Better photovoltaic efficiency grows from enormous solar crystals: MH Perovskites 


In-depth analysis of the mechanisms that generate floating crystals from hot liquids could lead to large-scale, printable solar cells


New evidence of surface-initiated crystallization may improve the efficiency of printable photovoltaic materials.

In the race to replace silicon in low-cost solar cells, semiconductors known as metal halide perovskites are favored because they can be solution-processed into thin films with excellent photovoltaic efficiency. 

A collaboration between King Abdullah University of Science and Technology (KAUST) and Oxford University researchers has now uncovered a strategy that grows perovskites into centimeter-scale, highly pure crystals thanks to the effect of surface tension (ACS Energy Letters, “The role of surface tension in the crystallization of metal halide perovskites”).

In their natural state, perovskites have difficultly moving solar-generated electricity because they crystallize with randomly oriented grains. 

Osman Bakr from KAUST’s Solar Center and coworkers are working on ways to dramatically speed up the flow of these charge carriers using inverse temperature crystallization (ITC). This technique uses special organic liquids and thermal energy to force perovskites to solidify into structures resembling single crystals—the optimal arrangements for device purposes.

While ITC produces high-quality perovskites far faster than conventional chemical methods, the curious mechanisms that initiate crystallization in hot organic liquids are poorly understood. Ayan Zhumekenov, a PhD student in Bakr’s group, recalls spotting a key piece of evidence during efforts to adapt ITC toward large-scale manufacturing. “At some point, we realized that when crystals appeared, it was usually at the solution’s surface,” he says. “And this was particularly true when we used concentrated solutions.”

The KAUST team partnered with Oxford theoreticians to identify how interfaces influence perovskite growth in ITC. They propose that metal halides and solvent molecules initially cling together in tight complexes that begin to stretch and weaken at higher temperatures. With sufficient thermal energy, the complex breaks and perovskites begin to crystallize.

But interestingly, the researchers found that complexes located at the solution surface can experience additional forces due to surface tension—the strong cohesive forces that enable certain insects to stride over lakes and ponds. The extra pull provided by the surface makes it much easier to separate the solvent-perovskite complexes and nucleate crystals that float on top of the liquid.

Exploiting this knowledge helped the team produce centimeter-sized, ultrathin single crystals and prototype a photodetector with characteristics comparable to state-of-the-art devices. Although the single crystals are currently fragile and difficult to handle due to their microscale thicknesses, Zhumekenov explains that this method could help direct the perovskite growth onto specific substrates.

“Taking into account the roles of interfaces and surface tension could have a fundamental impact,” he says, “we can get large-area growth, and it’s not limited to specific metal cations—you could have a library of materials with perovskite structures.”

Source: King Abdullah University of Science and Technology

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NREL, Swiss Scientists Power Past Solar Efficiency Records


NREL scientist Adele Tamboli, co-author of a recent article on silicon-based multijunction solar cells, stands in front of an array of solar panels. Credit: Dennis Schroeder

August 25, 2017




Second collaborative effort proves silicon-based multijunction cells that reach nearly 36% efficiency

Collaboration between researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), the Swiss Center for Electronics and Microtechnology (CSEM), and the École Polytechnique Fédérale de Lausanne (EPFL) shows the high potential of silicon-based multijunction solar cells.

The research groups created tandem solar cells with record efficiencies of converting sunlight into electricity under 1-sun illumination. The resulting paper, “Raising the One-Sun Conversion Efficiency of III–V/Si Solar Cells to 32.8% for Two Junctions and 35.9% for Three Junctions,” appears in the new issue of Nature Energy. Solar cells made solely from materials in Groups III and V of the Periodic Table have shown high efficiencies, but are more expensive.

Stephanie Essig, a former NREL post-doctoral researcher now working at EPFL in Switzerland, is lead author of the newly published research that details the steps taken to improve the efficiency of the multijunction cell. While at NREL, Essig co-authored “Realization of GaInP/Si Dual-Junction Solar Cells with 29.8% 1-Sun Efficiency,” which was published in the IEEE Journal of Photovoltaics a year ago.

