Amazing Science

A futuristic demonstration of emerging renewable energy material – printed solar cells, is being trialled in a public setting for the first time as it nears commercial readiness.

Creator of the organic printed solar material, Physicist Professor Paul Dastoor from the Faculty of Science said his team were excited to take their ‘science to the streets’ in what represented significant progress toward commercial availability of the material. “Globally, there’s been so few of these installations, we know very little about how they perform in a public setting. This installation is the next critical step in accelerating the development and commercialization of this technology. It presents a new scenario for us to test performance and durability against a range of new challenges,” said Professor Dastoor.

“Located within Lane Cove Council’s vibrant new urban space ‘The Canopy’, this demonstration plucks extraordinary science from behind sealed lab doors, and places it in an ordinary environment, where people will interact with it as they go about their grocery shopping, play with their children in the park, or enjoy food in one of the nearby restaurants. It’s an effortless and subtle way to spark conversation and showcase ‘what’s next’ in energy generation to thousands of people.” The renewable energy tech - which is ultra light-weight, ultra flexible, recyclable and cheap to manufacture, will power interactive public lighting in Sydney.

Professor Dastoor said he was hopeful the public installation would prompt further discussion on the subject of energy as the Federal Government considered submissions to its technology investment roadmap. "The government is seeking to bring down carbon emissions over the next 30 years and the community has been very engaged on this subject. Globally, there are many research groups like ours working on sustainable energy technologies and now, via the technology investment roadmap, is our opportunity to ensure we invest in and deliver clever solutions,” said Professor Dastoor.

Director of the University’s Newcastle Institute for Energy and Resources (NIER), Professor Alan Broadfoot, said the University was committed to bringing the world closer to a sustainable future through its next generation resources engagement priority. “The printed solar project highlights the transformational research coming out of NIER through valued partnerships with government, industry, and the community in critical areas such as new energy technologies,” said Professor Broadfoot.

A new advanced manufacturing industry for Australia

This installation follows a successful commercial-scale public sector installation with CHEP in late 2018. Professor Dastoor said global interest in printed solar was the highest he had ever witnessed and that an advanced manufacturing facility for printed solar in NSW was the imminent goal for his team. “We have a world-class manufacturing facility at the University’s Newcastle Institute for Energy and Resources (NIER), which has been generously supported by the Australian National Fabrication Facility (ANFF). This print facility can manufacture hundreds of meters of material a day, however we’re now reaching the point where we need to significantly scale this level of production,” said Professor Dastoor.

This technology will really disrupt and revitalise the contracting print industry. Printed solar is manufactured on conventional printers – our lab-scale system previously manufactured wine labels.

A massive Quebec geothermal spa and adjacent village is slated to begin construction in Petite-Rivière-Saint-François in the winter of 2023.

The small Quebec town of Petite-Rivière-Saint-François is about to get a very comfortable $300 million makeover. Plans for geoLAGON were announced on Tuesday by local developer Louis Massicotte, who will turn the small town into a 120,000 sqft tourism destination, drawing heavy inspiration from Iceland’s Blue Lagoon, one of the 25 wonders of the world.

GeoLAGON has plans to become the largest geothermal lagoon in the world and will become an “essential destination” for Quebecers and tourists alike, says Massicotte. The northeast destination will function as three separate projects, all forming one massive relaxing getaway:

• “Soleils Village”: a solar-powered condominium village of 150 Airbnb-type residences for both long-term and short-term rentals.
• “GeoLAGON”: a massive open-air geothermal lagoon that will be heated year-round to 38ºC. The lagoon will use a renewable energy ecosystem including geothermal, solar-air, and biomass. Massicotte says the Quebec creation will “rely on an ingenious model of self-sufficient energy” aimed at net-zero cost for heating both the lagoon and the chalets.
• “LagonVillage”: the third stage of the project is the construction of more than 100 solar-power chalets on the edge of the lagoon.

In total, Massicotte says the site will host a total of 600 rentable and purchasable chalets (functioning year-round), the giant spa, and a restaurant. “We are very pleased to see the reaction of Quebecers to our patented geoLAGON concept,” says Massicotte — the former president of Village Vacances Valcartier, Ice Hotel, and Calypso Park. “The choice of Petite-Rivière is a home run for us because it is the place of choice for investors in the vacation market in eastern Quebec.”

