Tag Archives: fuel

Sewage sludge dry.

Purple bacteria turn sewage into hydrogen fuel

Purple bacteria are poised to turn your toilet into a source of energy and useable organic material.

Desiccation cracks sludge.

Dried sewage sludge.
Image credits: Hannes Grobe.

Household sewage and industrial wastewater are very rich in organic compounds, and organic compounds can be very useful. But there’s a catch: we don’t know of any efficient way to extract them from the eww goo yet. So these resource-laden liquids get treated, and the material they contain is handled as a contaminant.

New research plans to address this problem — and by using an environmentally-friendly and cost-efficient solution to boot.

The future is purple (and bacterial)

“One of the most important problems of current wastewater treatment plants is high carbon emissions,” says co-author Dr. Daniel Puyol of King Juan Carlos University, Spain.

“Our light-based biorefinery process could provide a means to harvest green energy from wastewater, with zero carbon footprint.”

The study is the first effort to apply purple phototrophic bacteria — phototrophic means they absorb photons, i.e. light, as they’re feeding — together with electrical stimulation for organic waste recovery. The team showed that this approach can recover up to 100% of the carbon in any type of organic waste, supplying hydrogen gas in return — which is very nice, as hydrogen gas can be used to create power cells or energy directly.

Although green is the poster-color for photosynthesis, it’s far from the only one. Chlorophyll’s role is to absorb energy from light — we perceive this absorption as color. Green chlorophyll, for example, absorbs the wavelengths we perceive as red (which sits opposite green on the color wheel). If you’ve ever toyed around with the color-correction feature in graphical software (a la Photoshop, for example), you know that taking out the reds in a picture will make it look green. The same principle applies here.

Plants are generally green because red wavelengths carry the most energy — and plants need energy to create organic molecules. But the substance comes in all sorts of colors in a variety of different organisms. Phototrophic bacteria also capture energy from sunlight, but they use a different range of pigment — from orange, reds, and browns, to shades of purple — for the job. However, the color itself isn’t important here.

“Purple phototrophic bacteria make an ideal tool for resource recovery from organic waste, thanks to their highly diverse metabolism,” explains Puyol.

These bacteria use organic molecules and nitrogen gas in lieu of CO2 and water as food. This supplies all the carbon, electrons, and nitrogen they need for photosynthesis. The end result is that they tend to grow faster than other phototrophic bacteria or algae and generate hydrogen gas, proteins, and a biodegradable type of polyester as waste.

But what really sealed the deal for the team is that they can decide which of these waste products the bacteria churn out. Depending on environmental conditions such as light intensity, temperature, and the nutrients available, one of these products will predominate in the material they excrete.

The team doubled-down on this property by flooding the bacteria’s environment with electricity.

“Our group manipulates these conditions to tune the metabolism of purple bacteria to different applications, depending on the organic waste source and market requirements,” says co-author Professor Abraham Esteve-Núñez of University of Alcalá, Spain.

“But what is unique about our approach is the use of an external electric current to optimize the productive output of purple bacteria.”

This concept — a “bioelectrochemical system” — works because all of the purple bacteria’s metabolic pathways use electrons as energy carriers. They use up electrons when capturing light, for example. On the other hand, turning nitrogen into ammonia releases electrons, which the bacteria need to dissipate. By applying an electrical current to the bacteria (i.e. by pumping electrons into their environment) or by taking electrons out, the team can cause the bacteria to switch from one process to the other. It also helps improve the overall efficiency of both processes (see Le Chatelier’s principle).

The team included an analysis of the optimum conditions for hydrogen production in the paper (it relies on a mixture of purple bacteria species). They also tested the effect of a negative current (electrons supplied by metal electrodes in the growth medium) on the metabolic behavior of the bacteria.

Their first key finding was that the nutrient blend that fed the highest rate of hydrogen production also minimized the production of CO2 — this would allow the bacteria to recover biofuel from wastewater with a low carbon footprint, the team explains. The negative current experiment proved that these bacteria can use cathode electrons to perform photosynthesis.

Even more striking were the results using electrodes, which demonstrated for the first time that purple bacteria are capable of using electrons from a negative electrode, or “cathode“, to capture CO2 via photosynthesis.

“Recordings from our bioelectrochemical system showed a clear interaction between the purple bacteria and the electrodes: negative polarization of the electrode caused a detectable consumption of electrons, associated with a reduction in carbon dioxide production,” says Esteve-Núñez.

“This indicates that the purple bacteria were using electrons from the cathode to capture more carbon from organic compounds via photosynthesis, so less is released as CO2.”

The paper “Biological and Bioelectrochemical Systems for Hydrogen Production and Carbon Fixation Using Purple Phototrophic Bacteria” has been published in the journal Frontiers in Energy Research.

How Mars brine could produce breathable air and fuel for a colony

Our understanding of Mars has been a true rollercoaster. Centuries ago, scholars thought Mars could host rivers and oceans like on Earth and maybe teeming with life. When the first observations came in from Galileo Galilei in 1610, astronomers discovered a planet with polar ice caps that was seemingly similar to Earth, so the hypothesis seemed to stand. But as we learned increasingly more, it became apparent that Mars isn’t exactly a lush planet.

Mars is barren nowadays, and while it may have been water-rich at some point in the past, that’s not really the case now. But there’s one more twist to the story: Mars really does have ice caps, and it does have some liquid water. Granted, that water is full of salts and buried beneath the surface, but it’s still liquid water.

According to a new study, this brine can be used to produce breathable air and fuel for Martian colonists — two valuable resources we would absolutely need on the Red Planet.

Some Martian layers are hiding pockets of water beneath the surface. This water may be used by astronomers to produce breathable air and fuel. Image credits: NASA/MRO.

The rovers we’ve sent to Mars don’t really need oxygen. They do just fine in the ultra-thin atmosphere of the planet, wandering around and doing experiments in freezing temperatures. But if we want to establish a colony (or more likely, a research base), we can’t really manage without oxygen.

In 2008, NASA’s Phoenix Mars Lander came with some good news in that regard. It “tasted” the Martian water and upon analyzing it, found out how it manages to stay liquid on the freezing temperatures of Mars.

The key is something called perchlorate, a chemical compound containing chlorine and oxygen. Perchlorate is very stable in water, and its salts are very solluble — up to the point where they absorb and collect water vapor over time. As the perchlorate absorbs more water, it also dissolves into the water, substantially lowering its freezing temperature — this is how the water manages to remain liquid at temperatures way below the normal freezing point of water.

The European Space Agency’s Mars Express has found several such underground ponds of perchlorate brine and now, a new study reports that these pockets of liquid water could be used to produce valuable resources.

Of course, you can’t drink salty water. You also can’t use it for too many things. If you want to apply the electrolysis to break it down into oxygen (for breathing) and hydrogen (for fuel), you’d normally need to remove the salt — a very costly and complicated process in the harsh Martian environment. This is where the research team led by Vijay Ramani from the University of Connecticut comes in.

Typically, electrolysis requires purified water, but Ramani’s research team found a way to apply electrolysis efficiently to extract hydrogen and oxygen out of the brine simultaneously, without needing to also extract the perchlorate.

“Our Martian brine electrolyzer radically changes the logistical calculus of missions to Mars and beyond” said Ramani. “This technology is equally useful on Earth where it opens up the oceans as a viable oxygen and fuel source”

An outcrop of rocks on the surface of Mars. Image credits: NASA.

They built a modular electrolysis system and tested it at -33 Fahrenheit (-36 Celsius), showing that it really does work. The fact that it’s modular means you can start a small operation on Mars (say, a small research base) and then build on it. Ironically, they were also able to use the salt in their favor.

“Paradoxically, the dissolved perchlorate in the water, so-called impurities, actually help in an environment like that of Mars,” said Shrihari Sankarasubramanian, a research scientist in Ramani’s group and joint first author of the paper.

“They prevent the water from freezing,” he said, “and also improve the performance of the electrolyzer system by lowering the electrical resistance.”

The results are so promising, researchers say, that they’re even considering using a similar technology here on Earth. For instance, submarines or deep-sea could make great use of this technology, potentially enabling us to explore uncharted environments in the deep ocean.