In addition to Essig, authors of the new research paper are Timothy Remo, John F. Geisz, Myles A. Steiner, David L. Young, Kelsey Horowitz, Michael Woodhouse, and Adele Tamboli, all with NREL; and Christophe Allebe, Loris Barraud, Antoine Descoeudres, Matthieu Despeisse, and Christophe Ballif, all from CSEM.

“This achievement is significant because it shows, for the first time, that silicon-based tandem cells can provide efficiencies competing with more expensive multijunction cells consisting entirely of III-V materials,” Tamboli said. “It opens the door to develop entirely new multijunction solar cell materials and architectures.”

In testing silicon-based multijunction solar cells, the researchers found that the highest dual-junction efficiency (32.8%) came from a tandem cell that stacked a layer of gallium arsenide (GaAs) developed by NREL atop a film of crystalline silicon developed by CSEM. An efficiency of 32.5% was achieved using a gallium indium phosphide (GaInP) top cell, which is a similar structure to the previous record efficiency of 29.8% announced in January 2016. 

A third cell, consisting of a GaInP/GaAs tandem cell stacked on a silicon bottom cell, reached a triple-junction efficiency of 35.9%—just 2% below the overall triple-junction record.

The existing photovoltaics market is dominated by modules made of single-junction silicon solar cells, with efficiencies between 17% and 24%. 

The researchers noted in the report that making the transition from a silicon single-junction cell to a silicon-based dual-junction solar cell will enable manufacturers to push efficiencies past 30% while still benefiting from their expertise in making silicon solar cells.

The obstacle to the adoption of these multijunction silicon-based solar cells, at least in the near term, is the cost. Assuming 30% efficiency, the researchers estimated the GaInP-based cell would cost $4.85 per watt and the GaAs-based cell would cost $7.15 per watt. 

But as manufacturing ramps up and the efficiencies of these types of cells climbs to 35%, the researchers predict the cost per watt could fall to 66 cents for a GaInP-based cell and to 85 cents for the GaAs-based cell. 

The scientists noted that such a precipitous price drop is not unprecedented; for instance, the cost of Chinese-made photovoltaic modules fell from $4.50 per watt in 2006 to $1 per watt in 2011.

The cost of a solar module in the United States accounts for 20% to 40% of the price of a photovoltaic system. Increasing cell efficiency to 35%, the researchers estimated, could reduce the system cost by as much as 45 cents per watt for commercial installations. 

However, if the costs of a III-V cell cannot be reduced to the levels of the researchers’ long-term scenario, then the use of cheaper, high-efficiency materials for the top cell will be needed to make them cost-competitive in general power markets.

The funding for the research came from the Energy Department’s SunShot Initiative—which aims to make solar energy a low-cost electricity source for all Americans through research and development efforts in collaboration with public and private partners—and from the Swiss Confederation and the Nano-Tera.ch initiative.


NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

Google’s Parent Company Will Soon Compete With Tesla for Energy Storage Solutions: Project Malta at ‘Alphabet X’



Maximizing Renewables



Given the dramatic impact human-made carbon emissions are having on our planet, cleaner energy sources have become increasingly popular alternatives to their fossil fuel counterparts. Currently, solar and wind are the most widely used renewable energy sources, but both are dependent on certain conditions.

The former can capture energy only during daylight hours, while the latter is more unpredictable, but often peaks at night.
As such, there’s a mismatch between when solar and wind energy are available and when energy is needed.

The world needs a way to maximize renewable energy usage, and that’s what Malta, a project currently brewing at Alphabet X, the “moonshot” factory by Google’s parent company, is hoping to provide.

The goal of Alphabet X is to develop technologies that could “someday make the world a radically better place.” The organization follows a three-part blueprint for their moonshot projects that starts with identifying a “huge problem” and then providing a “radical solution” that could be implemented using a “breakthrough technology.”

For Malta, the idea was to find a way to maximize the use of energy generated from renewables. Their radical solution is bridging the gap between renewable energy and grid-scale energy storage technologies using a breakthrough technology developed by Stanford physicist and Nobel laureate Robert Laughlin.

