Batteries can’t solve the world’s biggest energy-storage problem – One startup in Denmark has a solution – Solving CO2 Emissions and … Energy Storage


Copenhagen, Denmark

Sometimes, there can be too much of a good thing.

Every so often, from California to Germany, there’s news of “negative electricity prices,” a peculiar side effect of global efforts to generate clean energy.

Solar farms and wind turbines produce varying amounts of power based on the vagaries of the weather. So we build electrical grids to handle only the power levels we expect in a given location.

But in some cases, there’s more sun or wind than expected, and these renewable energy sources pump in more power than the grid can handle. The producers of that power then have to pay customers to use up the excess electricity; otherwise, the grid would be overloaded and fail.

As we build more and more renewable-power capacity in efforts to meet the emissions-reduction goals of the Paris climate agreement, these situations will become more common. Startups led by entrepreneurs who see this future on the horizon are now looking for ways to make money off the inevitable excess clean electricity.

On a mildly chilly day in April, with the smell of poo in the air, I met one of these startups at a sewage-water treatment plant in Copenhagen, Denmark. 

Electrochaea takes carbon dioxide produced during the process of cleaning wastewater, and converts it into natural gas. That alone would be impressive enough; if we want to stop global warming in its tracks, we need to do everything we can to keep CO2 from entering the atmosphere. But Electrochaea has also figured out a way to power the whole enterprise with the excess green energy produced during particularly sunny and windy days that otherwise would have gone to waste, because there would have been no way to store it.

In other words, when scaled up, Electrochaea’s process could be an answer to one of the biggest problems of the 21st century: energy storage, while also making a dent in cutting emissions.

The Electrochaea pilot plant in Copenhagen, with the Biofos water-treatment plant in the background.
This article is part of The Race to Zero Emissions series investigating carbon-capture technology. You can also read our feature laying out the case for using the technology to fight climate change.

The battery problem

The biggest problem with wind and solar energy is that they’re intermittent. There might be violent winds one day, and calm skies the next; broiling sunshine on Monday and 100% cloud cover on Tuesday. Some argue this problem is easily overcome by storing any excess energy in batteries until it’s needed at a later time. Further, battery advocates say, even though the bookcase-sized batteries required to store solar energy for a small home are expensive today, prices are falling and will continue to fall for some time.

Except it’s not that easy. The batteries on the market for these applications are, essentially, large versions of the lithium-ion batteries found in mobile phones. They can only store energy for a certain amount of time—weeks, at most. As soon as the charging source is removed, they start to lose the charge.

That’s not a problem if the batteries are for ironing out the peaks and troughs of daily use. The trouble is that humanity’s energy demand is skewed based on local seasons, which requires sometimes drawing on every available source, and sometimes not using much energy at all.

Mumbai’s peak energy demand is during the hottest days of summer, when people run air conditioners to survive. London’s peak energy demand comes during the coldest days of winters, when people burn natural gas to heat their homes and offices.

Peak energy demand, whether for heating or cooling, can be as much as 20 times the energy consumed on an average day. Today, we shovel more coal or pump more natural gas into fossil-fuel power plants on those high-demand days. Some places, like Bridgeport in Connecticut, have old fossil-fuel plants, often coal, that they keep shut down most of the year and fire up only during peak demand. Obviously, that won’t work in a future powered by renewable energy.

There are two solutions on the table for inter-seasonal energy storage, and they both involve massive investment in infrastructure: First, you could build so many solar panel fields or so many wind turbines that you could produce much more than 20 times the power of an average day. The upshot: you’d have much more excess energy on a low-demand day, but would at least be able to fill demand on peak-demand days. The second option is to get so many batteries that they can store up enough excess energy that, even as they lose their charge, there’s still enough power to get the grid through peak-demand days.

Even if both renewable generation and storage were affordable enough for these plans—and they’re not, yet—there’s still another economic wall that might be impossible to traverse: Most of the time, your new gigantic power plant and fleet of batteries would be useless, because peak demand happens only a few times each year. No government can waste the money needed to build something with so little utility.

Store it another way

Beyond batteries, there are other mechanical ways to store energy. One is to pump water into elevated lakes. Another is to compress air with excess energy. Yet another is to store energy in the form of a high-speed rotating disk. But, like batteries, none of these options can store energy between seasons.

There is one option for the inter-seasonal problem called underground thermal-energy storage. It works on a simple principle: no matter the temperature above ground, at a depth of about 15 meters, temperature in most places on Earth is about the same: 10°C (or 50°F). The planet’s soil provides natural insulation, and, in theory, we could use that insulation to store energy.

There have been successful pilot projects around the world showing you can set up solar panels that, after filling the grid, use any excess electricity to heat gravel, heat-carrying chemicals, or water stored in tanks deep underground. With enough insulation, the heat could be stored for months, until it’s needed in homes nearby, and delivered to them via pipes and heat pumps. (This heat energy can also be converted to run air conditioners, where cooling is needed instead of heating.)

There are just two problems when it comes to scaling up: First, it’s expensive to build. Even if the cost of construction and management were to come down, if cities and towns haven’t already planned for underground reservoirs (and most haven’t), then it can be prohibitively exorbitant to find and secure the space. Second, the solution only works at a local scale, because transporting heat comes with natural losses. So the farther you need to move it from the storage site, the more loss you have to deal with.

Electrochaea provides another option, where renewable energy could be stored indefinitely and transported without losses.

The green goo

If you don’t mind the smell, wastewater treatment plants are fascinating. The Copenhagen plant takes in all the water sent down toilets, bathrooms, and kitchen sinks, and puts out H2O that’s nearly clean enough to drink—just one more step would be required, the plant operator told me. But since the city has no shortage of water, the treatment plant dumps its clean, but non-potable water into the North Sea.

Before that, the water goes through dozens of steps, including one where organic matter is allowed to settled to the bottom of large, open tanks. This sludge, rich in carbon-containing molecules, is transferred to a sealed bioreactor where microbes filtered from local soil are added. If this were done in the open tanks, the microbes would break the matter down slowly to produce carbon dioxide. But, in the bioreactor, in the absence of oxygen, a different set of microbes springs into action. They produce methane—the primary component of natural gas—instead.

The facility takes the methane (and any remaining sludge that can’t be broken down) and then burns it in a biomass power plant. “We produce more energy than we consume to clean up the water coming into our plant,” says Dines Thornberg, a manager at Biofos, the part-government-owned company that operates the treatment plant.

” … Batteries can’t solve the world’s biggest energy-storage problem. One startup has a solution.”

That may be true. But the process still does pollute, since some chemical degradation happens independent of microbes and creates carbon dioxide. To help Denmark hit its Paris agreement goals, Biofos wants to cut its own carbon footprint. That’s why the company gave Electrochaea valuable space at its plant to build the pilot-scale chemical plant that completes the job that Biofos’s microbes couldn’t do: convert the carbon dioxide released in the bioreactor into methane. To achieve this amazing transformation, Electrochaea gets help from microbial life called archaea.

Archaea are the oldest of the three branches of life, which include bacteria and eukaryotes (consisting of all other more advanced organisms including humans). Their ancient survival skills include one that us humans now can put to good use: an ability to naturally take in CO2 and turn it into methane.