“Having demonstrated these electrolyzers under demanding Martian conditions, we intend to also deploy them under much milder conditions on Earth to utilize brackish or salt water feeds to produce hydrogen and oxygen, for example through seawater electrolysis,” said Pralay Gayen, a postdoctoral research associate in Ramani’s group and also a joint first author on this study.

NASA’s Perseverance rover, currently en-route to Mars, is also carrying some instruments that will allow it to produce oxygen from the Martian brine — but no hydrogen. Perseverance’s equipment is also 25 times less efficient than that designed in Ramani’s lab, but it will be a test for the technology and could perhaps offer new insights on how to apply the technology.

While a Martian base is probably pretty distant possibility, a lunar outpost is almost in sight. NASA has concrete plans to send humans back to the moon in this decade, and it wants to lay down infrastructure for a permanent research base. If this is successful, a Martian base might not be that far off.

The study “Fuel and oxygen harvesting from Martian regolithic brine” was published in PNAS

A new study on biomass fuel says smoke is more damaging to lungs than we assumed

Biomass cooking fires can incur “considerable damage” to the lungs of people who use them, a new study reveals. This effect is caused by “dangerous concentrations” of pollutants and bacterial toxins released during the burning of plant matter.

A biomass-fueled kitchen of one of the participants.

Roughly 3 billion people the world over still use biomass fuel for cooking, such as dry brush. This is making a significant contribution to the number of deaths related to household air pollution — an estimated 4 million annually. Governments around the world have launched projects to support the transition towards cleaner cooking fuels, such as liquefied petroleum gas, but economic and social factors, alongside faulty education on the benefits of this transition, means that many fires still burn on wood or brush.

Smokey issues

“It is important to detect, understand and reverse the early alterations that develop in response to chronic exposures to biomass fuel emissions,” said study co-author Abhilash Kizhakke Puliyakote, Ph.D., a postdoctoral researcher from the University of California San Diego School of Medicine.

The team used computer tomography scanners to analyze the lungs of 23 people who cook with wood biomass fuels or liquefied gas from Thanjavur, India. They also took air samples from their homes (which they used to measure pollutant concentrations there) and studied the lung function of the participants through traditional testing methods (such as spirometry). The scans were used to make quantitative measurements, so the team would, for example, take a scan when a person inhaled and another one when they exhaled, so they could measure the difference.

All in all, those who cooked with wood biomass were routinely exposed to higher levels of pollution and bacterial endotoxins. They also showed a much higher quantity of air trapping in their lungs, which is associated with lung diseases. Among the group, some participants had very high levels of air trapping and also showed abnormal tissue mechanics in their lungs, even when compared to their peers. This subgroup (around 30% of all biomass-burners) had more than 50% of the air they inhaled ending up trapped in their lungs.

“Air trapping happens when a part of the lung is unable to efficiently exchange air with the environment, so the next time you breathe in, you’re not getting enough oxygen into that region and eliminating carbon dioxide,” Dr. Kizhakke Puliyakote said. “That part of the lung has impaired gas exchange.”

“This increased sensitivity in a subgroup is also seen in other studies on tobacco smokers, and there may be a genetic basis that predisposes some individuals to be more susceptible to their environment”.

Smoke tended to affect the small airways of the lungs of participants, the authors explain, although the exact process is not yet clear. The study focused on cooking and biomass-fueled fires, but the findings are applicable to smoke from any source. Furthermore, the authors say that conventional testing has underestimated just how damaging smoke is to the lungs.

“The extent of damage from biomass fuels is not really well captured by traditional tests,” Dr. Kizhakke Puliyakote said. “You need more advanced, sensitive techniques like CT imaging. The key advantage to using imaging is that it’s so sensitive that you can detect subtle, regional changes before they progress to full blown disease, and you can follow disease progression over short periods of time.”

It is “crucial” for anyone who is exposed to biomass smoke for any extended duration to have a complete assessment of lung function by healthcare professionals to ensure that any potential injury can be resolved with appropriate interventions,” he adds. With the blaze of wildfires we’ve seen this year, this probably means that many, many people need to get their lungs checked.

The findings have been presented at RSNA 2020 – Radiological Society of North America Annual Meeting in Chicago.

Mistaken beliefs are altering India’s transition to clean cooking fuels

Popular belief in India that using firewood for cooking is healthier than Liquefied Petroleum Gas (LPG) is making the transition to clean cooking fuels more difficult, a new study showed. This means better information programs are needed to train people, the researchers argued.

Credit Flickr Carl Stead

India has more people who rely on solid fuels for cooking than any other country in the world (780 million), and estimates indicate that it will stay in this top position at least until the end of 2030. The scale of solid fuel use in rural areas signals that the widespread uptake of clean fuels is a distant reality.

Women are the main family cooks in rural India. That’s why researchers decided to focus their study on them and their views on fuel transition. The team performed a qualitative analysis of data from focus group discussions with comparable groups of women who have those who have not transitioned to LPG, seeking to understand their views.

The findings showed women believe firewood causes health problems but feel that it contributes more to wellbeing than cooking with LPG. For the researchers, this helps explain why India’s switch from traditional solid fuels is going slower than expected.

Study co-author Rosie Day said in a statement: “Whilst cooking is not solely a woman’s job, the reality is that, in rural India, women are considered the primary cooks. It is, therefore, critical to unravel how women see the relationship between wellbeing and cooking fuel if India is to make progress in transitioning to clean fuels.”

The researchers from the Universities of Birmingham (UK) and Queensland (Australia) focused on women from four villages in the Chittoor district of Andhra Pradesh. This allowed to do a comparison, as two of the villages mostly used firewood and the other two LPG, having switched from using firewood.

Those who use firewood believed that cooking with this fuel improved their financial wellbeing because they generated income from its sale, whilst collecting firewood gave them an opportunity to socialize and is a tradition they would like to continue. They viewed LPG as a financial burden that gave food an undesirable taste.

On the other hand, LPG users said their fuel allowed them to maintain or improve social status, as well as making it easier to care for children and other family members. Cooking with LPG freed up time which they could use to work outside the home and earn money. They also enjoyed extra leisure time with their family.

The researchers suggested future interventions to promote new fuels should actively involve women who used solid fuels and clean fuels, opening discussion about the benefits of each and allowing cooks to observe different cooking practices. They said information should be distributed on the positive wellbeing of LPG.

“We have gained important understanding of women’s views in this setting, but further research is needed to analyze the perceived relationship between women’s fuel use and multi-dimensional wellbeing in other settings. This will help to increase our understanding of how social and cultural factors come into play in transition to clean fuels,” said Day.

The study was published in the journal Nature Energy.

A brewery in the Netherlands becomes the first iron-fueled factory in the world

A brewery in the Netherlands has become the first business in the world to use iron powder as fuel on an industrial scale.

Iron powder being burned in a combustion tube. Image credits Bart van Overbeeke / TU Eindhoven.

We tend to think of fire mostly as something that engulfs wood, coal, petrol, and other flammables. It’s practical to do so — those are the things we burn when we need something to burn. But from a chemical point of view, almost everything burns, given the right conditions — including iron.

The Swinkels Family Brewers in the Netherlands has become the first business to use iron as a fuel for industrial application. It worked together with the Metal Power Consortium and researchers at TU Eindhoven to install a cyclical iron fuel system (more on that shortly) at its Brewery Bavaria, which is able to heat up around 15 million glasses of beer a year.

Iron burn

“We are enormously proud to be the first company to test this new fuel on an industrial scale in order to help accelerate the energy transition,” said Peer Swinkels, CEO of Royal Swinkels Family Brewers. “As a family business, we invest in a sustainable and circular economy because we think in terms of generations, not years.”

“We combine this way of thinking with high-quality knowledge in the collaboration with the Metal Power Consortium. Through this innovative technology, we want to make our brewing process less dependent on fossil fuels. We will continue to invest in this innovation.”

Industries typically rely on fossil fuels for all their heat-intensive needs, since these hold a whole lot of energy in a very dense package. Finely-ground iron can serve the same purpose, however. In such a form and at high temperatures, iron burns easily.

Burning is the physical manifestation of a chemical reaction known as oxidation, and we perceive the energy given off by this reaction as light and heat. When iron is burned this way, there is no output of carbon dioxide (since there’s no carbon in iron). The only product is rust. The best part is that this rust, which is basically just iron oxide, can then be turned back into plain iron with the simple application of an electrical current.

