SOLAR TECH

It doesn’t generate much power, but it works during the one time of day that solar cells can’t: night. Aaswath Raman was driving through a village in Sierra Leone in 2013 when an idea came to him as suddenly as, perhaps, a light bulb switching on. The village was not equipped with electricity, and Dr. Raman, an electrical engineer at the University of California, Los Angeles, was unaware he was in a village until he heard the voices of shadowed human figures. “It took us about five minutes to realize we were passing through a town, because it was completely dark,” Dr. Raman said. “There wasn’t a single light on.” Dr. Raman wondered whether he could use all that darkness to make something to light it up, not unlike the way that solar panels generate electricity from the sun’s heat and light. He did. In new research published on Thursday in the journal Joule, Dr. Raman demonstrated a way to harness a dark night sky to power a light bulb. His prototype device employs radiative cooling, the phenomenon that makes buildings and parks feel cooler than the surrounding air after sunset. As Dr. Raman’s device releases heat, it does so unevenly, the top side cooling more than the bottom. It then converts the difference in heat into electricity. In the paper, Dr. Raman described how the device, when connected to a voltage converter, was able to power a white LED. “The core enabling feature of this device is that it can cool down,” Dr. Raman said. Jeffrey C. Grossman, a materials scientist at the Massachusetts Institute of Technology who studies passive cooling and solar technology, said the work was “quite exciting” and showed promise for the development of low-power applications at night. “They have suggested reasonable paths for increasing the performance of their device,” Dr. Grossman said. “But there is definitely a long way to go if they want to use it as an alternative to adding battery storage for solar cells.” Everything emits heat, according to the laws of thermodynamics. At night, when one side of Earth turns away from the sun, its buildings, streets and jacket-less people cool off. If no clouds are present to trap warmth, objects on the Earth can lose so much heat that they reach a lower temperature than the air surrounding them. This is why blades of grass may be glazed in frost on clear fall mornings, even when the air temperature is above freezing. The cloudless atmosphere becomes a porthole to the void, through which warmth flows like air through a porch screen. Dr. Raman’s device produces 25 milliwatts of power, about three orders of magnitude below what a typical solar panel generates. Read more.... https://www.nytimes.com/2019/09/12/science/solar-energy-power-electricity.html

