed 21% in laboratory devices using thin films of these materials, and their characteristic thinness results in negligible direct materials costs per unit area compared with wafers. Photovoltaic devices made from these materials have also been shown to be intrinsically stable, circumventing the historical disadvantage of degradation typical of earlier thin film solar cell technologies. However, these copper chalcogenide devices and materials are relatively complex. This article provides an overview of the current state of our scientific understanding and technological development of them.

333 citations


Journal ArticleDOI
TL;DR: In this paper, a hybrid photovoltaic (PV)-fuel cell generation system employing an electrolyzer for hydrogen generation is designed and simulated and applied for remote areas or isolated loads.

142 citations


Journal ArticleDOI
TL;DR: In this article, a solar desiccant cooling model was used to evaluate the potential for using solar power to drive a single-stage desicant cooling system in various locations in southern Europe, provided that the latent heat gains experienced are not excessive.

99 citations


Book
01 Jan 2002
TL;DR: From fossil fuels to solar power: The power of the pyromaniacs Fossil resource dependency - how economic processes have come adrift from their environmental and social bases Global competition in place of global environmental policy The origins of the fossil fuel economy Accelerating change and global displacement Business unbound - cutting loose from nature and society Reconnecting business and society through solar resources From the political to the economic solar manifesto as discussed by the authors.
Abstract: From fossil fuels to solar power: The power of the pyromaniacs Fossil resource dependency - how economic processes have come adrift from their environmental and social bases Global competition in place of global environmental policy The origins of the fossil-fuel economy Accelerating change and global displacement Business unbound - cutting loose from nature and society Reconnecting business and society through solar resources From the political to the economic solar manifesto. PART I CAPTIVITY OR LIBERATION: FOSSIL FUEL AND SOLAR SUPPLY CHAINS COMPARED: ensnared by fossil supply chains exploiting solar resources - the new political and and economic freedom. PART II THE PATHOLOGICAL POLITICS OF FOSSIL RESOURCES: the 21st-century writing on the wall - the political cost of fuel and resource conflict the distorting effects of fossil supply chains the mythology of fossil energy. PART III THROWING OFF THE FOSSIL SUPPLY CHAINS: energy beyond the grid the untapped wealth of solar resources The profitability of renewable energy and resources. PART IV TOWARDS A SOLAR ECONOMY: exploiting solar energy Regionalization of the global economy through solar resources the visible hand of the sun - blueprint for a solar world

94 citations


Patent
TL;DR: In this paper, a mini-optics tracking and focusing system is presented for solar power conversion that ranges from an individual's portable system to solar conversion of electrical power that can be used in large scale power plants for environmentally clean energy.
Abstract: This invention deals with the broad general concept for focussing light. A mini-optics tracking and focusing system is presented for solar power conversion that ranges from an individual's portable system to solar conversion of electrical power that can be used in large scale power plants for environmentally clean energy. It can be rolled up, transported, and attached to existing man-made, or natural structures. It allows the solar energy conversion system to be low in capital cost and inexpensive to install as it can be attached to existing structures since it does not require the construction of a superstructure of its own. This novel system is uniquely distinct and different from other solar tracking and focusing processes allowing it to be more economical and practical. Furthermore, in its capacity as a power producer, it can be utilized with far greater safety, simplicity, economy, and efficiency in the conversion of solar energy.

91 citations


Patent
22 Nov 2002
TL;DR: In this paper, a combustion turbine power plant and methods of operating the same are provided in which steam is produced using solar energy and injected into a turbine of the power plant to support combustion.
Abstract: Combustion turbine power plants and methods of operating the same are provided in which air is cooled using solar energy and supplied to an air inlet of the power plant to support combustion. Also, combustion turbine power plants and methods of operating the same are provided in which steam is produced using solar energy and injected into a turbine of the power plant.

85 citations


Journal ArticleDOI
TL;DR: Model-based control of the outlet temperature of a distributed solar collector field is studied and Convergence of the closed loop is proved and the method is experimentally verified to perform well on a pilot-scale solar power plant.

