From Horizon The EU Research and Innovation Magazine: “Record-breaking solar cells get ready for mass production”

From Horizon The EU Research and Innovation Magazine

21 November 2018
Benedict O’Donnell

Researchers in Europe are trying to work out how record-breaking solar cells contacts can be mass-produced. BedZed Eco village. Image credit: Flickr- Bioregional International, licensed under CC.

Sandwiching an oxygen-rich layer of silicon between a solar cell and its metal contact has allowed researchers in Europe to break performance records for the efficiency with which silicon solar cells convert sunlight into electricity. But the challenge now is how to make these so-called passivating contacts suitable for mass production.

‘There is currently a lot of excitement about passivating contacts among the solar cell community,’ said Dr Byungsul Min at the Institute for Solar Energy Research in Hamelin (ISFH), Germany. This year, the technology allowed his laboratory to set a new record efficiency of 26.1% for the kind of solar cells the kind that dominates the photovoltaics market. Commercial solar panels currently operate with an efficiency of around 20%.

Passivating contacts consist of two thin layers of oxidised and crystallised silicon sandwiched between a solar cell and its metal contact. Speaking to a packed hall this September at the European Photovoltaics Solar Energy Conference in Brussels, Belgium, Dr Min said that the layers work by healing broken atomic bonds on the silicon surface and reducing the risk of electric charges getting trapped as they flow out of the solar cell.

The design was developed in 2013 by ISFH and the Fraunhofer Institute for Solar Energy Systems ISE in Freiburg, Germany. In recent years, it has driven the energy conversion efficiency of silicon photovoltaics above 25% – a ceiling that had limited the efficiency that researchers could achieve in the lab for over a decade.

Mass fabrication

Still, Dr Min says that few manufacturers have so far adopted passivating contacts in industry. As part of a project called DISC, he is now coordinating work with research institutes and equipment manufacturers across Europe to streamline their design for mass fabrication.

Making record-setting solar cells with passivating contacts has so far required costly materials and complex laboratory techniques that Dr Min says cannot be adopted in factory assembly lines. However, by getting rid of these sophisticated approaches and substituting them with tools that are already common in the solar cell industry, the DISC consortium expects to bring down manufacturing costs for the technology.

ISFH has notably replaced an expensive and highly conductive indium-containing layer that is deposited on the cell surface to better collect electrical charges out of the passivating contact. By fine-tuning pressure and temperature conditions during production, Dr Min can now form a zinc-containing layer that presents comparable physical properties while using abundant materials.

Dutch equipment provider Meco is swapping complex lithography steps with plating techniques that can metallise the electrical contacts of passivating contact solar cells in throughputs high enough for factory assembly lines.

Over the past year, DISC samples have shuttled across France, Germany, Switzerland and the Netherlands as partners play their part in an international supply line. Each laboratory adds a layer of silicon or other materials in which it specialises, gradually building up the stack of semiconductors into a functioning solar cell.

‘This August, we completed our first industry-sized solar cells,’ said Dr Min. ‘They have already reached energy conversion efficiencies above 21%.’ This falls within the range of solar cells on the market today.

Over the coming year, Dr Min expects that fine-tuning the layers in these factory-friendly devices will help edge their performance above that of the competition. In an industry where a difference of just half a percentage can make or break companies, a technology with a proven potential of over 25% efficiency in the laboratory offers enticing prospects for manufacturers.

‘We have to go to higher solar cell efficiencies,’ agreed Dr Martin Hermle, one of the pioneers of passivating contacts at Fraunhofer ISE. His research group is now developing industrial deposition methods for the solar cells produced in DISC, and developing ways of further boosting their energy conversion efficiency in another project called Nano-Tandem.

‘The cost of solar panels is largely dictated by their surface area. If you can make cells with 30% efficiency instead of 20% or 15%, that really helps reduce the overall cost of solar energy.’

Technology developed by two German institutes set a new record efficiency for solar cells of 26.1%. Image credit: Institute for Solar Energy Research in Hamelin.

33% efficiency

Earlier this year, Fraunhofer ISE produced a solar cell that reached a staggering 33% efficiency. Researchers stacked a silicon solar cell that incorporated passivating contacts with two additional solar cells made of more exotic materials, based on elements in the third and fifth group of the periodic table.

‘These top cells are good at absorbing blue shades of light, but they are made of comparatively rare elements, like gallium or indium, that are also slower to assemble than conventional silicon solar cells,’ said Dr Hermle. ‘If you want to compete on the mass market, you have to bring the cost of the material deposition down by about two orders of magnitude.’

One solution Nano-Tandem is exploring is to use less of them. Fraunhofer ISE has shipped silicon solar cells with passivating contacts to IBM Research Zürich, where project partners are placing solar cells on top of them not as solid layers, but as carpets of wires barely 1000 atoms wide. Startup Sol Voltaics and Lund University in Sweden are developing a potentially cheaper way of manufacturing the nanowires, assembling them from gas molecules as they fly through a tube furnace.

Nano-Tandem coordinator Professor Lars Samuelson at Lund University says that the raw materials used are expensive, but that photonic effects in them could turn their economics around. He says that, assembled wisely, manufacturers could in principle use 90% less material without much impact on the efficiency or light absorption of their solar cells.

This is the kind of innovative edge that Dr Hermle describes as crucial in keeping European research institutes at the head of solar cell technology. As the market for solar cells skyrockets into 11-digit annual figures, Asian competition is increasingly muscling European manufacturers out of business.

Dr Hermle says that passivating contacts offer an example of how European industry can remain relevant in the face of global competition. ‘This is a technology that really came from Europe to the solar cell market,’ he said.

The research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.

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From Stanford University: “Stanford researchers develop a rooftop device that can make solar power and cool buildings”

From Stanford University

November 8, 2018
Tom Abate, Stanford Engineering
(650) 736-2245,
tabate@stanford.edu

Professor Shanhui Fan and postdoctoral scholar Wei Li atop the Packard Electrical Engineering building with the apparatus that is proving the efficacy of a double-layered solar panel. The top layer uses the standard semiconductor materials that go into energy-harvesting solar cells; the novel materials on the bottom layer perform the cooling task. (Image credit: L.A. Cicero)

Stanford electrical engineer Shanhui Fan wants to revolutionize energy-producing rooftop arrays.

