Edmund Becquerel discovered the photovoltaic (PV) effect in 1839, when he observed that avoltage and a current were produced when a silver chloride electrode immersed in an electrolyticsolution and connected to a counter metal electrode was illuminated with white light (Becquerel1839). However, the birth of the modern era of PV solar cells occurred in 1954, when D. Chapin,C. Fuller, and G. Pearson at Bell Labs demonstrated solar cells based on p-n junctions in singlecrystalSi with efficiencies of 5–6% (Chapin, Fuller, and Pearson 1954). This original Si solarcell still works today — single-crystal Si solar cells dominate the commercial PV market.From the mid 1950s to the early 1970s, PV research and development (R&D) was directedprimarily toward space applications and satellite power. Then, in 1973, a greatly increased levelof R&D on solar cells was initiated following the oil embargo in that year, which causedwidespread concern regarding energy supply. In 1976, the U.S. Department of Energy (DOE), along with its Photovoltaics Program, was created. DOE, as well as many other internationalorganizations, began funding PV R&D at appreciable levels, and a terrestrial solar cell industryquickly evolved. Figure 1 shows a plot of annual PV power production vs. time for the period1988–2003 (Surek 2005). Total global PV (or solar) cell production increased from less than 10MWp/yr in 1980 to about 1,200 MWp/yr in 2004; the current total global PV installed capacity isabout 3 GWp. The “peak watt” (Wp) rating is the power (in watts) produced by a solar moduleilluminated under the following standard conditions: 1,000 W/m2 intensity, 25°C ambienttemperature, and a spectrum that relates to sunlight that has passed through the atmosphere whenthe sun is at a 42° elevation from the horizon (defined as air mass [or AM] 1.5;i.e., when the path through the atmosphere is 1.5 times that when the sun is at high noon).Because of day/night and time-of-day variations in insolation and cloud cover, the averageelectrical power produced by a solar cell over a year is about 20% of its Wp rating.
Solar cells have a lifetime of approximately 30 yr. They incur no fuel expenses, but they doinvolve a capital cost. The cost for the electricity produced by the cell is calculated by amortizingthe capital cost over the lifetime of the cell and considering the total electrical output energyproduced over the cell lifetime. Higher PV efficiency thus directly impacts the overall electricitycost, because higher-efficiency cells will produce more electrical energy per unit of cell areaover the cell lifetime. The cost figure of merit for PV cell modules ($/Wp) is determined by theratio of the module cost per unit of area ($/m2) divided by the maximum amount of electricpower delivered per unit of area (module efficiency multiplied by 1,000 W/m2, the peakinsolation power). In Figure 2, this cost per peak watt ($/Wp) is indicated by a series of dashedstraight lines having different slopes. Any combination of areal cost and efficiency that is on agiven dashed line produces the same cost per peak watt indicated by the line labels. Presentsingle-crystalline Si PV cells, with an efficiency of 10% and a cost of $350/m2, thus have amodule cost of $3.50/Wp. The area labeled I in Figure 2 represents the first generation(Generation I) of solar cells and covers the range of module costs and efficiencies for these cells.In addition to module costs, a PV system also has costs associated with the non-photoactive partsof the system. These are called balance of system (BOS) costs, and they are currently in therange of $250/m2 for Generation I cells. Thus, the total cost of present PV systems is about$6/Wp. Taking into account the cost of capital funds, interest rates, depreciation, system lifetime,and the available annual solar irradiance integrated over the year (i.e., considering the diurnalcycle and cloud cover, which produces an average power over a year that is about 1/5 of the peakpower rating), the $/Wp cost figure of merit can be converted to $/kWh by the following simplerelationship: $1/Wp ~ $0.05/kWh. This calculation leads to a present cost for grid-connected PVelectricity of about $0.30/kWh. Areas labeled II and III in Figure 2 present the module costs forGeneration II (thin-film PV) and Generation III (advanced future structures) PV cells.
