Solar Power Station in Space

The UK government is reportedly considering a £16 billion proposal to build a solar power station in space. Space-based solar power is one of the technologies to feature in the government’s Net Zero Innovation Portfolio. It has been identified as a potential solution, alongside others, to enable the UK to achieve net zero by 2050. But how would a  in space work? What are the advantages and drawbacks to this technology?

Space-based solar power involves collecting solar energy in space and transferring it to Earth. While the idea itself is not new, recent technological advances have made this prospect more achievable.

The space-based  involves a solar power satellite—an enormous spacecraft equipped with . These panels generate electricity, which is then wirelessly transmitted to Earth through high-frequency radio waves. A ground antenna, called a rectenna, is used to convert the radio waves into electricity, which is then delivered to the .

A space-based solar power station in orbit is illuminated by the Sun 24 hours a day and could therefore generate electricity continuously. This represents an advantage over terrestrial solar power systems (systems on Earth), which can produce electricity only during the day and depend on the weather.

With  projected to increase by nearly 50% by 2050, space-based solar power could be key to helping meet the growing demand on the world’s energy sector and tackling global temperature rise.

Source: https://phys.org/

Ultrathin, Lightweight Solar Panels

A race is on in solar engineering to create almost impossibly-thin, flexible solar panels. Engineers imagine them used in mobile applications, from self-powered wearable devices and sensors to lightweight aircraft and electric vehicles. Against that backdrop, researchers at Stanford University have achieved record efficiencies in a promising group of photovoltaic materials. Chief among the benefits of these transition metal dichalcogenides – or TMDs – is that they absorb ultrahigh levels of the sunlight that strikes their surface compared to other solar materials.

Transition metal dichalcogenide solar cells on a flexible polyimide substrate

Imagine an autonomous drone that powers itself with a solar array atop its wing that is 15 times thinner than a piece of paper,” said Koosha Nassiri Nazif, a doctoral scholar in electrical engineering at Stanford and co-lead author of a study published in the Dec. 9 edition of Nature Communications. “That is the promise of TMDs.”

The search for new materials is necessary because the reigning king of solar materials, silicon, is much too heavy, bulky and rigid for applications where flexibility, lightweight and high power are preeminent, such as wearable devices and sensors or aerospace and electric vehicles.

Silicon makes up 95 percent of the solar market today, but it’s far from perfect. We need new materials that are light, bendable and, frankly, more eco-friendly,” said Krishna Saraswat, a professor of electrical engineering and senior author of the paper. While TMDs hold great promise, research experiments to date have struggled to turn more than 2 percent of the sunlight they absorb into electricity. For silicon solar panels, that number is closing in on 30 percent. To be used widely, TMDs will have to close that gap.

The new Stanford prototype achieves 5.1 percent power conversion efficiency, but the authors project they could practically reach 27 percent efficiency upon optical and electrical optimizations. That figure would be on par with the best solar panels on the market today, silicon included.

Moreover, the prototype realized a 100-times greater power-to-weight ratio of any TMDs yet developed. That ratio is important for mobile applications, like drones, electric vehicles and the ability to charge expeditionary equipment on the move. When looking at the specific power – a measure of electrical power output per unit weight of the solar cell – the prototype produced 4.4 watts per gram, a figure competitive with other current-day thin-film solar cells, including other experimental prototypes. “We think we can increase this crucial ratio another ten times through optimization,” Saraswat said, adding that they estimate the practical limit of their TMD cells to be a remarkable 46 watts per gram.”

Source: https://news.stanford.edu/

Transparent Solar Cells To Boost Personalized Energy

Today, the imminent climate change crisis demands a shift from conventionally used fossil fuels to efficient sources of green energy. This has led to researchers looking into the concept of “personalized energy,” which would make on-site energy generation possible. For example, solar cells could possibly be integrated into windows, vehicles, cellphone screens, and other everyday products. But for this, it is important for the solar panels to be handy and transparent. To this end, scientists have recently developed “transparent photovoltaic” (TPV) devices–transparent versions of the traditional solar cell. Unlike the conventionally dark, opaque solar cells (which absorb visible light), TPVs make use of the “invisible light that falls in the ultraviolet (UV) range.

