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.

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From Sanford Underground Research Facility: “Revolutionizing geothermal energy research”

From Sanford Underground Research Facility

June 11, 2018
Constance Walter

The SIMFIP tool is changing the way researchers measure and design hydro fractures.

Deep underground on the 4850 Level at Sanford Lab, engineer Paul Cook explains how the SIMFIP tool will be used to measure openings in hard rock. Matthew Kapust

On May 22, researchers with the SIGMA-V experiment worked in near silence in the West Drift on the 4850 Level. The locomotives sat quietly on the tracks, jack-leg drills rested against drift walls and operations ceased for several minutes at a time as the team began pumping pressurized water into the injection well, one of eight boreholes drilled for this experiment.

“We requested quiet because we use sensitive seismic monitoring equipment,” said Tim Kneafsey, earth scientist at Lawrence Berkeley National Laboratory (LBNL). “The signals we measure are very small and we don’t want vibrations from other sources overwhelming those signals.”

Kneafsey is the principal investigator for the Enhanced Geothermal Systems (EGS) Collab Project, a collaboration comprised of eight national laboratories and six universities who are working to improve geothermal technologies. The test featured the SIMFIP (Step-Rate Injection Method for Fracture In-Situ Properties), a tool that revolutionizes the way scientists can study geothermal energy, a process that pulls heat from the earth as it extracts steam or hot water, which is then converted to electricity.

Developed at LBNL, the SIMFIP allows precise measurements of displacements in the rock and, most importantly, the aperture, or opening, of a hydro fracture.

The extreme quiet paid off, Kneafsey said.

“Our goal was to create a fracture from a specific zone in our injection well that would connect to our production well—about 10 meters away. And we were successful in doing that,” Kneafsy said.

“People were excited when the connection between the boreholes was made and measured. But it took a while for the team to realize how far we had come and how much research, logistics, planning and collaboration went into that moment. It was gratifying to say the least, and there was certainly a sense of accomplishment.” —Hunter Knox

The experiment

Before the introduction of the SIMFIP, separate tools were used to create and measure hydro fractures. They work like this: “Straddle packers”—pipes with two deflated balloons on either end—are placed inside boreholes. Once inside, the balloons are inflated and water injected down the pipes to create an airtight section. They continue to pump water until the rock fractures, then remove the packers and insert the measuring tool. In the time it takes to do all that, much of the pertinent data is lost, leaving traces, but little else.

“Even if you did get the aperture, when you released the pressure, the hydro fracture was already closing,” said Yves Guglielmi, a geologist at LBNL who designed the tool. “You don’t have the ‘true’ aperture and you also don’t know how the aperture might vary during the test.”

With the introduction of the SIMFIP, a small device that sits between the two packers, they can the aperture in real-time.

“This is really a new way to do the work,” Guglielmi said. “It will help us understand the whole process of initiating and growing hydro fractures in hard rock, which is kind of new. This is fundamental science. If we understand how hydro fractures will behave in this kind of rock, we can begin to make intelligent, complex fractures that can capture more heat from the earth.”

The device is “bristling with sensors and other instrumentation that give us a close-up view of what happens when the rock is stimulated—all in real-time,” said Paul Cook, LBNL engineer.

The SIMFIP measures fracture openings in hard rock in the EGS Collab test site. The team had drilled eight slightly downward-sloping boreholes in the rib (side) of the West Drift: The injection hole, used for stimulating the rock, and production well, which produces the fluid, run parallel to each other through the rock. Six other boreholes contain equipment to monitor microseismic activity (rock displacement); electrical resistivity tomography (subsurface imaging); temperature; and strain (how rocks move when stimulated).

Nestled between the straddle packers in the injection hole, the SIMFIP measured the rock opening as the team looked on.

The SIMFIP difference

The SIGMA-V team hoped to see signals as small as a few microns of displacements in the rock. As they watched data accumulate in real time over a two-day period, the excitement in the West Drift was palpable.

“People were excited when the connection between the boreholes was made and measured,” said Hunter Knox, the field coordinator with Sandia National Laboratory, “But it took a while for the team to realize how far we had come and how much research, logistics, planning and collaboration went into that moment. It was gratifying to say the least, and there was certainly a sense of accomplishment.”

Measurements from the SIMFIP could remove barriers that stand in the way of commercializing geothermal systems, which have the potential to provide enough energy to power 100 million American homes.

“We know fracturing rock can be done. But can it be effective for geothermal purposes? We need good, well-monitored field tests of fracturing, particularly in crystalline rock, to better understand that,” Kneafsey said.

With the first test under its belt, the EGS Collab just moved a step closer to that goal.

No image credit or caption

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About us.
The Sanford Underground Research Facility in Lead, South Dakota, advances our understanding of the universe by providing laboratory space deep underground, where sensitive physics experiments can be shielded from cosmic radiation. Researchers at the Sanford Lab explore some of the most challenging questions facing 21st century physics, such as the origin of matter, the nature of dark matter and the properties of neutrinos. The facility also hosts experiments in other disciplines—including geology, biology and engineering.

The Sanford Lab is located at the former Homestake gold mine, which was a physics landmark long before being converted into a dedicated science facility. Nuclear chemist Ray Davis earned a share of the Nobel Prize for Physics in 2002 for a solar neutrino experiment he installed 4,850 feet underground in the mine.

Homestake closed in 2003, but the company donated the property to South Dakota in 2006 for use as an underground laboratory. That same year, philanthropist T. Denny Sanford donated $70 million to the project. The South Dakota Legislature also created the South Dakota Science and Technology Authority to operate the lab. The state Legislature has committed more than $40 million in state funds to the project, and South Dakota also obtained a $10 million Community Development Block Grant to help rehabilitate the facility.

In 2007, after the National Science Foundation named Homestake as the preferred site for a proposed national Deep Underground Science and Engineering Laboratory (DUSEL), the South Dakota Science and Technology Authority (SDSTA) began reopening the former gold mine.