Today, such arrays do one thing – they turn sunlight into electricity. But Fan’s lab has built a device that could have a dual purpose – generating electricity and cooling buildings.

“We’ve built the first device that one day could make energy and save energy, in the same place and at the same time, by controlling two very different properties of light,” said Fan, senior author of an article appearing Nov. 8 in Joule.

The sun-facing layer of the device is nothing new. It’s made of the same semiconductor materials that have long adorned rooftops to convert visible light into electricity. The novelty lies in the device’s bottom layer, which is based on materials that can beam heat away from the roof and into space through a process known as radiative cooling.

In radiative cooling, objects – including our own bodies – shed heat by radiating infrared light. That’s the invisible light night-vision goggles detect. Normally this form of cooling doesn’t work well for something like a building because Earth’s atmosphere acts like a thick blanket and traps the majority of the heat near the building rather allowing it to escape, ultimately into the vast coldness of space.

Holes in the blanket

Fan’s cooling technology takes advantage of the fact that this thick atmospheric blanket essentially has holes in it that allow a particular wavelength of infrared light to pass directly into space. In previous work, Fan had developed materials that can convert heat radiating off a building into the particular infrared wavelength that can pass directly through the atmosphere. These materials release heat into space and could save energy that would have been needed to air-condition a building’s interior. That same material is what Fan placed under the standard solar layer in his new device.

Zhen Chen, who led the experiments as a postdoctoral scholar in Fan’s lab, said the researchers built a prototype about the diameter of a pie plate and mounted their device on the rooftop of a Stanford building. Then they compared the temperature of the ambient air on the rooftop with the temperatures of the top and bottom layers of the device. The top layer device was hotter than the rooftop air, which made sense because it was absorbing sunlight. But, as the researchers hoped, the bottom layer of the device was significant cooler than the air on the rooftop.

“This shows that heat radiated up from the bottom, through the top layer and into space,” said Chen, who is now a professor at the Southeast University of China.

What they weren’t able to test is whether the device also produced electricity. The upper layer in this experiment lacked the metal foil, normally found in solar cells, that would have blocked the infrared light from escaping. The team is now designing solar cells that work without metal liners to couple with the radiative cooling layer.

“We think we can build a practical device that does both things,” Fan said.

Shanhui Fan is the director of the Edward L. Ginzton Laboratory, a professor of electrical engineering, a senior fellow at the Precourt Institute for Energy and a professor, by courtesy, of applied physics. Postdoctoral scholars Wei Li of Stanford and Linxiao Zhu of the University of Michigan, Ann Arbor, also co-authored the paper.

The research was supported by the Stanford University Global Climate and Energy Project, the National Science Foundation and the National Natural Science Foundation of China.

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Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

From SLAC National Accelerator Lab: “Researchers create most complete high-res atomic movie of photosynthesis to date”

From SLAC National Accelerator Lab

November 7, 2018

Andrew Gordon
agordon@slac.stanford.edu
(650) 926-2282

In a major step forward, SLAC’s X-ray laser captures all four stable states of the process that produces the oxygen we breathe, as well as fleeting steps in between. The work opens doors to understanding the past and creating a greener future.

Using SLAC’s X-ray laser, researchers have captured the most complete high-res atomic movie to date of Photosystem II, a key protein complex in plants, algae and cyanobacteria responsible for splitting water and producing the oxygen we breathe. (Gregory Stewart, SLAC National Accelerator Laboratory)

Despite its role in shaping life as we know it, many aspects of photosynthesis remain a mystery. An international collaboration between scientists at SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory and several other institutions is working to change that. The researchers used SLAC’s Linac Coherent Light Source (LCLS) X-ray laser to capture the most complete and highest-resolution picture to date of Photosystem II, a key protein complex in plants, algae and cyanobacteria responsible for splitting water and producing the oxygen we breathe. The results were published in Nature today.

SLAC/LCLS

Explosion of life

When Earth formed about 4.5 billion years ago, the planet’s landscape was almost nothing like what it is today. Junko Yano, one of the authors of the study and a senior scientist at Berkeley Lab, describes it as “hellish.” Meteors sizzled through a carbon dioxide-rich atmosphere and volcanoes flooded the surface with magmatic seas.

Over the next 2.5 billion years, water vapor accumulating in the air started to rain down and form oceans where the very first life appeared in the form of single-celled organisms. But it wasn’t until one of those specks of life mutated and developed the ability to harness light from the sun and turn it into energy, releasing oxygen molecules from water in the process, that Earth started to evolve into the planet it is today. This process, oxygenic photosynthesis, is considered one of nature’s crown jewels and has remained relatively unchanged in the more than 2 billion years since it emerged.

“This one reaction made us as we are, as the world. Molecule by molecule, the planet was slowly enriched until, about 540 million years ago, it exploded with life,” said co-author Uwe Bergmann, a distinguished staff scientist at SLAC. “When it comes to questions about where we come from, this is one of the biggest.”

A greener future

Photosystem II is the workhorse responsible for using sunlight to break water down into its atomic components, unlocking hydrogen and oxygen. Until recently, it had only been possible to measure pieces of this process at extremely low temperatures. In a previous paper, the researchers used a new method to observe two steps of this water-splitting cycle [Nature]at the temperature at which it occurs in nature.

Now the team has imaged all four intermediate states of the process at natural temperature and the finest level of detail yet. They also captured, for the first time, transitional moments between two of the states, giving them a sequence of six images of the process.

The goal of the project, said co-author Jan Kern, a scientist at Berkeley Lab, is to piece together an atomic movie using many frames from the entire process, including the elusive transient state at the end that bonds oxygen atoms from two water molecules to produce oxygen molecules.

“Studying this system gives us an opportunity to see how metals and proteins work together and how light controls such kinds of reactions,” said Vittal Yachandra, one of the authors of the study and a senior scientist at Berkeley Lab who has been working on Photosystem II for more than 35 years. “In addition to opening a window on the past, a better understanding of Photosystem II could unlock the door to a greener future, providing us with inspiration for artificial photosynthetic systems that produce clean and renewable energy from sunlight and water.”

Sample assembly line

For their experiments, the researchers grow what Kern described as a “thick green slush” of cyanobacteria — the very same ancient organisms that first developed the ability to photosynthesize — in a large vat that is constantly illuminated. They then harvest the cells for their samples.