Construction on the entire site, which will be located four hours outside of Montreal, is slated to begin in the winter of 2023.

Changing climate patterns have left millions of people vulnerable to weather extremes. As temperature fluctuations become more commonplace around the world, conventional power-guzzling cooling and heating systems need a more innovative, energy-efficient alternative, and in turn, lessen the burden on already struggling power grids.

In a new study, researchers at Texas A&M University have created novel 3D printable phase-change material (PCM) composites that can regulate ambient temperatures inside buildings using a simpler and cost-effective manufacturing process. Furthermore, these composites can be added to building materials, like paint, or 3D printed as decorative home accents to seamlessly integrate into different indoor environments.

"The ability to integrate phase-change materials into building materials using a scalable method opens opportunities to produce more passive temperature regulation in both new builds and already existing structures," said Dr. Emily Pentzer, associate professor in the Department of Materials Science and Engineering and the Department of Chemistry. Dr. Emily Pentzer and her team have created novel 3D printable phase-change material composites that can regulate ambient temperatures inside buildings using a simpler and cost-effective manufacturing process.

This study was published in the June issue of the journal Matter. Heating, ventilation and air conditioning (HVAC) systems are the most commonly used methods to regulate temperatures in residential and commercial establishments. However, these systems guzzle a lot of energy. Furthermore, they use greenhouse materials, called refrigerants, for generating cool, dry air. These ongoing issues with HVAC systems have triggered research into alternative materials and technologies that require less energy to function and can regulate temperature commensurate to HVAC systems.

One of the materials that have gained a lot of interest for temperature regulation is phase-change materials. As the name suggests, these compounds change their physical state depending on the temperature in the environment. So, when phase-change materials store heat, they convert from solid to liquid upon absorbing heat and vice versa when they release heat. Thus, unlike HVAC systems that rely solely on external power to heat and cool, these materials are passive components, requiring no external electricity to regulate temperature.

The Chattanooga Metropolitan Airport has announced the completion of a solar farm that can power 100% of its daily energy needs. It's the first airport in America to do so.

Chattanooga's been having quite a cultural moment recently, what with dozens of new restaurants and bars popping up across town. Last September,The Edwin Hotel, a member of The Autograph Collection, opened with much fanfare, joining The Dwell and The Moxy Chattanooga Downtown in The Scenic City's growing boutique hotel scene.

Now, Tennessee's fourth-largest city is once again turning heads by claiming a first in the sustainability sector. Earlier this month, the Chattanooga Metropolitan Airport announced that it had hit a much-anticipated milestone in becoming the first airfield in the United States powered by 100% solar energy.

The end result of an ambitious project that started seven years ago, the airport's 2.64-megawatt solar farm was completed with about $5 million of funding from the Federal Aviation Administration. That investment is expected to be earned back in under 20 years, as a renewable energy stream brings down the facility's overall costs of operation. According to a press release, the installation measures about the size of 16 football fields—eight long and two wide.

“This is a momentous day for the Chattanooga Airport as we complete our solar farm and achieve a major sustainability milestone,” said Terry Hart, president and CEO of the Chattanooga Airport in the release. “This project has immediate benefits to our airport and community, and we’re proud to set an example in renewable energy for other airports, businesses and our region.

While generating a local renewable resource, we are also increasing the economic efficiency of the airport.” According to Bloomberg, Chattanooga Airport's solar farm saves energy via storage units that allow operations to continue after sundown. The publication also reports that the system is expected to last between 30 and 40 years.

It's worth pointing out that Chattanooga Airport's operation is relatively small, with direct flights to just ten cities including Chicago, Dallas, and New York City via Allegiant, American, Delta, and United Airlines. Still, the airport saw growth in traffic in 2018, with an increase of 4% from the previous year for total of 504,298 passengers. Furthermore, the success of the project could inspire similar endeavors across the nation—already, solar grids are in place at Denver International Airport and Indianapolis International Airport, whose solar farm is the largest in the country.