In December 2010, the National Science Board decided not to fund further design of DUSEL. However, in 2011 the Department of Energy, through the Lawrence Berkeley National Laboratory, agreed to support ongoing science operations at Sanford Lab, while investigating how to use the underground research facility for other longer-term experiments. The SDSTA, which owns Sanford Lab, continues to operate the facility under that agreement with Berkeley Lab.

The first two major physics experiments at the Sanford Lab are 4,850 feet underground in an area called the Davis Campus, named for the late Ray Davis. The Large Underground Xenon (LUX) experiment is housed in the same cavern excavated for Ray Davis’s experiment in the 1960s.
LUX/Dark matter experiment at SURF

In October 2013, after an initial run of 80 days, LUX was determined to be the most sensitive detector yet to search for dark matter—a mysterious, yet-to-be-detected substance thought to be the most prevalent matter in the universe. The Majorana Demonstrator experiment, also on the 4850 Level, is searching for a rare phenomenon called “neutrinoless double-beta decay” that could reveal whether subatomic particles called neutrinos can be their own antiparticle. Detection of neutrinoless double-beta decay could help determine why matter prevailed over antimatter. The Majorana Demonstrator experiment is adjacent to the original Davis cavern.

Another major experiment, the Long Baseline Neutrino Experiment (LBNE)—a collaboration with Fermi National Accelerator Laboratory (Fermilab) and Sanford Lab, is in the preliminary design stages. The project got a major boost last year when Congress approved and the president signed an Omnibus Appropriations bill that will fund LBNE operations through FY 2014. Called the “next frontier of particle physics,” LBNE will follow neutrinos as they travel 800 miles through the earth, from FermiLab in Batavia, Ill., to Sanford Lab.

LBNE

From MIT: “A new era in fusion research at MIT”

MIT News

March 9, 2018
Francesca McCaffrey | MIT Energy Initiative

MIT Energy Initiative founding member Eni announces support for key research through MIT Laboratory for Innovation in Fusion Technologies.

A new chapter is beginning for fusion energy research at MIT.

This week the Italian energy company Eni, a founding member of the MIT Energy Initiative (MITEI), announced it has reached an agreement with MIT to fund fusion research projects run out of the MIT Plasma Science and Fusion Center (PSFC)’s newly created Laboratory for Innovation in Fusion Technologies (LIFT). The expected investment in these research projects will amount to about $2 million over the following years.

This is part of a broader engagement with fusion research and the Institute as a whole: Eni also announced a commitment of $50 million to a new private company with roots at MIT, Commonwealth Fusion Systems (CFS), which aims to make affordable, scalable fusion power a reality.

“This support of LIFT is a continuation of Eni’s commitment to meeting growing global energy demand while tackling the challenge of climate change through its research portfolio at MIT,” says Robert C. Armstrong, MITEI’s director and the Chevron Professor of Chemical Engineering at MIT. “Fusion is unique in that it is a zero-carbon, dispatchable, baseload technology, with a limitless supply of fuel, no risk of runaway reaction, and no generation of long-term waste. It also produces thermal energy, so it can be used for heat as well as power.”

Still, there is much more to do along the way to perfecting the design and economics of compact fusion power plants. Eni will fund research projects at LIFT that are a continuation of this research and focus on fusion-specific solutions. “We are thrilled at PSFC to have these projects funded by Eni, who has made a clear commitment to developing fusion energy,” says Dennis Whyte, the director of PSFC and the Hitachi America Professor of Engineering at MIT. “LIFT will focus on cutting-edge technology advancements for fusion, and will significantly engage our MIT students who are so adept at innovation.”

Tackling fusion’s challenges

The inside of a fusion device is an extreme environment. The creation of fusion energy requires the smashing together of light elements, such as hydrogen, to form heavier elements such as helium, a process that releases immense amounts of energy. The temperature at which this process takes place is too hot for solid materials, necessitating the use of magnets to hold the hot plasma in place.

One of the projects PSFC and Eni intend to carry out will study the effects of high magnetic fields on molten salt fluid dynamics. One of the key elements of the fusion pilot plant currently being studied at LIFT is the liquid immersion blanket, essentially a flowing pool of molten salt that completely surrounds the fusion energy core. The purpose of this blanket is threefold: to convert the kinetic energy of fusion neutrons to heat for eventual electricity production; to produce tritium — a main component of the fusion fuel; and to prevent the neutrons from reaching other parts of the machine and causing material damage.

It’s critical for researchers to be able to predict how the molten salt in such an immersion blanket would move when subjected to high magnetic fields such as those found within a fusion plant. As such, the researchers and their respective teams plan to study the effects of these magnetohydrodynamic forces on the salt’s fluid dynamics.

A history of innovation

During the 23 years MIT’s Alcator C-Mod tokamak fusion experiment was in operation, it repeatedly advanced records for plasma pressure in a magnetic confinement device. Its compact, high-magnetic-field fusion design confined superheated plasma in a small donut-shaped chamber.

“The key to this success was the innovations pursued more than 20 years ago at PSFC in developing copper magnets that could access fields well in excess of other fusion experiments. The coupling between innovative technology development and advancing fusion science is in the DNA of the Plasma Science and Fusion Center,” says PSFC Deputy Director Martin Greenwald.

In its final run in 2016, Alcator C-Mod set a new world record for plasma pressure, the key ingredient to producing net energy from fusion. Since then, PSFC researchers have used data from these decades of C-Mod experiments to continue to advance fusion research. Just last year, they used C-Mod data to create a new method of heating fusion plasmas in tokamaks which could result in the heating of ions to energies an order of magnitude greater than previously reached.

A commitment to low-carbon energy

MITEI’s mission is to advance low-carbon and no-carbon emissions solutions to efficiently meet growing global energy needs. Critical to this mission are collaborations between academia, industry, and government — connections MITEI helps to develop in its role as MIT’s hub for multidisciplinary energy research, education, and outreach.