At LCLS, the samples are zapped with ultrafast pulses of X-rays [Science] to collect both X-ray crystallography and spectroscopy data to map how electrons flow in the oxygen-evolving complex of photosystem II. In crystallography, researchers use the way a crystal sample scatters X-rays to map its structure; in spectroscopy, they excite the atoms in a material to uncover information about its chemistry. This approach, combined with a new assembly-line sample transportation system [Nature Methods], allowed the researchers to narrow down the proposed mechanisms put forward by the research community over the years.

Mapping the process

Previously, the researchers were able to determine the room-temperature structure of two of the states at a resolution of 2.25 angstroms; one angstrom is about the diameter of a hydrogen atom. This allowed them to see the position of the heavy metal atoms, but left some questions about the exact positions of the lighter atoms, like oxygen. In this paper, they were able to improve the resolution even further, to 2 angstroms, which enabled them to start seeing the position of lighter atoms more clearly, as well as draw a more detailed map of the chemical structure of the metal catalytic center in the complex where water is split.

This center, called the oxygen-evolving complex, is a cluster of four manganese atoms and one calcium atom bridged with oxygen atoms. It cycles through the four stable oxidation states, S0-S3, when exposed to sunlight. On a baseball field, S0 would be the start of the game when a player on home base is ready to go to bat. S1-S3 would be players on first, second, and third. Every time a batter connects with a ball, or the complex absorbs a photon of sunlight, the player on the field advances one base. When the fourth ball is hit, the player slides into home, scoring a run or, in the case of Photosystem II, releasing breathable oxygen.

The researchers were able to snap action shots of how the structure of the complex transformed at every base, which would not have been possible without their technique. A second set of data allowed them to map the exact position of the system in each image, confirming that they had in fact imaged the states they were aiming for.

In photosystem II, the water-splitting center cycles through four stable states, S0-S3. On a baseball field, S0 would be the start of the game when a batter on home base is ready to hit. S1-S3 would be players waiting on first, second, and third. The center gets bumped up to the next state every time it absorbs a photon of sunlight, just like how a player on the field advances one base every time a batter connects with a ball. When the fourth ball is hit, the player slides into home, scoring a run or, in the case of Photosystem II, releasing the oxygen we breathe. (Gregory Stewart/SLAC National Accelerator Laboratory)

Sliding into home

But there are many other things going on throughout this process, as well as moments between states when the player is making a break for the next base, that are a bit harder to catch. One of the most significant aspects of this paper, Yano said, is that they were able to image two moments in between S2 and S3. In upcoming experiments, the researchers hope to use the same technique to image more of these in-between states, including the mad dash for home — the transient state, or S4, where two atoms of oxygen bond together — providing information about the chemistry of the reaction that is vital to mimicking this process in artificial systems.

“The entire cycle takes nearly two milliseconds to complete,” Kern said. “Our dream is to capture 50-microsecond steps throughout the full cycle, each of them with the highest resolution possible, to create this atomic movie of the entire process.”

Although they still have a way to go, the researchers said that these results provide a path forward, both in unveiling the mysteries of how photosynthesis works and in offering a blueprint for artificial sources of renewable energy.

“It’s been a learning process,” said SLAC scientist and co-author Roberto Alonso-Mori. “Over the last seven years we’ve worked with our collaborators to reinvent key aspects of our techniques. We’ve been slowly chipping away at this question and these results are a big step forward.”

In addition to SLAC and Berkeley Lab, the collaboration includes researchers from Umeå University, Uppsala University, Humboldt University of Berlin, the University of California, Berkeley, the University of California, San Francisco and the Diamond Light Source.

Key components of this work were carried out at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL), Berkeley Lab’s Advanced Light Source (ALS) and Argonne National Laboratory’s Advanced Photon Source (APS). LCLS, SSRL, APS, and ALS are DOE Office of Science user facilities. This work was supported by the DOE Office of Science and the National Institutes of Health, among other funding agencies.

SLAC/SSRL

LBNL/ALS

ANL APS

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SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

From MIT News: “New battery gobbles up carbon dioxide”

From MIT News

September 21, 2018
David L. Chandler

This scanning electron microscope image shows the carbon cathode of a carbon-dioxide-based battery made by MIT researchers, after the battery was discharged. It shows the buildup of carbon compounds on the surface, composed of carbonate material that could be derived from power plant emissions, compared to the original pristine surface (inset). Courtesy of the researchers

Scanning transmission electron microscope Wikipedia

Lithium-based battery could make use of greenhouse gas before it ever gets into the atmosphere.

A new type of battery developed by researchers at MIT could be made partly from carbon dioxide captured from power plants. Rather than attempting to convert carbon dioxide to specialized chemicals using metal catalysts, which is currently highly challenging, this battery could continuously convert carbon dioxide into a solid mineral carbonate as it discharges.

While still based on early-stage research and far from commercial deployment, the new battery formulation could open up new avenues for tailoring electrochemical carbon dioxide conversion reactions, which may ultimately help reduce the emission of the greenhouse gas to the atmosphere.

The battery is made from lithium metal, carbon, and an electrolyte that the researchers designed. The findings are described today in the journal Joule, in a paper by assistant professor of mechanical engineering Betar Gallant, doctoral student Aliza Khurram, and postdoc Mingfu He.

Currently, power plants equipped with carbon capture systems generally use up to 30 percent of the electricity they generate just to power the capture, release, and storage of carbon dioxide. Anything that can reduce the cost of that capture process, or that can result in an end product that has value, could significantly change the economics of such systems, the researchers say.

However, “carbon dioxide is not very reactive,” Gallant explains, so “trying to find new reaction pathways is important.” Generally, the only way to get carbon dioxide to exhibit significant activity under electrochemical conditions is with large energy inputs in the form of high voltages, which can be an expensive and inefficient process. Ideally, the gas would undergo reactions that produce something worthwhile, such as a useful chemical or a fuel. However, efforts at electrochemical conversion, usually conducted in water, remain hindered by high energy inputs and poor selectivity of the chemicals produced.

Gallant and her co-workers, whose expertise has to do with nonaqueous (not water-based) electrochemical reactions such as those that underlie lithium-based batteries, looked into whether carbon-dioxide-capture chemistry could be put to use to make carbon-dioxide-loaded electrolytes — one of the three essential parts of a battery — where the captured gas could then be used during the discharge of the battery to provide a power output.