Conventional solar cells can be either “wet type” (solution based) or “dry type” (made up of metal-oxide semiconductors). Of these, dry-type solar cells have a slight edge over the wet-type ones: they are more reliable, eco-friendly, and cost-effective. Moreover, metal-oxides are well-suited to make use of the UV light. Despite all this, however, the potential of metal-oxide TPVs has not been fully explored until now. To this end, researchers from Incheon National University, Republic of Korea, came up with an innovative design for a metal-oxide-based TPV device. They inserted an ultra-thin layer of silicon (Si) between two transparent metal-oxide semiconductors with the goal of developing an efficient TPV device.

Our aim was to devise a high-power-producing transparent solar cell, by embedding an ultra-thin film of amorphous Si between zinc oxide and nickel oxide,” explains Prof Joondong Kim, who led the study.

This novel design consisting of the Si film had three major advantages. First, it allowed for the utilization of longer-wavelength light (as opposed to bare TPVs). Second, it resulted in efficient photon collection. Third, it allowed for the faster transport of charged particles to the electrodes. Moreover, the design can potentially generate electricity even under low-light situations (for instance, on cloudy or rainy days). The scientists further confirmed the power-generating ability of the device by using it to operate the DC motor of a fan.

These findings has been published in a study in Nano Energy.

Source: http://www.inu.ac.kr/

Toyota To Build A Smart City Powered By Hydrogen

 

Japanese carmaker Toyota has announced plans to create a 175-acre smart city in Japan where it will test driverless cars and artificial intelligence. The project, announced at the Consumer Electronics Show in Las Vegas, will break ground at the base of Mount Fuji in 2021. Woven City will initially be home to 2,000 people who will test technologies including robots and smart homesToyota said in a press release that only driverless and electric vehicles will be allowed on the main streets of Woven CityStreets will be split into three types of thoroughfare: roads for fast vehicles, lanes which are a mixture of personal vehicles and pedestrians, and pedestrian footpaths.

Danish architect Bjarke Ingels has been commissioned to design the new city. His business previously worked on projects including Google’s London and US headquartersToyota said the city will be powered by hydrogen fuel cells and solar panels fitted to the roofs of housesBuildings in Woven City will mostly be made of wood and assembled using “robotised production methods,” Toyota said. 

 “Building a complete city from the ground up, even on a small scale like this, is a unique opportunity to develop future technologies, including a digital operating system for the infrastructure.
“With people, buildings and vehicles all connected and communicating with each other through data and sensors, we will be able to test connected AI technology, in both the virtual and physical realms, maximising its potential,” said Akio Toyoda, Toyota’s president.

Google has also experimented with the creation of its own smart city through its Sidewalk Labs division. The company is hoping to transform a 12-acre plot in Toronto’s waterfront district into a smart city, with the first homes due to appear in 2023.

Source: https://www.telegraph.co.uk/

How To Make A Car Run Forever

Put together the best solar panels money can buy, super-efficient batteries and decades of car-making know-how and, theoretically, a vehicle might run forever. That’s the audacious motivation behind a project by Toyota Motor Corp., Sharp Corp. and New Energy and Industrial Technology Development Organization of Japan, or NEDO, to test a Prius that could revolutionize transportation.

The solar car’s advantage is that — while it can’t drive for a long range — it’s really independent of charging facilities,” said Koji Makino, a project manager at Toyota.

Even if fully electric cars overtake petroleum-powered vehicles in sales, they still need to be plugged in, which means building a network of charging stations across the globe. The sun, on the other hand, shines everywhere for free, and when that energy is paired with enough battery capacity to propel automobiles at night, solar-powered cars could leapfrog all the new-energy technologies being developed, from plug-in hybrids to hydrogen fuel-cell vehicles, in one fell swoop. But the current forecast is only partly sunny because there’s still some work left to reach that level of efficiency.