According to the project’s website, this technology is still theoretical and involves storing electricity as either heat within molten salt or cold within a liquid similar to the antifreeze used in cars. They claim this energy could remain stored for up to weeks at a time.

Storing Energy


Essentially, Malta is hoping to develop clean and cost-effective energy storage devices, which is similar to the concept behind Tesla’s Powerpack. The difference between the Malta project’s tech and the Powerpack is mostly what’s inside. While Tesla’s energy storage device uses 16 individual battery pods, Malta’s relies on molten salt or the antifreeze-like liquid.

Additionally, the tanks used to store the salt used by Malta’s system could potentially last for up to 40 years, which the project claims is three or more times longer than other current storage options. That extended lifespan would make Malta a cheaper alternative to other renewable energy storage devices.
alphabet x malta renewable energy.

Image credit: Malta/X

After two years of developing and designing their system, the Malta team is now gearing up to test the commercial viability of their technology. “The next step is to build a megawatt-scale prototype plant which would be large enough to prove the technology at commercial scale,” according to their website.
We now have multiple ways to generate energy from renewables, but if we ever hope to fully transition away from traditional energy solutions, we need better storage devices.

Though they are clearly better for the environment, renewables aren’t as consistent as fossil fuels, and that unreliability is a huge barrier to widespread adoption.

Storage systems like those proposed by Malta could collect the energy generated by renewables and ensure it is available to power grids whenever needed, putting us one step closer to a future completely free of fossil fuels.

Watch Our Video on a New Energy Storage Company for Nano-Enabled Batteries and Super Capacitors

Update: Super Capacitor Assisted Silicon Nanowire Batteries for EV and Small Form Factor Markets. A New Class of Battery /Energy Storage Materials is being developed to support the High Energy – High Capacity – High Performance High Cycle Battery Markets.

“Ultrathin Asymmetric Porous-Nickel Graphene-Based
Supercapacitor with High Energy Density and Silicon Nanowire,”

A New Generation Battery that is:

 Energy Dense
 High Specific Power
 Simple Manfacturing Process
 Low Manufacturing Cost
 Rapid Charge/ Re-Charge
 Flexible Form Factor
 Long Warranty Life
 Non-Toxic
 Highly Scalable

Key Markets & Commercial Applications

 EV, (18650 & 21700); Drone and Marine Batteries
 Wearable Electronics and The Internet of Things
 Estimated $240 Billion Market by 2025



Harnessing the Functionality and ‘Power’ of Perovskites for Better Solar and LED’s



Originally a mineral, the perovskite used in today’s technology is quite different from the rock found in the Earth mantle. 

A “perovskite structure” uses a different combination of atoms but keep the general 3-dimensional structure originally observed in the mineral, which possesses superb optoelectronic properties such as strong light absorption and facilitated charge transport. These advantages qualify the perovskite structure as particularly suited for the design of electronic devices, from solar cells to lights.

The accelerating progress in perovskite technology over the past few years suggest new perovskite-based devices will soon outperform current technology in the energy sector. 

The Energy Materials and Surface Sciences Unit at OIST led by Prof. Yabing Qi is at the forefront of this development, with now two new scientific publications focusing on the improvement of perovskite solar cells and a cheaper and smarter way to produce emerging perovskite-based LED lights.

An extra layer in a solar cell “sandwich”

Perovskite-based solar cells is a rising technology forecast to replace the classic photovoltaic cells currently dominating the industry. 




In just seven years of development, the efficiency of perovskite solar cells increased to almost rival – and is expected to soon overtake – commercial photovoltaic cells, but the perovskite structure still plagued by a short lifespan due to stability issues. 


OIST
scientists have made constant baby steps in improving the cells stability, identifying the degradations factors and providing solutions towards better solar cell architecture.

The new finding, reported in the Journal of Physical Chemistry B (“Engineering Interface Structure to Improve Efficiency and Stability of Organometal Halide Perovskite Solar Cells”), suggests interactions between components of the solar cell itself are responsible for the rapid degradation of the device. 