Solar cells have a lifetime of approximately 30 yr. They incur no fuel expenses, but they doinvolve a capital cost. The cost for the electricity produced by the cell is calculated by amortizingthe capital cost over the lifetime of the cell and considering the total electrical output energyproduced over the cell lifetime. Higher PV efficiency thus directly impacts the overall electricitycost, because higher-efficiency cells will produce more electrical energy per unit of cell areaover the cell lifetime. The cost figure of merit for PV cell modules ($/Wp) is determined by theratio of the module cost per unit of area ($/m2) divided by the maximum amount of electricpower delivered per unit of area (module efficiency multiplied by 1,000 W/m2, the peakinsolation power). In Figure 2, this cost per peak watt ($/Wp) is indicated by a series of dashedstraight lines having different slopes. Any combination of areal cost and efficiency that is on agiven dashed line produces the same cost per peak watt indicated by the line labels. Presentsingle-crystalline Si PV cells, with an efficiency of 10% and a cost of $350/m2, thus have amodule cost of $3.50/Wp. The area labeled I in Figure 2 represents the first generation(Generation I) of solar cells and covers the range of module costs and efficiencies for these cells.In addition to module costs, a PV system also has costs associated with the non-photoactive partsof the system. These are called balance of system (BOS) costs, and they are currently in therange of $250/m2 for Generation I cells. Thus, the total cost of present PV systems is about$6/Wp. Taking into account the cost of capital funds, interest rates, depreciation, system lifetime,and the available annual solar irradiance integrated over the year (i.e., considering the diurnalcycle and cloud cover, which produces an average power over a year that is about 1/5 of the peakpower rating), the $/Wp cost figure of merit can be converted to $/kWh by the following simplerelationship: $1/Wp ~ $0.05/kWh. This calculation leads to a present cost for grid-connected PVelectricity of about $0.30/kWh. Areas labeled II and III in Figure 2 present the module costs forGeneration II (thin-film PV) and Generation III (advanced future structures) PV cells.
solar vehicle :- A solar vehicle is an electric vehicle powered by a type of renewable energy, by solar energy obtained from solar panels on the surface (generally, the roof) of the vehicle. Photovoltaic (PV) cells convert the Sun's energy directly into electrical energy. Solar vehicles are not practical day-to-day transportation devices at present, but are primarily demonstration vehicles and engineering exercises, often sponsored by government agencies.Solar cars combine technology typically used in the aerospace, bicycle, alternative energy and automotive industries. The design of a solar vehicle is severely limited by the energy input into the car (batteries and power from the sun). Virtually all solar cars ever built have been for the purpose of solar car races (with notable exceptions).combine technology typically used in the aerospace, bicycle, alternative energy and automotive industries. The design of a solar vehicle is severely limited by the energy input into the car (batteries and power from the sun). Virtually all solar cars ever built have been for the purpose of solar car races (with notable exceptions).Like many race cars, the driver's cockpit usually only contains room for one person, although a few cars do contain room for a second passenger. They contain some of the features available to drivers of traditional vehicles such as brakes, accelerator, turn signals, rear view mirrors (or camera), ventilation, and sometimes cruise control. A radio for communication with their support crews is almost always included.Solar cars are often fitted with gauges as seen in conventional cars. Aside from keeping the car on the road, the driver's main priority is to keep an eye on these gauges to spot possible problems. Cars without gauges available for the driver will almost always feature wireless telemetry. Wireless telemetry allows the driver's team to monitor the car's energy consumption, solar energy capture and other parameters and free the driver to concentrate on just driving.
Electrical and mechanical systems :- The electrical system is the most important part of the car's systems as it controls all of the power that comes into and leaves the system. The battery pack plays the same role in a solar car that a petrol tank plays in a normal car in storing power for future use. Solar cars use a range of batteries including lead-acid batteries, nickel-metal hydride batteries (NiMH), Nickel-Cadmium batteries (NiCd), Lithium ion batteries and Lithium polymer batteries.Many solar race cars have complex data acquisition systems that monitor the whole electrical system while even the most basic cars have systems that provide information on battery voltage and current to the driver.The mechanical systems of a solar car are designed to keep friction and weight to a minimum while maintaining strength. Designers normally use titanium and composites to ensure a good strength-to-weight ratio.Solar cars usually have three wheels, but some have four. Three wheelers usually have two front wheels and one rear wheel: the front wheels steer and the rear wheel follows. Four wheel vehicles are set up like normal cars or similarly to three wheeled vehicles with the two rear wheels close together.
Solar array :- The solar array consists of hundreds of photovoltaic solar cells converting sunlight into electricity. The larger arrays in use can produce over 2 kilowatts (2.6 hp).The solar array can be mounted in several ways:
horizontal. This most common arrangement gives most overall power during most of the day in low latitudes or higher latitude summers and offers little interaction with the wind. Horizontal arrays can be integrated or be in the form of a free canopy. This most common arrangement gives most overall power during most of the day in low latitudes or higher latitude summers and offers little interaction with the wind. Horizontal arrays can be integrated or be in the form of a free canopy.vertical. This arrangement is sometimes found in free standing or integrated sails to harness wind energy. Useful solar power is limited to mornings, evenings, or winters and when the vehicle is pointing in the right direction. This arrangement is sometimes found in free standing or integrated sails to harness wind energy. Useful solar power is limited to mornings, evenings, or winters and when the vehicle is pointing in the right direction. adjustable. Free solar arrays can often be tilted around the axis of travel in order to increase power when the sun is low and well to the side. An alternative is to tilt the whole vehicle when parked. Two-axis adjustment is only found on marine vehicles, where the aerodynamic resistance is of less importance than with road vehicles.