This is not a technology we are going to see widely used in the next decades,” said Takeshi Miyao, an auto analyst at consultancy Carnorama. “It’s going to take a long time.”

Not for lack of trying. Toyota and Hyundai Motor Coalready introduced commercial models with solar panels on the roof, but they were too underpowered and could barely juice the sound system. A Prius plug-in hybrid that sells for more than 3 million yen offers solar panels as an option, but they only charge the battery when parked. The maximum amount of power for driving only lasts about 6 kilometers (about 4 miles), said Mitsuhiro Yamazaki, director at the solar energy systems division of NEDO. Toyota has been testing a new solar-powered Prius since July, though it acknowledges that cars running nonstop without connecting to a hose or plug are still far away. Even so, the Toyota City-based company said the research will pay off in other ways.

Indeed, there have been some breakthroughs, mainly due to advancements by Sharp. The prototype’s solar panel converts sunlight at an efficiency level of more than 34%, compared with about 20% for current panels on the market. Because the solar cell being used by Toyota, Sharp and NEDO is only about 0.03 mm thick, it can be placed on more surfaces, including the curvy parts of the roof, hood and hatchback. The electrical system can charge the vehicle even when it’s on the move.

Source: https://www.bloomberg.com/

How To Make Solar Panels More Sustainable And Cheaper

An innovative way to pattern metals has been discovered by scientists in the Department of Chemistry at the University of Warwick in UK, which could make the next generation of  solar panels more sustainable and cheaperSilver and copper are the most widely used electrical conductors in modern electronics and solar cells. However, conventional methods of patterning these metals to make the desired pattern of conducting lines are based on selectively removing metal from a film by etching using harmful chemicals or printing from costly metal inks.

Scientists from the Department of Chemistry at the University of Warwick, have developed a way of patterning these metals that is likely to prove much more sustainable and cheaper for large scale production, because there is no metal waste or use of toxic chemicals, and the fabrication method is compatible with continuous roll-to-roll processing. Dr Ross Hatton and Dr Silvia Varagnolo have discovered that silver and copper do not condense onto extremely thin films of certain highly fluorinated organic compounds when the metal is deposited by simple thermal evaporation.

Thermal evaporation is already widely used on a large scale to make the thin metal film on the inside of crisp packets, and organofluorine compounds are already common place as the basis of non-stick cooking pans. The researchers have shown that the organofluorine layer need only be 10 billionths of a metre thick to be effective, and so only tiny amounts are needed. This unconventional approach also leaves the metal surface uncontaminated, which Hatton believes will be particularly important for the next generation sensors, which often require uncontaminated patterned films of these metals as platforms onto which sensing molecules can be attached.

To help address the challenges posed by climate change, there is a need for colour tuneable, flexible and light weight solar cells that can be produced at low cost, particularly for applications where conventional rigid silicon solar cells are unsuitable such as in electric cars and semi-transparent solar cells for buildings. Solar cells based on thin films of organic, perovskite or nano-crystal semiconductors all have potential to meet this need, although they all require a low cost, flexible transparent electrode. Hatton and his team have used their method to fabricate semi-transparent organic solar cells in which the top silver electrode is patterned with millions of tiny apertures per square centimetre, which cannot be achieved by any other scalable means directly on top of an organic electronic device.

This innovation enables us to realise the dream of truly flexible, transparent electrodes matched to needs of the emerging generation of thin film solar cells, as well as having numerous other potential applications ranging from sensors to low-emissivity glass” explains Dr Hatton from the Department of Chemistry at the University of Warwick.

The work is published in the journal Materials Horizons.

Source: https://warwick.ac.uk/

How To Collect And Harvest More Solar Energy

In an article published in the SPIE Journal of Nanophotonics (JNP), researchers from a collaboration of three labs in Mexico demonstrate aninnovative nanodevice for harvesting solar energy. The paper,Thermoelectric efficiency optimization of nanoantennas for solar energy harvesting,reports that evolutive dipole nanoantennas (EDNs) generate a thermoelectric voltage three times larger than the classic dipole nanoantenna (CDN).