In essence, if you use energy from solar, wind, or other clean sources, you can use iron filings as a sort of clean battery that charges with electricity and outputs heat — which is neat!

Other advantages of this system include how cheap and abundant iron is, how easy it is to transport (it doesn’t need to be cooled like hydrogen, for example), its high energy density, and the high temperatures it can output (up to 1,800 °C / 3,272 °F). It also doesn’t spoil and won’t lose its properties even if stored for a long time.

The cyclical iron system installed at Brewery Bavaria handles both the burning and recharging phases of the process. Depending on how energy is fed back into the used iron, it can store up to 80% of the energy input back into the iron fuel, which is comparable to the efficiencies of modern hydrogen-splitting techniques.

“While we’re proud of this huge milestone, we also look at the future,” says Chan Botter, who leads student team SOLID at TU Eindhoven, a group dedicated to the advancement of metal fuels.

“There’s already a follow-up project which aims to realize a 1-MW system in which we also work on the technical improvement of the system. We’re also making plans for a 10-MW system that should be ready in 2024. Our ambition is to convert the first coal-fired power plants into sustainable iron fuel plants by 2030.”

The system Botter talks about would have a theoretical efficiency of around 40%, which isn’t great, but it could prove to be a convenient and flexible way of storing energy, either for later use or for transport to another site. An advantage of this approach would be that our current energy-generation infrastructure can be adapted to use iron quite easily (as all that is changed is the type of fuel used).

It’s not yet clear if it would be economically-viable, but it’s definitely a very exciting idea — at least, I think it is. There’s also something very cool about the idea of burning iron for power.

Here’s a video detailing how the technology would work from TU Eindhoven:

New ceramic catalyst sponge promises to turn waste organic matter into cheap biofuel, medicine

A new, ultra-efficient catalyst could pave the way towards turning various products from food waste to old tires into biofuels or medicine.

Stock photo — biofuel doesn’t actually look like this. Image credits Chokniti Khongchum.

The new material allows for efficient, low-cost recycling of low-grade organic material into valuable chemical products. Food scraps, used cooking oil, agricultural waste, or even plastic can be used in the process (even when relatively impure) can be used as part of the process.

Leftover fuel

“The quality of modern life is critically dependent on complex molecules to maintain our health and provide nutritious food, clean water, and cheap energy,” says co-lead author Professor Adam Lee from RMIT University, Australia.”These molecules are currently produced through unsustainable chemical processes that pollute the atmosphere, soil, and waterways.”

“Our new catalysts can help us get the full value of resources that would ordinarily go to waste to advance the circular economy. And by radically boosting efficiency, they could help us reduce environmental pollution from chemical manufacturing and bring us closer to the green chemistry revolution.”

Turning unwanted organic material into useful products isn’t out of our reach. Currently, however, the processes we use to do so are slow and inefficient, and the tools we have to improve on them, such as chemical catalysts or engineering solutions, are quite expensive. They also require that the raw materials used be very pure. For example, waste cooking oil needs to undergo a very energy-intensive purification process before being used for biodiesel production, as our current methods can only handle around 1-2% contaminants in their raw materials.

The new catalyst, however, can work with ingredients (‘feedstock’) comprising up to 50% contaminants. According to the authors, it’s so efficient it could also double the efficiency of our current processing methods.

The team first fabricated a porous ceramic sponge 100 times thinner than a human hair that contains several different (and specialized) active components. Feedstock molecules enter through the larger pores and undergo an initial chemical reaction, and later flow into smaller pores where final reactions take place. It’s the first catalyst that can mediate several chemical reactions in a sequence in a single particle, the authors note, which helps simplify the process and keeps costs low.

This approach, they explain, mimics the way enzymes handle complex chemical processes in living cells.

“Catalysts have previously been developed that can perform multiple simultaneous reactions, but these approaches offer little control over the chemistry and tend to be inefficient and unpredictable,” said Professor Karen Wilson, also from RMIT.

“Our bio-inspired approach looks to nature’s catalysts — enzymes — to develop a powerful and precise way of performing multiple reactions in a set sequence. It’s like having a nanoscale production line for chemical reactions – all housed in one, tiny and super-efficient catalyst particle.”

Even better, these sponges are cheap to manufacture and don’t use any rare and expensive materials like precious metals. They’re also meant to be employed in a similarly simple manner: mix feedstock such as agricultural waste with the catalysts in a large container, heat gently, and stir.

Their ease of use and low cost should make them attractive in developing countries where diesel is widely employed. Farmers, in particular, are well suited to using these catalyst sponges, as they have access to large quantities of agricultural byproducts to turn into fuel for their farms and machinery.

“If we could empower farmers to produce biodiesel directly from agricultural waste like rice bran, cashew nut and castor seed shells, on their own land, this would help address the critical issues of energy poverty and carbon emissions,” Wilson said.

The team now plans to further refine their catalyst sponges to allow for production of a greater range of final products and useful feedstock, such as producing jet fuel from forestry waste or old rubber. Until then, however, they will be hard at work scaling up production, which is currently limited to the order of a few grams.

The paper “A spatially orthogonal hierarchically porous acid-base catalyst for cascade and antagonistic reactions” has been published in the journal Nature Catalysis.

Carbon emission growth rates go down, overall emissions reach record highs (again)

The rate of carbon emission growth in 2019 has dropped compared to those of 2018 and 2017. However, overall CO2 emission levels are expected to reach 37 billion tons — a record high.

Industrial zone in the Rhur area, Germany.
Image via Pixabay.

The estimates come from the Global Carbon Project, an initiative led by Stanford University scientist Rob Jackson, and have been published in advance of the 25th conference of the United Nations Framework Convention on Climate Change in Madrid. Overall, emission levels in 2019 are projected to rise by 0.6% over 2018 levels, compared to a 2.1% and 1.5% rise in 2018 and 2017, respectively.

The authors warn that while the rise in emissions is slowing down, emission rates are very likely to keep increasing through to 2030 unless world leaders take meaningful action to reduce fossil fuel use in national energy, transportation, and industry sectors.

Good, not good enough

“When the good news is that emissions growth is slower than last year, we need help,” said Jackson, a professor of Earth system science at the Stanford School of Earth, Energy & Environmental Sciences.

“When will emissions start to drop?”

On the one hand, we see reasons for hope: coal use is in decline across most developed, western states (such as the EU and US). On the other hand, reductions here are canceled out by increased use of oil and natural gas around the world. Fossil fuel use accounted for roughly 90% of all emissions from human activities in 2018, according to Carbon Brief.

Global carbon dioxide emissions by fuel type and emissions from cement production and flaring, with the average annual growth rate for 2013-2018.
Image credits Jackson et al., 2019, Environmental Research Letters.

Rich, developed countries also release a disproportionately high level of emissions per capita, although they are in the best position to switch to alternative energy sources. This is particularly worrying and likely to throw a wrench in climate negotiations, the team explains, as developing countries are (understandably) keen on using fossil fuels to strengthen their economies and provide better lives for their citizens — which, in essence, is exactly what developed countries have done in the past.

“Because per capita oil consumption in the US and Europe remains 5- to 20-fold higher than in China and India, increasing vehicle ownership and air travel in Asia are poised to increase global CO2 emissions from oil over the next decade or more,” notes one of three papers detailing the findings, published in Environmental Research Letters.

About 40% of fossil-fuel-related carbon dioxide emissions were attributable to coal use, 34% from oil, 20% from natural gas, and the remaining 6% from cement production and other sources, they report. The US, EU, and China together account for over half of all carbon emissions globally. Some success has been registered in the US and EU, whose emissions are projected to drop by 1.7% compared to 2018. However, this is more than offset by increases in other countries. China, for example, is projected to emit 2.6% more carbon in 2019 than it did in 2018 — and it’s far from the only place to see such a trend.

Changes in the energy grid mosaic

“Emissions cuts in wealthier nations must outpace increases in poorer countries where access to energy is still needed,” said Pierre Friedlingstein, a mathematics professor at the University of Exeter and lead author of the Environmental Research Letters study.