Globally, Chattanooga Airport joins the likes of South Africa's George Airport, The Galapagos' Seymour Airport, and most impressively, India's Cochin International Airport, which became the world's first solar-powered airport back in 2015. Using a 12-megawatt plant, the airport operates 1,000 weekly flights for 27 airlines, serving 10 million passengers annually. Meanwhile Spain's airport operator, Aena, earlier this year approved a $280 million plan to install solar panels in half of its airports.

Airborne Wind Energy Systems (AWES) are a new kind of technology to harvest wind energy. The expensive and heavy tower and rotor of a conventional wind turbine are here substituted by a light tether and an aircraft (flexible giant kites or large drones), respectively. In the so-called ground generation scheme, AWES use the tension force of the tether to move an electrical generator on the ground whereas, in fly generation scenarios, the electrical energy is produced by wind turbines onboard the aircraft and transmitted to the ground by a conductive tether. In both cases, AWES present low installation and material costs and operate at high altitude (over 500 meters) where winds are more intense and less intermittent. They also present a low visual impact and their easier transportation make them suitable for producing energy in remote and difficult access areas.

"AWES are disruptive technologies that operate at high altitudes and generate electrical energy," explains Gonzalo Sánchez Arriaga, Ramón y Cajal research fellow at the department of Bioengineering and Aerospace Engineering at the UC3M. "They combine well-known disciplines from electrical engineering and aeronautics, such as the design of electric machines, aeroelasticity and control, with novel and non-conventional disciplines related to drones and tether dynamics," he adds.

Within this framework, the UC3M researchers have presented a novel flight simulator for AWES in a scientific article recently published in Applied Mathematical Modelling. "The simulator can be used to study the behaviour of AWES, optimise their design and find the trajectories maximizing the generation of energy," explains Mr. Ricardo Borobia Moreno, aerospace engineer from the Flight Mechanics Area at the Spanish National Institute of Aerospace Technology (INTA) and studying a PhD in the department of Bioengineering and Aerospace Engineering at UC3M. The software, owned by UC3M, is registered and can be freely downloaded and used for research purposes by other groups.

Along with the simulator, the researchers have developed a flight testbed for AWES. Two kitesurf kites have been equipped with several instruments and key information, such as the position and speed of the kite, attack and sideslip angles, and tether tensions, have been recorded throughout many flights. The experimental data were then used to validate different software tools, such as the aforementioned simulator and an estimator of the different parameters characterizing the state of the kite at each instant.

"The preparation of the testbed has required a significant investment of time, effort and resources, but it has also raised the interest from a large number of our students. Besides research, the project has enriched our teaching activities, as many of them have carried out their undergraduate and master final projects on AWES," comments Gonzalo Sánchez Arriaga, who teaches the Flight Mechanics course in the Aerospace Engineering Degree at UC3M.

Investigations into non-precious metal catalysts for hydrogen evolution are ongoing. Here, the authors report that a hierarchical nanoporous copper-titanium bimetallic electrocatalyst is able to produce hydrogen from water under a mild overpotential at more than twice the rate of state-of-the-art carbon-supported platinum catalyst. Although both copper and titanium are known to be poor hydrogen evolution catalysts, the combination of these two elements creates unique copper-copper-titanium hollow sites, which have a hydrogen-binding energy very similar to that of platinum, resulting in an exceptional hydrogen evolution activity. In addition, the hierarchical porosity of the nanoporous copper-titanium catalyst also contributes to its high hydrogen evolution activity, because it provides a large-surface area for electrocatalytic hydrogen evolution, and improves the mass transport properties. Moreover, the catalyst is self-supported, eliminating the overpotential associated with the catalyst/support interface.

MIT researchers have devised a new way of providing cooling on a hot sunny day, using inexpensive materials and requiring no fossil fuel-generated power. The passive system, which could be used to supplement other cooling systems to preserve food and medications in hot, off-grid locations, is essentially a high-tech version of a parasol.

The system allows emission of heat at mid-infrared range of light that can pass straight out through the atmosphere and radiate into the cold of outer space, punching right through the gases that act like a greenhouse. To prevent heating in the direct sunlight, a small strip of metal suspended above the device blocks the sun's direct rays.