More precisely, the titanium oxide layer extracting electrons made available through solar energy – effectively creating an electric current – causes unwanted deterioration of the neighboring perovskite layer. 

Imagine the solar cell as a multi-layered club sandwich: if not properly assembled, fresh and juicy vegetables in contact with the bread slices will make the bread very soggy in a matter of hours. 

But if you add a layer of ham or turkey between the vegetables and the bread, then your sandwich stays crisp all day in the lunchroom refrigerator.


A perovskite-based layer includes many layers, including for example the electrodes on both sides, and the perovskite in the middle. The addition of a polystyrene layer in-between prevents the titanium oxide layer to deteriorate the perovskite, but does not affect the overall power conversion efficiency. (© American Chemical Society)

This is exactly what the OIST researchers achieved: they inserted in the solar cell an additional layer made from a polymer to prevent direct contact between the titanium oxide and the perovskite layers. 
This polymer layer is insulating but very thin, which means it lets the electron current tunnel through yet does not diminish the overall efficiency of the solar cell, while efficiently protecting the perovskite structure.

“We added a very thin sheet, only a few nanometers wide, of polystyrene between the perovskite layer and the titanium oxide layer,” explained Dr. Longbin Qiu. 

“Electrons can still tunnel cross this new layer and it does not affect the light absorption of the cell. This way, we were able to extend the lifetime of the cell four-fold without loss in energy conversion efficiency”.

The lifespan of the new perovskite device was extended to over 250 hours – still not enough to compete with commercial photovoltaic cells regarding stability, but an important step forward toward fully functional perovskite solar cells.

Manufacturing LED lights from gasses

The bipolar electronic properties of the perovskite structure not only confer them the ability to generate electricity from solar energy but also can convert electricity into vivid light. Light-Emitting Diode – LED – technology, omnipresent in our daily life from laptop and smartphone screens to car lights and ceiling tubes, currently relies on semi-conductors that are difficult and expensive to manufacture. Perovskite LEDs are envisaged to become the new industry standard in the near future due to the lower cost and their efficiency to convert power into light. Moreover, by changing the atomic composition in the perovskite structure, perovskite LED can be easily tuned to emit specific colors.

The manufacturing of these perovskite LEDs is currently based on dipping or covering the targeted surface with liquid chemicals, a process which is difficult to setup, limited to small areas and with low consistency between samples. To overcome this issue, OIST researchers reported in the Journal of Physical Chemistry Letters (“Methylammonium Lead Bromide Perovskite Light-Emitting Diodes by Chemical Vapor Deposition”) the first perovskite LED assembled with gasses, a process called chemical vapor deposition or CVD.

“Chemical vapor deposition is already compatible with the industry, so in principle it would be easy to use this technology to produce LEDs,” commented Prof. Yabing Qi. “The second advantage in using CVD is a much lower variation from batch to batch compared to liquid-based techniques. Finally, the last point is scalability: CVD can achieve a uniform surface over very large areas”.

Like the solar cell, the perovskite LED also comprises many layers working in synergy. First, an indium tin oxide glass sheet and a polymer layer allow electrons into the LED. The chemicals required for the perovskite layer – lead bromide and methylammonium bromide – are then successively bound to the sample using CVD, in which the sample is exposed to gasses in order to convert to perovskite instead of typically solution-coating processes with liquid. In this process, the perovskite layer is composed of nanometer-small grains, whose sizes play a critical role in the efficiency of the device. Finally, the last step involves the deposition of two additional layers and a gold electrode, forming a complete LED structure. The LED can even form specific patterns using lithography during the manufacturing process.

Perovskite LED fabrication


Top: the perovskite LED sits in a furnace, where the Methylammonium Bromide (MABr) in gaseous form will be introduced into the system and deposit on the LED surface. Bottom left: a glass-based LED, glowing green when electricity is applied. Bottom right: size and shapes of the perovskite grains on the surface of the LED. (© American Chemical Society)

“With large grains, the surface of the LED is rough and less efficient in emitting light. The smaller the grain size, the higher the efficiency and the brighter the light,” explained Dr. Lingqiang Meng. “By changing the assembly temperature, we can now control the growth process and the size of the grains for the best efficiency”.