So where is all this carbon coming from? The good news is, it’s not from coal. This old-timer of a fossil fuel has seen a 0.9% drop in use, worldwide, compared to 2018. Its fading popularity — displaced by cheaper natural gas, wind, and solar power — can explain much of the drop in emissions seen by the US: coal use dropped 11% here compared to last year. The EU has reduced its coal use by around 10%. China, the single largest coal consumer in the world (making up around half the global demand for coal), has registered an increase of only 0.8% in coal use this year, largely due to an economic downturn.

At the same time, natural gas use has risen sharply. While it does indeed result in fewer emissions than coal or oil, its greater availability and the lower price have encouraged consumption so, overall, we’ve seen 2.6% more use and 2.5% more emissions (to 7.7 billion tons) from natural gas compared to 2018. The team singles out natural gas as a leading cause of carbon emission growth in recent years, accounting for around 60% of the total increase.

“Liquified natural gas exports from Australia and the United States are surging, lowering natural gas prices in Asia and increasing global access to this fossil resource,” Friedlingstein’s team adds.  

“The global LNG trade grew 10% in 2018 to 317 million tonnes, the fifth consecutive year of record trade. [….] Greater natural gas supply coupled with cheaper prices could extend the market penetration of natural gas for decades.”

However, natural gas has been marketed as a “bridge fuel” — a stop-gap measure to help countries wean off of fossil fuels. The team says this hope is somewhat grounded in reality, but only if policymakers take concrete action to help make it so. Measures in support of carbon capture and storage (to mediate CO2 emissions) and a reduction in methane leakage from natural gas infrastructure are vital for this goal.

Some are more equal than the others

Global fossil carbon dioxide emissions (including cement production) for five regions, showing the average annual growth rate for 2013-2018.
Image credits Jackson et al., 2019, Environmental Research Letters.

And now for the contentious part: per capita emission inequality. The average human today is responsible for around 4.8 tons of fossil carbon dioxide emissions per year. The average US citizen, in contrast, emits three to three-and-a-half times as much. Developing countries are catching up, both in the standard of living and emission levels — per capita emissions in China now rival or even exceed those in the EU, for example. The Global Carbon Project explains that oil consumption per capita in the US is 16 times greater than in India, and 6 times greater than in China. In the US, there’s almost one car on the road for every citizen — there’s one for every 6 people in China, and one for every 40 people in India.

This leaves calls to reduce fossil fuel open to critique for a holier-than-thou attitude. If wealthy nations got where they are by burning and polluting, why should developing countries ‘pay the bill’?

Do I think this is a healthy attitude? No, I think it leaves us all worse off and will come around to bite us, all of us, in the back. But I do see the point. National governments, first and foremost, have to answer to their citizens. In their view, people in other countries made this mess and got rich off of it, and those people are now are asking everybody else to give up the same wellbeing to clean it up — without compensation. It’s a very raw deal if you ignore the whole ‘climate emergency’ bit.

What to do about it

Not all is lost, however. Previous research has found that 18 or so countries have managed to both expand their economies and reduce emissions over the last decade, most notably the United Kingdom and Denmark, showing that countries (especially rich ones) can switch to clean energy without sacrificing prosperity. Key to their success was a reduction in energy use overall while new renewable fuel capacity was being installed to displace fossil fuels.

The team writes that stronger commitments and policy, both at a national and global level, can help us out of this bind. They list carbon pricing, improvements in the energy sector, reductions in energy use, the use of electric vehicles, as well as carbon capture and storage as some areas to focus on in the future. Of course, there’s also the straightforward way: doing our absolute best in phasing out fossil fuels for clean energy.

“We need every arrow in our climate quiver,” Jackson said. “That means stricter fuel efficiency standards, stronger policy incentives for renewables, even dietary changes and carbon capture and storage technologies.”

The three papers describing the findings are:

“Persistent fossil fuel growth threatens the Paris Agreement and planetary health”, published in the journal Environmental Research Letters.

“Global Carbon Budget 2019”, published in the journal Earth System Science Data.

“Carbon dioxide emissions continue to grow amidst slowly emerging climate policies”, published in the journal Nature Climate Change.

An artificial leaf can turn carbon dioxide into fuel

Seeking innovative ways to deal with the rise in greenhouse gas emissions, a group of scientists has developed a so-called “artificial leaf” that can convert carbon dioxide (CO2) into a useful alternative fuel – with almost no costs.

Credit Wikipedia Commons

The research, published in the journal Nature Energy, was inspired by the way plants use energy from sunlight to turn carbon dioxide into food.

“We call it an artificial leaf because it mimics real leaves and the process of photosynthesis,” said Yimin Wu, an engineering professor at the University of Waterloo who led the research. “A leaf produces glucose and oxygen. We produce methanol and oxygen.”

Carbon dioxide is the primary contributor to global warming. Making methanol out of it would both reduce greenhouse gas emissions and provide a substitute for the fossil fuels that create them. The key to the process is a cheap, optimized red powder called cuprous oxide.

The powder is created by a chemical reaction when four substances – glucose, copper acetate, sodium hydroxide, and sodium dodecyl sulfate – are added to water that has been heated to a particular temperature. It’s engineered to have as many eight-sided particles as possible

Then, the powder serves as the catalyst, or trigger, for another chemical reaction when it is mixed with water into which carbon dioxide is blown and a beam of white light is directed with a solar simulator.

“This is the chemical reaction that we discovered,” said Wu, who has worked on the project since 2015. “Nobody has done this before.”

The reaction produces oxygen, as in photosynthesis, while also converting carbon dioxide in the water-powder solution into methanol. The methanol is collected as it evaporates when the solution is heated.

Looking ahead, the next steps in the research include increasing the methanol yield and commercializing the patented process to convert carbon dioxide collected from major greenhouse gas sources such as power plants, vehicles, and oil drilling.

“I’m extremely excited about the potential of this discovery to change the game,” said Wu, a professor of mechanical and mechatronics engineering, and a member of the Waterloo Institute for Nanotechnology. “Climate change is an urgent problem and we can help reduce CO2 emissions while also creating an alternative fuel.”

Desert tank.

The military is the largest emitter in the US Gov’t — in fact, it’s the world 55th largest polluter

The American military is actually one of the largest emitters of greenhouse gases in the world — more than many nations.

Desert tank.

Image via Pixabay.

A new analysis by Dr. Neta Crawford, a professor of Political Science and Department Chair at Boston University, shows that the Pentagon was responsible for around 59 million metric tons of carbon dioxide and other greenhouse gas emissions in 2017. This figure places the U.S. military higher on the list of the world’s largest emitters than industrialized countries such as Sweden or Portugal.

The Costs of War

“In a newly released study published by Brown University’s Costs of War Project, I calculated U.S. military greenhouse gas emissions in tons of carbon dioxide equivalent from 1975 through 2017,” Dr. Crawford explains in a piece for LiveScience.

“Since 2001, the DOD has consistently consumed between 77 and 80 percent of all US
government energy consumption,” her paper explains.

In “any one year”, she explains, the Pentagon’s emissions were greater than “many smaller countries’ [emissions],” the study explains. In fact, if the Pentagon were a country, it would be the world’s 55th largest greenhouse gas emitter, overtaking even industrialized countries.

The largest single sources of military greenhouse gas emissions identified in the study are buildings and fuel. The DoD maintains over 560,000 buildings, which account for about 30% of its emissions. “The Pentagon building itself emitted 24,620.55 metric tons of [CO2 equivalent] in the fiscal year 2013,” the study says. The lion’s share of total energy use, around 70%, comes from operations. This includes moving troops and material about, as well as their use in the field, and is kept running by massive quantities of jet and diesel fuel, Crawford said.

Where to?

This January, the Pentagon listed climate change as “a national security issue” in a report it presented to Congress. The military has launched several initiatives to prepare for its impacts but seems just as thirsty for fuel as ever before. It is understandable; tanks, trucks, planes, bombers without fuel — and a lot of fuel — they’re just fancy paperweights.

But, at the same time, the use of fossil fuels is changing the climate. Global climate models estimate a 3ºC to 5ºC (5.4ºF to 9ºF) rise in mean temperatures this century alone under a business as usual scenario. In a paper published in Nature that we covered earlier today, we’ve seen how 4ºC would increase the effect of climate on conflict more than five-fold. More conflict would probably mean more fuel guzzled by the army’s engines.