The new system is described this week in the journal Nature Communications in a paper by research scientist Bikram Bhatia, graduate student Arny Leroy, professor of mechanical engineering and department head Evelyn Wang, professor of physics Marin Soljacic, and six others at MIT.

In theory, the system they designed could provide cooling of as much as 20 degrees Celsius (36 degrees Fahrenheit) below the ambient temperature in a location like Boston, the researchers say. So far, in their initial proof-of-concept testing, they have achieved a cooling of 6 C (about 11 F). For applications that require even more cooling, the remainder could be achieved through conventional refrigeration systems or thermoelectric cooling.

Other groups have attempted to design passive cooling systems that radiate heat in the form of mid-infrared wavelengths of light, but these systems have been based on complex engineered photonic devices that can be expensive to make and not readily available for widespread use, the researchers say. The devices are complex because they are designed to reflect all wavelengths of sunlight almost perfectly, and only to emit radiation in the mid-infrared range, for the most part. That combination of selective reflectivity and emissivity requires a multilayer material where the thicknesses of the layers are controlled to nanometer precision.

But it turns out that similar selectivity can be achieved by simply blocking the direct sunlight with a narrow strip placed at just the right angle to cover the sun's path across the sky, requiring no active tracking by the device. Then, a simple device built from a combination of inexpensive plastic film, polished aluminum, white paint, and insulation can allow for the necessary emission of heat through mid-infrared radiation, which is how most natural objects cool off, while preventing the device from being heated by the direct sunlight. In fact, simple radiative cooling systems have been used since ancient times to achieve nighttime cooling; the problem was that such systems didn't work in the daytime because the heating effect of the sunlight was at least 10 times stronger than the maximum achievable cooling effect.

Solar power accounts for less than 2 percent of U.S. electricity but could make up more than that if the cost of electricity generation and energy storage for use on cloudy days and at nighttime were cheaper.

A Purdue University-led team developed a new material and manufacturing process that would make one way to use solar power – as heat energy – more efficient in generating electricity.

The innovation is an important step for putting solar heat-to-electricity generation in direct cost competition with fossil fuels, which generate more than 60 percent of electricity in the U.S.

“Storing solar energy as heat can already be cheaper than storing energy via batteries, so the next step is reducing the cost of generating electricity from the sun's heat with the added benefit of zero greenhouse gas emissions,” said Kenneth Sandhage, Purdue’s Reilly Professor of Materials Engineering.

The research, which was done at Purdue in collaboration with the Georgia Institute of Technology, the University of Wisconsin-Madison and Oak Ridge National Laboratory, published in the journal Nature.

A YouTube video is available at https://youtu.be/PMC3EE19ouw.

Air conditioning accounts for 10% of global energy consumption. Now researchers at Columbia University and Argonne National Laboratory in the US have produced a polymer “paint” capable of cooling surfaces to around 6 °C below ambient temperatures without using any energy at all. Used in combination with conventional air conditioning, it could allow significant reductions in the time these units are switched on, as well as providing some cooling relief in areas where air conditioning is not so widely available.

The approach uses a solution process at room temperature to produce a film of a polymer with nanometer- and micrometer-sized air voids trapped inside. “There are a lot of examples of substances that are white from air voids – like snow for example,” says Nanfang Yu associate professor in Applied Physics at Columbia University in the US. “Snow is white because there are a lot of air bubbles inside, otherwise you have ice which is transparent – it’s as simple as that. We are just pushing this to the extreme by this chemical process.”

The solution process they use is based on “phase inversion” and involves mixing the polymer with a solvent alongside water, in which the polymer is insoluble. After painting the mixture onto a surface, the solvent evaporates leaving just the polymer interspersed with water droplets. Finally the water evaporates leaving air voids.

Adjusting the percentage of water in the mix allows precise control over the size and density of the air voids, so that they can be tuned to maximize reflection of solar energy. In addition the micrometer-sized voids give the coating a thermal emissivity close to that of a black body, that is, a perfect radiator of heat. This high thermal emissivity of the polymer coating can be used to cool objects that are already hot.