What sounds more innovative than ‘solar paint’? A paint that can generate electricity, but still works as normal paint? The ability to turn not only a roof, but an entire building into a solar-generating surface? If that doesn't scream innovation, then I don't know what does. So far, the lifeblood of the solar industry has been traditional photovoltaic solar panels. Solar panels are a well-proven technology that save homeowners a ton of money. However, the hassle and expense of rooftop panel installations often deter people from switching to solar energy. Now imagine a world where we could simply paint our roofs and walls with a type of paint that can generate electricity. I am imagining this world - and it looks very promising. So, what is solar paint? The most important thing to know is that it isn’t a single product; currently there are three different technologies that are referred to as 'solar paint'. The 3 types of solar paint The idea of using a paint-like substance to generate electricity has been discussed within the scientific community for many years. Only recently have promising, real-world applications emerged. There are three separate innovations that are classified as solar paints. Here we explore what they are and what they might mean for the future of solar energy. #1 Solar paint Hydrogen A team of researchers from the Royal Melbourne Institute of Technology (RMIT) have developed solar paint that generates energy from water vapor. Put simply, the paint works by absorbing moisture from the air and using solar energy to break the water molecules into hydrogen and oxygen. The hydrogen can then be used to produce clean energy. This is how the paint actually works: it contains a newly developed substance, synthetic molybdenum-sulphide. Absorbing moisture from the air, it works similarly to silica gel, which you’ve undoubtedly seen packaged with consumer products in order to keep them dry. This solar paint also contains titanium oxide, a substance already present in conventional paint. The titanium oxide helps the paint use solar energy to break down the absorbed moisture into hydrogen and oxygen particles. The hydrogen can then be used to produce clean energy. #2 Quantum dot solar cells, aka photovoltaic paint Quantum dots, also known as photovoltaic paint, were developed at the University of Toronto. They are nanoscale semiconductors that can capture light and turn it into an electric current. ‘Colloidal quantum dot photovoltaics’ - to use the full technical term - are not only cheaper to manufacture, but are also significantly more efficient than traditional solar cells. According to research paper author Susanna Thon, “There are two advantages to colloidal quantum dots. First, they’re much cheaper, so they reduce the cost of electricity generation measured in cost per watt of power. But the main advantage is that by simply changing the size of the quantum dot, you can change its light-absorption spectrum.”  These dots could end up being up to 11% more efficient than traditional solar panels. At some point in the future, we might even be able to paint these quantum dots on our roofs and other surfaces in order to transform sunlight into electricity. #3: Perovskite solar paint Known alternatively as spray-on solar cells, what makes this type of solar paint possible is Perovskites. Named after Russian mineralogist Lev Perovski, Perovskite materials are derived from a calcium titanium oxide mineral. Perovskite structure was first discovered in 1839, but it was only 10 years ago that a research team in Japan debuted the first-ever application of Perovskite for the production of solar cells. There are many properties that make Perovskite solar cells special, but the most revolutionary is the fact that they can take liquid form, making them the perfect candidate for solar paint. In fact, researchers have developed a way to spray liquid perovskite cells on surfaces, known as spray-on solar cells. The first-ever spray-on solar cell was developed at the University of Sheffield in 2014. A Perovskite-based mixture was sprayed onto a surface to form a sun-harnessing layer. Out of all the new inventions that could potentially revolutionize the solar industry, Perovskite cells are possibly the most promising. Read more... https://www.solar-estimate.org/news/solar-paint-hydrogen-quantum-dot-perovskite-solar-cells

Bridge to India report says the share of imported modules is still 90%, while domestic manufacturing is stagnating as developers wait for two-year duty period to end. BENGALURU: One year after India imposed an additional import duty on solar cells and modules to stimulate local production and reduce dependence on imports, no new domestic manufacturing unit has been set up, according to a renewable energy consultancy firm. India imposed a safeguard duty in July 2018 for two years. The duty was pegged at 25% for the first year, 20% for the next six months, and 15% for the last six-month period. Before it was imposed, around 90% of solar panels and modules used in local solar projects were imported, mostly from China and Malaysia, as they were cheaper than locally manufactured ones. The imposition of safeguard duty has not changed the situation. “Share of imported modules in utility scale solar still hovers around the 90% mark, consistent with the preceding years,” said Bridge to India in a recent weekly report on the solar industry. “Share of imported modules in utility scale solar still hovers around the 90% mark, consistent with the preceding years,” said Bridge to India in a recent weekly report on the solar industry. The report noted that local manufacturing remained in dire straits. “Most of the cell manufacturers have indeed shut down and module manufacturers are operating at low capacity utilisation and/or betting on exports.” As electricity distribution companies insist on driving down solar power tariffs and, at times, cancelling solar auctions if the discovered tariff is too high, developers appear to be waiting for the duty’s two-year limit to pass rather than pay more for local solar cells and modules. Existing units also claim they are not getting better prices. “We are not selling our modules at a better rate as a result of safeguard duty imposition,” said Amit Gupta, director of legal and corporate affairs at Vikram Solar, a large solar module manufacturer. “After one year, the situation is even worse than before because the new projects which are being allotted now have a completion period of 15 months, which means bids are taking place without taking the duty into consideration.” Six months ago, ET reported that no new investments had been made. “The implementation period of two years is too short to attract new manufacturing investments,” Bridge  .. Read more at: //economictimes.indiatimes.com/articleshow/70634317.cms?utm_source=contentofinterest&utm_medium=text&utm_campaign=cppst