Most scientists believe life on Earth was formed in hydrothermal vents, created by underwater volcanoes. The temperatures there can reach 400°C (750°F), far higher than that of boiling water. But the water in the vents doesn’t boil and the gases the vents release—including carbon dioxide and hydrogen—don’t explode thanks to the tremendous pressure applied by miles of seawater above. Some archaea that live in the vents have learned to use carbon dioxide as food, combining the carbon (C) from carbon dioxide (CO2) with hydrogen (H2) to form and release methane (CH4). Humans do the reverse, consuming carbon-rich food and combining it with oxygen—both readily available on land—to make and expel carbon dioxide.

Electrochaea’s pilot plant on Biofos’s premises takes up an area the size of a tennis court. As usual for a chemical factory, there’s a tangle of stainless steel pipes with sensors and control valves. The pipes all lead to a big cylindrical bioreactor, about 10 meters (30 ft) tall, kept at 60°C (140°F) and eight times the atmospheric pressure. Through a small glass window at the bottom of the bioreactor, I can see a bubbling mixture the color of an avocado milkshake. That’s Electrochaea’s proprietary species of archaea, cultured and bred to efficiently combine carbon dioxide and hydrogen to produce methane.

           Electrochaea’s lab-scale bioreactor with archaea producing methane.

The gases injected into the bioreactor come from two sources. The wastewater-treatment plant sends a mixture of carbon dioxide and methane. Meanwhile, two shipping container-sized electrolyzers use renewable electricity to split water into hydrogen and oxygen. The oxygen is sent off into the atmosphere, and the hydrogen to the Electrochaea bioreactor.

The microbes are so effective that in the time the mixture of gases travels from the bottom of the bioreactor to its top, 99 out of every 100 molecules of carbon dioxide and hydrogen are converted into methane, water, and heat. The heat is useful: it helps keep the temperature inside the reactor steady. Meanwhile, as the archaea consume the CO2 and H2, they multiply. Because they are naturally occurring species, extra archaea can be simply dumped into sewers, flushed out by the water also created in the process.

The valuable product from the reaction is methane. In fact, the stuff created through this process is even more valuable than typical methane. It’s “renewable methane” or “biomethane,” because the gas was produced from non-fossil-fuel sources and without any fossil-fuel power. This methane can be used to run boilers in homes, power plants, and even cars or buses. It’s a cleaner fuel than coal and oil, producing the fewest emissions for each unit of energy released. Methane can also be very easily stored. In fact, across Europe, there are large underground stores, connected by pipes that can safely transport the gas.

When the system runs at full capacity, the archaea produce about 50 cubic meters of natural gas per hour. For every unit of energy of electricity fed into the system, it produces about 0.75 units of energy stored in the form of methane, according to Doris Hafenbradl, Electrochaea’s chief scientist. That’s not as good as lithium-ion batteries, which can reach near 100% efficiency. But unlike the energy stored in batteries, once methane is produced it can be stored indefinitely, because it doesn’t spontaneously degrade into other chemicals. If this process could be scaled up, it could solve renewable energy’s inter-seasonal storage problem.

Electrochaea’s plant does not need to be close to solar farms or wind turbines, because excess electricity can be extracted from anywhere on the grid. The limitations on location come based on access to CO2. Water treatment plants are fair game and so are ethanol producers (such as beer and liquor factories). Exhaust gases from power plants could be used, but they will need to be cleaned to remove sulfur and particulate emissions, which could harm archaea.

Solving problems at scale

The Copenhagen plant is one of three where Electrochaea has successfully installed its technology. The US National Renewable Energy Laboratory has one installation on its campus in Boulder, Colorado, and the last is part of a European Commission-funded project in Solothurn, Switzerland. Ultimately, Electrochaea’s core business model is to license the technology. The company is currently courting a Hungarian power company that wants to build a plant 10 times the size of the one in Copenhagen. It would be the startup’s biggest yet. And the carmaker Audi has shown interest in Electrochaea’s technology as a way to use biomethane in its natural-gas-powered cars.

Electrochaea is one of a growing number of players in the “power-to-gas” industry. ITM Power and Hydrogenics, for example, make electrolyzers that convert excess renewable energy into storable hydrogen. But hydrogen is not as widely used as natural gas. That’s why companies such as Electrochaea, MicrobEnergy, and ETOGas are betting that it’s worth the extra step of turning that hydrogen into methane. MicrobEnergy, as the name suggests, uses microbes for the conversion, just like Electrochaea. ETOGas, a Hitachi-supported startup, uses metal catalysts.

Doing it this way also gives these companies a potential second business model: Because these processes all involve injecting carbon dioxide into the system, it could turn out to be the case that they are hired to install their power-to-gas systems simply to reduce a facility’s CO2 emissions, whether it has an excess of renewable energy or not.

Electrochaea hasn’t secured a carbon-capture customer yet. And to be sure, its technology is carbon-capture and recycling—not storage or removal. The methane produced in the process will eventually be burned again, and that will put carbon dioxide into the atmosphere. In other words, it simply delays the production of greenhouse gases, instead of eliminating them.

That said, there is some value in delaying emissions. Every CO2 molecule not dumped in the atmosphere right now is a CO2 molecule that doesn’t absorb and retain sun’s heat. If nothing else, Electrochaea and companies like it may do their part in saving the planet simply by helping change the conversation around carbon dioxide, from treating it as a byproduct to considering it as a feedstock.

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MIT – 10 Technology Breakthroughs for 2019 Part II with Guest Curator – Bill Gates


MIT Nuclear 2 c-mod-internal-1

This is Part II of MIT’s  10 Technology Breakthroughs for 2019′ Re-Posted from MIT Technology Review, with Guest Curator Bill Gates. You can Read Part I Here

Part I Into from Bill Gates: How We’ll Invent the Future

was honored when MIT Technology Review invited me to be the first guest curator of its 10 Breakthrough Technologies. Narrowing down the list was difficult. I wanted to choose things that not only will create headlines in 2019 but captured this moment in technological history—which got me thinking about how innovation has evolved over time.

 

Robot dexterity

NICOLAS ORTEGA

  • Why it matters If robots could learn to deal with the messiness of the real world, they could do many more tasks.
  • Key Players OpenAI
    Carnegie Mellon University
    University of Michigan
    UC Berkeley
  • Availability 3-5 years

Robots are teaching themselves to handle the physical world.

For all the talk about machines taking jobs, industrial robots are still clumsy and inflexible. A robot can repeatedly pick up a component on an assembly line with amazing precision and without ever getting bored—but move the object half an inch, or replace it with something slightly different, and the machine will fumble ineptly or paw at thin air.

But while a robot can’t yet be programmed to figure out how to grasp any object just by looking at it, as people do, it can now learn to manipulate the object on its own through virtual trial and error.

One such project is Dactyl, a robot that taught itself to flip a toy building block in its fingers. Dactyl, which comes from the San Francisco nonprofit OpenAI, consists of an off-the-shelf robot hand surrounded by an array of lights and cameras. Using what’s known as reinforcement learning, neural-network software learns how to grasp and turn the block within a simulated environment before the hand tries it out for real. The software experiments, randomly at first, strengthening connections within the network over time as it gets closer to its goal.

It usually isn’t possible to transfer that type of virtual practice to the real world, because things like friction or the varied properties of different materials are so difficult to simulate. The OpenAI team got around this by adding randomness to the virtual training, giving the robot a proxy for the messiness of reality.

We’ll need further breakthroughs for robots to master the advanced dexterity needed in a real warehouse or factory. But if researchers can reliably employ this kind of learning, robots might eventually assemble our gadgets, load our dishwashers, and even help Grandma out of bed. —Will Knight

New-wave nuclear power

BOB MUMGAARD/PLASMA SCIENCE AND FUSION CENTER/MIT

Advanced fusion and fission reactors are edging closer to reality. 