This approach is different from releasing the carbon dioxide back to the gas phase for long-term storage, as is now used in carbon capture and sequestration, or CCS. That field generally looks at ways of capturing carbon dioxide from a power plant through a chemical absorption process and then either storing it in underground formations or chemically altering it into a fuel or a chemical feedstock.

Instead, this team developed a new approach that could potentially be used right in the power plant waste stream to make material for one of the main components of a battery.

While interest has grown recently in the development of lithium-carbon-dioxide batteries, which use the gas as a reactant during discharge, the low reactivity of carbon dioxide has typically required the use of metal catalysts. Not only are these expensive, but their function remains poorly understood, and reactions are difficult to control.

By incorporating the gas in a liquid state, however, Gallant and her co-workers found a way to achieve electrochemical carbon dioxide conversion using only a carbon electrode. The key is to preactivate the carbon dioxide by incorporating it into an amine solution.

“What we’ve shown for the first time is that this technique activates the carbon dioxide for more facile electrochemistry,” Gallant says. “These two chemistries — aqueous amines and nonaqueous battery electrolytes — are not normally used together, but we found that their combination imparts new and interesting behaviors that can increase the discharge voltage and allow for sustained conversion of carbon dioxide.”

They showed through a series of experiments that this approach does work, and can produce a lithium-carbon dioxide battery with voltage and capacity that are competitive with that of state-of-the-art lithium-gas batteries. Moreover, the amine acts as a molecular promoter that is not consumed in the reaction.

The key was developing the right electrolyte system, Khurram explains. In this initial proof-of-concept study, they decided to use a nonaqueous electrolyte because it would limit the available reaction pathways and therefore make it easier to characterize the reaction and determine its viability. The amine material they chose is currently used for CCS applications, but had not previously been applied to batteries.

This early system has not yet been optimized and will require further development, the researchers say. For one thing, the cycle life of the battery is limited to 10 charge-discharge cycles, so more research is needed to improve rechargeability and prevent degradation of the cell components. “Lithium-carbon dioxide batteries are years away” as a viable product, Gallant says, as this research covers just one of several needed advances to make them practical.

But the concept offers great potential, according to Gallant. Carbon capture is widely considered essential to meeting worldwide goals for reducing greenhouse gas emissions, but there are not yet proven, long-term ways of disposing of or using all the resulting carbon dioxide. Underground geological disposal is still the leading contender, but this approach remains somewhat unproven and may be limited in how much it can accommodate. It also requires extra energy for drilling and pumping.

The researchers are also investigating the possibility of developing a continuous-operation version of the process, which would use a steady stream of carbon dioxide under pressure with the amine material, rather than a preloaded supply the material, thus allowing it to deliver a steady power output as long as the battery is supplied with carbon dioxide. Ultimately, they hope to make this into an integrated system that will carry out both the capture of carbon dioxide from a power plant’s emissions stream, and its conversion into an electrochemical material that could then be used in batteries. “It’s one way to sequester it as a useful product,” Gallant says.

“It was interesting that Gallant and co-workers cleverly combined the prior knowledge from two different areas, metal-gas battery electrochemistry and carbon-dioxide capture chemistry, and succeeded in increasing both the energy density of the battery and the efficiency of the carbon-dioxide capture,” says Kisuk Kang, a professor at Seoul National University in South Korea, who was not associated with this research.

“Even though more precise understanding of the product formation from carbon dioxide may be needed in the future, this kind of interdisciplinary approach is very exciting and often offers unexpected results, as the authors elegantly demonstrated here,” Kang adds.

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The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

From University of Cambridge: “Scientists pioneer a new way to turn sunlight into fuel”

From University of Cambridge

03 Sep 2018
No writer credit

The quest to find new ways to harness solar power has taken a step forward after researchers successfully split water into hydrogen and oxygen by altering the photosynthetic machinery in plants.

Experimental two-electrode setup showing the photoelectrochemical cell illuminated with simulated solar light. Credit: Katarzyna Sokół

Photosynthesis is the process plants use to convert sunlight into energy. Oxygen is produced as a by-product of photosynthesis when the water absorbed by plants is ‘split’. It is one of the most important reactions on the planet because it is the source of nearly all of the world’s oxygen. Hydrogen which is produced when the water is split could potentially be a green and unlimited source of renewable energy.

A new study led by academics at the University of Cambridge, used semi-artificial photosynthesis to explore new ways to produce and store solar energy. They used natural sunlight to convert water into hydrogen and oxygen using a mixture of biological components and manmade technologies.

The research could now be used to revolutionise the systems used for renewable energy production. A new paper, published in [Nature Energy], outlines how academics at the Reisner Laboratory in Cambridge’s Department of Chemistry developed their platform to achieve unassisted solar-driven water-splitting.

Their method also managed to absorb more solar light than natural photosynthesis.

Katarzyna Sokół, first author and PhD student at St John’s College, said: “Natural photosynthesis is not efficient because it has evolved merely to survive so it makes the bare minimum amount of energy needed – around 1-2 per cent of what it could potentially convert and store.”

Artificial photosynthesis has been around for decades but it has not yet been successfully used to create renewable energy because it relies on the use of catalysts, which are often expensive and toxic. This means it can’t yet be used to scale up findings to an industrial level.

The Cambridge research is part of the emerging field of semi-artificial photosynthesis which aims to overcome the limitations of fully artificial photosynthesis by using enzymes to create the desired reaction.

Sokół and the team of researchers not only improved on the amount of energy produced and stored, they managed to reactivate a process in the algae that has been dormant for millennia.

She explained: “Hydrogenase is an enzyme present in algae that is capable of reducing protons into hydrogen. During evolution, this process has been deactivated because it wasn’t necessary for survival but we successfully managed to bypass the inactivity to achieve the reaction we wanted – splitting water into hydrogen and oxygen.”

Sokół hopes the findings will enable new innovative model systems for solar energy conversion to be developed.

She added: “It’s exciting that we can selectively choose the processes we want, and achieve the reaction we want which is inaccessible in nature. This could be a great platform for developing solar technologies. The approach could be used to couple other reactions together to see what can be done, learn from these reactions and then build synthetic, more robust pieces of solar energy technology.”