Eni is an inaugural, founding member of the MIT Energy Initiative, and it was through their engagement with MITEI that they became aware of the fusion technology commercialization being pursued by CFS and its immense potential for revolutionizing the energy system. It was through these discussions, as well, that Eni investors learned of the high-potential fusion research projects taking place through LIFT at MIT, spurring them to support the future of fusion at the Institute itself.

Eni CEO Claudio Descalzi said, “Today is a very important day for us. Thanks to this agreement, Eni takes a significant step forward toward the development of alternative energy sources with an ever lower environmental impact. Fusion is the true energy source of the future, as it is completely sustainable, does not release emissions or waste, and is potentially inexhaustible. It is a goal that we are determined to reach quickly.” He added, “We are pleased and excited to pursue such a challenging goal with a collaborator like MIT, with unparalleled experience in the field and a long-standing and fruitful alliance with Eni.”

These fusion projects are the latest in a line of MIT-Eni collaborations on low- and no-carbon energy projects. One of the earliest of these was the Eni-MIT Solar Frontiers Center, established in 2010 at MIT. Through its mission to develop competitive solar technologies, the center’s research has yielded the thinnest, lightest solar cells ever produced, effectively able to turn any surface, from fabric to paper, into a functioning solar cell. The researchers at the center have also developed new, luminescent materials that could allow windows to efficiently collect solar power.

Other fruits of MIT-Eni collaborations include research into carbon capture systems to be installed in cars, wearable technologies to improve workplace safety, energy storage, and the conversion of carbon dioxide into fuel.

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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 Horizon: “Turning landfill into energy”

Horizon

07 March 2018
Jon Cartwright

Advanced gasification methods can turn any waste except metal and rubble into fuel for electricity. Credit – Pixabay/ Prylarer

Landfill is both ugly and polluting. But a new breed of technology promises to make it a thing of the past, transforming a huge portion of landfill material into clean gas.

It’s thanks to a process called gasification, which involves turning carbon-based materials into gas by heating them to a high temperature but without burning them. The gas can be stored until it is needed for the generation of electricity.

According to its developers, advanced gasification can be fed by plastic, biomass, textiles – just about anything except metal and rubble. Out of the other end comes syngas – a clean, easily combustible gas made up of carbon monoxide and hydrogen.

The basics of the technology are old. Back in the 19th century, gasification plants existed in many of Europe’s major cities, turning coal into coal gas for heating and lighting.

Gasification waned after the discovery of natural gas reserves early last century. Then in the past 20 years or so, it had a small renaissance, as gasification plants sprung up to process waste wood.

In a new, advanced implementation, however, a much broader range of materials can be processed, and the output gas is much cleaner. ‘Gasification is clearly gaining a lot of traction, but we’ve taken it further,’ said Jean-Eric Petit of French company CHO Power, based in Bordeaux.

Gasification

Gasification involves heating without combustion. At temperatures greater than 700°C, a lot of hydrocarbon-based materials break down into a gas of carbon monoxide and hydrogen – syngas – which can be used as a fuel.

For materials such as wood, this is relatively straightforward. Try it with other hydrocarbon materials, and especially hard-to-recycle industrial waste, however, and the reaction tends to generate pollutants, such as tar.

But tar itself is just a more complex hydrocarbon. That is why Petit and his colleagues have developed a higher temperature process, at some 1200°C, in which even tar is broken down.

The result is syngas, which, unline other thermal processes, does not create dangerous pollutants. In fact, it is high-quality enough to be fed directly into high-efficiency gas engines, generating electricity with twice the efficiency of the steam turbines used with conventional gasification, says Petit.

CHO Power has already built an advanced gasification plant in Morcenx, France, which converts 55,000 tonnes of wood, biomass and industrial waste a year into 11 megawatts of electricity.

In December the EU announced that the company will receive a €30 million loan from the European Investment Bank to construct another plant in the Thouarsais area of France.

The company is not the first to attempt advanced gasification on a commercial scale. But, said Petit: ‘We think we’re the first to crack it.’

CHO Power’s gasification plants still need to have waste delivered to them. Hysytech, a company in Torino, Italy, however, plans to bring gasification to industry’s door.

The idea is to build a small gasification plant, processing at least 100 kilos per hour of waste, next to any industrial plant that deals with hydrocarbon materials – a textiles or plastics manufacturer, for instance.

Then, any waste the industrial plant generates can be turned straight into syngas for electricity generation on site, avoiding the emissions associated with transporting waste to a distant gasification plant.

The gas produced by CHO Power’s gasification process is refined at 1,200°C in their turboplasma facility (left) so that it can be used in a gas engine (right) to generate electricity. Credit – CHO Power

Small-scale

The problem is that, historically, gasification on this scale has cost too much to be in an industry’s interests. But Hysytech believes it has made small-scale gasification cost effective, by developing a novel reactor known as a fluidised bed.

When waste materials are fed into this reactor, a fluid is passed through them to create an even temperature and to allow the gas to leave easily. If the materials need a lot of time to turn to gas, they remain in the reactor until they are gasified, but the fluid can be sped up if the materials turn to gas quickly.

The result, for smaller plants at least, is a more efficient and cost-effective process. ‘Our system is designed and built to operate year-round with a good efficiency, easy operation and little maintenance,’ said Andrés Saldivia, Hysytech’s head of business development.

Hysytech has built a pilot plant that has about one-tenth the envisaged output, processing 10 kilos of waste an hour into syngas. Currently, its engineers are constructing a full-sized demo plant that will include an additional power-to-gas system, to link the gasification to surplus energy from wind turbines and solar panels so the energy is not wasted.

With this additional system, the surplus energy is used to split water into hydrogen and oxygen. Using a carbon source, this hydrogen is then converted into methane, which can be used like everyday natural gas.