New nuclear designs that have gained momentum in the past year are promising to make this power source safer and cheaper. Among them are generation IV fission reactors, an evolution of traditional designs; small modular reactors; and fusion reactors, a technology that has seemed eternally just out of reach. Developers of generation IV fission designs, such as Canada’s Terrestrial Energy and Washington-based TerraPower, have entered into R&D partnerships with utilities, aiming for grid supply (somewhat optimistically, maybe) by the 2020s.

Small modular reactors typically produce in the tens of megawatts of power (for comparison, a traditional nuclear reactor produces around 1,000 MW). Companies like Oregon’s NuScale say the miniaturized reactors can save money and reduce environmental and financial risks.

There has even been progress on fusion. Though no one expects delivery before 2030, companies like General Fusion and Commonwealth Fusion Systems, an MIT spinout, are making some headway. Many consider fusion a pipe dream, but because the reactors can’t melt down and don’t create long-lived, high-level waste, it should face much less public resistance than conventional nuclear. (Bill Gates is an investor in TerraPower and Commonwealth Fusion Systems.) —Leigh Phillips

NENOV | GETTY

Predicting preemies

  • Why it matters 15 million babies are born prematurely every year; it’s the leading cause of death for children under age five
  • Key player Akna Dx
  • Availability A test could be offered in doctor’s offices within five years

A simple blood test can predict if a pregnant woman is at risk of giving birth prematurely.

Our genetic material lives mostly inside our cells. But small amounts of “cell-free” DNA and RNA also float in our blood, often released by dying cells. In pregnant women, that cell-free material is an alphabet soup of nucleic acids from the fetus, the placenta, and the mother.

Stephen Quake, a bioengineer at Stanford, has found a way to use that to tackle one of medicine’s most intractable problems: the roughly one in 10 babies born prematurely.

Free-floating DNA and RNA can yield information that previously required invasive ways of grabbing cells, such as taking a biopsy of a tumor or puncturing a pregnant woman’s belly to perform an amniocentesis. What’s changed is that it’s now easier to detect and sequence the small amounts of cell-free genetic material in the blood. In the last few years researchers have begun developing blood tests for cancer (by spotting the telltale DNA from tumor cells) and for prenatal screening of conditions like Down syndrome.

The tests for these conditions rely on looking for genetic mutations in the DNA. RNA, on the other hand, is the molecule that regulates gene expression—how much of a protein is produced from a gene. By sequencing the free-floating RNA in the mother’s blood, Quake can spot fluctuations in the expression of seven genes that he singles out as associated with preterm birth. That lets him identify women likely to deliver too early. Once alerted, doctors can take measures to stave off an early birth and give the child a better chance of survival.

The technology behind the blood test, Quake says, is quick, easy, and less than $10 a measurement. He and his collaborators have launched a startup, Akna Dx, to commercialize it. —Bonnie Rochman

BRUCE PETERSON

Gut probe in a pill

Why it matters The device makes it easier to screen for and study gut diseases, including one that keeps millions of children in poor countries from growing properly

  • Key player Massachusetts General Hospital
  • Availability Now used in adults; testing in infants begins in 2019

A small, swallowable device captures detailed images of the gut without anesthesia, even in infants and children.

Environmental enteric dysfunction (EED) may be one of the costliest diseases you’ve never heard of. Marked by inflamed intestines that are leaky and absorb nutrients poorly, it’s widespread in poor countries and is one reason why many people there are malnourished, have developmental delays, and never reach a normal height. No one knows exactly what causes EED and how it could be prevented or treated.

Practical screening to detect it would help medical workers know when to intervene and how. Therapies are already available for infants, but diagnosing and studying illnesses in the guts of such young children often requires anesthetizing them and inserting a tube called an endoscope down the throat. It’s expensive, uncomfortable, and not practical in areas of the world where EED is prevalent.

So Guillermo Tearney, a pathologist and engineer at Massachusetts General Hospital (MGH) in Boston, is developing small devices that can be used to inspect the gut for signs of EED and even obtain tissue biopsies. Unlike endoscopes, they are simple to use at a primary care visit.

Tearney’s swallowable capsules contain miniature microscopes. They’re attached to a flexible string-like tether that provides power and light while sending images to a briefcase-like console with a monitor. This lets the health-care worker pause the capsule at points of interest and pull it out when finished, allowing it to be sterilized and reused. (Though it sounds gag-­inducing, Tearney’s team has developed a technique that they say doesn’t cause discomfort.) It can also carry technologies that image the entire surface of the digestive tract at the resolution of a single cell or capture three-dimensional cross sections a couple of millimeters deep.

The technology has several applications; at MGH it’s being used to screen for Barrett’s esophagus, a precursor of esophageal cancer. For EED, Tearney’s team has developed an even smaller version for use in infants who can’t swallow a pill. It’s been tested on adolescents in Pakistan, where EED is prevalent, and infant testing is planned for 2019.

The little probe will help researchers answer questions about EED’s development—such as which cells it affects and whether bacteria are involved—and evaluate interventions and potential treatments. —Courtney Humphrie

PAPER BOAT CREATIVE | GETTY

Custom cancer vaccines

  • Why it matters Conventional chemotherapies take a heavy toll on healthy cells and aren’t always effective against tumors
  • Key players BioNTech
    Genentech
  • Availability In human testing

The treatment incites the body’s natural defenses to destroy only cancer cells by identifying mutations unique to each tumor

Scientists are on the cusp of commercializing the first personalized cancer vaccine. If it works as hoped, the vaccine, which triggers a person’s immune system to identify a tumor by its unique mutations, could effectively shut down many types of cancers.

By using the body’s natural defenses to selectively destroy only tumor cells, the vaccine, unlike conventional chemotherapies, limits damage to healthy cells. The attacking immune cells could also be vigilant in spotting any stray cancer cells after the initial treatment.

The possibility of such vaccines began to take shape in 2008, five years after the Human Genome Project was completed, when geneticists published the first sequence of a cancerous tumor cell.

Soon after, investigators began to compare the DNA of tumor cells with that of healthy cells—and other tumor cells. These studies confirmed that all cancer cells contain hundreds if not thousands of specific mutations, most of which are unique to each tumor.

A few years later, a German startup called BioNTech provided compelling evidence that a vaccine containing copies of these mutations could catalyze the body’s immune system to produce T cells primed to seek out, attack, and destroy all cancer cells harboring them.

In December 2017, BioNTech began a large test of the vaccine in cancer patients, in collaboration with the biotech giant Genentech. The ongoing trial is targeting at least 10 solid cancers and aims to enroll upwards of 560 patients at sites around the globe.

The two companies are designing new manufacturing techniques to produce thousands of personally customized vaccines cheaply and quickly. That will be tricky because creating the vaccine involves performing a biopsy on the patient’s tumor, sequencing and analyzing its DNA, and rushing that information to the production site. Once produced, the vaccine needs to be promptly delivered to the hospital; delays could be deadly. —Adam Pior

BRUCE PETERSON/STYLING: MONICA MARIANO

The cow-free burger

  • Why it matters Livestock production causes catastrophic deforestation, water pollution, and greenhouse-gas emissions
  • Key players Beyond Meat
    Impossible Foods
  • Availability Plant-based now; lab-grown around 2020

Both lab-grown and plant-based alternatives approximate the taste and nutritional value of real meat without the environmental devastation.