Capturing visible and infrared radiation using nanodevices is anessential aspect of collecting solar energy: solar cells and solar panels are common devices that utilize nanoantennas, which link electromagnetic radiation to specific optical fields. The EDNcan be useful in many areas where high thermoelectric efficiency is needed from energy harvesting to applications across the aerospace industry.

“The paper reports on a novel design and demonstration of a nanoantenna for efficient thermoelectric energy harvesting,” says Professor Ibrahim Abdulhalim, JNP Associate Editor, SPIE Fellow and a professor in the Electrooptics and Photonics Engineering Department at Ben-Gurion Universityof the Negev. “They demonstrated thermoelectric voltage three times larger than a classical antenna. This type of antenna can be useful in many fields from harvesting of energy from waste heat, in sensing and solar thermal energy harvesting.”

The nanoantennas are bimetallic, using nickel and platinum, and were fabricated using e-beam lithography. The nanoantenna design wasoptimized using simulations to determine the distance between the elements. In comparing their thermoelectric voltage to the classic dipole nanoantenna, the EDNs were 1.3 times more efficient. The characterization was done using a solar simulator analyzing the I-V curves. The results indicate that EDN arrays would be good candidates for the harvesting of waste heat energy.

Source: http://spie.org/

Optical Circuits Up To 100 Times Faster Than Electronic Circuits

Optical circuits are set to revolutionize the performance of many devices. Not only are they 10 to 100 times faster than electronic circuits, but they also consume a lot less power. Within these circuits, light waves are controlled by extremely thin surfaces called metasurfaces that concentrate the waves and guide them as needed. The metasurfaces contain regularly spaced nanoparticles that can modulate electromagnetic waves over sub-micrometer wavelength scales.

Metasurfaces could enable engineers to make flexible and ultra-thin optics for a host of applications, ranging from flexible tablet computers to solar panels with enhanced light-absorption characteristics. They could also be used to create flexible sensors for direct placement on a patient’s skin, for example, in order to measure things like pulse and blood pressure or to detect specific chemical compounds.

The catch is that creating metasurfaces using the conventional method, lithography, is a fastidious process that takes several hours and must be done in a cleanroom. But EPFL engineers from the Laboratory of Photonic Materials and Fiber Devices (FIMAP) in Switzerland have now developed a simple method for making them in just a few minutes at low temperatures—or sometimes even at room temperature—with no need for a cleanroom. The EPFL‘s School of Engineering method produces dielectric glass metasurfaces that can be either rigid or flexible. The results of their research appear in Nature Nanotechnology.

The new method employs a natural process already used in : dewetting. This occurs when a thin film of material is deposited on a substrate and then heated. The heat causes the film to retract and break apart into tiny nanoparticles.

Dewetting is seen as a problem in manufacturing—but we decided to use it to our advantage,” says Fabien Sorin, the study’s lead author and the head of FIMAP.

With their method, the engineers were able to create dielectric glass metasurfaces, rather than metallic metasurfaces, for the first time. The advantage of dielectric metasurfaces is that they absorb very little light and have a high refractive index, making it possible to modulate the light that propagates through them.

Source: https://phys.org/

Invisible Plastic For Super Efficient Solar Panels

Antireflection (AR) coatings on plastics have a multitude of practical applications, including glare reduction on eyeglasses, computer monitors and the display on your smart-phone when outdoors. Now, researchers at Penn State have developed an AR coating that improves on existing coatings to the extent that it can make transparent plastics, such as Plexiglas, virtually invisible.

Plastic dome coated with a new antireflection coating (right), and uncoated dome (left)

This discovery came about as we were trying to make higher-efficiency solar panels,” said Chris Giebink, associate professor of electrical engineering, Penn State. “Our approach involved concentrating light onto small, high-efficiency solar cells using plastic lenses, and we needed to minimize their reflection loss.”