Patent
28 Jan 2002
TL;DR: In this paper, an AC leakage current component due to the capacitance to ground of the solar battery is removed from the differential current, and it is determined whether a ground fault state has occurred by comparing a current value after removal of the AC leakage currents with a predetermined threshold value.
Abstract: In a solar power generation system which causes a non-insulated type inverter to convert DC power generated by a solar battery into AC power and outputs the AC power to a commercial power system, in detecting a ground fault, the differential current between the output lines of the solar battery is detected, an AC leakage current component due to the capacitance to ground of the solar battery is removed from the differential current, and it is determined whether a ground fault state has occurred by comparing a current value after removal of the AC leakage current component with a predetermined threshold value. With this arrangement, a false ground fault state determination that is caused by the influence of the AC leakage current component due to the electrostatic capacitance although the DC current path can be prevented, and a ground fault state can accurately be determined.

Journal ArticleDOI
TL;DR: In this article, the authors proposed a solar triple cycle with a high-temperature MHD generator and two additional cycles in series, which achieved a higher peak conversion efficiency than the solar combined cycle scheme.

Proceedings ArticleDOI
01 Jan 2002
TL;DR: In this article, the authors presented a study on the locomotion and energy utilization of a rover for regional mobility on planetary surfaces without contribution of batteries, which is called SOLERO.
Abstract: This abstract presents a perform study on SOLERO, a new and innovative rover concept for regional mobility on planetary surfaces. A rover is the most suited element to bring scientific instrument to a specific site in order to examine geology, mineralogy or exobiology on extraterrestrial planets. In contrast with the Mars Pathfinder mission, the actual need increases in terms of range and duration. These aspects lead to redesign many aspect of the past rovers, in particular the development of most suitable all terrain performances, autonomous navigation and a new power management concept. In this paper we’ll focus on the locomotion and the energy utilization without contribution of batteries. To validate the SOLERO possibilities in these domains and its use for future planetary exploration missions, modelization, testing and Mars like mission simulation have been done. Due to extreme temperatures the use of batteries is a critical point and becomes too expensive in term of size and mass for long-time missions. In this case, a locomotion concept reducing power consumption with exclusive use of on board power generation has to be investigated. The SOLERO mechanical structure is an optimization of the “Shrimp” rover developed at EPFL. It has one wheel mounted on a fork in the front, one wheel in the rear and two bogies on each side. The parallel architecture of the bogies and the spring suspended fork provides a high ground clearance while keeping all its 6 motorized wheels in ground contact. This ensures excellent climbing capabilities over obstacles higher that the wheel diameter. Moreover, this original combination of wheeled locomotion and passive adaptation to help to reduce power consumption compared to active design such as legged rovers, without sensible reduction of climbing abilities. To remove the problems linked with energy storage, not only power reduction is important, but also the power management. SOLERO uses exclusively solar cells to generate the electrical power, because it’s currently the most adapted solution for local energy generation on a rover. However the use of solar power only, have several constraints linked with the incoming solar radiation (insolation). To determine SOLERO’s power budget and performances, a Mars insolation and environment model has been chosen as reference. The integrated solar power generation restricts the operation time and power to specific daytime. The electrical power provided by a solar panel of 0.3m2 is over 14W during the four hours around noon, this is sufficient for locomotion. The 1kg scientific payload needs less that 8W power and can be used during a maximal time of height hours during daylight. However, the limited power storage capacities and the reduction of power consumption for locomotion allowed this rover to be small, light and operational during more that 100 sols (Martian days). The total mass is only 10kg and its locomotion performance, in comparison with actual rovers, leads SOLERO to become the perfect candidate for long range mission on near-sun planets

Proceedings ArticleDOI
19 May 2002
TL;DR: In this article, Fraunhofer ISE extended the fabrication of high-efficiency solar cells from a laboratory scale to a small pilot-line production at a very low illumination level.
Abstract: At Fraunhofer ISE the fabrication of high-efficiency solar cells was extended from a laboratory scale to a small pilot-line production. Primarily, the fabricated cells are used in small high-efficiency modules integrated in prototypes of solar-powered portable electronic devices such as cellular phones, handheld computers etc. Compared to other applications of high-efficiency cells such as solar cars and planes, the illumination densities found in these mainly indoor applications are significantly below 1 sun. Thus, special care was taken to keep the cell efficiency level high even at very low illumination levels. For this reason, particularly the cell border was analyzed and optimized carefully. The excellent cell characteristics achieved at low illumination densities increase the benefit of a solar power supply for such devices by an order of magnitude if compared to standard solar cells.