The UN expects the world to have 9.8 billion people by 2050. And those people are getting richer. Neither trend bodes well for climate change—especially because as people escape poverty, they tend to eat more meat.

By that date, according to the predictions, humans will consume 70% more meat than they did in 2005. And it turns out that raising animals for human consumption is among the worst things we do to the environment.

Depending on the animal, producing a pound of meat protein with Western industrialized methods requires 4 to 25 times more water, 6 to 17 times more land, and 6 to 20 times more fossil fuels than producing a pound of plant protein.

The problem is that people aren’t likely to stop eating meat anytime soon. Which means lab-grown and plant-based alternatives might be the best way to limit the destruction.

Making lab-grown meat involves extracting muscle tissue from animals and growing it in bioreactors. The end product looks much like what you’d get from an animal, although researchers are still working on the taste. Researchers at Maastricht University in the Netherlands, who are working to produce lab-grown meat at scale, believe they’ll have a lab-grown burger available by next year. One drawback of lab-grown meat is that the environmental benefits are still sketchy at best—a recent World Economic Forum report says the emissions from lab-grown meat would be only around 7% less than emissions from beef production.

The better environmental case can be made for plant-based meats from companies like Beyond Meat and Impossible Foods (Bill Gates is an investor in both companies), which use pea proteins, soy, wheat, potatoes, and plant oils to mimic the texture and taste of animal meat.

Beyond Meat has a new 26,000-square-foot (2,400-square-meter) plant in California and has already sold upwards of 25 million burgers from 30,000 stores and restaurants. According to an analysis by the Center for Sustainable Systems at the University of Michigan, a Beyond Meat patty would probably generate 90% less in greenhouse-gas emissions than a conventional burger made from a cow. —Markkus Rovito

 

NICO ORTEGA

Carbon dioxide catcher

  • Why it matters Removing CO2 from the atmosphere might be one of the last viable ways to stop catastrophic climate change
  • Key players Carbon Engineering
    Climeworks
    Global Thermostat
  • Availability 5-10 years

 

Practical and affordable ways to capture carbon dioxide from the air can soak up excess greenhouse-gas emissions.

Even if we slow carbon dioxide emissions, the warming effect of the greenhouse gas can persist for thousands of years. To prevent a dangerous rise in temperatures, the UN’s climate panel now concludes, the world will need to remove as much as 1 trillion tons of carbon dioxide from the atmosphere this century.

In a surprise finding last summer, Harvard climate scientist David Keith calculated that machines could, in theory, pull this off for less than $100 a ton, through an approach known as direct air capture. That’s an order of magnitude cheaper than earlier estimates that led many scientists to dismiss the technology as far too expensive—though it will still take years for costs to fall to anywhere near that level.

But once you capture the carbon, you still need to figure out what to do with it.

Carbon Engineering, the Canadian startup Keith cofounded in 2009, plans to expand its pilot plant to ramp up production of its synthetic fuels, using the captured carbon dioxide as a key ingredient. (Bill Gates is an investor in Carbon Engineering.)

Zurich-based Climeworks’s direct air capture plant in Italy will produce methane from captured carbon dioxide and hydrogen, while a second plant in Switzerland will sell carbon dioxide to the soft-drinks industry. So will Global Thermostat of New York, which finished constructing its first commercial plant in Alabama last year.

Still, if it’s used in synthetic fuels or sodas, the carbon dioxide will mostly end up back in the atmosphere. The ultimate goal is to lock greenhouse gases away forever. Some could be nested within products like carbon fiber, polymers, or concrete, but far more will simply need to be buried underground, a costly job that no business model seems likely to support.

In fact, pulling CO2 out of the air is, from an engineering perspective, one of the most difficult and expensive ways of dealing with climate change. But given how slowly we’re reducing emissions, there are no good options left. —James Temple

BRUCE PETERSON

An ECG on your wrist

Regulatory approval and technological advances are making it easier for people to continuously monitor their hearts with wearable devices.

Fitness trackers aren’t serious medical devices. An intense workout or loose band can mess with the sensors that read your pulse. But an electrocardiogram—the kind doctors use to diagnose abnormalities before they cause a stroke or heart attack— requires a visit to a clinic, and people often fail to take the test in time.

ECG-enabled smart watches, made possible by new regulations and innovations in hardware and software, offer the convenience of a wearable device with something closer to the precision of a medical one.

An Apple Watch–compatible band from Silicon Valley startup AliveCor that can detect atrial fibrillation, a frequent cause of blood clots and stroke, received clearance from the FDA in 2017. Last year, Apple released its own FDA-cleared ECG feature, embedded in the watch itself.

The health-device company Withings also announced plans for an ECG-equipped watch shortly after.
Current wearables still employ only a single sensor, whereas a real ECG has 12. And no wearable can yet detect a heart attack as it’s happening.

But this might change soon. Last fall, AliveCor presented preliminary results to the American Heart Association on an app and two-­sensor system that can detect a certain type of heart attack. —Karen Hao

THEDMAN | GETTY

Sanitation without sewers

  • Why it matters 2.3 billion people lack safe sanitation, and many die as a result
  • Key players Duke University
    University of South Florida
    Biomass Controls
    California Institute of Technology
  • Availability 1-2 years

 

Energy-efficient toilets can operate without a sewer system and treat waste on the spot.

About 2.3 billion people don’t have good sanitation. The lack of proper toilets encourages people to dump fecal matter into nearby ponds and streams, spreading bacteria, viruses, and parasites that can cause diarrhea and cholera. Diarrhea causes one in nine child deaths worldwide.

Now researchers are working to build a new kind of toilet that’s cheap enough for the developing world and can not only dispose of waste but treat it as well.

In 2011 Bill Gates created what was essentially the X Prize in this area—the Reinvent the Toilet Challenge. Since the contest’s launch, several teams have put prototypes in the field. All process the waste locally, so there’s no need for large amounts of water to carry it to a distant treatment plant.

Most of the prototypes are self-contained and don’t need sewers, but they look like traditional toilets housed in small buildings or storage containers. The NEWgenerator toilet, designed at the University of South Florida, filters out pollutants with an anaerobic membrane, which has pores smaller than bacteria and viruses. Another project, from Connecticut-based Biomass Controls, is a refinery the size of a shipping container; it heats the waste to produce a carbon-rich material that can, among other things, fertilize soil.

One drawback is that the toilets don’t work at every scale. The Biomass Controls product, for example, is designed primarily for tens of thousands of users per day, which makes it less well suited for smaller villages. Another system, developed at Duke University, is meant to be used only by a few nearby homes.

So the challenge now is to make these toilets cheaper and more adaptable to communities of different sizes. “It’s great to build one or two units,” says Daniel Yeh, an associate professor at the University of South Florida, who led the NEWgenerator team. “But to really have the technology impact the world, the only way to do that is mass-produce the units.” —Erin Winick

BRUCE PETERSON

Smooth-talking AI assistants

  • Why it matters AI assistants can now perform conversation-based tasks like booking a restaurant reservation or coordinating a package drop-off rather than just obey simple commands
  • Key players Google
    Alibaba
    Amazon
  • Availability 1-2 years

 

New techniques that capture semantic relationships between words are making machines better at understanding natural language.

We’re used to AI assistants—Alexa playing music in the living room, Siri setting alarms on your phone—but they haven’t really lived up to their alleged smarts. They were supposed to have simplified our lives, but they’ve barely made a dent. They recognize only a narrow range of directives and are easily tripped up by deviations.