This model is the first to successfully use hydrogenase and photosystem II to create semi-artificial photosynthesis driven purely by solar power.

Dr Erwin Reisner, Head of the Reisner Laboratory, a Fellow of St John’s College, University of Cambridge, and one of the paper’s authors described the research as a ‘milestone’.

He explained: “This work overcomes many difficult challenges associated with the integration of biological and organic components into inorganic materials for the assembly of semi-artificial devices and opens up a toolbox for developing future systems for solar energy conversion.”

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The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

From UCLA Newsroom: “Dual-layer solar cell developed at UCLA sets record for efficiently generating power”

From UCLA Newsroom

August 30, 2018
Matthew Chin

A solar cell developed by UCLA Engineering researchers converts 22.4 percent of incoming energy from the sun, a record for this type of cell. Oszie Tarula/UCLA

Materials scientists from the UCLA Samueli School of Engineering have developed a highly efficient thin-film solar cell that generates more energy from sunlight than typical solar panels, thanks to its double-layer design.

The device is made by spraying a thin layer of perovskite — an inexpensive compound of lead and iodine that has been shown to be very efficient at capturing energy from sunlight — onto a commercially available solar cell. The solar cell that forms the bottom layer of the device is made of a compound of copper, indium, gallium and selenide, or CIGS.

The team’s new cell converts 22.4 percent of the incoming energy from the sun, a record in power conversion efficiency for a perovskite–CIGS tandem solar cell. The performance was confirmed in independent tests at the U.S. Department of Energy’s National Renewable Energy Laboratory. (The previous record, set in 2015 by a group at IBM’s Thomas J. Watson Research Center, was 10.9 percent.) The UCLA device’s efficiency rate is similar to that of the poly-silicon solar cells that currently dominate the photovoltaics market.

The research, which was published today in Science, was led by Yang Yang, UCLA’s Carol and Lawrence E. Tannas Jr. Professor of Materials Science.

Qifeng Han, Yang Yang and Lei Meng. Oszie Tarula/UCLA

“With our tandem solar cell design, we’re drawing energy from two distinct parts of the solar spectrum over the same device area,” Yang said. “This increases the amount of energy generated from sunlight compared to the CIGS layer alone.”

Yang added that the technique of spraying on a layer of perovskite could be easily and inexpensively incorporated into existing solar-cell manufacturing processes.

The cell’s CIGS base layer, which is about 2 microns (or two-thousandths of a millimeter) thick, absorbs sunlight and generates energy at a rate of 18.7 percent efficiency on its own, but adding the 1 micron-thick perovskite layer improves its efficiency — much like how adding a turbocharger to a car engine can improve its performance. The two layers are joined by a nanoscale interface that the UCLA researchers designed; the interface helps give the device higher voltage, which increases the amount of power it can export.

And the entire assembly sits on a glass substrate that’s about 2 millimeters thick.

“Our technology boosted the existing CIGS solar cell performance by nearly 20 percent from its original performance,” Yang said. “That means a 20 percent reduction in energy costs.”

He added that devices using the two-layer design could eventually approach 30 percent power conversion efficiency. That will be the research group’s next goal.

The study’s lead authors are Qifeng Han, a visiting research associate in Yang’s laboratory, and Yao-Tsung Hsieh and Lei Meng, who both recently earned their doctorates at UCLA. The study’s other authors are members of Yang’s research group and researchers from Solar Frontier Corp.’s Atsugi Research Center in Japan.

The research was supported by the National Science Foundation and the Air Force Office of Scientific Research. Yang and his research group have been working on tandem solar cells for several years and their accomplishments include developing transparent tandem solar cells that could be used in windows.

See the full article here .

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For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

From CSIROscope: “How hydrogen power can help us cut emissions, boost exports, and even drive further between refills”

From CSIROscope

24 August 2018
Sam Bruce

Could this be the way to fill up in future?

Hydrogen could become a significant part of Australia’s energy landscape within the coming decade, competing with both natural gas and batteries, according to our new roadmap for the industry.

Hydrogen gas is a versatile energy carrier with a wide range of potential uses. However, hydrogen is not freely available in the atmosphere as a gas. It therefore requires an energy input and a series of technologies to produce, store and then use it.

Why would we bother? Because hydrogen has several advantages over other energy carriers, such as batteries. It is a single product that can service multiple markets and, if produced using low- or zero-emissions energy sources, it can help us significantly cut greenhouse emissions.

Potential uses for hydrogen. No image credit.

Compared with batteries, hydrogen can release more energy per unit of mass. This means that in contrast to electric battery-powered cars, it can allow passenger vehicles to cover longer distances without refuelling. Refuelling is quicker too and is likely to stay that way.

The benefits are potentially even greater for heavy vehicles such as buses and trucks which already carry heavy payloads, and where lengthy battery recharge times can affect the business model.

Hydrogen can also play an important role in energy storage, which will be increasingly necessary both in remote operations such as mine sites, and as part of the electricity grid to help smooth out the contribution of renewables such as wind and solar. This could work by using the excess renewable energy (when generation is high and/or demand is low) to drive hydrogen production via electrolysis of water. The hydrogen can then be stored as compressed gas and put into a fuel cell to generate electricity when needed.

Australia is heavily reliant on imported liquid fuels and does not currently have enough liquid fuel held in reserve. Moving towards hydrogen fuel could potentially alleviate this problem. Hydrogen can also be used to produce industrial chemicals such as ammonia and methanol, and is an important ingredient in petroleum refining.

Further, as hydrogen burns without greenhouse emissions, it is one of the few viable green alternatives to natural gas for generating heat.

Our roadmap predicts that the global market for hydrogen will grow in the coming decades. Among the prospective buyers of Australian hydrogen would be Japan, which is comparatively constrained in its ability to generate energy locally. Australia’s extensive natural resources, namely solar, wind, fossil fuels and available land lend favourably to the establishment of hydrogen export supply chains.

Why embrace hydrogen now?

Given its widespread use and benefit, interest in the “hydrogen economy” has peaked and troughed for the past few decades. Why might it be different this time around? While the main motivation is hydrogen’s ability to deliver low-carbon energy, there are a couple of other factors that distinguish today’s situation from previous years.

Our analysis shows that the hydrogen value chain is now underpinned by a series of mature technologies that are technically ready but not yet commercially viable. This means that the narrative around hydrogen has now shifted from one of technology development to “market activation”.