Proceedings Article
01 Jan 2002
TL;DR: Quaschning and Blanco as mentioned in this paper compared photovoltaic and solar thermal power plants and provided a short description of how they work, areas in which they operate and cost-developments.
Abstract: Many people associate solar energy directly with photovoltaics and not with solar thermal power generation. Nevertheless, large commercial concentrating solar thermal power plants have been generating electricity at a reasonable cost for more than 15 years and some new solar thermal power plants are soon to be erected. This paper compares the two technologies, providing a short description of how they work, areas in which they operate and cost-developments. 1 Principles About one percent of the surface of the Sahara desert would be sufficient to supply the entire worldwide electricity demand from solar thermal power plants. For that reason, many people hope solar thermal power will be implanted in sun-belt countries. In contrast to photovoltaic plants, solar thermal power plants are not based on the photo effect, but generate electricity from the heat produced by sunlight. 1.1 Photovoltaics Semiconductor materials such as silicon are used in photovoltaic solar cells. In the cells incoming photons separate positive and negative charge carriers. This produces an electrical voltage and the electrical current can drive a load. Since solar cells are modular, they can be assembled in units of any size (Figure 1). An inverter converts DC voltage to AC and feeds the solar power into the grid. ~ ~ ~ Figure 1: Photovoltaic modules and inverters build up a photovoltaic system V. Quaschning and M. Blanco Solar Power – Photovoltaic or Solar Thermal Power Plants? 2 1.2 Solar Thermal Power Plants Of the various types of solar thermal power plants, parabolic trough and solar power tower plants are described in more detail below. The “trough” collectors that make up the solar field of a parabolic trough power plant are large cylindrical parabolic mirrors that concentrate the sunlight on a line of focus (Figure 2). Several of these collectors are installed in rows about a hundred meters long and the total solar field is composed of many such parallel rows. Figure 2: Principle of the parabolic trough solar collector Solar Trough Field Preheater Steam Generator Reheater

Journal ArticleDOI
TL;DR: In this article, the solar thermal reduction of ZnO, using solar process heat and CH 4 or C as reducing agent, is investigated for CH 4 :ZnO or C:ZnOs molar ratios ranging from 0 (thermal decomposition at above about 2000°C) to 1 (stoichiometric reduction at above approximately 1000°C).
Abstract: The solar thermal reduction of ZnO, using solar process heat and CH 4 or C as reducing agent, is investigated for CH 4 :ZnO or C:ZnO molar ratios ranging from 0 (thermal decomposition at above about 2000°C) to 1 (stoichiometric reduction at above about 1000°C). At 1400°C, in thermodynamic equilibrium ZnO can be completely reduced using a CH 4 :ZnO molar ratio of 0.3 and produces one fuel (Zn-metal) rather than two for the stoichiometric case (Zn and syngas). The maximal reactor thermal efficiency without heat recovery from the offgas, defined as the ratio of the heating-value of the zinc produced to the total thermal energy input, is 55%. CO 2 -emissions are reduced by a factor of 10-15 compared to fossil-fuel-based zinc-production technologies. For a closed materials cycle, in which power is extracted from the solar zinc using a fuel cell and the ZnO formed is recycled to the solar reactor, the total exergy efficiency, defined as the work output of the fuel cell to the thermal energy input, varies between 30 to 40% when based on the absorbed solar power in the reactor. These efficiency values are very encouraging, especially since the solar ZnO/Zn cycle allows-in contrast to other regenerative power plants-to store and transport solar energy.