They needed an antireflection coating that worked well over the entire solar spectrum and at multiple angles as the sun crossed the sky. They also needed a coating that could stand up to weather over long periods of time outdoors. “We would have liked to find an off-the-shelf solution, but there wasn’t one that met our performance requirements,” he said. “So, we started looking for our own solution.”

That was a tall order. Although it is comparatively easy to make a coating that will eliminate reflection at a particular wavelength or in a particular direction, one that could fit all their criteria did not exist. For instance, eyeglass AR coatings are targeted to the narrow visible portion of the spectrum. But the solar spectrum is about five times as broad as the visible spectrum, so such a coating would not perform well for a concentrating solar cell system.

Reflections occur when light travels from one medium, such as air, into a second medium, in this case plastic. If the difference in their refractive index, which specifies how fast light travels in a particular material, is large — air has a refractive index of 1 and plastic 1.5 — then there will be a lot of reflection. The lowest index for a natural coating material such as magnesium fluoride or Teflon is about 1.3. The refractive index can be graded — slowly varied — between 1.3 and 1.5 by blending different materials, but the gap between 1.3 and 1 remains.

In a paper recently posted online ahead of print in the journal Nano Letters, Giebink and coauthors describe a new process to bridge the gap between Teflon and air. They used a sacrificial molecule to create nanoscale pores in evaporated Teflon, thereby creating a graded index Teflon-air film that fools light into seeing a smooth transition from 1 to 1.5, eliminating essentially all reflections.

The interesting thing about Teflon, which is a polymer, is when you heat it up in a crucible, the large polymer chains cleave into smaller fragments that are small enough to volatize and send up a vapor flux. When these land on a substrate they can repolymerize and form Teflon,” Giebink explained.

 

We’ve been interacting with a number of companies that are looking for improved antireflection coatings for plastic, and some of the applications have been surprising,” he said. “They range from eliminating glare from the plastic domes that protect security cameras to eliminating stray reflections inside virtual/augmented -reality headsets.”

Source: https://news.psu.edu/

Perovskite Solar Panels Go To The Market

Across the globe, a clutch of companies from Oxford, England to Redwood City, Calif. are working to commercialize a new solar technology that could further boost the adoption of renewable energy generation. Earlier this year, Oxford PV, a startup working in tandem with Oxford Universityreceived $3 million from the U.K. government to develop the technology, which uses a new kind of material to make solar cells. Two days ago, in the U.S., a company called Swift Solar raised $7 million to bring the same technology to marketaccording to a filing with the Securities and Exchange Commission.

Called a perovskite cell, the new photovoltaic tech uses hybrid organic-inorganic lead or tin halide-based material as the light-harvesting active layer. It’s the first new technology to come along in years to offer the promise of better efficiency in the conversion of light to electric power at a lower cost than existing technologies.

Perovskite has let us truly rethink what we can do with the silicon-based solar panels we see on roofs today,” said Sam Stranks, the lead scientific advisor and one of the co-founders of Swift Solar, in a Ted Talk. “Another aspect that really excites me: how cheaply these can be made. These thin crystalline films are made by mixing two inexpensive readily abundant salts to make an ink that can be deposited in many different ways… This means that perovskite solar panels could cost less than half of their silicon counterparts.”

First incorporated into solar cells by Japanese researchers in 2009, the perovskite solar cells suffered from low efficiencies and lacked stability to be broadly used in manufacturing. But over the past nine years researchers have steadily improved both the stability of the compounds used and the efficiency that these solar cells generate.

Oxford PV, in the U.K., is now working on developing solar cells that could achieve conversion efficiencies of 37 percentmuch higher than existing polycrystalline photovoltaic or thin-film solar cells.

New chemistries for solar cell manufacturing have been touted in the past, but cost has been an obstacle to commercial rollout, given how cheaply solar panels became thanks in part to a massive push from the Chinese government to increase manufacturing capacity.

Source: https://techcrunch.com/