‘Our goal is to have it ready for the market (by) 2019,’ said Saldivia.

See the full article here .

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From PI: Women in STEM-“Celebrating International Women’s Day”

Is it not a shame that we need to have a special day to celebrate women when they are so already fantastic and exceptionally brilliant in the physical sciences?

Check out this blog post-
https://sciencesprings.wordpress.com/2018/03/08/from-the-conversation-women-in-stem-perish-not-publish-new-study-quantifies-the-lack-of-female-authors-in-scientific-journals/

“”I have done a couple of STEM events, but there have never been this many girls. There are so many here. It is really empowering. Go girls in STEM!” Eama, Grade 12

Today’s Inspiring Future Women in Science conference was a success. Mona Nemar, Canada’s Chief Science Advisor, gave opening remarks encouraging the students in attendance to take advantage of the opportunity to learn from the speakers to come.

“The days of women being held back or being excluded from science are over. Now, more than ever women are entering, remaining in, and revolutionizing the science fields. Today is a shining example of that.”
-Mona Nemar, Chief Science Advisor, Government of Canada

Mona, read my above post on women getting not published.

The speakers and panelists, who included a chemist, engineer, astronomer, ecologist, and surgeon, talked about the challenges and triumphs that a career in STEM brings. Students were then treated to a speed mentoring session where they were able to ask questions and interact with women from a broad number of STEM careers. Read more about how this conference is inspiring young women here.

“This conference showed me there are so many things you can do going into [a career in STEM], so now I feel more inspired, and I feel more confident and not scared to go into science.” Lealan, Age 16

Programs like Perimeter’s “Inspiring Future Women in Science” conference are helping young women see their own potential and reach out for careers in STEM. And more talented female scientists today, means a brighter future tomorrow.

Thank you for being part of the equation.

From Brown: “Researchers discover new lead-free perovskite material for solar cells”

Brown University

February 13, 2018
Kevin Stacey
kevin_stacey@brown.edu
401-863-3766

Getting the lead out
Researchers have shown that titanium is an attractive choice to replace the toxic lead in the prevailing perovskite thin film solar cells. Padture Lab / Brown University

A class of materials called perovskites has emerged as a promising alternative to silicon for making inexpensive and efficient solar cells. But for all their promise, perovskites are not without their downsides. Most contain lead, which is highly toxic, and include organic materials that are not particularly stable when exposed to the environment.

Now a group of researchers at Brown University and University of Nebraska – Lincoln (UNL) has come up with a new titanium-based material for making lead-free, inorganic perovskite solar cells. In a paper published in the journal Joule (a new energy-focused sister journal to Cell), the researchers show that the material can be a good candidate, especially for making tandem solar cells — arrangements in which a perovskite cells are placed on top of silicon or another established material to boost the overall efficiency.

“Titanium is an abundant, robust and biocompatible element that, until now, has been largely overlooked in perovskite research,” said the senior author of the new paper, Nitin Padture, the Otis E. Randall University Professor in Brown’s School of Engineering and director of Institute for Molecular and Nanoscale Innovation. “We showed that it’s possible to use titanium-based material to make thin-film perovskites and that the material has favorable properties for solar applications which can be tuned.”

Interest in perovskites, a class of materials with a particular crystalline structure, for clean energy emerged in 2009, when they were shown to be able to convert sunlight into electricity. The first perovskite solar cells had a conversion efficiency of only about 4 percent, but that has quickly skyrocketed to near 23 percent, which rivals traditional silicon cells. And perovskites offer some intriguing advantages. They’re potentially cheaper to make than silicon cells, and they can be partially transparent, enabling new technologies like windows that generate electricity.

“One of the big thrusts in perovskite research is to get away from lead-based materials and find new materials that are non-toxic and more stable,” Padture said. “Using computer simulations, our theoretician collaborators at UNL predicted [ACS Energy Letters] that a class of perovskites with cesium, titanium and a halogen component (bromine or/and iodine) was a good candidate. The next step was to actually make a solar cell using that material and test its properties, and that’s what we’ve done here.”

The team made semi-transparent perovskite films that had bandgap — a measure of the energy level of photons the material can absorb — of 1.8 electron volts, which is considered to be ideal for tandem solar applications. The material had a conversion efficiency of 3.3 percent, which is well below that of lead-based cells, but a good start for an all-new material, the researchers say.

“There’s a lot of engineering you can do to improve efficiency,” Yuanyuan Zhou, an assistant professor (research) of engineering at Brown and a study co-author. “We think this material has a lot of room to improve.”

Min Chen, a Ph.D. student of materials science at Brown and the first author of the paper, used a high-temperature evaporation method to prepare the films, but says the team is investigating alternative methods. “We are also looking for new low-temperature and solvent-based methods to reduce the potential cost of cell fabrication,” he said.

The research showed the material has several advantages over other lead-free perovskite alternatives. One contender for a lead-free perovskite is a material made largely from tin, which rusts easily when exposed to the environment. Titanium, on the hand, is rust-resistant. The titanium-perovskite also has an open-circuit voltage — a measure of the total voltage available from a solar cell — of over one volt. Other lead-free perovskites generally produce voltage smaller than 0.6 volts.

“Open-circuit voltage is a key property that we can use to evaluate the potential of a solar cell material,” Padture said. “So, having such a high value at the outset is very promising.”

The researchers say that material’s relatively large bandgap compared to silicon makes it a prime candidate to serve as the top layer in a tandem solar cell. The titanium-perovskite upper layer would absorb the higher-energy photons from the sun that the lower silicon layer can’t absorb because of its smaller bandgap. Meanwhile, lower energy photons would pass through the semi-transparent upper layer to be absorbed by the silicon, thereby increasing the cell’s total absorption capacity.