The paper also looks at how the U.S. military “spends about $81 billion annually defending the global oil supply” to ensure both domestic and military life can continue without a hitch.

“The military uses a great deal of fossil fuel protecting access to Persian Gulf Oil,” the paper explains. “Because the current trend is that the US is becoming less dependent on oil, it may be that the mission of protecting Persian Gulf oil is no longer vital and the US military can reduce its presence in the Persian Gulf.”

“Which raises the question of whether, in protecting against a potential oil price increase, the US does more harm than it risks by not defending access to Persian Gulf oil. In sum, the Persian Gulf mission may not be as necessary as the Pentagon assumes.”

However, not all is dead and dreary. Crawford says the Pentagon had reduced its fuel consumption significantly since 2009, mainly by making its vehicles more efficient and shifting towards cleaner sources of energy at bases. Further reductions could be achieved by cutting missions to the Persian Gulf, the paper advises, seeing as it is no longer a top priority to protect oil supply from this area as renewable energy is gaining in the overall grid make-up.

“Many missions could actually be rethought, and it would make the world safer,” Crawford concludes.

The paper “Pentagon Fuel Use, Climate Change, and the Costs of War” can be accessed here.


Researchers create fuel from water, CO2, and artificial photosynthesis

New research at the University of Illinois is bringing working artificial photosynthesis one step closer to reality.


Image via Pixabay.

The team has successfully produced fuel from water, carbon dioxide, and visible light through artificial photosynthesis. Their method effectively converts carbon dioxide into longer, more complex molecules, like propane. When fully developed, artificial photosynthesis of this kind could be used to store solar energy in chemical bonds (i.e. fuel) for peak-demand times.


“The goal here is to produce complex, liquefiable hydrocarbons from excess CO2 and other sustainable resources such as sunlight,” said Prashant Jain, a chemistry professor and co-author of the study.

“Liquid fuels are ideal because they are easier, safer and more economical to transport than gas and, because they are made from long-chain molecules, contain more bonds — meaning they pack energy more densely.”

Plants use photosynthesis to capture energy from sunlight in the form of glucose. Glucose is a relatively energy-dense compound (it’s a sugar), so plants can effectively use it as a type of chemical energy that they assemble from (relatively energy-poor) CO2. Researchers have long strived to recreate this process in the lab, with various degrees of success, as it holds great promise for clean energy applications.

The new study reports on probably the most successful attempt to emulate photosynthesis so far. The artificial process the team developed draws on the same green light that powers photosynthesis in plants. It mixes CO2 and water into fuel with a little help from gold nanoparticles that serve as a catalyst. The electron-rich particles of gold absorb green light and handle the transfer of protons and electrons between water and CO2 — in broad lines, playing the same role as the pigment chlorophyll in natural photosynthesis.

Gold nanoparticles work particularly well in this role, says Jain, because their surfaces interact with CO2 molecules in just the right way. They’re also pretty efficient at absorbing light and do not break down or degrade like other metals do.

While the resulting fuel can simply be combusted to retrieve all that energy, it wouldn’t be the best approach, the team writes. Simply burning it re-releases all the CO2 back into the atmosphere, which is counterproductive to the notion of harvesting and storing solar energy in the first place, says Jain.

“There are other, more unconventional potential uses from the hydrocarbons created from this process,” he says.

“They could be used to power fuel cells for producing electrical current and voltage. There are labs across the world trying to figure out how the hydrocarbon-to-electricity conversion can be conducted efficiently.”

Exciting though the development might be, the team acknowledges that their artificial photosynthesis process is nowhere near as efficient as it is in plants.

“We need to learn how to tune the catalyst to increase the efficiency of the chemical reactions,” he said.

“Then we can start the hard work of determining how to go about scaling up the process. And, like any unconventional energy technology, there will be many economic feasibility questions to be answered, as well.”

The paper “Plasmonic photosynthesis of C1–C3 hydrocarbons from carbon dioxide assisted by an ionic liquid” has been published in the journal Nature Communications.

Wall fans.

New paper proposes we use air conditioners to make fuel out of thin air

Cool down your home and the climate at the same time.

Wall fans.

Image credits Sławomir Kowalewski.

New research from the Karlsruhe Institute of Technology and the University of Toronto wants to put your air conditioning unit to work on fighting climate change. The idea is to outfit air conditioners — devices which move huge amounts of air per day — with carbon-capture technology and electrolyzers, which would turn the gas into fuel.

Crowd oil

“Carbon capture equipment could come from a Swiss ‘direct air capture’ company called Climeworks, and the electrolyzers to convert carbon dioxide and water into hydrogen are available from Siemens, Hydrogenics or other companies,” said paper co-author Geoffrey Ozin for Scientific American.

Air-conditioner units are very energy-thirsty. As most of our energy today is derived from fossil fuels, this means that air conditioners can be linked to a sizeable quantity of greenhouse emissions. It’s estimated that, by the end of the century, we’ll be using enough energy on air conditioning to push the average global temperature up by half a degree. Which is pretty ironic.

The team’s idea is pretty simple — what if heating, ventilation, and air conditioning (or HVAC) systems could act as carbon sinks, instead of being net carbon contributors? Carbon-capture devices need to be able to move and process massive quantities of air in order to be effective. HVAC systems already do this, being able to move the entire volume of air in an average office building five to ten times every hour. So they’re ideally suited for one another. The authors propose “retrofitting air conditioning units as integrated, scalable, and renewable-powered devices capable of decentralized CO2 conversion and energy democratization.”

“It would be not that difficult technically to add a CO2 capture functionality to an A/C system,” the authors write, “and an integrated A/C-DAC unit is expected to show favourable economics.”

Modular attachments could be used to add CO2-scrubbing filters to pre-existing HVAC systems. After collection, that CO2 can be mixed with water to make, basically, fossil fuels. As Ozin told Scientific American, the required technology is commercially available today.

But, in order to see if it would also be effective, the team used a large office tower in Frankfurt, Germany, as a case study. HVAC systems installed on this building could capture enough CO2 to produce around 600,000 gallons of fuel in a year. They further estimate that installing similar systems on all the city’s buildings could generate in excess of 120 million gallons of (quite wittily-named) “crowd oil” per year.

“Renewable oil wells, a distributed social technology whereby people in homes, offices, and commercial buildings all around the world collectively harvest renewable electricity and heat and use air conditioning and ventilation systems to capture CO2 and H2O from ambient air, by chemical processes, into renewable synthetic oil — crowd oil — substituting for non-renewable fossil-based oil — a step towards a circular CO2 economy.”

Such an approach would still take a lot of work and polish before it could be implemented on any large scale. Among some of the problems is that it would, in effect, turn any HVAC-equipped system into a small, flammable oil refinery. The idea also drew criticism as it could potentially distract people from the actual goal — reducing emission levels.

“The preliminary analysis […] demonstrates the potential of capturing CO2 from air conditioning systems in buildings, for making a substantial amount of liquid hydrocarbon fuel,” the paper reads.

“While the analysis considers the CO2 reduction potential, carbon efficiency and overall energy efficiency, it does not touch on spatial, or economic metrics for the requisite systems. These have to be obtained from a full techno-economic and life cycle analysis of the entire system.”

The paper “Crowd oil not crude oil” has been published in the journal Nature Communications.

Saltwater electrolysis.

New process can make hydrogen fuel out of seawater without destroying the devices

Researchers from Stanford University have developed a process to make hydrogen fuel using only electrodes, solar power, and saltwater from the San Francisco Bay.

Saltwater electrolysis.

A prototype device used solar energy to create hydrogen fuel from seawater.
Image credits Yun Kuang et al., (2019), PNAS.

Hydrogen fuel holds a lot of promise as the energy source of the future. It’s clean, doesn’t emit anything, it’s energy-dense, and it’s beyond abundant — if only we were able to develop a way of retrieving the element from its chemical constraints. A new paper describes a way to do just that, starting from saltwater.

Salt of the water

Why is this news? Well, it simply comes down to quantities — the Earth has a lot of saltwater, but not very much fresh water. Methods of producing hydrogen fuel from the latter have already been developed, but the fact of the matter is that fresh water is valuable. We need it to drink, we need it to wash, we need it to grow our crops and, as our planet’s population increases, we run a very real risk of not having enough water for everyone. So it doesn’t make sense to use it for energy — we need it elsewhere.

