Innumerable benefits of solar power as an alternative source of energy have come to light in recent times. A new tidbit gives insight of an innovative process that possibly doubles the productivity of existing solar cell technology. Stanford engineers have apparently developed a novel process known as photon enhanced thermionic emission (PETE) which not only combines the light and heat of solar radiation to generate electricity, but also decreases the cost of solar energy production.
The technology is believed to take solar energy production at the next level, wherein it can give a tough competition to oil as an energy source. Present day photovoltaic technology employed in solar panels seemingly becomes less productive with elevation in temperature. On the other hand, PETE is assumed to increase its efficiency with rise in temperature. If the scientists are to be believed, then the technology could overcome existing photovoltaic and thermal conversion technologies in the near future.
Nick Melosh, an assistant professor of materials science and engineering, who led the research group remarked, “This is really a conceptual breakthrough, a new energy conversion process, not just a new material or a slightly different tweak. It is actually something fundamentally different about how you can harvest energy.”
The process appears to be affordable because materials required to build a device are inexpensive and easily available. Photovoltaic cells that are put to use in rooftop solar panels employ the semiconducting material silicon for converting energy from photons of light to electricity. The drawback of this process is that the cells may only utilize a section of the light spectrum and the rest just generate heat. This heat supposedly accounts for a loss of more than 50 percent of the initial solar energy reaching the cell.
Investigators identified that simply coating a piece of semiconducting material with a thin layer of the metal cesium can help use both light and heat for the generation of electricity. PETE shows progressive results at higher temperatures, allowing solar concentrators namely parabolic dishes which can get as hot as 800 C to boost the efficiency of this process.
Melosh alleged, “What we’ve demonstrated is a new physical process that is not based on standard photovoltaic mechanisms, but can give you a photovoltaic-like response at very high temperatures. In fact, it works better at higher temperatures. The higher the better.”
Dishes encompassing a thermal conversion mechanism are seemingly used in large solar farms. These dishes also appear to aid PETE in generating electricity at lower costs by connecting with present day technology. It has been claimed that photovoltaic systems by no means waste heat, yet the process working in high temperatures can potentially produce usable high-temperature waste heat.
Melosh added, “The light would come in and hit our PETE device first, where we would take advantage of both the incident light and the heat that it produces, and then we would dump the waste heat to their existing thermal conversion systems. So the PETE process has two really big benefits in energy production over normal technology.”
It has been estimated that PETE can develop twice the efficiency or more under solar concentration. A combination of this novel process and a thermal conversion cycle is affirmed to reach 55 or even 60 percent which is nearly triple the productivity of existing systems. Experts aim to further design devices rendering this process more affordable.
Melosh quoted, “For each device, we are figuring something like a 6-inch wafer of actual material is all that is needed. So the material cost in this is not really an issue for us, unlike the way it is for large solar panels of silicon.”
While conducting the ‘proof of concept’ tests, scientists employed a gallium nitride semiconductor. It was noted that only gallium nitride was able to endure the high temperature range. Experts share that precise semiconductor material such as gallium arsenide can help the process in reaching up to 50 or 60 percent.
Melosh concluded, “The PETE process could really give the feasibility of solar power a big boost. Even if we don’t achieve perfect efficiency, let’s say we give a 10 percent boost to the efficiency of solar conversion, going from 20 percent efficiency to 30 percent, that is still a 50 percent increase overall.”
Allegedly one more merit of the PETE system is that only small quantities of semiconductor material may be required for the device. Further investigations employing other materials are being initiated. The newly developed process can possibly decrease the investment capital required for building a solar farm.
The investigation was published online August 1 in Nature Materials.