The solar panel industry provides a recent precedent for this kind of burgeoning energy industry. Large-scale solar farms are now generating attractive returns on investment, without any assistance from government. One of the main factors that enabled solar power to reach this tipping point was the increase in production economies of scale, particularly in China. Notably, China has recently emerged as a proponent for hydrogen, earmarking its use in both transport and distributed electricity generation.

But whereas solar power could feed into a market with ready-made infrastructure (the electricity grid), the case is less straightforward for hydrogen. The technologies to help produce and distribute hydrogen will need to develop in concert with the applications themselves.

A roadmap for hydrogen

In light of this, the primary objective of our National Hydrogen Roadmap is to provide a blueprint for the development of a hydrogen industry in Australia. With several activities already underway, it is designed to help industry, government and researchers decide where exactly to focus their attention and investment.

Our first step was to calculate the price points at which hydrogen can compete commercially with other technologies. We then worked backwards along the value chain to understand the key areas of investment needed for hydrogen to achieve competitiveness in each of the identified potential markets. Following this, we modelled the cumulative impact of the investment priorities that would be feasible in or around 2025.

What became evident from the report was that the opportunity for clean hydrogen to compete favourably on a cost basis with existing industrial feedstocks and energy carriers in local applications such as transport and remote area power systems is within reach. On the upstream side, some of the most material drivers of reductions in cost include the availability of cheap low emissions electricity, utilisation and size of the asset.

The development of an export industry, meanwhile, is a potential game-changer for hydrogen and the broader energy sector. While this industry is not expected to scale up until closer to 2030, this will enable the localisation of supply chains, industrialisation and even automation of technology manufacture that will contribute to significant reductions in asset capital costs. It will also enable the development of fossil-fuel-derived hydrogen with carbon capture and storage, and place downward pressure on renewable energy costs dedicated to large scale hydrogen production via electrolysis.

In light of global trends in industry, energy and transport, development of a hydrogen industry in Australia represents a real opportunity to create new growth areas in our economy. Blessed with unparalleled resources, a skilled workforce and established manufacturing base, Australia is extremely well placed to capitalise on this opportunity. But it won’t eventuate on its own.

See the full article here .

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SKA/ASKAP radio telescope at the Murchison Radio-astronomy Observatory (MRO) in Mid West region of Western Australia

So what can we expect these new radio projects to discover? We have no idea, but history tells us that they are almost certain to deliver some major surprises.

Making these new discoveries may not be so simple. Gone are the days when astronomers could just notice something odd as they browse their tables and graphs.

Nowadays, astronomers are more likely to be distilling their answers from carefully-posed queries to databases containing petabytes of data. Human brains are just not up to the job of making unexpected discoveries in these circumstances, and instead we will need to develop “learning machines” to help us discover the unexpected.

With the right tools and careful insight, who knows what we might find.

CSIRO, the Commonwealth Scientific and Industrial Research Organisation, is Australia’s national science agency and one of the largest and most diverse research agencies in the world.

From PPPL: Two Items

From PPPL

Advances in plasma and fusion science are described in Quest, PPPL’s research magazine.

July 9, 2018
Larry Bernard

From analyzing solar flares to pursuing “a star in a jar” to produce virtually limitless electric power, scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) have developed insights and discoveries over the past year that advance understanding of the universe and the prospect for safe, clean, and abundant energy for all humankind.

“Our research sheds new light on the function of plasma, the state of matter that comprises 99 percent of the visible universe,” writes Steve Cowley, new director of PPPL, in the 2018 edition of Quest, PPPL’s annual research magazine. Quest, just published in July 2018, summarizes in short, easy-to-digest format, much of the research that occurred at PPPL over the last year.

Among the stories are descriptions of how scientists are finding ways to calm instabilities that can lead to the disruption of fusion reactions. Such research is critical to the next steps in advancing fusion energy to enable fusion devices to produce and sustain reactions that require temperatures many times hotter than the core of the sun.

Fusion, the power that drives the sun and stars, fuses light elements and releases enormous energy. If scientists can capture and control fusion on Earth, the process could provide clean energy to produce electricity for millions of years.

Plasma, the state of matter composed of free electrons and atomic nuclei that fuels fusion reactions and makes up 99 percent of the visible universe, unites PPPL research from astrophysics to nanotechnology to the science of fusion energy. Could planets beyond our solar system be habitable, for example? PPPL and Princeton scientists say that stellar winds — the outpouring of charged plasma particles from the sun into space — could deplete a planet’s atmosphere and dry up life-giving water over hundreds of millions of years, rendering a blow to the theory that these planets could host life as we know it.

Quest details efforts to understand the scientific basis of fusion and plasma behavior. For example, in the section on Advancing Fusion Theory, physicists describe how bubble-like “blobs” that arise at the edge of the plasma can carry off heat needed for fusion reactions. Improved understanding of such behavior could lead to better control of the troublesome blobs.

Another story outlines how researchers are using a form of artificial intelligence called “machine learning” to predict when disruptions that can halt fusion reactions and damage fusion devices occur. The innovative technique has so far yielded outstanding results.

Included in Quest are descriptions of collaborations PPPL scientists and engineers have working on fusion devices around the world. These collaborations include ITER, the large multinational fusion device under construction in France, as well as research on devices in China, South Korea, and at the National Ignition Facility in the United States.

Read also about PPPL’s long-standing efforts to educate students, teachers, and the public around STEM (science, technology, engineering, and math), as well as some of the award-winning work by scientists and inventors at PPPL.

Quest can be accessed here, or at this web address: https://www.pppl.gov/quest

See the full article here .

PPPL diagnostic is key to world record of German fusion experiment
July 9, 2018
John Greenwald

PPPL physicist Novimir Pablant, right, and Andreas Langenberg of the Max Planck Institute in front of the housing for the x-ray crystal spectrometer prior to its installation in the W7-X. (Photo by Scott Massida )

When Germany’s Wendelstein 7-X (W7-X) fusion facility set a world record for stellarators recently, a finely tuned instrument built and delivered by the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) proved the achievement.

Wendelstein 7-AS built in built in Greifswald, Germany

The record strongly suggests that the design of the stellarator can be developed to capture on Earth the fusion that drives the sun and stars, creating “a star in a jar” to generate a virtually unlimited supply of electric energy.