. Free solar arrays can often be tilted around the axis of travel in order to increase power when the sun is low and well to the side. An alternative is to tilt the whole vehicle when parked. Two-axis adjustment is only found on marine vehicles, where the aerodynamic resistance is of less importance than with road vehicles. integrated. Some vehicles cover every available surface with solar cells. Some of the cells will be at an optimal angle whereas others will be shaded.
. Some vehicles cover every available surface with solar cells. Some of the cells will be at an optimal angle whereas others will be shaded. trailer. Solar trailers are especially useful for retrofitting existing vehicles with little stability, e.g. bicycles. Some trailers also include the batteries and others also the drive motor.
. Solar trailers are especially useful for retrofitting existing vehicles with little stability, e.g. bicycles. Some trailers also include the batteries and others also the drive motor. remote. By mounting the solar array at a stationary location instead of the vehicle, power can be maximised and resistance minimized. The virtual grid-connection however involves more electrical losses than with true solar vehicles and the battery must be larger.
. By mounting the solar array at a stationary location instead of the vehicle, power can be maximised and resistance minimized. The virtual grid-connection however involves more electrical losses than with true solar vehicles and the battery must be larger. The choice of solar array geometry involves an optimization between power output, aerodynamic resistance and vehicle mass, as well as practical considerations. For example, a free horizontal canopy gives 2-3 times the surface area of a vehicle with integrated cells but offers better cooling of the cells and shading of the riders. There are also thin flexible solar arrays in development.
horizontal. This most common arrangement gives most overall power during most of the day in low latitudes or higher latitude summers and offers little interaction with the wind. Horizontal arrays can be integrated or be in the form of a free canopy. This most common arrangement gives most overall power during most of the day in low latitudes or higher latitude summers and offers little interaction with the wind. Horizontal arrays can be integrated or be in the form of a free canopy.vertical. This arrangement is sometimes found in free standing or integrated sails to harness wind energy. Useful solar power is limited to mornings, evenings, or winters and when the vehicle is pointing in the right direction. This arrangement is sometimes found in free standing or integrated sails to harness wind energy. Useful solar power is limited to mornings, evenings, or winters and when the vehicle is pointing in the right direction. adjustable. Free solar arrays can often be tilted around the axis of travel in order to increase power when the sun is low and well to the side. An alternative is to tilt the whole vehicle when parked. Two-axis adjustment is only found on marine vehicles, where the aerodynamic resistance is of less importance than with road vehicles.
. Free solar arrays can often be tilted around the axis of travel in order to increase power when the sun is low and well to the side. An alternative is to tilt the whole vehicle when parked. Two-axis adjustment is only found on marine vehicles, where the aerodynamic resistance is of less importance than with road vehicles. integrated. Some vehicles cover every available surface with solar cells. Some of the cells will be at an optimal angle whereas others will be shaded.
. Some vehicles cover every available surface with solar cells. Some of the cells will be at an optimal angle whereas others will be shaded. trailer. Solar trailers are especially useful for retrofitting existing vehicles with little stability, e.g. bicycles. Some trailers also include the batteries and others also the drive motor.
. Solar trailers are especially useful for retrofitting existing vehicles with little stability, e.g. bicycles. Some trailers also include the batteries and others also the drive motor. remote. By mounting the solar array at a stationary location instead of the vehicle, power can be maximised and resistance minimized. The virtual grid-connection however involves more electrical losses than with true solar vehicles and the battery must be larger.
. By mounting the solar array at a stationary location instead of the vehicle, power can be maximised and resistance minimized. The virtual grid-connection however involves more electrical losses than with true solar vehicles and the battery must be larger. The choice of solar array geometry involves an optimization between power output, aerodynamic resistance and vehicle mass, as well as practical considerations. For example, a free horizontal canopy gives 2-3 times the surface area of a vehicle with integrated cells but offers better cooling of the cells and shading of the riders. There are also thin flexible solar arrays in development.
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