Controlling the grain size is not the only challenge for this first-of-its-kind assembling technique of LED lights.

“Perovskite is great, but the choice in the adjacent layers is really important too,” added Dr. Luis K. Ono. “To achieve high electricity-to-light conversion rates, every layer should be working in harmony with the others.”

The result is a flexible, thick film-like LED with a customizable pattern. The luminance, or brightness, currently reaches 560 cd/m2, while a typical computer screen emits 100 to 1000 cd/m2 and a ceiling fluorescent tube around 12,000 cd/m2.

Perovskite-LED


This large perovskite-LED was produced using chemical vapor deposition and connect to a 5V current, illuminating through an OIST pattern etched on the surface. (© American Chemical Society)

“Our next step is to improve the luminance a thousand-fold or more,” concluded Dr. Meng. “In addition, we have achieved a CVD-based LED emitting green light but we are now trying to repeat the process with different combinations of perovskite to obtain a vivid blue or red light”.

Source: By Wilko Duprez, Okinawa Institute of Technology

MIT team creates flexible, transparent solar cells with graphene electrodes



Researchers at the Massachusetts Institute of Technology (MIT) have developed flexible and transparent graphene-based solar cells, which can be mounted on various surfaces ranging from glass to plastic to paper and tape. The graphene devices exhibited optical transmittance of 61% across the whole visible regime and up to 69% at 550 nanometers. The power conversion efficiency of the graphene solar cells ranged from 2.8% to 4.1%.

MIT team’s flexible, transparent solar cell with graphene electrodes image

A common challenge in making transparent solar cells with graphene is getting the two electrodes to stick together and to the substrate, as well as ensuring that electrons only flow out of one of the graphene layers. Using heat or glue can damage the material and reduce its conductivity, so the MIT team developed a new technique to tackle this issue. Rather than applying an adhesive between the graphene and the substrate, they sprayed a thin layer of ethylene-vinyl acetate (EVA) over the top, sticking them together like tape instead of glue.

The MIT team compared their graphene electrode solar cells against others made from standard materials like aluminum and indium tin oxide (ITO), built on rigid glass and flexible substrates. The power conversion efficiency (PCE) of the graphene solar cells was far lower than regular solar panels, but much better than previous transparent solar cells. This is a positive advancement, obviously.
Samples of solar cells using electrodes of different materials for testing image


Efficiency is often a trade-off from the graphene solar cells being flexible and transparent. In that regard the cells performed well, transmitting almost 70% of the light in the middle of the human range of vision. Hopefully the numbers will continue to improve. According to the researchers’ calculations, the efficiency of these graphene solar cells could be pushed as high as 10% without losing any transparency, and doing just that is the next step in the project. The researchers are also working on ways to scale up the system to cover windows and walls.
Source:  newatlas

New Nanomaterial helps Store Solar Energy (as Hydrogen) Efficiently and Inexpensively


Perovskite New Solar Material pic3

Efficient storage technologies are necessary if solar and wind energy is to help satisfy increased energy demands.

One important approach is storage in the form of hydrogen extracted from water using solar or wind energy. This process takes place in a so-called electrolyser. Thanks to a new material developed by researchers at the Paul Scherrer Institute PSI and Empa, these devices are likely to become cheaper and more efficient in the future. The material in question works as a catalyst accelerating the splitting of water molecules: the first step in the production of hydrogen. Researchers also showed that this new material can be reliably produced in large quantities and demonstrated its performance capability within a technical electrolysis cell – the main component of an electrolyser. The results of their research have been published in the current edition of the scientific journal Nature Materials.

Perovskite New Material Researchers pic1

The scientists Emiliana Fabbri and Thomas Schmidt in a lab at PSI where they conducted experiments to study the performance of the newly developed catalyst for electrolysers. (Photo: Paul Scherrer Institute/Mahir Dzambegovic.)

