Swedish advanced materials start-up Sol Voltaics today announced a research breakthrough that allows nanowires to be used to boost the efficiency of thin-film solar modules by as much as 50%.
The vast majority of solar modules being manufactured today have a sunlight conversion efficiency rating of 15% to 17%; the rating refers to the percentage of photons striking the modules that can be turned into electric current. The best solar module efficiency ratings from companies such as SolarCity, SunPower and Panasonic, are in the 22% range.
Sol Voltaics technology could theoretically boost the efficiency level to 27% or higher; that would represent a 30% to 50% increase over current technology, the company said.
Nanowires, thousands of times thinner than a human hair, are highly conductive.
Sol Voltaics makes gallium arsenide nanowires through a process called Aerotaxy, which was invented by company founder Lars Samuelson. The gallium arsenide nanowires in Sol Voltaics' Solfilm thin-film modules consist of only a small number of atoms, but they are fully-functioning solar cells.
While nanowires have displayed promising characteristics in solar energy generation, they are also notoriously difficult to align due to their high aspect ratios and material characteristics. Sol Voltaics said it can control nanowire orientation and alignment at the centimeter scale on standard-sized wafers, "a major step toward the commercial production of solar films for... solar PV modules."
"Today's announcement marks a significant moment for both Sol Voltaics and the global solar energy industry," CEO Erik Smith said in a statement. "Gallium arsenide (GaAs) nanowires have recently come to the forefront as holding great promise for boosting solar module efficiencies well beyond current levels.
"This will enable solar panel manufacturers to greatly enhance the energy-generating capability of their products," Smith said.
The majority of photovoltaic modules are made using abundant crystalline silicon. The idea of creating thin-film solar modules dates back to the inception of photovoltaics, and it holds the promise of producing lower cost products because less material is needed to produce the same or more electricity.
However, new PV technology is rarely adopted in the solar industry.
Solar installations have an enormous upfront investment cost but then there is little ongoing operational expense. So, the longer solar panels work, the more revenue a solar electricity plant can generate as the levelized cost of electricity drops over time.
Due to the fact that there are no fuel costs and little maintenance required, solar has already become a cheaper energy source than coal in some regions of the world, including India.
Therefore, solar panel resiliency has trumped higher efficiency, according to Jenya Meydbray, vice president of strategy and business development at DNV GL, an international PV certification body.
For example, investment banks financing 10,000 rooftop solar systems or large power plants in the desert are very risk averse.
"They don't make bets on technology," Meydbray said. "That's why a totally different technology coming into the market isn't typically adopted very well. This is part of the reason the majority of thin-film companies that were the future back in 2006 are now bankrupt."
However, Sol Voltaic argues that its the use of nanowires in its PVs is far less expensive than previous materials being utilized by thin films manufacturers.
"Most importantly, Sol Voltaic's patented Aerotaxy process, their secret sauce, will enable them to produce the films at a very cost competitive level," a spokeperson wrote in a reply to Computerworld.
The thin film modules Sol Voltaic is developing are aimed at crystalline silicon module manufacturers. "By building the simple film into the final stages of their manufacturing process and laying the film on top of the cells, they will be able to reach these unprecedented levels of efficiency," the spokesman added.
In addition to the nanowire alignment breakthrough, Sol Voltaics said it has progressed through several generations of development of its Aerotaxy production technology. The patented process allows cost-effective nanowire solar cell production via a continuous gas phase process.
"Realistically, we have a few remaining hurdles to get over in order to get into commercialization, but we're very confident we can deliver a truly transformative energy solution," Smith said.
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