“You need so much hydrogen [to power our cities and economies that] it is not conceivable to use purified water,” said Hongjie Dai, J.G. Jackson and C.J. Wood professor in chemistry at Stanford and co-senior author on the paper. “We barely have enough water for our current needs in California.”

Salty water, in contrast, is plentiful — which also means cheap. There’s enough of it that we can turn it into hydrogen without upsetting the natural balance of Earth’s ecosystems too much. Hydrogen fuel also doesn’t emit carbon dioxide as it ‘burns’, only water. Given our current troubles with man-made climate change and habitat destruction, both are very appealing qualities.

Saltwater does, however, come with a major drawback. It’s not that hard to split water into hydrogen and oxygen, and we’ve known how to do it for a long time now. Just take a power source, connect two wires to and place their other end (or some electrodes if you want to be fancy about it) in water. Turn the power on, and you’ll get hydrogen bubbles at the negative end (cathode), and oxygen bubbles at the positive end (anode). This process is called electrolysis.

So far so good. But, if you try the same thing with saltwater, the chloride ions in salt (salt is a mix of chloride and sodium atoms) will corrode the anode and break down the system pretty quickly. Dai and his team wanted to find a way to stop those components from breaking down in the process.

Their approach was to coat the anode in several layers of negatively-charged material, which would repeal chloride, thus prolonging the useable life of the electrolysis rig. They layered nickel-iron hydroxide on top of nickel sulfide, over a nickel foam core. The nickel foam acts as a conductor, carrying electricity from the power source, while the nickel-iron hydroxide performs the electrolysis proper, separating water into oxygen and hydrogen.

As this happens, the nickel sulfide becomes negatively charged, protecting the anode. Just as the negative ends of two magnets push against one another, the negatively charged layer repels chloride and prevents it from reaching the core metal. Without the coating, the anode only works for around 12 hours in seawater, according to Michael Kenney, a graduate student in the Dai lab and co-lead author on the paper.

“The whole electrode falls apart into a crumble,” Kenney said. “But with this layer, it is able to go more than a thousand hours.”

Another bonus this coating brings to the table is that it allows for electrolysis to be performed at much higher currents. Previous efforts to split seawater had to use low current, as higher values promote corrosion. The team was able to conduct up to 10 times more electricity through their multi-layer device, which helps it generate hydrogen faster. Dai says they likely “set a record on the current to split seawater.” By eliminating the corrosive effect of salt, the team was able to use the same currents as those in devices that use purified water.

The team conducted most of their tests in controlled laboratory conditions, where they could regulate the amount of electricity entering the system. But, they also designed a solar-powered demonstration machine that produced hydrogen and oxygen gas from seawater collected from San Francisco Bay. Dai says the team pointed the way forward but will leave it up to manufacturers to scale and mass produce the design.

“One could just use these elements in existing electrolyzer systems and that could be pretty quick,” he adds. “It’s not like starting from zero — it’s more like starting from 80 or 90 percent.”

In the future, the technology could be used to generate breathable oxygen for divers or submarines while also providing power. And, perhaps, it could also be used in space exploration to limit the need for water purification systems — at least as far as power and oxygen are concerned.

The paper ” Solar-driven, highly sustained splitting of seawater into hydrogen and oxygen fuels” has been published in the journal Proceedings of the National Academy of Sciences.


New design hotfix could make artificial leaves better than actual leaves

A new design could bring artificial leaves out of the lab to convert CO2 into raw materials for fuel.


Image credits Jeon Sang-O.

The idea behind artificial leaves isn’t very complicated — just make them do the same job regular leaves perform, but faster, if possible. Despite this, we’ve had a hard time actually delivering on the idea outside of laboratory conditions. New research, however, could improve on the technology enough to make it viable in the real world.

Leaf it to the catalysts

The sore point with our present artificial leaves is that they simply don’t gobble up CO2 at the concentrations it’s found in the atmosphere.

“So far, all designs for artificial leaves that have been tested in the lab use carbon dioxide from pressurized tanks. In order to implement successfully in the real world, these devices need to be able to draw carbon dioxide from much more dilute sources, such as air and flue gas, which is the gas given off by coal-burning power plants,” said Meenesh Singh, assistant professor of chemical engineering in the UIC College of Engineering and corresponding author on the paper.

While artificial leaves are meant to mimic photosynthesis, even our most refined leaves only work if supplied with pure, pressurized CO2 from tanks in the lab. It’s good that they work, it means we’re on the right track, but they’re not useable in practical applications. Because they only work with high concentrations of CO2, they can’t be used to scrub this gas out of the wider atmosphere, which is what we want to do with them.

Researchers at the University of Illinois at Chicago, however, propose a design solution that could fix this shortcoming. Their relatively simple addition to the design would make artificial leaves over 10 times more efficient than their natural counterparts at absorbing CO2. The gas can then be converted to fuel, they add.

Singh and his colleague Aditya Prajapati, a graduate student in his lab, say that encapsulating artificial leaves inside a transparent, semi-permeable capsule filled with water is all we need to do. The membrane allows water inside to evaporate which, as it passes through the quaternary ammonium resin membrane, pulls in CO2 from the air.

Artificial leaf.

A schematic showing the main principles behind this process.
Carbon dioxide (red and black) enters the leaf as water (white and red) evaporates from the bottom of the leaf. An artificial photosystem (purple circle at the center of the leaf) made of a light absorber coated with catalysts converts carbon dioxide to carbon monoxide and converts water to oxygen (double red spheres) using sunlight.
Image credits Meenesh Singh.

The artificial photosynthetic unit inside the capsule then converts carbon dioxide to carbon monoxide, which can be siphoned off and used to make fuel. Oxygen is also produced and can either be collected or released into the surrounding environment.

“By enveloping traditional artificial leaf technology inside this specialized membrane, the whole unit is able to function outside, like a natural leaf,” Singh said.

The duo estimates that 360 such leaves, each measuring 1.7 meters by 0.2 meters (5.5 by 0.6 feet), could produce around half a ton of carbon monoxide per day. Spread over a 500 sq meter area, the leaves could reduce CO2 levels by 10% within 100 meters of the array in a single day, they add.

“Our conceptual design uses readily available materials and technology, that when combined can produce an artificial leaf that is ready to be deployed outside the lab where it can play a significant role in reducing greenhouse gases in the atmosphere,” Singh said.

The paper “Assessment of Artificial Photosynthetic Systems for Integrated Carbon Capture and Conversion” has been published in the journal ACS Sustainable Chemistry & Engineering.

Test device.

Newly-developed fuel can store solar energy for up to 18 years

Sweedish researchers have developed a new liquid that can store solar heat for almost two decades.

Oil on Water.

Oil on water.
Image via Pixabay.

The main drawback of solar power is that we’re yet to develop reliable, dense, and long-term storage for the energy that it generates. Our only realistic option at this time are batteries, but they’re quite expensive, use on rare or polluting materials, and have a limited capacity. The current research, however, might provide exactly the breakthrough that the industry needs — the new compound, a specialized fluid called solar thermal fuel, can store and release solar heat for up to 18 years.

Chemical storage

“The energy in this isomer can now be stored for up to 18 years,” says one of the team, nanomaterials scientist Kasper Moth-Poulsen from Chalmers University.

“And when we come to extract the energy and use it, we get a warmth increase which is greater than we dared hope for.”

Solar fuels work similarly to a rechargeable battery that substitutes sunlight and heat in lieu of electricity. The team’s compound is a molecule (norbornadiene) in a liquid form that researchers at the Chalmers University of Technology, Sweden have been developing for over a year. It’s composed mainly of carbon, with some hydrogen and nitrogen atoms thrown in. So, up to now, it’s a pretty standard organic compound.

What makes this fluid stand out is its interaction with sunlight. When exposed to sunlight, the bonds between the molecule’s atoms get rearranged and stabilize in an energized form — an isomer (called quadricyclane). This transforms heat energy from the sun into chemical energy that can be stored and released. The isomer itself is stable enough to last unaltered for up to 18 years (which is a lot), even at room temperatures.

When the energy is needed, the ‘charged’ fluid can be drawn through a catalyst that unpacks the molecule to its original form. The excess chemical energy is given off as heat.