Since solar and wind energy is not always available, it will only contribute significantly to meeting energy demands once a reliable storage method has been developed. One promising approach to this problem is storage in the form of hydrogen. This process requires an electrolyser, which uses electricity generated by solar or wind energy to split water into hydrogen and oxygen. Hydrogen serves as an energy carrier. It can be stored in tanks and later transformed back into electrical energy with the help of fuel cells. This process can be carried out locally, in places where energy is needed such as domestic residences or fuel cell vehicles, enabling mobility without the emission of CO2.

Inexpensive and efficient

Researchers at the Paul Scherrer Institute PSI have now developed a new material that functions as a catalyst within an electrolyser and thus accelerates the splitting of water molecules: the first step in the production of hydrogen. “There are currently two types of electrolysers on the market: one is efficient but expensive because its catalysts contain noble metals such as iridium. The others are cheaper but less efficient”, explains Emiliana Fabbri, researcher at the Paul Scherrer Institute. “We wanted to develop an efficient but less expensive catalyst that worked without using noble metals.”

Exploring this procedure, researchers were able to use a material that had already been developed: an intricate compound of the elements barium, strontium, cobalt, iron and oxygen – a so-called perovskite. But they were the first to develop a technique enabling its production in the form of miniscule nanoparticles. This is the form required for it to function efficiently since a catalyst requires a large surface area on which many reactive centres are able to accelerate the electrochemical reaction. Once individual catalyst particles have been made as small as possible, their respective surfaces combine to create a much larger overall surface area.

Researchers used a so-called flame-spray device to produce this nanopowder: a device operated by Empa that sends the material’s constituent parts through a flame where they merge and quickly solidify into small particles once they leave the flame. “We had to find a way of operating the device that reliably guaranteed the solidifying of the atoms of the various elements in the right structure,” emphasizes Fabbri. “We were also able to vary the oxygen content where necessary, enabling the production of different material variants.”

Successful Field Tests

Researchers were able to show that these procedures work not only in the laboratory but also in practice. The production method delivers large quantities of the catalyst powder and can be made readily available for industrial use. “We were eager to test the catalyst in field conditions. Of course, we have test facilities at PSI capable of examining the material but its value ultimately depends upon its suitability for industrial electrolysis cells that are used in commercial electrolysers,” says Fabbri. Researchers tested the catalyst in cooperation with an electrolyser manufacturer in the US and were able to show that the device worked more reliably with the new PSI-produced perovskite than with a conventional iridium-oxide catalyst.

Examining in Milliseconds

Researchers were also able to carry out precise experiments that provided accurate information on what happens in the new material when it is active. This involved studying the material with X-rays at PSI’s Swiss Light Source SLS. This facility provides researchers with a unique measuring station capable of analysing the condition of a material over successive timespans of just 200 milliseconds. “This enables us to monitor changes in the catalyst during the catalytic reaction: we can observe changes in the electronic properties or the arrangement of atoms,” says Fabbri. At other facilities, each individual measurement takes about 15 minutes, providing only an averaged image at best.” These measurements also showed how the structures of particle surfaces change when active – parts of the material become amorphous which means that the atoms in individual areas are no longer uniformly arranged. Unexpectedly, this makes the material a better catalyst.

Use in the ESI Platform

Working on the development of technological solutions for Switzerland’s energy future is an essential aspect of the research carried out at PSI. To this end, PSI makes its ESI (Energy System Integration) experimental platform available to research and industry, enabling promising solutions to be tested in a variety of complex contexts. The new catalyst provides an important base for the development of a new generation of water electrolysers.

Grid Batteries Are Poised to Become Cheaper Than Natural-Gas Plants in Minnesota



A 60-acre solar farm in Camp Ripley, a National Guard base in Minnesota.

A new report suggests the economics of large-scale batteries are reaching an important inflection point.

When it comes to renewable energy, Minnesota isn’t typically a headline-grabber: in 2016 it got about 18 percent of its energy from wind, good enough to rank in the top 10 states. 
But it’s just 28th in terms of installed solar capacity, and its relatively small size means projects within its borders rarely garner the attention that giants like California and Texas routinely get.

