Did you know that many analysts would like to identify light-catching elements in order to transform more of the sun’s energy into carbon-free electricity?
A new analysis announced in the magazine Applied Physics Letters in August this year (released by the American Institute of Physics), describes how solar power could potentially be collected by using oxide elements that include the element selenium. A team at the Lawrence Berkeley National Laboratory in Berkeley, California, embedded selenium in zinc oxide, a relatively low-priced substance that could make more efficient use of the sun’s power.
The team observed that even a relatively small level of selenium, just nine percent of the mostly zinc-oxide base, dramatically improved the material’s efficiency in absorbing light.
The most important author of this analysis, Marie Mayer (a fourth-year University of California, Berkeley doctoral student) states that photo-electrochemical water splitting, that signifies employing energy from the sun to cleave water into hydrogen and oxygen gases, could possibly be the most fascinating future application for her labor. Using this reaction is key to the eventual creation of zero-emission hydrogen powered cars, which hypothetically will run only on water and sunlight.
Journal Reference: Marie A. Mayer et all. Applied Physics Letters, 2010 [link: https://link.aip.org/link/APPLAB/v97/i2/p022104/s1]
The conversion efficiency of a PV cell is the amount of sunlight energy that the photo voltaic cell converts to electricity. This is very important when discussing Photovoltaic units, because boosting this efficiency is vital to making Photovoltaic electricity competitive with more classic sources of energy (e.g., classic fuels).
For comparison, the very first Photo voltaic units converted about 1%-2% of sunlight energy into electric energy. Today’s Photo voltaic products convert 7%-17% of light energy into electric energy. Of course, the other side of the equation is the money it costs to produce the PV devices. This has been enhanced 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 twice as thick, efficiencies were much smaller than nowadays and lifetimes were reduced, it may well have cost more energy to make 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 required for generating the energy spent to manufacture 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 – reach substantially shorter energy payback times than conventional systems (often < 1 year). With a common lifetime of 20 to 30 years, this means that contemporary photovoltaic cells are net energy producers, i.e. they produce significantly more energy over their lifetime than the energy expended in producing them.
***The author – Rosalind Sanders publishes articles for the ‘solar covers’ blog, her personal hobby blog site centered on guidelines to help home owners to spend less energy with solar power.