“Tandem cells are the low-hanging fruit when it comes to perovskites,” Padture said. “We’re not looking to replace existing silicon technology just yet, but instead we’re looking to boost it. So if you can make a lead-free tandem cell that’s stable, then that’s a winner. This new material looks like a good candidate.”

Other co-authors on the paper were Ming-Gang Ju, Alexander Carl, Yingxia Zong, Ronald Grimm, Jiajun Gu and Xiao Cheng Zeng. The research was supported by the National Science Foundation (OIA-1538893, DMR-1420645).

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Welcome to Brown

Located in historic Providence, Rhode Island and founded in 1764, Brown University is the seventh-oldest college in the United States. Brown is an independent, coeducational Ivy League institution comprising undergraduate and graduate programs, plus the Alpert Medical School, School of Public Health, School of Engineering, and the School of Professional Studies.

With its talented and motivated student body and accomplished faculty, Brown is a leading research university that maintains a particular commitment to exceptional undergraduate instruction.

Brown’s vibrant, diverse community consists of 6,000 undergraduates, 2,000 graduate students, 400 medical school students, more than 5,000 summer, visiting and online students, and nearly 700 faculty members. Brown students come from all 50 states and more than 100 countries.

Undergraduates pursue bachelor’s degrees in more than 70 concentrations, ranging from Egyptology to cognitive neuroscience. Anything’s possible at Brown—the university’s commitment to undergraduate freedom means students must take responsibility as architects of their courses of study.

From WIRED: “The Sunny Optimism of Clean Energy Shines Through Tech’s Gloom”

WIRED

01.01.18
Clive Thompson

ZOHAR LAZAR

The mood around tech is dark these days. Social networks are a cesspool of harassment and lies. On-demand firms are producing a bleak economy of gig labor. AI learns to be racist. Is there anyplace where the tech news is radiant with old-fashioned optimism? Where good cheer abounds?

Why, yes, there is: clean energy. It is, in effect, the new Silicon Valley—filled with giddy, breathtaking ingenuity and flat-out good news.

This might seem surprising given the climate-change denialism in Washington. But consider, first, residential solar energy. The price of panels has plummeted in the past decade and is projected to drop another 30 percent by 2022. Why? Clever engineering breakthroughs, like the use of diamond wire to slice silicon wafers into ever-skinnier slabs, producing higher yields with less raw material.

Manufacturing costs are down. According to US government projections, the fastest-growing occupation of the next 10 years will be solar voltaic installer. And you know who switched to solar power last year, because it was so cheap? The Kentucky Coal Museum.

Tech may have served up Nazis in social media streams, but, hey, it’s also creating microgrids—a locavore equivalent for the solar set. One of these efforts is Brooklyn-based LO3 Energy, a company that makes a paperback-sized device and software that lets owners of solar-equipped homes sell energy to their neighbors—verifying the transactions using the blockchain, to boot. LO3 is testing its system in 60 homes on its Brooklyn grid and hundreds more in other areas.

“Buy energy and you’re buying from your community,” LO3 founder Lawrence Or­sini tells me. His chipsets can also connect to smart appliances, so you could save money by letting his system cycle down your devices when the network is low on power. The company uses internet logic—smart devices that talk to each other over a dumb network—to optimize power consumption on the fly, making local clean energy ever more viable.

But wait, doesn’t blockchain number-crunching use so much electricity it generates wasteful heat? It does. So Orsini invented DareHenry, a rack crammed with six GPUs; while it processes math, phase-­changing goo absorbs the outbound heat and uses it to warm a house. Blockchain cogeneration, people! DareHenry is 4 feet of gorgeous, Victorian­esque steampunk aluminum—so lovely you’d want one to show off to guests.

Solar and blockchain are only the tip of clean tech. Within a few years, we’ll likely see the first home fuel-cell systems, which convert natural gas to electricity. Such systems are “about 80 percent efficient,” marvels Garry Golden, a futurist who has studied clean energy. (He’s also on LO3’s grid, with the rest of his block.)

The point is, clean energy has a utopian spirit that reminds me of the early days of personal computers. The pioneers of the 1970s were crazy hackers, hell-bent on making machines cheap enough for the masses. Everyone thought they were nuts, or small potatoes—yet they revolutionized communication. When I look at Orsini’s ­blockchain-based energy-trading routers, I see the Altair. And there are oodles more inventors like him.

Mind you, early Silicon Valley had something crucial that clean energy now does not: massive federal government support. The military bought tons of microchips, helping to scale up computing. Trump’s band of climate deniers aren’t likely to be buyers of first resort for clean energy, but states can do a lot. California already has, for instance, by creating quotas for renewables. So even if you can’t afford this stuff yourself, you should pressure state and local officials to ramp up their solar energy use. It’ll give us all a boost of much-needed cheer.

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From MIT: “A bipartisan message of clean energy progress”

MIT News

December 7, 2017
Francesca McCaffrey

MIT Vice President for Research Maria Zuber and former U.S. Secretary of Energy Ernest Moniz, the Cecil and Ida Green Professor of Physics and Engineering Systems emeritus at MIT, engaged in a fireside chat at the C3E Women in Clean Energy Symposium, discussing technology, policy, and the importance of women’s leadership in STEM fields. Photo: Justin Knight

In the face of global challenges, leading women in energy and climate convene at the C3E 2017 Clean Energy Symposium.

The diverse group of energy leaders who spoke at the 2017 Clean Energy, Education, and Empowerment (C3E) Women in Clean Energy Symposium hailed from different professional, personal, and political backgrounds, bringing many viewpoints on the conference’s theme of transforming energy infrastructure — nationally and internationally — for a transition to a low-carbon future. Though opinions on the best strategies to bring about this transition differed, all agreed on the urgency of deploying strategies and technologies to achieve it.

“It’s inspiring to be surrounded by so many women at different stages of their careers, approaching clean energy issues from a wide range of perspectives and professions,” MIT Energy Initiative (MITEI) executive director Martha Broad told the audience, which included industry professionals, government officials, and academic researchers, as well as students who were giving poster presentations.