But some recent advances are about to expand your digital assistant’s repertoire. In June 2018, researchers at OpenAI developed a technique that trains an AI on unlabeled text to avoid the expense and time of categorizing and tagging all the data manually. A few months later, a team at Google unveiled a system called BERT that learned how to predict missing words by studying millions of sentences. In a multiple-choice test, it did as well as humans at filling in gaps.

These improvements, coupled with better speech synthesis, are letting us move from giving AI assistants simple commands to having conversations with them. They’ll be able to deal with daily minutiae like taking meeting notes, finding information, or shopping online.

Some are already here. Google Duplex, the eerily human-like upgrade of Google Assistant, can pick up your calls to screen for spammers and telemarketers. It can also make calls for you to schedule restaurant reservations or salon appointments.

In China, consumers are getting used to Alibaba’s AliMe, which coordinates package deliveries over the phone and haggles about the price of goods over chat.

But while AI programs have gotten better at figuring out what you want, they still can’t understand a sentence. Lines are scripted or generated statistically, reflecting how hard it is to imbue machines with true language understanding. Once we cross that hurdle, we’ll see yet another evolution, perhaps from logistics coordinator to babysitter, teacher—or even friend? —Karen Hao

Researchers at Melbourne’s RMIT University Convert CO2 back into Coal in Carbon Breakthrough – (Captured) Carbon produced could also be used as an electrode … Watch Video


 

 

CO2 to Coal 1 1551205544-GettyImages-96390221-960x540

Australian scientists have unlocked a new and more “efficient” way  to turn carbon dioxide back into solid coal, in a world-first breakthrough that could combat rising greenhouse gas levels.

Researchers at Melbourne’s RMIT University have used liquid metals to convert CO2 from a gas to a solid at room temperature.

The technique has potential to “safely and permanently” remove CO2 from the atmosphere, according to the new study published in the journal Nature Communications.

Carbon technologies have previously tended to focus on compressing CO2 into a liquid form, transporting it to a suitable site and injecting it underground.

The use of underground injections to capture and store carbon is not economically viable and sparks fears of an environmental catastrophe due to possible leaks from the storage site.

However, the new technique transforms CO2 into solid flakes of carbon, similar to coal, which can be stored more easily and securely.

Carbon dioxide is dissolved into a beaker containing an electrolyte liquid, then a small amount of the liquid metal catalyst is added, which is then charged with an electrical current.

The electrical current serves as a catalyst to slowly converts the CO2 into solid flakes of carbon.

Watch how researchers made their discovery

This is a “crucial first step” to developing a more sustainable approach to converting CO2 into a solid, RMIT researcher Dr Torben Daeneke said, noting that more research is required cement the process.

He described the process as “efficient and scalable”.

“While we can’t literally turn back time, turning carbon dioxide back into coal and burying it back in the ground is a bit like rewinding the emissions clock.

“To date, CO2 has only been converted into a solid at extremely high temperatures, making it industrially un-viable,” Dr Daeneke said.

The study’s lead author, Dr Dorna Esrafilzadeh, said the carbon produced could also be used as an electrode.

“A side benefit of the process is that the carbon can hold electrical charge, becoming a supercapacitor, so it could potentially be used as a component in future vehicles,” she said.

“The process also produces synthetic fuel as a by-product, which could also have industrial applications.”

The study was completed in collaboration with researchers from Germany (University of Munster), China (Nanjing University of Aeronautics and Astronautics), the US (North Carolina State University) and Australia (UNSW, University of Wollongong, Monash University, QUT).

Learn More About ‘Great Things from Small Things’ ~ Watch A Video on Our Current Project: Nano Enabled Batteries and Super Capacitors

University of Waterloo Researchers develop New Powder that is 2X More Effective for ‘Carbon Capture’ – Could Drastically Reduce CO2 Emissions – Also Applications for Energy Storage and Water Filtration


Carbon capture 1 novelfunctioNovel functionalized nanomaterials for CO2 capture. Credit: Copyright Royal Society of Chemistry (RSC). Polshettiwar et al. Chemical Science

Scientists at the University of Waterloo have created a powder that can capture CO2 from factories and power plants.

The powder, created in the lab of Zhongwei Chen, a chemical engineering professor at Waterloo, can filter and remove CO2 at facilities powered by fossil fuels before it is released into the atmosphere and is twice as efficient as conventional methods.

Chen said the new process to manipulate the size and concentration of pores could also be used to produce optimized carbon powders for applications including water filtration and energy storage, the other main strand of research in his lab.

“This will be more and more important in the future,” said Chen, “We have to find ways to deal with all the CO2 produced by burning fossil fuels.”

CO2 molecules stick to the surface of carbon when they come in contact with it, a process known as adsorption. Since it is abundant, inexpensive and environmentally friendly, that makes carbon an excellent material for CO2 capture. The researchers, who collaborated with colleagues at several universities in China, set out to improve adsorption performance by manipulating the size and concentration of pores in carbon materials.

The technique they developed uses heat and salt to extract a black carbon powder from plant matter. Carbon spheres that make up the powder have many, many pores and the vast majority of them are less than one-millionth of a metre in diameter.Carbon Capture 2 16-MS-2494-EE-Science-Cover_v6-

“The porosity of this material is extremely high,” said Chen, who holds a Tier 1 Canada Research Chair in advanced materials for clean energy. “And because of their size, these pores can capture CO2 very efficiently. The performance is almost doubled.”

Once saturated with carbon dioxide at large point sources such as fossil fuel power plants, the powder would be transported to storage sites and buried in underground geological formations to prevent CO2 release into the atmosphere.

A paper on the CO2 capture work, In-situ ion-activated carbon nanospheres with tunable ultra-microporosity for superior CO2 capture, appears in the journal Carbon.

Professor Chen can be reached at zhwchen@uwaterloo.ca or 519-888-4567 ext. 38664.

Read More About Recent CO2 Capture Technologies

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Our Environment: An Underwater Irish Canyon Is Sucking CO2 Out of the Atmosphere (We heard the Irish were good at “drinking” but … )


Porcupine_Bank_and_Seabight,_NE_Atlantic

Northeast Atlantic bathymetry, with Porcupine Bank and the Porcupine Seabight labelled.

A research expedition to a huge underwater canyon off the Irish coast has shed light on a hidden process that sucks the greenhouse gas carbon dioxide (CO2) out of the atmosphere.

Researchers led by a team from the University College Cork (UCC) took an underwater research drone by boat out to Porcupine Bank Canyon — a massive, cliff-walled underwater trench where Ireland’s continental shelf ends — to build a detailed map of its boundaries and interior. Along the way, the researchers reported in a statement, they noted a process at the edge of the canyon that pulls CO2 from the atmosphere and buries it deep under the sea.

ColdWaterCoral_largeAll around the rim of the canyon live cold-water corals, which thrive on dead plankton raining down from the ocean surface. Those tiny, surface-dwelling plankton build their bodies out of carbon extracted from CO2 in the air. Then, when they die, the coral on the seafloor consume them and build their bodies out of the same carbon. Over time, as the coral die and the cliff faces shift and crumble, which sends the coral   falling deep into the canyon. There, the carbon pretty much stays put for long periods. [ In Photos: ROV Explores Deep-Sea Marianas Trench

There’s evidence that a lot of carbon is moving this way; the researchers said they found “significant” dead coral buildup at the canyon bottom.

This process doesn’t move nearly enough carbon dioxide to prevent climate change, the researchers said. But it does shed light on yet another mechanism that keeps the planet’s CO2 levels regulated when human industry doesn’t interfere.

