Everybody wants to get off the grid. The public is desperate to save on energy costs and the only way is to tap into natural sources. Until free energy becomes a reality, all we realistically have as a non-polluting source of energy is solar
The world record for triple-junction solar cell efficiency is 44 percent, but a collaboration between the U.S. Naval Research Laboratory (NRL), the Imperial College of London, and MicroLink Devices Inc. led to a multi-junction photovoltaic cell design that broke the 50 percent conversion efficiency barrier under concentrated solar illumination.
The best examples of traditional silicon solar cells top out at around 25 percent efficiency, whereas multi-junction cells have achieved more than 40 percent.
Scientists at Stanford University have improved the efficiency of a revolutionary solar cell by around 100 times. Unlike standard photovoltaic cells, which only capture light energy, Stanford’s new device captures both light and heat, potentially boosting solar cell efficiency towards 60% â€” way beyond the 30-40% limit of traditional silicon photovoltaic solar cells.
This device uses a process calledÂ photon-enhanced thermionic emission (PETE). In photovoltaic cells, photons strike a semiconductor (usually silicon), creating electricity by knocking electrons loose from their parent atoms. The PETE process is similar, but also very different and altogether rather complex. In essence, think of it as the photovoltaic equivalent of a turbocharger.
Unlike normal photovoltaic cells which break down at high temperatures, PETE actually improves in efficiency as it gets hotter. One of the easiest applications of PETE would be in concentrating solar power plants, where thousands of mirrors concentrate light on a central vat of boiling water, which drives a steam turbine. By concentrating the light on PETE devices instead, Stanford estimates that their power output could increase by 50%, bringing the cost of solar power generation down into the range of fossil fuels.
But the most impressive solar powered devices may potentially belong to
an Inventor who is developing solar power designed to operate four or five times more efficiently than the beat photovoltaic cells now in use, and at a small fraction of the cost.
Alvin M. Marks, an inventor who, holds patents for a 3-D movie process and polarized film for sunglasses, is working with the Westinghouse Electric Corporation to build prototypes of the solar power devices. He received one patent for the devices earlier this year and another in 1984.
Mr. Marks says solar panels made with Lepcon or Lumeloid, the materials he patented, could turn 70 to 80 percent of the energy from sunlight they receive into electricity. Most photovoltaic cells are only about 15 percent efficient. The electricity would cost three or four cents per kilowatt hour, as against about 10 cents a kilowatt hour for commercially generated electric power. Most photovoltaic cells produce energy for around $1 per kilowatt hour.
Typical photovoltaic cells use layers of chemically treated metals that produce electric current when struck by sunlight. The basic problem has always been the quantity of current produced per unit cost of the materials used to produce it.
Lepcon, which was a preliminary design, consists of glass panels covered with a vast array of millions of aluminum or copper strips, each less than a micron or thousandth of a millimeter wide. As sunlight hits the metal strips, the energy in the light is transferred to electrons in the metal. which escape at one end in the form of electricity.
Lumeloid uses a similar approach. but substitutes cheaper, filmlike sheets of plastic for the glass panels and covers the plastic with conductive polymers, long chains of molecular plastic units. Lumeloid is easier to manufacture and handle than Lepcon. The company declines, for competitive reasons, to identify the chemicals it uses to produce Lumeloid polymers.
Professor Stuart A Rice, dean of the division of physical sciences at the University of Chicago, has also reviewed the patents.
"It is an intellectually challenging idea," he said, "I do not know whether it can be brought into practice, so I don't know whether to be optimistic or pessimistic. If it turned out to work, and was very efficient, it would he very significant."
Mr Marks said he believed Lumeloid would be available for commercial use within two or three years. He added that Lepcon and Lumeloid could be used to create lasers, an application he said he had discussed with the Pentagon in conjunction with Westinghouse.
Mr Marks conceded that getting his ideas to the major prototype stage would cost around $5 million. Commercial production of solar panels would cost between $30 million to $50 million, he estimated, and the preliminary work, supported by Westinghouse, is now underway, he said.
Kelley Bergman is a media consultant, critic and geopolitical investigator. She has worked as a journalist and writer, specializing in geostrategic issues around the globe.