“MITEI is thrilled to host this event, celebrate our awardees, and hear from thought leaders in this space.” Broad is also a U.S. C3E ambassador — part of a cohort of senior leaders in business, government, and academia who serve as role models and advocates for women in clean energy.

Now in its sixth year being held at MIT, the C3E Symposium brings women at all stages of their careers together to discuss solutions to the most pressing energy issues of the day and to celebrate awardees from various disciplines. Founded under the auspices of the 25-government Clean Energy Ministerial, the U.S. C3E Initiative aims to advance clean energy by helping to close the gender gap and enabling the full participation of women in the clean energy sector. MITEI and the U.S. Department of Energy (DOE) have collaborated on the symposium since 2012, and the Stanford Precourt Institute for Energy joined the collaboration in 2016.

Inclusive clean energy solutions for the future

Panels throughout the two-day conference focused on strategies across the technology, policy, and business spheres to address energy challenges both local and global. Nevada State Senator Pat Spearman stressed the importance of forward-looking governance on a panel about innovative policies. For Spearman, innovation means taking advantage of Nevada’s natural energy resources, from an abundance of solar energy in the south to the potential for geothermal in the north. It also means developing progressive policies that facilitate timely regulatory changes in response to new and emerging technologies.

Spearman is particularly determined to account for low-income constituents with provisions in energy policy measures.

“We need to always include the fact that those who are on the lower spectrum of the income level are usually the ones who are the least likely to adopt because the price has not come down far enough,” she said. ”So those who can afford it do, and those who can’t, don’t. For me, it’s a matter of environmental and economic justice.”

On a panel about the future of the electric grid, Marcy Reed, National Grid’s chief of business operations, expanded on the importance of being mindful of customers’ needs.

“We have 20th-century infrastructure operating in a world with 21st-century demands,” she said, adding that at Massachusetts-based National Grid, and her colleagues take their cue on how to best affect change from their customers. “They’re savvy and passionate and environmentally-minded. They also want their energy delivery system to be modern and responsive to their needs.” She added that having the right tools and information enables customers to make energy-efficient choices.

Ugwem Eneyo, a Stanford University graduate and co-founder of Solstice Energy Solutions, explained how data are similarly important to her customers in sub-Saharan Africa.

“With the development and integration of solar and storage into the energy mix, data and connectivity will play a significant role in enabling future distributed energy grids, and will also play a significant role in driving efficiency and productivity of these distributed energy assets,” Eneyo said. Her company’s technology uses a data-driven approach to intelligently manage distributed energy, helping consumers plan for their own cost- and energy-efficient power use.

As a panelist for a session on international energy infrastructure developments, Radhika Khosla discussed ongoing changes in India’s energy system.

“Not only is India a very large emitter, but it is also one of the most vulnerable countries to climate change,” said Khosla, who is a visiting scientist at the MIT Tata Center for Technology and Design. Citing rising temperatures, impending infrastructure and demographic transitions, and increased air pollution as a few among several factors, Khosla added, “What happens to India in terms of its growth trajectory matters not only in the global context, but also in the Indian context.”

Leveraging women’s expertise for the clean energy transition

Underscoring the bipartisan message of the importance of women’s involvement in the clean energy transition, U.S. Secretary of Energy Rick Perry gave a video keynote address in which he noted the positive effect that gatherings like the C3E Symposium can have in trying to address current energy challenges.

“Each of you here today helps advance innovation, connect new ideas with existing markets, and use technology to promote clean energy solutions,” Perry said. “But even more importantly, your work will inspire the next generation of women leaders in STEM, and that is sorely needed.”

Secretary Perry’s predecessor under President Obama, Ernest Moniz, engaged in a fireside chat with MIT Vice President for Research Maria T. Zuber, the E. A. Griswold Professor of Geophysics. Zuber and Moniz, who is the Cecil and Ida Green Professor of Physics and Engineering Systems Emeritus and special advisor to the MIT president, discussed the need for a rapid transition to a low-carbon economy and also highlighted the significance of initiatives like C3E in the mission to support and increase women’s involvement in STEM fields.

“If you can see it, you can be it”

Every year, C3E honors mid-career women who have made particular contributions to their area of energy and invites previous awardees to attend the conference. This year’s award-winners were: Anna Bautista, vice president of construction and workforce development for Grid Alternatives (Advocacy Award); Leslie Marshall, corporate energy engineering lead for General Mills (Business Award); Nicole Lautze, associate faculty member at the University of Hawaii Manoa and founder of the Hawaii Groundwater and Geothermal Resources Center (Education Award); Emily Kirsch, founder and CEO of intelligent energy incubator Powerhouse (Entrepreneurship Award); Chris LaFleur, program lead for Hydrogen Safety, Codes, and Standards at Sandia National Laboratories (Government Award); Allison Archambault, president of EarthSpark International (International Award); Sarah Valdovinos, co-founder of Walden Green Energy (Law and Finance Award); and Inês M.L. Azevedo, principal investigator and co-director for the Climate and Energy Decision-Making Center at Carnegie Mellon University (Research Award).

Senators Lisa Murkowski (R-Alaska) and Maria Cantwell (D-Washington) were co-recipients of the C3E Lifetime Achievement award for their work on energy issues, including their leadership roles on the Senate Energy and Natural Resources Committee and their stewardship of the bipartisan Energy and Natural Resources Act of 2017.

In her prerecorded remarks, Murkowski said “We all recognize [that] women bring a different perspective to problem-solving, so it’s imperative, whether in your fields or mine, if we want to find the best and most innovative solutions to our biggest challenges, the female perspective must be present and active at the decision table.”

Cantwell, in written remarks delivered by C3E Ambassador Melanie Kenderdine, said, “I am proud to work alongside you as we continue to celebrate the women who are making incredible achievements in clean energy.”