“Increasing CO2 concentrations in our atmosphere are causing our extreme weather,” Andy Wheeler, a UCC geoscientist and one of the researchers on the expedition, said in the statement. “Oceans absorb this CO2 and canyons are a rapid route for pumping it into the deep ocean where it is safely stored away.”

The mapping expedition covered an area about the size of Chicago and revealed places where the canyon has moved and shifted significantly in the past.

“We took cores with the ROV, and the sediments reveal that although the canyon is quiet now, periodically it is a violent place where the seabed gets ripped up and eroded,” Wheeler said.

The expedition will return to shore today (Aug. 10).

Related

Will underwater drones bring a sea change to naval – and nuclear – warfare? 

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MIT Technology Review: Sustainable Energy: The daunting math of climate change means we’ll need carbon capture … eventually


 

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 Net Power’s pilot natural gas plant with carbon capture, near Houston, Texas.

An Interview with Julio Friedmann

At current rates of greenhouse-gas emissions, the world could lock in 1.5 ˚C of warming as soon as 2021, an analysis by the website Carbon Brief has found. We’re on track to blow the carbon budget for 2 ˚C by 2036.

Amid this daunting climate math, many researchers argue that capturing carbon dioxide from power plants, factories, and the air will have to play a big part in any realistic efforts to limit the dangers of global warming.

If it can be done economically, carbon capture and storage (CCS) offers the world additional flexibility and time to make the leap to cleaner systems. It means we can retrofit, rather than replace, vast parts of the global energy infrastructure. And once we reach disastrous levels of warming, so-called direct air capture offers one of the only ways to dig our way out of trouble, since carbon dioxide otherwise stays in the atmosphere for thousands of years.

Julio Friedmann has emerged as one of the most ardent advocates of these technologies. He oversaw research and development efforts on clean coal and carbon capture at the US Department of Energy’s Office of Fossil Energy under the last administration. Among other roles, he’s now working with or advising the Global CCS Institute, the Energy Futures Initiative, and Climeworks, a Switzerland-based company already building pilot plants that pull carbon dioxide from the air.

In an interview with MIT Technology Review, Friedmann argues that the technology is approaching a tipping point: a growing number of projects demonstrate that it works in the real world, and that it is becoming more reliable and affordable. He adds that the boosted US tax credit for capturing and storing carbon, passed in the form of the Future Act as part of the federal budget earlier this year, will push forward many more projects and help create new markets for products derived from carbon dioxide (see “The carbon-capture era may finally be starting”).

But serious challenges remain. Even with the tax credit, companies will incur steep costs by adding carbon capture systems to existing power plants. And a widely cited 2011 study, coauthored by MIT researcher Howard Herzog, found that direct air capture will require vast amounts of energy and cost 10 times as much as scrubbing carbon from power plants.

(This interview has been edited for length and clarity.)

In late February, you wrote a Medium post saying that with the passage of the increased tax credit for carbon capture and storage, we’ve “launched the climate counter-strike.” Why is that a big deal?

It actually sets a price on carbon formally. It says you should get paid to not emit carbon dioxide, and you should get paid somewhere between $35 a ton and $50 a ton. So that is already a massive change. In addition to that, it says you can do one of three things: you can store CO2, you can use it for enhanced oil recovery, or you can turn it into stuff. Fundamentally, it says not emitting has value.

As I’ve said many times before, the lack of progress in deploying CCS up until this point is not a question of cost. It’s really been a question of finance.

The Future Act creates that financing.

I identified an additional provision which said not only can you consider a power plant a source or an industrial site a source, you can consider the air a source.

Even if we zeroed out all our emissions today, we still have a legacy of harm of two trillion tons of CO2 in the air, and we need to do something about that.

And this law says, yeah, we should. It says we can take carbon dioxide out of the air and turn it into stuff.

At the Petra Nova plant in Texas, my understanding is the carbon capture costs are something like $60 to $70 a ton, which is still going to outstrip the tax credit today. How are we going to close that gap?

There are many different ways to go about it. For example, the state of New Jersey today passed a 90 percent clean energy portfolio standard. Changing the policy from a renewable portfolio standard [which would exclude CCS technologies] to a clean energy standard [which would allow them] allowed higher ambition.

In that context, somebody who would build a CCS project and would get a contract to deliver that power, or deliver that emissions abatement, can actually again get staked, get financed, and get built. That can happen without any technology advancement.

The technology today is already cost competitive. CCS today, as a retrofit, is cheaper than a whole bunch of stuff. It’s cheaper than new-build nuclear, it’s cheaper than offshore wind. It’s cheaper than a whole bunch of things we like, and it’s cheaper than rooftop solar, almost everywhere. It’s cheaper than utility-scale concentrating solar pretty much everywhere, and it is cheaper than what solar and wind were 10 years ago.

What do you make of the critique that this is all just going to perpetuate the fossil-fuel industry?

The enemy is not fossil fuels; the enemy is emissions.

In a place like California that has terrific renewable resources and a good infrastructure for renewable energy, maybe you can get to zero [fossil fuels] someday.

If you’re in Saskatchewan, you really can’t do that. It is too cold for too much of the year, and they don’t have solar resources, and their wind resources are problematic because they’re so strong they tear up the turbines. Which is why they did the CCS project in Saskatchewan. For them it was the right solution.

Shifting gears to direct air capture, the basic math says that you’re moving 2,500 molecules to capture one of CO2. How good are we getting at this, and how cheaply can we do this at this point?

If you want to optimize the way that you would reduce carbon dioxide economy-wide, direct air capture is the last thing you would tackle. Turns out, though, that we don’t live in that society. We are not optimizing anything in any way.

So instead we realize we have this legacy of emissions in the atmosphere and we need tools to manage that. So there are companies like ClimeworksCarbon Engineering, and Global Thermostat. Those guys said we know we’re going to need this technology, so I’m going to work now. They’ve got decent financing, and the costs are coming down and improving (see “Can sucking CO2 out of the atmosphere really work?”).

The cost for all of these things now today, all-in costs, is somewhere between $300 and $600 a ton. I’ve looked inside all those companies and I believe all of them are on a glide path to get to below $200 a ton by somewhere between 2022 and 2025. And I believe that they’re going to get down to $100 a ton by 2030. At that point, these are real options.

At $200 a ton, we know today unambiguously that pulling CO2 out of the air is cheaper than trying to make a zero-carbon airplane, by a lot. So it becomes an option that you use to go after carbon in the hard-to-scrub parts of the economy.

Is it ever going to work as a business, or is it always going to be kind of a public-supported enterprise to buy ourselves out of climate catastrophes?

Direct air capture is not competitive today broadly, but there are places where the value proposition is real. So let me give you a couple of examples.

In many parts of the world there are no sources of CO2. If you’re running a Pepsi or a Coca-Cola plant in Sri Lanka, you literally burn diesel fuel and capture the CO2 from it to put into your cola, at a bonkers price. It can cost $300 to $800 a ton to get that CO2. So there are already going to be places in some people’s supply chain where direct air capture could be cheaper.

We talk to companies like Goodyear, Firestone, or Michelin. They make tires, and right now the way that they get their carbon black [a material used in tire production that’s derived from fossil fuel] is basically you pyrolize bunker fuel in the Gulf Coast, which is a horrible, environmentally destructive process. And then you ship it by rail cars to wherever they’re making the tires.

