Did you know that many scientists would like to discover light-catching substances in order to transform more of the sun’s energy into carbon-free electric power?
A new study announced in the magazine Applied Physics Letters in August 2010 (published by the American Institute of Physics), explains how solar power could potentially be collected by using oxide materials that contain the element selenium. A team at the Lawrence Berkeley National Laboratory in Berkeley, California, inserted selenium in zinc oxide, a relatively low-priced material that could make more economical use of the sun’s energy.
The team discovered that even a relatively small level of selenium, just 9 per-cent of the mostly zinc-oxide base, significantly enhanced the material’s efficiency in absorbing light.
The primary author of this study, Marie Mayer reveals that photo-electrochemical water splitting, that signifies employing power from the sun to cleave water into hydrogen and oxygen gases, could potentially be the most interesting future application for her efforts. Utilizing this reaction is key to the eventual production of zero-emission hydrogen powered cars, which hypothetically will run only on water and sunlight.
The conversion performance of a PV cell is the portion of sunlight energy that the photo voltaic cell converts to electrical energy. This is very important when discussing Pv products, because boosting this efficiency is vital to making Photovoltaic power competitive with more traditional sources of energy (e.g., fossil fuels).
For comparison, the very first Photo voltaic devices converted about 1%-2% of sunlight energy into electrical energy. Today’s Photo voltaic devices convert 7%-17% of light energy into electrical energy. Of course, the other side of the equation is the money it costs to manufacture the PV devices. This has been enhanced over the decades as well. In fact, today’s PV systems generate electricity at a fraction of the cost of first PV systems.
In the 1990s, when silicon cells were twice as thick, efficiencies were much lower than today and lifetimes were shorter, it may well have cost more energy to make a cell than it could generate in a lifetime. In the meantime, the technology has moved on considerably, 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 normally from 1 to 4 years depending on the module type and location.
Typically, thin-film technologies – despite having comparatively low conversion efficiencies – obtain substantially shorter energy repayment times than standard systems (often < 1 year). With a normal lifetime of 20 to 30 years, this means that current solar cells are net energy producers, i.e. they create significantly more energy over their lifetime than the energy expended in producing them.
About the author – Rosalind Sanders publishes articles for the pool solar covers review blog, her personal hobby weblog based on tips to help home owners to save energy with solar energy.