Carol Battershell, principal deputy director of the DOE’s Office of Energy Policy and Systems Analysis and a U.S. C3E ambassador, noted how meaningful it was for the C3E ambassadors to have the honor of choosing the awardees. Several other speakers also remarked on how it felt to be in the presence of a group of such impactful leaders and diverse practitioners in the clean energy sector.

Sherina Maye Edwards, energy commissioner for the Illinois Commerce Commission, prefaced her comments by saying, “So often, I am on the road talking to rooms full of people who look nothing like me. It is so nice to see not just such a fantastic group of women, but also such a diverse group of women.”

Awardee Emily Kirsch, who attended the first C3E conference in 2013, met many C3E ambassadors there who mentored and encouraged her while she was launching her company. Accepting the Entrepreneurship Award, Kirsch said, “C3E is a testament to the idea that if you can see it, you can be it.”

See the full article here .

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Stem Education Coalition

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 AGU: “22 Years of Solar and Heliospheric Observatory”

American Geophysical Union

From the Prow

30 November 2017
Bernhard Fleck (ESA SOHO Project Scientist, NASA/GSFC)
Joseph Gurman (NASA SOHO Project Scientist, NASA/GSFC)
David Sibeck (Past President, AGU Space Physics and Aeronomy Section, NASA/GSFC)

ESA/NASA SOHO

The Solar and Heliospheric Observatory (SOHO) studies the internal structure of the Sun, its outer atmosphere and solar winds, and the stream of ionized gas that is constantly blowing outward through the Solar System.

The 2nd of December 2017 marks the 22nd launch anniversary of the European Space Agency (ESA) – NASA Solar and Heliospheric Observatory (SOHO). SOHO is the longest-lived heliophysics mission still operating and has provided a nearly continuous record of solar and heliospheric phenomena over a full 22-year magnetic cycle (two 11-year sunspot cycles).

SOHO’s findings have been documented in over 5000 papers in the peer reviewed literature, authored by more than 4,000 scientists worldwide.

SOHO provided the first ever images of structures and flows below the Sun’s surface and of activity on the far side of the Sun. SOHO discovered sunquakes and eliminated uncertainties in the internal structure of the Sun as a possible explanation for the “neutrino problem” which concerned the large discrepancy between the high flux of solar neutrinos – particles which are now believed to possess mass and travel at almost the speed of light – predicted from the Sun’s luminosity and the much lower flux that is observed.

The ultraviolet imagers and spectrometers on SOHO have revealed an extremely dynamic solar atmosphere where plasma flows play an important role and discovered dynamic solar phenomena such as coronal waves.

SOHO measured the acceleration profiles of both the slow and fast solar wind and identified the source regions of the fast solar wind.

SOHO revolutionized our understanding of solar-terrestrial relations and dramatically boosted space weather forecasting capabilities by providing, in a near-continuous stream, a comprehensive suite of images covering the dynamic atmosphere and extended corona.

SOHO has measured and characterized over 28,000 coronal mass ejections (CMEs). CMEs are the most energetic eruptions on the Sun and the major driver of space weather. They are responsible for all of the largest solar energetic particle events in the heliosphere and are the primary cause of major geomagnetic storms. SOHO’s visible-light CME measurements are considered a critical part of the US National Space Weather Action Plan.

For two solar activity cycles SOHO has measured the total solar irradiance (the “solar constant”) as well as variations in the extreme ultraviolet flux, both of which are important to understand the impact of solar variability on Earth’s climate.

Besides watching the Sun, SOHO has become the most prolific discoverer of comets in astronomical history: as of late 2017, more than 3,400 comets have been found by SOHO, most of them by amateurs accessing SOHO real-time data via the Internet.

In such complex areas of research as solar physics, progress is not limited to the work of a few people working by themselves. The scientific achievements of the SOHO mission result from a concerted, multi-disciplinary effort by a large, international community of solar scientists, including sound investments in space hardware, coupled with vigorous and well-coordinated scientific operations and interpretation efforts.

Also, it is important to note that SOHO was not conceived as a “stand-alone” mission. Together with Cluster – a set of four identical spacecraft operated as a single experiment to explore in three dimensions the plasma and small-scale structure in the Earth’s plasma environment – SOHO formed the Solar-Terrestrial Science Programme (STSP), the first cornerstone of the European Space Agency’s long-term program called “Space Science Horizon 2000”, which was implemented in collaboration with NASA.

ESA Cluster (4 spacecraft) which work with SOHO

STSP itself was part of an even larger international effort by NASA, ESA, and JAXA: The International Solar-Terrestrial Physics (ISTP) program, which included SOHO, Cluster, Geotail, Wind, and Polar, achieved an unprecedented understanding of the physics of solar-terrestrial relations by coordinated, simultaneous investigations of the Sun-Earth space environment over an extended period of time and, thus, can be considered the predecessor of NASA’s Living With a Star (LWS) program.

While SOHO’s continued operation into the 2020s depends only on the longevity of its solar arrays, there is as yet no defined mission to succeed it in providing continuous, earth-Sun-line coronagraph observations. Prior to SOHO, our maximum warning time for extreme, earth-directed solar storms was measured in minutes; now it is 1 – 2 days. It would be prudent to preserve that advantage.

See the full post here .

Please help promote STEM in your local schools.

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The purpose of the American Geophysical Union is to promote discovery in Earth and space science for the benefit of humanity.

To achieve this mission, AGU identified the following core values and behaviors.