If they can decouple from that market by gathering CO2 wherever they are and turn that into carbon black, they can actually avoid market shocks. So even if it costs a little more, the value to that company might be high enough to bring it into the market. That’s where I see direct air actually gaining real traction in the next few years.

It’s not going to be enough for climate. We know that we will have to do carbon storage, for sure, if we want to really manage the atmospheric emissions. But there’s a lot of ground to chase this, and we never know quite where technology goes.

In one of your earlier Medium posts you said that we’re ultimately going to have to pull 10 billion tons of CO2 out of the atmosphere every year. Climeworks is doing about 50 [at their pilot plant in Iceland]. So what does that scale-up look like?

You don’t have to get all 10 billion tons with direct air capture. So let’s say you just want one billion.

Right now, Royal Dutch Shell as a company moves 300 million tons of refined product every year. This means that you need three to four companies the size of Royal Dutch Shell to pull CO2 out of the atmosphere.

The good news is we don’t need that billion tons today. We have 10 or 20 or 30 years to get to a billion tons of direct air capture. But in fact we’ve seen that kind of scaling in other kinds of clean-tech markets. There’s nothing in the laws of physics or chemistry that stops that.

Making Hydrogen Production Cheaper using New Ultra-Thin nano-material for splitting water


newultrathinThis is a water drop falling into water. Credit: Sarp Saydam/UNSW

UNSW Sydney chemists have invented a new, cheap catalyst for splitting water with an electrical current to efficiently produce clean hydrogen fuel.

The technology is based on the creation of ultrathin slices of porous metal-organic complex coated onto a foam electrode, which the researchers have unexpectedly shown is highly conductive of electricity and active for .

“Splitting water usually requires two different catalysts, but our catalyst can drive both of the reactions required to separate water into its two constituents, oxygen and hydrogen,” says study leader Associate Professor Chuan Zhao.

“Our fabrication method is simple and universal, so we can adapt it to produce ultrathin nanosheet arrays of a variety of these materials, called .

“Compared to other water-splitting electro-catalysts reported to date, our is also among the most efficient,” he says.

The UNSW research by Zhao, Dr Sheng Chen and Dr Jingjing Duan is published in the journal Nature Communications.

Hydrogen is a very good carrier for renewable energy because it is abundant, generates zero emissions, and is much easier to store than other energy sources, like solar or wind energy.

But the cost of producing it by using electricity to split water is high, because the most efficient catalysts developed so far are often made with precious metals, like platinum, ruthenium and iridium.

The catalysts developed at UNSW are made of abundant, non-precious metals like nickel, iron and copper. They belong to a family of versatile porous materials called , which have a wide variety of other potential applications.

Until now, metal-organic frameworks were considered poor conductors and not very useful for electrochemical reactions. Conventionally, they are made in the form of bulk powders, with their catalytic sites deeply embedded inside the pores of the material, where it is difficult for the water to reach.

By creating nanometre-thick arrays of metal-organic frameworks, Zhao’s team was able to expose the pores and increase the surface area for electrical contact with the .

“With nanoengineering, we made a unique metal-organic structure that solves the big problems of conductivity, and access to active sites,” says Zhao.

“It is ground-breaking. We were able to demonstrate that metal-organic frameworks can be highly conductive, challenging the common concept of these materials as inert electro-catalysts.”

Metal-organic frameworks have potential for a large range of applications, including fuel storage, drug delivery, and carbon capture. The UNSW team’s demonstration that they can also be highly conductive introduces a host of new applications for this class of material beyond electro-catalysis.

Explore further: Researchers report new, more efficient catalyst for water splitting

More information: Jingjing Duan et al, Ultrathin metal-organic framework array for efficient electrocatalytic water splitting, Nature Communications (2017). DOI: 10.1038/ncomms15341

 

 

Penn State U. – New ‘Flow-Cell’ Battery Recharged with Carbon Dioxide – Capturing CO2 Emissions for an Untapped Source of Energy


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The pH-gradient flow cell has two channels: one containing an aqueous solution sparged with carbon dioxide (low pH) and the other containing an aqueous solution sparged with ambient air (high pH). The pH gradient causes ions to flow across …more

Researchers have developed a type of rechargeable battery called a flow cell that can be recharged with a water-based solution containing dissolved carbon dioxide (CO2) emitted from fossil fuel power plants. The device works by taking advantage of the CO2 concentration difference between CO2 emissions and ambient air, which can ultimately be used to generate electricity.

The new flow cell produces an average power density of 0.82 W/m2, which is almost 200 times higher than values obtained using previous similar methods. Although it is not yet clear whether the process could be economically viable on a large scale, the early results appear promising and could be further improved with future research.

The scientists, Taeyong Kim, Bruce E. Logan, and Christopher A. Gorski at The Pennsylvania State University, have published a paper on the new method of CO2-to-electricity conversion in a recent issue of Environmental Science & Technology Letters.

“This work offers an alternative, simpler means to capturing energy from CO2 emissions compared to existing technologies that require expensive catalyst materials and very high temperatures to convert CO2 into useful fuels,” said Gorski.

While the contrast of gray-white smoke against a blue sky illustrates the adverse environmental impact of burning , the large difference in CO2 concentration between the two gases is also what provides an untapped energy source for generating electricity.fossil-fuels-co2-to-green-images

In order to harness the potential energy in this concentration difference, the researchers first dissolved CO2 gas and in separate containers of an aqueous solution, in a process called sparging. At the end of this process, the CO2-sparged solution forms bicarbonate ions, which give it a lower pH of 7.7 compared to the air-sparged solution, which has a pH of 9.4.

After sparging, the researchers injected each solution into one of two channels in a flow cell, creating a pH gradient in the cell. The flow cell has electrodes on opposite sides of the two channels, along with a semi-porous membrane between the two channels that prevents instant mixing while still allowing ions to pass through. Due to the pH difference between the two solutions, various ions pass through the membrane, creating a voltage difference between the two electrodes and causing electrons to flow along a wire connecting the electrodes.

After the flow cell is discharged, it can be recharged again by switching the channels that the solutions flow through. By switching the solution that flows over each electrode, the charging mechanism is reversed so that the electrons flow in the opposite direction. Tests showed that the cell maintains its performance over 50 cycles of alternating solutions.

The results also showed that, the higher the pH difference between the two channels, the higher the average power density. Although the pH-gradient flow cell achieves a power density that is high compared to similar cells that convert waste CO2 to electricity, it is still much lower than the power densities of fuel cell systems that combine CO2 with other fuels, such as H2.

However, the new flow cell has certain advantages over these other devices, such as its use of inexpensive materials and room-temperature operation. These features make the flow cell attractive for practical applications at existing .

“A system containing numerous identical flow cells would be installed at power plants that combust fossil fuels,” Gorski said. “The flue gas emitted from fossil fuel combustion would need to be pre-cooled, then bubbled through a reservoir of water that can be pumped through the flow cells.”

In the future, the researchers plan to further improve the flow cell performance.

“We are currently looking to see how the solution conditions can be optimized to maximize the amount of energy produced,” Gorski said. “We are also investigating if we can dissolve chemicals in the water that exhibit pH-dependent redox properties, thus allowing us to increase the amount of energy that can be recovered. The latter approach would be analogous to a flow battery, which reduces and oxidizes dissolved chemicals in aqueous solutions, except we are causing them to be reduced and oxidized here by changing the solution pH with CO2.”

