Pool Solar Panels
Title: American institute of physics indicates us more productive Selenium solar cells
By: Rosalind Sanders
Did you know that many scientists would like to discover light-catching elements in order to convert more of the sun's energy into carbon-free electrical energy?
A new analysis announced in the magazine Applied Physics Letters in August 2010 (published by the American Institute of Physics), describes how solar power could potentially be harvested by using oxide materials that include the element selenium. A team at the Lawrence Berkeley National Laboratory in Berkeley, California, embedded selenium in zinc oxide, a relatively cheap material that could make more successful use of the sun's power.
The team identified that even a relatively small level of selenium, just 9 % of the mostly zinc-oxide base, dramatically enhanced the material's productivity in absorbing light.
The primary author of this analysis, Marie Mayer (a 4th-year University of California, Berkeley doctoral student) suggests that photo-electrochemical water splitting, that signifies using energy from the sun to cleave water into hydrogen and oxygen gases, could probably be the most interesting future application for her efforts. Using this reaction is key to the eventual production of zero-emission hydrogen powered automobiles, which hypothetically will run only on water and sunlight.
Journal Reference: Marie A. Mayer et all. Applied Physics Letters, 2010 [link: http://link.aip.org/link/APPLAB/v97/i2/p022104/s1]
The conversion performance of a PV cell is the proportion of sunlight energy that the photo voltaic cell converts to electrical power. This is very important when discussing Photo voltaic devices, because improving this efficiency is vital to making Photovoltaic electricity competitive with more classic sources of energy (e.g., non-renewable fuels).
For comparison, the 1st Photo voltaic units converted about 1%-2% of sunlight power into electric energy. Today's Photo voltaic units convert 7%-17% of light energy into electrical power. Of course, the other side of the equation is the dollars it costs to produce the PV devices. This has been improved over the decades as well. In fact, today's PV systems make electricity at a fraction of the cost of early PV systems.
In the 1990s, when silicon cells were two times as thick, efficiencies were much smaller than today and lifetimes were shorter, it may well have cost more energy to produce a cell than it could generate in a lifetime. In the meantime, the technological innovation has developed substantially, and the energy payback time (defined as the recovery time necessary for generating the energy spent to produce the respective technical energy systems) of a modern photovoltaic module is commonly from 1 to 4 years depending on the module type and location.
Commonly, thin-film technologies - despite having comparatively low conversion efficiencies - obtain significantly shorter energy repayment times than conventional systems (often < 1 year). With a typical lifetime of 20 to 30 years, this means that current solar cells are net energy producers, i.e. they produce significantly more energy over their lifetime than the energy expended in producing them.
About the author - Rosalind Sanders publishes articles for the swiming pool solar covers blog, her personal hobby website based on tips to help home owners to spend less energy with solar power.
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