A new report on the future of energy in the state should turn some heads (PDF). According to the University of Minnesota’s Energy Transition Lab, starting in 2019 and for the foreseeable future, the overall cost of building grid-scale storage there will be less than that of building natural-gas plants to meet future energy demand.


Minnesota currently gets about 21 percent of its energy from renewables. That’s not bad, but current plans also call for bringing an additional 1,800 megawatts of gas-fired “peaker” plants online by 2028 to meet growing demand. As the moniker suggests, these plants are meant to spin up quickly to meet daily peaks in energy demand—something renewables tend to be bad at because the wind doesn’t always blow and the sun doesn’t always shine.

Storing energy from renewables could solve that problem, but it’s traditionally been thought of as too expensive compared with other forms of energy.

The new report suggests otherwise. According to the analysis, bringing lithium-ion batteries online for grid storage would be a good way to stockpile energy for when it’s needed, and it would prove less costly than building and operating new natural-gas plants.

The finding comes at an interesting time. For one thing, the price of lithium-ion batteries continues to plummet, something that certainly has the auto industry’s attention. And grid-scale batteries, while still relatively rare, are popping up more and more these days. The Minnesota report, then, suggests that such projects may become increasingly common—and could be a powerful way to lower emissions without sending our power bills skyrocketing in the process.
(Read more: Minnesota Public Radio, “Texas and California Have Too Much Renewable Energy,” 

“The One and Only Texas Wind Boom,” “By 2040, More Than Half of All New Cars Could Be Electric”)

World’s Largest Lithium-Ion Battery System to be Built in Australia by Tesla + Video


AS TESLA MODEL 3 PRODUCTION BEGINS, ELON MUSK ANNOUNCES BIGGEST BATTERY ON OTHER SIDE OF THE WORLD 

You’d think the biggest Tesla news today would be surrounding landmark production of Tesla Model 3 SN1 — aka serial number 1. 



However, news emerged that Elon Musk was on the other side of the world. Wall Street Journal* reports, “Tesla Inc.’s Elon Musk has agreed to build the world’s largest lithium-ion battery system in Australia, an ambitious project that he hopes will show how the technology can help solve energy problems.”


Above: Tesla is planning the world’s biggest battery installation in South Australia (Image: Tesla)




It’s reported that, “The plan is to build a 100-megawatt storage system in the state of South Australia—which has been hit by a string of blackouts over the past year—that will collect power generated by a wind farm built by French energy company Neoen.” Musk emphasized the magnitude of the project, explaining: ““This is not a minor foray into the frontier, this is like going three times further than anyone has gone before.”

Above: More on Tesla’s project in South Australia (Youtube: Jay Weatherill)
It turns out that “Tesla was selected from more than 90 bids to build a storage system for the state, said South Australia Premier Jay Weatherill. The value of the project wasn’t disclosed. The origins of the deal trace back to a Twitter exchange in March between Mr. Musk and local entrepreneur Mike Cannon-Brookes, which led to conversations between Mr. Musk and Mr. Weatherill and Australian Prime Minister Malcolm Turnbull.”

Above: Tesla CEO Elon Musk and South Australia Premier Jay Weatherill (Twitter: Jay Weatherill)

True to his word, “Mr. Musk pledged to complete the project—which he said will be three times more powerful than any other battery system in the world—within 100 days of signing an agreement or it would be free.” In addition, “Once the project is completed, which Tesla expects will happen by the start of the Australian summer in December, it will be larger than a storage facility in the Southern California desert also built on Tesla batteries.”


Above: Tesla Powerpack installation (Image: Tesla)
According to Tesla, “The project will provide enough power for more than 30,000 homes, about equal to the number of homes that lost power during the blackouts.” Back in Fremont, the Tesla factory will get started on the first-ever production Model 3. Coming off historic rocket launches at SpaceX, chalk up another landmark milestone (or two) for Tesla today — just another week of work for the Iron Man, Elon Musk.