Patent
12 Nov 2002
TL;DR: In this article, a stable, manually portable floating electronic platform for use in pools and spas is equipped with recesses for receiving beverage containers and equipped with any of a variety of electronic audio/visual entertainment devices that are powered by an onboard battery, or a remote rechargeable battery or a conventional remote low-voltage power supply unit via a power cable.
Abstract: A stable, manually portable floating electronic platform for use in pools and spas is equipped with recesses for receiving beverage containers and is equipped with any of a variety of electronic audio/visual entertainment devices that are powered by an on-board battery, or a remote rechargeable battery or a conventional remote low-voltage power supply unit via a power cable. Solar power collector panels on the platform provide a recharging current to on-board or remote batteries via a power cable.

Proceedings ArticleDOI
13 Oct 2002
TL;DR: In this article, the harmonic distortion of the output current waveform of the inverter fed to the grid is within the stipulated limits laid down by the utility companies, and the simulation and experimental results of a new solar photovoltaic inverter configuration interconnected with the grid are presented.
Abstract: Detailed analysis, simulation and hardware results of a new solar photovoltaic inverter configuration interconnected to the grid are presented. From the simulation and experimental results it is confirmed that the harmonic distortion of the output current waveform of the inverter fed to the grid is within the stipulated limits laid down by the utility companies. To harvest the vast solar energy, it would be desirable if the energy conversion units are simple, reliable, and of low cost and high efficiency. High efficiency can be achieved by the use of all the power generated for the unit and even contribute to the gird while the energy is not used.

Patent
13 Nov 2002
TL;DR: In this article, a solar stepping stone (10) comprises a housing (70) having an upper surface (12), side walls (16, 18, 20, 22), a lower surface (14), the housing defining a chamber (32), and a solar energy collector (48) associated with the housing for collecting solar energy.
Abstract: A solar stepping stone (10) comprises a housing (70) having an upper surface (12), side walls (16, 18, 20, 22) and a lower surface (14), the housing (70) defining a chamber (32). A solar energy collector (48) is associated with the housing (70) for collecting solar energy. A solar power storage device (42) is provided in the chamber (32) for receiving and storing solar energy (42) received from the solar energy collectors (40). An illuminator (48) for illuminating at least a portion of the upper surface (12) of the solar stepping stone (10) is contained in the chamber (32) and is powered by solar energy stored by the solar power member (42).

ReportDOI
01 Jan 2002
TL;DR: In this paper, the authors presented an analysis to reduce the cost of power production from modular concentrating solar power plants through a relatively new and exciting concept that merges two mature technologies to produce distributed modular electric power in the range of 500 to 1,500 kWe.
Abstract: This report summarizes an analysis to reduce the cost of power production from modular concentrating solar power plants through a relatively new and exciting concept that merges two mature technologies to produce distributed modular electric power in the range of 500 to 1,500 kWe These are the organic Rankine cycle (ORC) power plant and the concentrating solar parabolic (CSP) trough technologies that have been developed independent of each other over many years

01 Jan 2002
TL;DR: In this paper, a review of concentrating solar power technologies and their perspectives for sustainable development and climate protection is presented together with instruments for enhanced project assessment using remote sensing technologies and geographic information systems.
Abstract: The paper gives a review of concentrating solar power technologies and shows their perspectives for sustainable development and climate protection. New concepts for the combined generation of power and water are presented together with instruments for enhanced project assessment using remote sensing technologies and geographic information systems. The vast solar energy resources of the South can be activated by international renewable energy alliances and allow for a smooth transition of the present electricity schemes to a sustainable power system based on renewable energy sources.