Explore further: Chemists present an innovative redox-flow battery based on organic polymers and water

More information: Taeyoung Kim et al. “A pH-Gradient Flow Cell for Converting Waste CO2 into Electricity.” Environmental Science & Technology Letters. DOI: 10.1021/acs.estlett.6b00467

 

Rice University: Graphene Quantum Dots take on a NEW ‘green’ recycling role


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Graphene quantum dots may offer a simple way to recycle waste carbon dioxide into valuable fuel rather than release it into the atmosphere or bury it underground, according to Rice University scientists.

Nitrogen-doped (NGQDs) are an efficient electrocatalyst to make complex hydrocarbons from carbon dioxide, according to the research team led by Rice materials scientist Pulickel Ajayan. Using electrocatalysis, his lab has demonstrated the conversion of the greenhouse gas into small batches of ethylene and ethanol.

The research is detailed this week in Nature Communications.

Though they don’t entirely understand the mechanism, the researchers found NGQDs worked nearly as efficiently as copper, which is also being tested as a catalyst to reduce carbon dioxide into liquid fuels and chemicals. And NGQDs keep their catalytic activity for a long time, they reported.

“It is surprising because people have tried all different kinds of catalysts. And there are only a few real choices such as copper,” Ajayan said. “I think what we found is fundamentally interesting, because it provides an efficient pathway to screen new types of catalysts to convert carbon dioxide to higher-value products.”

Those problems are hardly a secret. Atmospheric carbon dioxide rose above 400 parts per million earlier this year, the highest it’s been in at least 800,000 years, as measured through ice-core analysis.

Carbon dots dash toward 'green' recycling role
Nitrogen-doped graphene quantum dots stand out from a substrate in a transmission electron microscope image. The dots are effective electrocatalysts that can reduce carbon dioxide, a greenhouse gas, to valuable hydrocarbons like ethylene …more

 

“If we can convert a sizable fraction of the carbon dioxide that is emitted, we could curb the rising levels of levels, which have been linked to climate change,” said co-author Paul Kenis of the University of Illinois.

In lab tests, NGQDs proved able to reduce carbon dioxide by up to 90 percent and convert 45 percent into either ethylene or alcohol, comparable to copper electrocatalysts.

Graphene quantum dots are atom-thick sheets of carbon atoms that have been split into particles about a nanometer thick and just a few nanometers wide. The addition of nitrogen atoms to the dots enables varying chemical reactions when an electric current is applied and a feedstock like carbon dioxide is introduced.

“Carbon is typically not a catalyst,” Ajayan said. “One of our questions is why this doping is so effective. When nitrogen is inserted into the hexagonal graphitic lattice, there are multiple positions it can take. Each of these positions, depending on where nitrogen sits, should have different . So it’s been a puzzle, and though people have written a lot of papers in the last five to 10 years on doped and defective carbon being catalytic, the puzzle is not really solved.”

Carbon dots dash toward 'green' recycling role
An illustration of a nitrogen-doped graphene quantum dot like those being tested at Rice University for use as catalysts to reduce carbon dioxide, a greenhouse gas, into valuable hydrocarbons. Credit: Ajayan Group/Rice University

 

“Our findings suggest that the pyridinic nitrogen (a basic organic compound) sitting at the edge of graphene leads the catalytic conversion of to hydrocarbons,” said Rice postdoctoral researcher Jingjie Wu, co-lead author of the paper. “The next task is further increasing nitrogen concentration to help increase the yield of hydrocarbons.” (Article continued below)

rice QD finetuneWhat is … A Quantum Dot

A quantum dot is a semiconductor whose excitons are confined in all three spatial dimensions. As a result, they have properties that are between those of bulk semiconductors and those of discrete molecules. They were discovered by Louis E. Brus, who was then at Bell Labs. The term “Quantum Dot” was coined by Mark Reed.

Researchers have studied quantum dots in transistors, solar cells, LEDs, and diode lasers. They have also investigated quantum dots as agents for medical imaging and hope to use them as qubits.

 

(Article Continued) Ajayan noted that while electrocatalysis is effective at lab scales for now, industry relies on scalable thermal catalysis to produce fuels and chemicals. “For that reason, companies probably won’t use it any time soon for large-scale production. But electrocatalysis can be easily done in the lab, and we showed it will be useful in the development of new catalysts.”

Explore further: Catalyst could make production of key chemical more eco-friendly

More information: Jingjie Wu et al, A metal-free electrocatalyst for carbon dioxide reduction to multi-carbon hydrocarbons and oxygenates, Nature Communications (2016). DOI: 10.1038/ncomms13869

 

Rice University: Carbon-Capture from Asphalt Based Nano-Materials: 154% of its Weight in CO2


rice-tour-asphalt-0916-id44535

 

A Rice University laboratory has improved its method to turn plain asphalt into a porous material that can capture greenhouse gases from natural gas. In research detailed this month in Advanced Energy Materials (“Ultra-High Surface Area Activated Porous Asphalt for CO2 Capture through Competitive Adsorption at High Pressures”), Rice researchers showed that a new form of the material can sequester 154 percent of its weight in carbon dioxide at high pressures that are common at gas wellheads.

Raw natural gas typically contains between 2 and 10 percent carbon dioxide and other impurities, which must be removed before the gas can be sold. The cleanup process is complicated and expensive and most often involves flowing the gas through fluids called amines that can soak up and remove about 15 percent of their own weight in carbon dioxide. The amine process also requires a great deal of energy to recycle the fluids for further use.

“It’s a big energy sink,” said Rice chemist James Tour, whose lab developed a technique last year to turn asphalt into a tough, sponge-like substance that could be used in place of amines to remove carbon dioxide from natural gas as it was pumped from ocean wellheads.

rice-tour-asphalt-0916-id44535

 

Rice University scientists have improved their asphalt-derived porous carbon’s ability to capture carbon dioxide, a greenhouse gas, from natural gas. The capture material derived from untreated Gilsonite asphalt has a surface area of 4,200 square meters per gram. (Image: Almaz Jalilov/Rice University) 

 

Initial field tests in 2015 found that pressure at the wellhead made it possible for that asphalt material to adsorb, or soak up, 114 percent of its weight in carbon at ambient temperatures.

Tour said the new, improved asphalt sorbent is made in two steps from a less expensive form of asphalt, which makes it more practical for industry.

“This shows we can take the least expensive form of asphalt and make it into this very high surface area material to capture carbon dioxide,” Tour said. “Before, we could only use a very expensive form of asphalt that was not readily available.”

 

 micropores in carbon capture material
A scanning electron microscope image shows micropores in carbon capture material derived from common asphalt. The material created at Rice University sequesters 154 percent of its weight in carbon dioxide at 54 bar pressure, a common pressure at wellheads. (Image: Tour Group/Rice University)

 

 

The lab heated a common type asphalt known as Gilsonite at ambient pressure to eliminate unneeded organic molecules, and then heated it again in the presence of potassium hydroxide for about 20 minutes to synthesize oxygen-enhanced porous carbon with a surface area of 4,200 square meters per gram, much higher than that of the previous material.

The Rice lab’s initial asphalt-based porous carbon collected carbon dioxide from gas streams under pressure at the wellhead and released it when the pressure was released. The carbon dioxide could then be repurposed or pumped back underground while the porous carbon could be reused immediately.
In the latest tests with its new material, Tours group showed its new sorbent could remove carbon dioxide at 54 bar pressure. One bar is roughly equal to atmospheric pressure at sea level, and the 54 bar measure in the latest experiments is characteristic of the pressure levels typically found at natural gas wellheads, Tour said.
Source: Rice University