Test device.

Image credits Chalmers University of Technology.

A prototype rig using this new fuel is already undergoing tests on one of the university’s buildings, the team adds. The system is based on a circuit that pumps the fluid through transparent tubes under a concave reflector (this focuses sunlight on the fuel). The charged fuel is then pumped into storage. The whole installation acts much like a sunflower, tracking the Sun as it moves across the sky.

When the energy is needed, the fluid is filtered through the catalyst, warming it by 63 degrees Celsius (113 degrees Fahrenheit). The team hopes that the heat can be used in various roles around the house — heating systems, dishwashers, anything and everything, really — before being pumped back to the roof once again.

“We have made many crucial advances recently, and today we have an emissions-free energy system which works all year around,” says Moth-Poulsen.

So far, the researchers have tested their fuel through 125 such cycles without observing any significant damage to the molecule. Furthermore, they report that one kilogram of the fuel can store 250 watt-hours of energy — which is double what a Tesla Powerwall can boast. However, they’re confident that there are still areas where the fuel can be improved. They hope to have the system generate at least 110 degrees Celsius (230 degrees Fahrenheit) more with further tweaks.

“There is a lot left to do. We have just got the system to work. Now we need to ensure everything is optimally designed,” says Moth-Poulsen.

Moth-Poulsen thinks the technology could be available for commercial use within 10 years.

The paper “Macroscopic heat release in a molecular solar thermal energy storage system” has been published in the journal Energy & Environmental Science.

Hydrogen sign.

Solar fuels just years away, propelled by breakthrough in catalyst research

New research from Caltech could bring an economically-viable solar fuel to the market in the next few years.

Hydrogen sign.

Image credits Zero Emission Resource Organisation / Flickr.

One of the holy grails of renewable energy researchers which they have been pursuing for decades, is the brewing of economically-viable solar fuel. It sounds like something you drill out of the core of a star, but in reality, it’s both much more useful and less dramatic than that: “solar fuels” are chemical compounds which can be used to store solar energy.

Most of the recent research performed in this field focused on splitting water into its constituent parts (hydrogen and oxygen) using only sunlight. It’s easy to see why — hydrogen produced this way would be a clean, cheap, easy-to-produce and generally widely-available fuel. It could be used to power solar cells, motor vehicles, or even spin the turbines of power plants. One of it’s most attractive qualities is that it would be virtually endless and produces zero emissions: the only reactionary product of a hydrogen engine (which burns the gas, i.e. combines it back with oxygen) would be plain old water.

We’re actually pretty close to having the solar fuels we so desire, the only thing we’re missing is the “cheap” part. Back in 2014, a team of Caltech researchers led by Professor Harry developed a water-splitting catalyst from layers of nickel and iron. It worked pretty well for a prototype, showing that it has potential and could be scaled-up. However, while the catalyst clearly worked, nobody knew exactly how it did so. The working theory was that the nickel layers were somehow responsible for the material’s water-splitting ability.

Catalyst model chemical structure.

Ball-and-stick model of the catalyst’s molecular structure. Iron atoms are blue, nickel is green, oxygen is shown in red and hydrogen in white.
Image credits Caltech.

To get to the bottom of things, a team led by Bryan Hunter from Caltech’s Resnick Institute created an experiment during which the catalyst was starved of water, and observed how it behaved.

“When you take away some of the water, the reaction slows down, and you are able to take a picture of what’s happening during the reaction,” Bryan says.

The experiment revealed that the spot where water gets broken down on the catalyst — called its “active site” — wasn’t nickel, but iron atoms. The results are “very different” from what researchers expected to find, Hunter says. However, that isn’t a bad thing. Our initial hypothesis was a dud, but now that we know exactly how the alloy works — meaning we won’t waste time researching the wrong avenues.

“Now we can start making changes to this material to improve it.”

Gray believes the discovery will be a “game changer” in the field of solar fuels, alerting people that iron is “particularly good” for this type of applications. As we now know what we should look for, we can go on to the next step — which is finding out how to make such processes unfold faster and more efficient, which translates to lower costs of the final fuel.

“I wouldn’t be at all shocked if people start using these catalysts in commercial applications in four or five years.”

The paper “Trapping an Iron(VI) Water Splitting Intermediate in Nonaqueous Media” has been published in the journal Joule.

Gas cannister.

Aggressive driving burns up to 40% more fuel and can waste one dollar per gallon

Researchers from the DOE’s Oak Ridge National Laboratory say you should drive more sensibly — if you like saving money, that is. They’ve recently published a paper analyzing the impact patterns of aggressive driving, such as speeding and forceful breaking, have on fuel economy.

Gas cannister.

Image via Pixabay.

Aggressive driving doesn’t pay — unless you’re a gas pump. Oak Ridge National Laboratory researchers report that aggressive driving can slash fuel efficiency by between 10 to 40% in stop and go traffic, or between 15 to 30% at highway speeds in light-duty vehicles. All in all, it could end up costing you about $0.25 to $1 per gallon in wasted gas.

A burning question

The team started by analyzing previous studies to develop a new energy model that would be used for the paper. It was applied to two similar mid-sized sedans, one being a hybrid-electric vehicle (HEV) and the other a conventional gasoline vehicle. Both were run through driving experiments at the lab’s National Transportation Research Center, to see what difference in fuel consumption an aggressive driving style would cause. A point of particular interest for the team was to evaluate an HEV’s limitations when recapturing energy to replenish the battery during different levels of hard braking.

“The new vehicle energy model we created focused on the limitations of regenerative braking along with varying levels of driving-style aggressiveness to show that this could account for greater fuel economy variation in an HEV compared to a similar conventional vehicle,” said ORNL’s John Thomas, lead author of the paper.

“Our findings added credence to the idea that an aggressive driving style does affect fuel economy probably more than people think.”

In the end, the team’s result confirmed popular wisdom, often self-reported by drivers — aggressive driving does impact fuel economy. They also showed that HEVs are more sensitive to driving style than conventional gasoline vehicles, although HEVs almost always achieve much better fuel economy. All in all, driving aggressively could take up to one dollar from your pocket per gallon of gas burned.

So if you like money (of course you do), driving more sensibly could be just the thing to put save up. Plus, you and yours will be safer on the road and you’ll also go to sleep with a smile knowing you helped save the penguins. Win-win-WIN!

You can see the team’s full dataset on the government site fueleconomy.gov, a platform maintained by the ORNL for DOE’s Office of Energy Efficiency and Renewable Energy with data provided by the Environmental Protection Agency. The project aims to help consumers make informed fuel economy choices, along with other simple fuel-saving measures such as obeying posted speed limits, avoiding excessive idling or carrying too much weight, and using cruise control.

The paper “Fuel Consumption Sensitivity of Conventional and Hybrid Electric Light-Duty Gasoline Vehicles to Driving Style” has been published in the journal SAE International Journal of Fuels and Lubricants.

New method developed to create biocrude oil from wastewater

A newly-developed process could create fuel from our waste. Researchers at the Department of Energy’s Pacific Northwest National Laboratory have created a method to turn ordinary sewage and other organic waste into biocrude oil.

Biocrude oil produced with hydrothermal liquefaction.
Image credits WE&RF.

It may sound like fiction, it does sound yucky, but one day, wastewater treatment plants may be powering your car. The Department of Energy’s Pacific Northwest National Laboratory researchers have developed a novel process, which they call hydrothermal liquefaction, that mimics the geological conditions involved in creating crude oil. Using high pressures and temperatures, they only need a few minutes and the stuff we flush down our toilets to create a liquid that takes millions of years to form in nature.

I’m talking, of course, about crude oil. With wastewater treatment plants across the U.S. treating some 34 billion gallons of sewage every day, the PNNL estimates they could produce some 30 million barrels of crude a year — so each person could churn out two or three gallons of biocrude each year.

This material is very similar to the oil we pump out of the ground, with a little more water and oxygen mixed in. It can be refined through the installations we already have to produce gasoline, diesel, even jet fuel.