Patent
18 Jan 2002
TL;DR: In this paper, a DC/DC converter connected to a solar light power generation device is used to attain both the followability and stability of maximum power point tracking control in a method for controlling a DC and DC converter.
Abstract: PROBLEM TO BE SOLVED: To attain both the followability and stability of maximum power point tracking control in a method for controlling a DC/DC converter connected to a solar light power generation device. SOLUTION: A control part 7 changes continuity rate change amounts in accordance with an operating point and can attain both the followability and stability of maximum power point tracking control in changing a continuity rate of a switching element 11 to perform maximum power point tracking control of the solar light power generation device 1. Since this method for controlling a DC/DC converter can be realized only with software, the converter can be produced at a low cost. COPYRIGHT: (C)2003,JPO

Patent
07 Aug 2002
TL;DR: In this article, a duty ratio control circuit was coupled to a voltage converter for supplying a driving clock to the voltage converter, where the duty ratio controller adjusts the duty ratios of the driving clock based on a maximum charge power which depends on the original voltage generated by the solar battery.
Abstract: A solar power charging system comprising: a voltage converter for converting a voltage level of all original voltage generated by a solar battery into generate a charging voltage and for charging a capacitor by the charging voltage; and a duty ratio control circuit electrically coupled to the voltage converter for supplying a driving clock to the voltage converter for allowing the voltage converter to operate based on the driving clock, wherein the duty ratio control circuit adjusts a duty ratio of the driving clock based on a maximum charge power which depends on the original voltage generated by the solar battery.

Patent
20 Dec 2002
TL;DR: In this paper, a solar power system is provided for converting sunlight into electricity using a mirror to focus the sunlight into a cavity of an absorption chamber, which includes heat conducting shoes which absorb the solar energy reflected by the mirror and conduct the thermal energy to a plurality of free piston Stirling converters mounted to the absorption chamber.
Abstract: A solar power system is provided for converting sunlight into electricity. The solar power system utilizes a mirror to focus the sunlight into a cavity of an absorption chamber. The cavity includes heat conducting shoes which absorb the solar energy reflected by the mirror and conduct the thermal energy to a plurality of a free piston Stirling converters mounted to the absorption chamber. The Stirling converter converts the thermal energy into electrical energy. The solar power system of the present invention reduces costs of typical solar power systems by using a plurality of free piston Stirling converters of a size small enough to allow the use of a simple monolithic heater head which is simple and inexpensive to fabricate and does not require complex external tubular heat exchangers. The free piston Stirling converter does not require a crankshaft or contacting seals and thereby is reliable and low maintenance.

Patent
30 Dec 2002
TL;DR: In this paper, a photoelectric unit is provided with a solar cell module 2 having a plurality of solar battery cells 22, and a reflector 3 arranged with its planar projected area almost the same as that of the solar battery module 2 so that a light receiving face 2a of the photovoltaic unit 2 can face the reflecting face 31a.
Abstract: PROBLEM TO BE SOLVED: To provide a solar power generation system capable of taking countermeasures to typhoon, preventing the load on a building by the mounting of a solar cell module, making compact a plurality of solar cell modules, and efficiently collecting the insolation. SOLUTION: This photoelectric unit 1 is provided with a solar cell module 2 having a plurality of solar battery cells 22, and a reflector 3 arranged with its planar projected area almost the same as that of the solar battery module 2 so that a light receiving face 2a of the solar battery module 2 can face the reflecting face 31a. This photoelectric unit 1 is provided with a multi-stage laminate unit A, a sunlight condensing device 6 and an optical fiber cable 7 connecting the condensing device 6 with each solar battery module 2 associated with the photovoltaic unit 1. Lights condensed by the condensing device 6 are transferred through the optical fiber cable 7 to the solar battery module 2, the lights are reflected on a reflecting face 31a, and the solar battery cell 22 of the solar battery module 2 is irradiated with the light for power generation. COPYRIGHT: (C)2004,JPO&NCIPI