*Source: Wall Street Journal

NREL: Semiconducting Single-Walled Carbon Nanotubes in Solar Energy Harvesting


National Renewable Energy Laboratory, Golden, Colorado 

Semiconducting single-walled carbon nanotubes (s-SWCNTs) represent a tunable model one-dimensional system with exceptional optical and electronic properties. 

High-throughput separation and purification strategies have enabled the integration of s-SWCNTs into a number of optoelectronic applications, including photovoltaics (PVs). In this Perspective, we discuss the fundamental underpinnings of two model PV interfaces involving s-SWCNTs. 

We first discuss s-SWCNT–fullerene heterojunctions where exciton dissociation at the donor–acceptor interface drives solar energy conversion. Next, we discuss charge extraction at the interface between s-SWCNTs and a photoexcited perovskite active layer. 

In each case, the use of highly enriched semiconducting SWCNT samples enables fundamental insights into the thermodynamic and kinetic mechanisms that drive the efficient conversion of solar photons into long-lived separated charges. 

These model systems help to establish design rules for next-generation PV devices containing well-defined organic semiconductor layers and help to frame a number of important outstanding questions that can guide future studies.

EPPL Creates a low-cost system for splitting carbon dioxide – Turning Renewable Energy into Fuel


Ball-and-stick model of carbon dioxide. Credit: Wikipedia

Using Earth-abundant materials, EPFL scientists have built the first low-cost system for splitting CO2 into CO, a reaction necessary for turning renewable energy into fuel.
The future of clean energy depends on our ability to efficiently store energy from renewable sources and use it later. 


A popular way to do this is to electrolyze carbon dioxide to carbon monoxide, which is then mixed with hydrogen to produce liquid hydrocarbons like gasoline or kerosene that can be used as fuel. 

However, we currently lack efficient and Earth-abundant catalysts for the initial splitting of CO2 into CO and oxygen, which makes the move into renewable energy expensive and prohibitive. 

EPFL scientists have now developed an Earth-abundant catalyst based on copper-oxide nanowires modified with tin oxide. 
The system can split CO2 with an efficiency of 13.4%. 
The work is published in Nature Energy, and can help worldwide efforts to synthetically produce carbon-based fuels from CO2 and water.

The research was carried out by the lab of Michael Grätzel at EPFL. Grätzel is known worldwide for the invention of the first ever dye-sensitized solar cells (or “Grätzel cells”). 

The catalyst, developed by PhD student Marcel Schreier and postdoc Jingshan Luo, is made by depositing an atomic layer of tin oxide on copper oxide nanowires

By using such Earth-abundant materials, the design keeps the cost of the catalyst low while significantly increasing the yield of CO, as opposed to the other products that are generated from CO2 electrocatalysis.
The catalyst was integrated into a CO2 electrolysis system and linked to a triple-junction solar cell (GaInP/GaInAs/Ge) to make a CO2 electrolyzer. 

The system uses the catalyst as a bifunctional electrode that both reduces CO2 into CO and produces oxygen through what is known as the “oxygen evolution” reaction. The two products are separated with a bipolar membrane.

Using solar energy, the system was able to selectively convert CO2 to CO with an efficiency of 13.4%, and do so with a Faradaic efficiency up to 90%—this describes how efficiently electrical charge is transferred in a electrocatalysis system like the one developed here. “The work sets a new benchmark for solar-driven CO2 reduction,” says Luo.

“This is the first time that such a bi-functional and low-cost catalyst is demonstrated,” adds Schreier. “Very few catalysts—except expensive ones, like gold and silver—can selectively transform CO2 to CO in water, which is crucial for industrial applications.”

 
More information: Marcel Schreier, Florent Héroguel, Ludmilla Steier, Shahzada Ahmad, Jeremy S. Luterbacher, Matthew T. Mayer, Jingshan Luo, Michael Grätzel. Solar conversion of CO2 to CO using Earth-abundant electrocatalysts prepared by atomic layer modification of CuO. Nature Energy 2, 17087 (05 June 2017). nature.com/articles/doi:10.1038/nenergy.2017.87
Provided by: Ecole Polytechnique Federale de Lausanne