Photovoltaic power cells

Since the first photovoltaic (PV) cells were fabricated for the U.S. space program in 1958, PV technology has evolved from once being a very high cost but essential and effective space power source to later becoming a small but diversified and enduring worldwide industry (1 6). Led by firms based in the United States, Japan, and Germany, this industry serves multiple markets (see Photovoltaic cells). 

Photovoltaic devices typically consist of a series of thin semiconductor layers that are designed to convert sunlight to dkect-current electricity (see Semiconductors). As long as the device is exposed to sunlight, a photovoltaic (PV) cell produces an electric current proportional to the amount of light it receives. The photovoltaic effect, first observed in 1839, did not see commercial appHcation until the 1950s when photovoltaic modules were used to power early space sateHites. Many good descriptions of the photovoltaic phenomenon are available (7). 

Solar power has the potential of becoming more consequential as an energy alternative. Photovoltaic (PV) cells are becoming less expensive... 

Cells made from GaAs are more costly than silicon cells, because the production process is not as well developed, and gallium and arsenic are not abundant materials. GaAs cells have been used when very high efficiency is needed regardless of cost such as required in space applications. They were also used in the Sunraycer, a photovoltaic-powered electric car, which won the Pentax World Solar Challenge race for solar-powered vehicles in 1987. It ran the 3000-km from Darwin to Adelaide, Australia at an average day time speed of 66-km per hour. The 1990 race was won by a... 

UL 1741 Underwriters Laboratory 1741 is a standard for the testing, listing and safety certification for electric inverters. This standard is for static inverters and charge controllers for use in photovoltaic power systems, but may be used for fuel cells. 

Photovoltaic Electrolysis Cells. These cells produce both fuel (e.g. H2) and electrical power by means of a low-energy electrochemical reaction such as the dissociation of HI. The principle of this cell is shown in Figure 6.27. 

Photovoltaic (PV) Module An integrated assembly of interconnected photovoltaic cells designed to deliver a selected level of working voltage and current at its output terminals, packaged for protection against environment degradation and suited for incorporation in photovoltaic power systems. 

Solar Energy Energy produced from the sun s radiation for the purposes of heating or electric generation. Also, see Photovoltaic (PV) Cell, Concentrated Solar Power (CSP) and Passive Solar. ... 

The key ingredient for new ways to harness sunlight is the solar cell, or photovoltaic (PV) cell, a device that absorbs photons from sunlight (or artificial sunlight) and generates an electrical current [9]. Figure 10.6 shows the evolution over time of photovoltaic cells since 1975 [4]. The first photovoltaic cell was a pn junction based on Si and had an efficiency of 5% to 6% [3] at present, Si pn junctions have overall power efficiencies of about 22% (maybe 10% in commerce) at the moment, Si solar cells are expensive but durable. 

While there is tremendous potential for solar energy to contribute substantially to the future carbon free power needs, none of the routes listed above are currently competitive with fossil fuels from cost, reliability, and performance perspectives. Photovoltaic solar cells have been around for decades and have been widely dep loyed in space vehicles. Terrestrially, their utilization thus far has been limited to niche applications or remote locales where less expensive electricity is not available. Costs for turnkey installations were 6 10 times more expensive in 1999 for solar... 

Based on the fraction these activities constitute of the total power usage, estimate which percentage of total electricity use it would be possible to base on renewable energy sources such as wind or photovoltaic power, used solely to charge either batteries or fuel cells (two separate estimates). 

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