Crude nr. 2

Any organic mater, in theory, can be used to produce biofuel. Sewage, however, has long been considered as a poor ingredient for the task because it contains too much water.  But PNNL’s doesn’t require for it to be dried — the step which historically has made wastewater-to-fuel conversion too energy intensive to be economically viable. Through HTL, organic matter is pressurized to 3,000 pounds per square inch (about 100 times the pressure in a car tire), then fed into a reactor system which cooks it to 660 degrees Fahrenheit (350 Celsius). These extreme conditions break the matter down to its simple chemical compounds — the cells in the material rip apart, forming biocrude and an aqueous-liquid phase.

“There is plenty of carbon in municipal waste water sludge and interestingly, there are also fats,” said Corinne Drennan, who is responsible for bioenergy technologies research at PNNL.

“The fats or lipids appear to facilitate the conversion of other materials in the wastewater such as toilet paper, keep the sludge moving through the reactor, and produce a very high quality biocrude that, when refined, yields fuels such as gasoline, diesel and jet fuels.”

Not only that, but the method could provide governments with a method to save significant costs by eliminating the need for sewage processing, transport, and disposal. It’s also very simple to implement, as Drennan says.

“The best thing about this process is how simple it is. The reactor is literally a hot, pressurized tube. We’ve really accelerated hydrothermal conversion technology over the last six years to create a continuous, and scalable process which allows the use of wet wastes like sewage sludge.”

HTL may also be used to make fuel from other types of wet organic feedstock, such as agricultural waste. In addition to the biocrude, the liquid phase can be treated to create other fuels and chemical products. A small amount of solid material is also generated, which contains important nutrients. For example, early efforts have demonstrated the ability to recover phosphorus, which can replace phosphorus ore used in fertilizer production.

PNNL has licensed the technology to Utah-based Genifuel Corporation, which is now working with Metro Vancouver, a partnership of 23 local authorities in British Columbia, Canada, to build a demonstration plant.



Photosynthetic solar cell turns carbon dioxide and sunlight into fuel

A team of researchers from the University of Illinois at Chicago (UIC) has created a photosynthetic solar cell that converts atmospheric carbon dioxide into usable hydrocarbon fuel.

The solar cell that converts atmospheric carbon dioxide directly into fuel. Credit: University of Illinois at Chicago/Jenny Fontaine

The solar cell that converts atmospheric carbon dioxide directly into fuel. Credit: University of Illinois at Chicago/Jenny Fontaine

Conventional solar cells convert sunlight into electricity that must be stored in heavy batteries. The new solar cell is potentially game-changing because it converts atmospheric carbon dioxide into fuel, which could not only remove large amounts of carbon from the atmosphere but also create energy-dense fuel.

“The new solar cell is not photovoltaic – it’s photosynthetic,” said Amin Salehi-Khojin, an assistant professor of mechanical and industrial engineering at UIC and senior author of the study. “Instead of producing energy in an unsustainable one-way route from fossil fuels to greenhouse gas, we can now reverse the process and recycle atmospheric carbon into fuel using sunlight.”

If the new solar cell can be taken advantage of on a global scale, it would render fossil fuels obsolete by giving us the ability to turn carbon dioxide into fuel at a cost similar to a gallon of gasoline.

Past studies have failed to find effective catalysts for the conversion of carbon dioxide into burnable forms of carbon. In the current study, Salehi-Khojin and his team focused on using transition metal dichalcogenides (TMDCs) as catalysts, which they paired with an unconventional ionic liquid as the electrolyte. They were then placed inside a two-compartment, three-electrode electrochemical cell.

Of all of the TMDCs that they tried, nanoflake tungsten diselenide turned out to be the ideal catalyst.

“The new catalyst is more active; more able to break carbon dioxide’s chemical bonds,” said Mohammad Asadi of UIC and first author of the paper.

The final solar cell is an artificial leaf that consists of two silicon triple-junction photovoltaic cells that harvest light. On the cathode side is the tungsten diselenide and ionic liquid co-catalyst system, while the anode side possesses cobalt oxide in potassium phosphate electrolyte.

The team hopes that the technology will be able to be adapted not only to large-scale applications such as solar farms, but also small-scale applications.

Journal Reference: Nanostructured transition metal dichalcogenide electrocatalysts for CO2 reduction in ionic liquid. 29 July 2016. 10.1126/science.aaf4767

NASA plans to make airplanes cleaner and 50% more fuel efficient by reviving the wing truss

NASA plans to improve today’s planes with a blast from the past — re-implementing a structure known as a wing truss would reduce fuel consumption and carbon emissions of common commercial aircraft by as much as 50%, according to computational models.

Early aircraft were… Well they were horrible, really. These flimsy cloth-and-wire machines offered their pilots virtually no protection against the cold. Their open cabins also meant that it was impossible to create a pressurized environment so the pilots wouldn’t black out from lack of oxygen at high altitudes. Thankfully that wasn’t much of a problem as their engines barely had enough power to get them off the ground in the first place.

This meant that early pioneers of aircraft design had to squeeze every ounce of lift from their designs, while keeping them as light as possible. Designs such as the biplane, triplane and wacky multiplane generated enough lift even at low speeds but also huge amounts of drag, and were thus limited in maximum speed.

Another piece of technology from the era however, the wing truss, has recently caught NASA engineers’ as a possible avenue for improvement of modern designs.

A wing truss is a support structure connecting the body of the plane to the wing, and can be seen in modern ultra-light prop-planes such as the Cessna 182.

Trust in the truss.
Image credits wikimedia – author unknown.

By transferring part of the strain to the fuselage, trusses allow for longer, thinner but also lighter wings to be constructed without sacrificing lift. Lower weight and improved carrying capacity would translate into lower much more efficient use of engine power, according to NASA:

“Researchers expect the lighter weight, lower drag truss-braced wing to reduce both fuel burn and carbon emissions by at least 50% over current technology transport aircraft, and by 4 to 8% compared to equivalent advanced technology conventional configurations with unbraced wings.”

But there’s a reason trusses were abandoned in the first place: they add drag and disturb the flow of air around the aircraft. But, by using modern digital modeling techniques, engineers can design around this problem.

“Using computational results showing how air would flow around the model, they [the researchers] modify the dimensions and shape of the wing and truss to improve areas that may generate undesirable air flow that would increase drag and reduce lift. Then engineers test models in a wind tunnel using multiple experimental techniques to validate the computations and aircraft performance predictions.’

If higher fuel efficiency and reduced emissions aren’t enough to impress you, there’s another quieter benefit to consider: trussed wings produce less noise during flight, meaning you won’t hear jets roaring overhead anymore.


Significant breakthrough in biofuels

I was writing a while ago that major biofuel production is not really that far away and the good news is things seem to be moving in that direction. The importance of biofuels has been underlined as a possible solution to fight the crisis, but the big problem was that creating such alternative fuels required too big amounts of power, despite numerous options that were considered (sugar, waste materials and even algae).

biofuel_logo11However, an innovative device constructed by researchers from the University of Sheffield promises to give the necessary power lowering necessary to make this method viable. This invention was awarded with a prestigious international award (Moulton Medal from the Institution of Chemical Engineers) and it’s estimated that it will make biofuel production efficient.

The invention is basically a bioreactor that creates microbubbles using 18% less energy. Microbubbles are miniature gas bubbles (measuring less than 50 microns in diameter) which means they can transfer materials in a bioreactor much more faster than with regular bubbles, thus using less energy. This innovative approach has the whole scientific world excited and it’s currently being tested with a local water company, and it’s also estimated that the necessary electricity current will be 30% lower;we will post updates as they are released by the researchers.

Professor Will Zimmerman, from the Department of Chemical and Process Engineering at the University of Sheffield, said: “I am delighted that our team’s work in energy efficient microbubble generation is being recognized by the Institution of Chemical Engineers. The potential for large energy savings with our microbubble generation approach is huge. I hope the award draws more industry attention to our work, particularly in commodity chemicals production for gas dissolution and stripping, where energy savings could enhance profitability. There are many routes to becoming green, and reducing energy consumption with the same or better performance must be the most painless.”

Professor Martin Tillotson, from Yorkshire Water, added: “Many of our processes use forced air in order to treat water and wastewater streams and, given the huge volumes, it is very costly in electricity and carbon terms. This technology offers the potential to produce a step-change in energy performance. We are pleased to be working with Professor Zimmerman and his group in developing the microbubble technology, and delighted with the recognition they have received from the Moulton Medal award.”