The record achieved by the W7-X, the world’s largest and most advanced stellarator, was the highest “triple product” that a stellarator has ever created. The product combines the temperature, density and confinement time of a fusion facility’s plasma — the state of matter composed of free electrons and atomic nuclei that fuels fusion reactions — to measure how close the device can come to producing self-sustaining fusion power. (The triple product was 6 x 1026 degrees x second per cubic meter — the new stellarator record.)

Spectrometer maps the temperature

The achievement produced temperatures of 40 million degrees for the ions and an energy confinement time, which measures how long it takes energy to leak out across the confining magnetic fields of 0.22 seconds. (The density was 0.8 x 1020 particles per cubic meter.) Measuring the temperature was an x-ray imaging crystal spectrometer (XICS) built by PPPL physicist Novimir Pablant, now stationed at W7-X, and engineer Michael Mardenfeld at PPPL. “The spectrometer provided the primary measurement,” said PPPL physicist Sam Lazerson, who also collaborates on W7-X experiments.

Pablant implemented the device with scientists and engineers of the Max Planck Institute of Plasma Physics (IPP), which operates the stellarator in the Baltic Sea town of Greifswald, Germany. “It has been a great experience to work closely with my colleagues here on W7-X,” Pablant said. “Installing the XICS system was a major undertaking and it has been a pleasure to work with this world-class research team. The initial results from these high-performance plasmas are very exciting, and we look forward to using the measurements from our instrument to further understanding of the confinement properties of W7-X, which is a truly unique magnetic fusion experiment.”

Researchers at IPP welcomed the findings. “Without XICS we could not have confirmed the record,” said Thomas Sunn Pedersen, director of stellarator edge and divertor physics at IPP. Concurred physicist Andreas Dinklage, lead author of a Nature Physics (link is external) paper confirming a key feature of the W7-X physical design: “The XICS data set was one of the very valuable inputs that confirmed the physics predictions.”

PPPL physicist David Gates, technical coordinator of the U.S. collaboration on W7-X, oversaw construction of the instrument. “The XICS is an incredibly precise device capable of measuring very small shifts in wavelength,” said Gates. “It is a crucial part of our collaboration and we are very grateful to have the opportunity to participate in these important experiments on the groundbreaking W7-X device.”

PPPL provides added components

PPPL has designed and delivered additional components installed on the W7-X. These include a set of large trim coils that correct errors in the magnetic field that confines W7-X plasma, and a scraper unit that will lessen the heat reaching the divertor that exhausts waste heat from the fusion facility.

The recent world record was a result of upgrades that IPP made to the stellarator following the initial phase of experiments, which began in December 2015. Improvements included new graphite tiles that enabled the higher temperatures and longer duration plasmas that produced the results. A new round of experiments is to begin this July using the new scraper unit that PPPL delivered.

Stellarators, first constructed in the 1950s under PPPL founder Lyman Spitzer, can operate in a steady state, or continuous manner, with little risk of the plasma disruptions that doughnut-shaped tokamak fusion facilities face. But tokamaks are simpler to design and build, and historically have confined plasma better, which accounts for their much wider use in fusion laboratories around the world.

An overall goal of the W7-X is to show that the twisty stellarator design can confine plasma just as well as tokamaks. When combined with the ability to operate virtually free of disruptions, such improvement could make stellarators excellent models for future fusion power plants.

See the full article here .

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PPPL campus

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

From Pacific Northwest National Lab: “New approaches to chemical and electrical energy conversions”

From Pacific Northwest National Lab

July 16, 2018
Susan Bauer
susan.bauer@pnnl.gov
(509) 372-6083

For the second time, the U.S. Department of Energy renewed funding for a center designed to explore fundamental scientific principles that underpin technologies such as solar energy and fuel cells. Researchers at Pacific Northwest National Laboratory, together with partners at Yale University, the University of Wisconsin, Massachusetts Institute of Technology, the University of Washington, and Purdue University, earned the renewal through significant achievements in developing catalysts that can convert energy between electrical and chemical forms. Building on their success, and expanding their team, researchers are now poised to take on new challenges.

The Center for Molecular Electrocatalysis was established in 2009 as a DOE Energy Frontier Research Center. DOE recently announced awards of $100 million for 42 new or continuing EFRCs, including this one led by PNNL. The centers are charged with pursuing the scientific underpinnings of various aspects of energy production, storage and use.

Since 2009, CME researchers have been studying molecules called catalysts that convert electrical energy into chemical bonds and back again. Chemical bonds can store a huge amount of energy in a small amount of physical space. Of interest are catalysts that pack energy into bonds involving hydrogen, oxygen or nitrogen. Among the reactions studied are production of hydrogen, which can be used in fuel cells, and the reduction of oxygen, the reaction that balances the oxidation reaction of fuel cells.

In the past four years, the Center for Molecular Electrocatalysis has reported:

the fastest electrocatalysts for production of hydrogen,
the fastest electrocatalysts for reduction of oxygen,
and the most energy-efficient molecular electrocatalyst for reduction of oxygen.

These fundamental scientific discoveries are important for our energy future. For example, a catalyst breaks chemical bonds to produce electricity in a fuel cell. An energy-efficient catalyst produces more power from fuel than an inefficient one — and fuel cells for vehicles need to release energy as fast as the explosions in a gasoline engine do.

These efforts have sharpened scientists’ understanding of the central challenges in the field and laid the foundation for the ambitious goals for future studies.

Directed by PNNL chemist Morris Bullock, the Center for Molecular Electrocatalysis expects to receive $3.2 million per year for the next four years and involve researchers from several complementary disciplines.

“We are excited to be able to further our scientific mission by developing new approaches to circumventing traditional relationships found between rates and energy efficiency,” said Bullock. “These parameters are often correlated, such that improvements in one are obtained at the expense of the others. Typically, the faster catalysts are less energy efficient, and the more energy efficient catalysts are slower. To make breakthrough progress, we seek to remarkably improve catalyst performance through system-level design.”

PNNL leads another Energy Frontier Research Center, Interfacial Dynamics in Radioactive Environments and Materials (IDREAM) which is focused on solving the chemistry challenges found in tanks holding a wide array of radioactive chemical waste generated from weapons production.

See the full article here .