Journal ArticleDOI
TL;DR: Pudney et al. as mentioned in this paper showed that the optimal driving strategy is a critical speed strategy for an optimal journey with no beginning and no ending the solar car must always travel at the critical speed.
Abstract: The World Solar Challenge is a 3000 km race for solar powered cars across the Australian continent from Darwin to Adelaide. Each car is powered by a panel of photovoltaic cells which convert sunlight into electrical power. The power can be used directly to drive the car or stored in a battery for later use. Previous papers (P. Howlett, P. Pudney, T. Tarnopolskaya, and D. Gates, IMA Journal of Mathematics Applied in Business and Industry vol. 8, pp. 59-81, 1997; P.G. Howlett and P.J. Pudney, Dynamics of Continuous, Discrete and Impulsive Systems vol. 4, pp. 553-567, 1998) using a simplified model of the battery, have shown that the optimal strategy is essentially a speedholding strategy. In this paper, with a more realistic model of the battery, we show that the optimal driving strategy is a critical speed strategy. For an optimal journey with no beginning and no ending the solar car must always travel at the critical speed. For an optimal journey of finite length the speed must be close to the critical speed for most of the journey. The critical speed depends on the solar power and will normally vary slowly with time.

10 Oct 2002
TL;DR: The economic viability of space solar power is maximized if the power can be sold at peak power rates, instead of baseline rate as mentioned in this paper, and the economic viability is maximised if the energy can be exported at peak rates instead of a baseline rate.
Abstract: The selling price of electrical power varies with time The economic viability of space solar power is maximum if the power can be sold at peak power rates, instead of baseline rate Price and demand of electricity was examined from spot-market data from four example markets: New England, New York City, suburban New York, and California The data was averaged to show the average price and demand for power as a function of time of day and time of year Demand varies roughly by a factor of two between the early-morning minimum demand, and the afternoon maximum; both the amount of peak power, and the location of the peak, depends significantly on the location and the weather The demand curves were compared to the availability curves for solar energy and for tracking and non-tracking satellite solar power systems in order to compare the market value of terrestrial and solar electrical power In part 2, new designs for a space solar power (SSP) system were analyzed to provide electrical power to Earth for economically competitive rates The approach was to look at innovative power architectures to more practical approaches to space solar power A significant barrier is the initial investment required before the first power is returned Three new concepts for solar power satellites were invented and analyzed: a solar power satellite in the Earth-Sun L2 point, a geosynchronous no-moving parts solar power satellite, and a nontracking geosynchronous solar power satellite with integral phased array The integral-array satellite had several advantages, including an initial investment cost approximately eight times lower than the conventional design

Journal ArticleDOI
TL;DR: A historical view of the research and development in photovoltaics from the perspective of both the terrestrial and the space communities is presented from the early days through the '70s and '80s and the '90s and beyond.
Abstract: A historical view of the research and development in photovoltaics from the perspective of both the terrestrial and the space communities is presented from the early days through the '70s and '80s and the '90s and beyond. The synergy of both communities in the beginning and once again in the present and hopefully future are highlighted, with examples of the important features in each program. The space community which was impressed by the light-weight and reliability of photovoltaics drove much of the early development. Even up to today, nearly every satellites and other scientific space probe that has been launched has included some solar power. However, since the cost of these power systems were only a small fraction of the satellite and launch cost, the use of much of this technology for the terrestrial marketplace was not feasible. It was clear that the focus of the terrestrial community would be best served by reducing costs. This would include addressing a variety of manufacturing issues and raising the rate of production. Success in these programs and a resulting globalization of effort resulted in major strides in the reduction of PV module costs and increased production. Although, the space community derived benefit from some of these advancements, its focus was on pushing the envelope with regard to cell efficiency. The gap between theoretical efficiencies and experimental efficiencies for silicon, gallium arsenide and indium phosphide became almost non-existent. Recent work by both communities have focused on the development thin film cells of amorphous silicon, CuInSe2 and CdTe. These cells hold the promise of lower costs for the terrestrial community as well as possible flexible substrates, better radiation resistance, and higher specific power for the space community. It is predicted that future trends in both communities will be directed toward advances through the application of nanotechnology. A picture is emerging in which the space and terrestrial solar cell communities shall once again share many common goals and, in fact, companies may manufacture both space and terrestrial solar cells in III-V materials and thin film materials. Basic photovoltaics research including these current trends in nanotechnology provides a valuable service for both worlds in that fundamental understanding of cell processes is still vitally important, particularly with new materials or new cell structures. It is entirely possible that one day we might have one solar array design that will meet the criteria for success in both space and on the Earth or perhaps the Moon or Mars.