This is a guest post from Rosalind Sanders who writes for the solar pool cover blog, her personal hobby blog focused on tips to help home owners to save energy with solar energy.
American institute of physics demonstrates us more economical Selenium solar cells
Did you know that many analysts would like to find light-catching elements in order to transform more of the sun’s power into carbon-free electric power?
A new study described in the journal Applied Physics Letters in August this year (written and published by the American Institute of Physics), describes how solar power could potentially be collected 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 economical use of the sun’s power.
The team identified that even a relatively small amount of selenium, just nine percent of the mostly zinc-oxide base, significantly enhanced the material’s effectiveness in absorbing light.
The primary author of this analysis, Marie Mayer (a 4th-year University of California, Berkeley doctoral student) states that photo-electrochemical water splitting, that means employing energy from the sun to cleave water into hydrogen and oxygen gases, could potentially be the most fascinating future application for her efforts. Managing this reaction is key to the eventual creation of zero-emission hydrogen powered vehicles, which hypothetically will run only on water and sunlight.
Journal Research: Marie A. Mayer et all. Applied Physics Letters, 2010
Photo Voltaic Efficiency
The conversion effectiveness of a PV cell is the proportion of sunlight energy that the photo voltaic cell converts to electrical energy. This is very important when discussing Photo voltaic units, because boosting this efficiency is vital to making Pv power competitive with more common sources of energy (e.g., non-renewable fuels).
For comparison, the earliest Pv units converted about 1%-2% of sunlight energy into electric energy. Today’s Photovoltaic 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 produce electricity at a fraction of the cost of early PV systems.
In the 1990’s, when silicon cells were twice as thick, efficiencies were much lower than nowadays 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 technology has progressed considerably, and the energy repayment 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 normally from 1 to 4 years depending on the module type and location.
Typically, thin-film technologies – despite having relatively low conversion efficiencies – achieve considerably shorter energy payback times than conventional systems (often < 1 year). With a common lifetime of 20 to 30 years, this signifies that contemporary photovoltaic cells are net energy producers, i.e. they create significantly more energy over their lifetime than the energy expended in producing them.
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