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Pacific Northwest National Laboratory (PNNL) is one of the United States Department of Energy National Laboratories, managed by the Department of Energy’s Office of Science. The main campus of the laboratory is in Richland, Washington.

PNNL scientists conduct basic and applied research and development to strengthen U.S. scientific foundations for fundamental research and innovation; prevent and counter acts of terrorism through applied research in information analysis, cyber security, and the nonproliferation of weapons of mass destruction; increase the U.S. energy capacity and reduce dependence on imported oil; and reduce the effects of human activity on the environment. PNNL has been operated by Battelle Memorial Institute since 1965.

From Max Planck Institute for Plasma Physics: “Wendelstein 7-X achieves world record”

From Max Planck Institute for Plasma Physics

June 25, 2018
Isabella Milch

Wendelstgein 7-X stellarator, built in Greifswald, Germany

Stellarator record for fusion product / First confirmation for optimisation

In the past experimentation round Wendelstein 7-X achieved higher temperatures and densities of the plasma, longer pulses and the stellarator world record for the fusion product. Moreover, first confirmation for the optimisation concept on which Wendelstein 7-X is based, was obtained. Wendelstein 7-X at Max Planck Institute for Plasma Physics (IPP) in Greifswald, the world’s largest fusion device of the stellarator type, is investigating the suitability of this concept for application in power plants.

View inside the plasma vessel with graphite tile cladding. Photo: IPP, Jan Michael Hosan

Unlike in the first experimentation phase 2015/16, the plasma vessel of Wendelstein 7-X has been fitted with interior cladding since September last year (see PI 8/2017). The vessel walls are now covered with graphite tiles, thus allowing higher temperatures and longer plasma discharges. With the so-called divertor it is also possible to control the purity and density of the plasma: The divertor tiles follow the twisted contour of the plasma edge in the form of ten broad strips along the wall of the plasma vessel. In this way, they protect particularly the wall areas onto which the particles escaping from the edge of the plasma ring are made to impinge. Along with impurities, the impinging particles are here neutralised and pumped off.

“First experience with the new wall elements are highly positive”, states Professor Dr. Thomas Sunn Pedersen. While by the end of the first campaign pulse lengths of six seconds were being attained, plasmas lasting up to 26 seconds are now being produced. A heating energy of up to 75 megajoules could be fed into the plasma, this being 18 times as much as in the first operation phase without divertor. The heating power could also be increased, this being a prerequisite to high plasma density.

Wendelstein 7-X attained the Stellarator world record for the fusion product. This product of the ion temperature, plasma density and energy confinement time specifies how close one is getting to the reactor values needed to ignite a plasma. Graphic: IPP

In this way a record value for the fusion product was attained. This product of the ion temperature, plasma density and energy confinement time specifies how close one is getting to the reactor values needed to ignite a plasma. At an ion temperature of about 40 million degrees and a density of 0.8 x 1020 particles per cubic metre Wendelstein 7-X has attained a fusion product affording a good 6 x 1026 degrees x second per cubic metre, the world’s stellarator record. “This is an excellent value for a device of this size, achieved, moreover, under realistic conditions, i.e. at a high temperature of the plasma ions”, says Professor Sunn Pedersen. The energy confinement time attained, this being a measure of the quality of the thermal insulation of the magnetically confined plasma, indicates with an imposing 200 milliseconds that the numerical optimisation on which Wendelstein 7-X is based might work: “This makes us optimistic for our further work.”

The fact that optimisation is taking effect not only in respect of the thermal insulation is testified to by the now completed evaluation of experimental data from the first experimentation phase from December 2015 to March 2016, which has just been reported in Nature Physics (see below). This shows that also the bootstrap current behaves as expected. This electric current is induced by pressure differences in the plasma and could distort the tailored magnetic field. Particles from the plasma edge would then no longer impinge on the right area of the divertor. The bootstrap current in stellarators should therefore be kept as low as possible. Analysis has now confirmed that this has actually been accomplished in the optimised field geometry. “Thus, already during the first experimentation phase important aspects of the optimisation could be verified”, states first author Dr. Andreas Dinklage. “More exact and systematic evaluation will ensue in further experiments at much higher heating power and higher plasma pressure.”

Since the end of 2017 Wendelstein 7-X has undergone further extensions: These include new measuring equipment and heating systems. Plasma experiments are to be resumed in July. Major extension is planned as of autumn 2018: The present graphite tiles of the divertor are to be replaced by carbon-reinforced carbon components that are additionally water-cooled. They are to make discharges lasting up to 30 minutes possible, during which it can be checked whether Wendelstein 7-X permanently meets its optimisation objectives as well.

Background

The objective of fusion research is to develop a power plant favourable to the climate and environment. Like the sun, it is to derive energy from fusion of atomic nuclei. Because the fusion fire needs temperatures exceeding 100 million degrees to ignite, the fuel, viz. a low-density hydrogen plasma, ought not to come into contact with cold vessel walls. Confined by magnetic fields, it is suspended inside a vacuum chamber with almost no contact.

The magnetic cage of Wendelstein 7-X is produced by a ring of 50 superconducting magnet coils about 3.5 metres high. Their special shapes are the result of elaborate optimisation calculations. Although Wendelstein 7-X will not produce energy, it hopes to prove that stellarators are suitable for application in power plants.

Its aim is to achieve for the first time in a stellarator the quality of confinement afforded by competing devices of the tokamak type. In particular, the device is to demonstrate the essential advantage of stellarators, viz. their capability to operate in continuous mode.

Science paper:
Magnetic configuration effects on the Wendelstein 7-X stellarator. Nature Physics

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The Max Planck Institute of Plasma Physics (Max-Planck-Institut für Plasmaphysik, IPP) is a physics institute for the investigation of plasma physics, with the aim of working towards fusion power. The institute also works on surface physics, also with focus on problems of fusion power.

The IPP is an institute of the Max Planck Society, part of the European Atomic Energy Community, and an associated member of the Helmholtz Association.

The IPP has two sites: Garching near Munich (founded 1960) and Greifswald (founded 1994), both in Germany.

It owns several large devices, namely

the experimental tokamak ASDEX Upgrade (in operation since 1991)
the experimental stellarator Wendelstein 7-AS (in operation until 2002)
the experimental stellarator Wendelstein 7-X (awaiting licensing)
a tandem accelerator

It also cooperates with the ITER and JET projects.