Core Principles

As an organization, AGU holds a set of guiding core values:

The scientific method
The generation and dissemination of scientific knowledge
Open exchange of ideas and information
Diversity of backgrounds, scientific ideas and approaches
Benefit of science for a sustainable future
International and interdisciplinary cooperation
Equality and inclusiveness
An active role in educating and nurturing the next generation of scientists
An engaged membership
Unselfish cooperation in research
Excellence and integrity in everything we do

When we are at our best as an organization, we embody these values in our behavior as follows:

We advance Earth and space science by catalyzing and supporting the efforts of individual scientists within and outside the membership.
As a learned society, we serve the public good by fostering quality in the Earth and space science and by publishing the results of research.
We welcome all in academic, government, industry and other venues who share our interests in understanding the Earth, planets and their space environment, or who seek to apply this knowledge to solving problems facing society.
Our scientific mission transcends national boundaries.
Individual scientists worldwide are equals in all AGU activities.
Cooperative activities with partner societies of all sizes worldwide enhance the resources of all, increase the visibility of Earth and space science, and serve individual scientists, students, and the public.
We are our members.
Dedicated volunteers represent an essential ingredient of every program.
AGU staff work flexibly and responsively in partnership with volunteers to achieve our goals and objectives.

From EPFL: “Hydroelectric power plants have to be adapted for climate change”

École Polytechnique Fédérale de Lausanne EPFL

19.10.17
Clara Marc

© 2017 LMH – Grande Dixence dam. This hydroelectric power complex generates some 2 billion kWh of power per year
Of all the electricity produced in Switzerland, 56% comes from hydropower. The life span of hydroelectric plants, which are massive and expensive to build and maintain, is measured in decades, yet the rivers and streams they depend on and the surrounding environment are ever-changing. These changes affect the machinery and thus the amount of electricity that can be revised. EPFL’s Laboratory for Hydraulic Machines (LMH) is working on an issue that will be very important in the coming years: the impact of sediment erosion on turbines, which are the main component of this machinery. The laboratory’s work could help prolong these plants’ ability to produce electricity for Switzerland’s more than eight million residents.

One of the aims of Switzerland’s 2050 Energy Strategy is to increase hydroelectric production. The Swiss government therefore also needs to predict the environment in which these power plants will operate so that the underlying technology can keep pace with changing needs and future conditions. “In Switzerland, the glaciers and snow are melting more and more quickly. This affects the quality of the water, with a sharp rise in the content of sediments,” says François Avellan, who heads the LMH and is one of the study’s authors. “The sediments are very aggressive and erode the turbines.” This undermines the plants’ efficiency, leaves cavities in the equipment and leads to an increase in vibrations – and in the frequency and cost of repairs. To top things off, the turbines’ useful life is reduced. Under the umbrella of the Swiss Competence Center for Energy Research – Supply of Electricity (SCCER-SoE) and with the support of the Commission for Technology and Innovation (CTI), EPFL has teamed up with General Electric Renewable Energy in an effort to better understand and predict the process of sediment erosion. The aim is to lengthen the hydropower plants’ life span through improved turbines and more effective operating strategies.

Tiny particles with an outsized impact

One of the challenges facing researchers in the field of hydropower is that they cannot run experiments directly on power plants because of the impact and cost of a plant’s outage. They must therefore limit their investigations to simulations and reduced-scale physical model tests. In response to this challenge, the LMH has come up with a novel multiscale computer model that predicts sediment erosion in turbines with much greater accuracy than other approaches. The results have been published in the scientific journal Wear. “Sediment erosion, like many other problems in nature, is a multiscale phenomenon. It means that behavior observed at the macroscopic level is the result of a series of interactions at the microscopic level,” says Sebastián Leguizamón, an EPFL doctoral student and lead author of the study. “The sediments are extremely small and move very fast, and their impact lasts less than a microsecond. On the other hand, the erosion process we see is gradual, taking place over the course of many operating hours and affecting all the turbine.”

A multiscale solution

The researchers therefore opted for a multiscale solution and modeled the two processes involved in erosion separately. At the microscopic level, they focused on the extremely brief impact of the minuscule sediments that strike the turbines, taking into account parameters such as the angle, speed, size, shape – and even composition – of the slurry. At the macroscopic level, they looked at how the sediments are transported by water flow, as this affects the flux, distribution and density of sediments reaching the walls of the turbine flow passages. The results were then combined in order to develop erosion predictions. “It’s not possible to study the entire process of erosion as a whole. The sediments are so small and the period of time over which the process takes place so long that replicating the process would take hundreds of years of calculations and require a computer that doesn’t exist yet,” says Leguizamón. “But the problem becomes manageable when you decouple the different phases.”

Adapting to the future

With conclusive results in hand, the LMH has now moved on to the next phase, which consists in characterizing the materials used in the turbines. Following this step, the researchers will be able to apply the new model to existing hydroelectric facilities. The stakes are global when it comes to retrofitting turbines in response to climate change, as hydropower accounts for 17% of the world’s electricity production. Turbines offer little leeway and have to operate in a wide range of environments – including monsoon regions and anything from tropical to alpine climates. If turbines are to last, changes will have to be made to both their underlying design and how they are operated. “While I was evaluating a hydro plant in the Himalayas, my contacts there told me that if a turbine made it through more than one monsoon season, that was a success!” says Avellan.

This study is part of CTI project No. 17568.1 PFEN-IW GPUSpheros. It was conducted in conjunction with General Electric Renewable Energy under the umbrella of the Swiss Competence Center for Energy Research – Supply of Electricity (SCCER-SoE).

A multiscale model for sediment impact erosion simulation using the finite volume particle method, Sebastián Leguizamón, Ebrahim Jahanbakhsh, Audrey Maertens, Siamak Alimirzazadeh and François Avellan. Science Direct.

See the full article here .

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Stem Education Coalition

EPFL is Europe’s most cosmopolitan technical university with students, professors and staff from over 120 nations. A dynamic environment, open to Switzerland and the world, EPFL is centered on its three missions: teaching, research and technology transfer. EPFL works together with an extensive network of partners including other universities and institutes of technology, developing and emerging countries, secondary schools and colleges, industry and economy, political circles and the general public, to bring about real impact for society.