With Air Quality at an All-Time High, Solar Energy Efficiency Skyrockets. But Can It Last?April 23, 2020 by Gary Elinoff
England recently reported a record-setting 9.68 GW of solar power generation. New solar technology seeks to keep these levels high—even after government lock-downs lift.
The Sheffield Solar live PV generation tracker in England recently reported a record-setting 9.68 GW of solar power generation on April 20, meeting close to 30% of the country’s total demand for electricity.
That’s the equivalent of about ten fossil fuel or nuclear power plants. Significantly, as the UK's Solar Trade Association notes, this has contributed to the nation’s ability to go for 11.5 days without using any coal to generate electricity. The Solar Trade Association points to ideal weather conditions and decreased pollution levels (a result of stay-at-home orders) as the cause of maximized solar PV efficiency.
PV generation on April 20th—a record high at 9.68 GW. Image used courtesy of Sheffield Solar
But when life returns back to normal, solar energy technology must improve to compensate for pollution levels that will rise once again. Here are a few research developments in solar energy generation to that end.
Solar Cells for Different Portions of the Sun's UV Spectrum
Scientists from the National Renewable Energy Laboratory (NREL) have successfully fabricated a solar cell that has registered an astonishing 39.2% efficiency when converting unconcentrated, ground-level sunlight to electricity. When presented with 143 times that level, the novel new device recorded an almost unbelievable 47.1%. The results were recorded in a paper published in Nature Energy.
The research reveals that the "six-junction solar cell," or novel junction cell III-V solar cell, earned its name because of its component elements’ locations on the periodic table. Each of the six junctions is purposefully designed to absorb sunlight from different portions of the sun’s radiating spectrum. The junctions are composed of a total of 140 total layers, yet a summary of the research in Science Daily describes the overall thickness as “three times narrower than a human hair.”
Researchers John Geisz (left), Ryan France (right), and others worked together to create a solar cell that is nearly 50% efficient. Image used courtesy of National Renewable Energy Laboratory
Solar cells of this nature will find use in space-based endeavors where the sun’s intensity is far greater than it is on earth. Ryan France, one of the paper’s authors, states that the new solar cell will find terrestrial use in concentrator photovoltaic applications. In these applications, sunlight impinging a wide area of ground is concentrated at one point via mirrors. This methodology saves semiconductor material and conveys many other engineering advantages.
Instead of covering an expanse of land in solar cells, technicians could cover land largely with mirrors. Because of the unprecedented efficiency of the new finding, less total land will be needed.
A Clear, Tin-Based Semiconductor to Generate Solar Power
Mobility in semiconductors relates to how easily and quickly electrons can move within a substance. University of Tokyo researchers have demonstrated the highest mobility through thin films of tin dioxide ever reported. The scientists predict that a clear semiconductor based on thin films of tin dioxide could lead to advances in solar power generation.
The research is revealed in a paper published in Nature. According to one of the authors of the research, Shoichiro Nakao, transparency and conductivity don't typically coexist in a material. He elaborates, "Typical transparent materials such as glass or plastic are insulating, whereas conducting materials like metals are opaque. Few materials exhibit transparent conductivity—it’s very interesting!”
But the researchers sought a material that had the best of both worlds.
Researchers started with tin dioxide pellets, the raw material for the transparent tin semiconductor. Image used courtesy of the University of Tokyo
To achieve this, they employed a highly-focused laser to evaporate pellets of pure tin dioxide and precisely deploy the material. Nakao said that this process allowed them to explore various growth conditions and assess how they could incorporate additional substances.
"This means we can endow tin dioxide semiconductors with high mobility and useful functionality," he explains.
Through laser deposition, a thin film of tin dioxide is obtained. Image used courtesy of the University of Tokyo
The tin oxide thin film that Nakao and his associates have made allows visible light and near-infrared light to pass. The researchers suspect that this material may foreshadow improvements in the power conversion efficiency of future photovoltaic solar panels.
The Future Is Bright for Solar Energy
While it's unlikely that solar PV efficiency in England will remain quite as high post-quarantine as it is now, these advancements represent important steps in solar energy technology. These advancements may become increasingly important once stay-at-home orders are lifted and solar technology will again need to compensate for atmospheric limitations, like air pollution.
Learn More About Solar Technology
If you've worked with solar technologies, what design precautions did you put in place to compensate for poor weather conditions and air pollution? Share your experiences in the comments below.