There's enough potential wind energy moving across the Earth's oceans to power all of humanity, according to a new study. But, the researchers warn, trying to harness it would be a bad idea.

There is, of course, lots of wind over the Earth's land. There's so much wind that it's not uncommon for surplus wind energy to overwhelm the infrastructure built to carry it, as happened in Texas last year. But the land is no match for the sea in this regard. On land, wind gets diluted through impediments both natural and man-made, from mountains to skyscrapers. The oceans have no such monuments, which the authors of the study, Anna Possnera and Ken Caldeira of Stanford, say could make a huge difference.

"Mean surface wind speeds are, on average, 70% higher than on land," they say, "and could, therefore, prove to be a viable source for wind energy technologies."

What sort of difference would that make? "Even in the relative calm of summer," Possnera and Caldeira conclude, "the upper geophysical limit on sustained wind power in the North Atlantic alone could be sufficient to supply all of Europe's electricity. On an annual mean basis, the wind power available in the North Atlantic could be sufficient to power the world."

However, there would need to be a lot of wind turbines put in place in the ocean for this project to happen. So much so that humanity would be creating the same sort of impediments that weaken wind on land. That would prevent wind from chilling the icy poles, giving us the same problem renewables were supposed to solve: melting ice caps, rising oceans.

But just because humanity can't take all of its energy from the North Atlantic doesn't mean that the study isn't tremendously useful. In attempting to grasp the geophysical limit of wind power, Possnera and Caldeira show how dramatically we could scale up. The United States, for example, only opened its first offshore wind farm last year.

The chance of accidentally destroying the Earth with too much wind energy is science fiction, the opportunity to radically help the planet and get cheap power to boot is stone-cold fact.

New all-inorganic perovskite solar cells tackle three key challenges in solar cell technology: efficiency, stability, and cost.

Harnessing energy from the sun, which emits immensely powerful energy from the center of the solar system, is one of the key targets for achieving a sustainable energy supply. Light energy can be converted directly into electricity using electrical devices called solar cells. To date, most solar cells are made of silicon, a material that is very good at absorbing light. But silicon panels are expensive to produce.

Scientists have been working on an alternative, made from perovskite structures. True perovskite, a mineral found in the earth, is composed of calcium, titanium and oxygen in a specific molecular arrangement. Materials with that same crystal structure are called perovskite structures.

Perovskite structures work well as the light-harvesting active layer of a solar cell because they absorb light efficiently but are much cheaper than silicon. They can also be integrated into devices using relatively simple equipment. For instance, they can be dissolved in solvent and spray coated directly onto the substrate. Materials made from perovskite structures could potentially revolutionize solar cell devices, but they have a severe drawback: they are often very unstable, deteriorating on exposure to heat. This has hindered their commercial potential.

The Energy Materials and Surface Sciences Unit at the Okinawa Institute of Science and Technology Graduate University (OIST), led by Prof. Yabing Qi, has developed devices using a new perovskite material that is stable, efficient and relatively cheap to produce, paving the way for their use in the solar cells of tomorrow. Their work was recently published in Advanced Energy Materials. Postdoctoral scholars Dr. Jia Liang and Dr. Zonghao Liu made major contributions to this work.

This material has several key features. First, it is completely inorganic -- an important shift, because organic components are usually not thermostable and degrade under heat. Since solar cells can get very hot in the sun, heat stability is crucial. By replacing the organic parts with inorganic materials, the researchers made the perovskite solar cells much more stable.

"The solar cells are almost unchanged after exposure to light for 300 hours," says Dr. Zonghao Liu, an author on the paper. All-inorganic perovskite solar cells tend to have lower light absorption than organic-inorganic hybrids, however. This is where the second feature comes in: The OIST researchers doped their new cells with manganese in order to improve their performance. Manganese changes the crystal structure of the material, boosting its light harvesting capacity. "Just like when you add salt to a dish to change its flavor, when we add manganese, it changes the properties of the solar cell," says Liu.

Sources of energy frequently in the limelight are solar, wind and hydropower.

Giant Kelp (Macrocystis pyrifera) is one of the fastest growing producers of biomass.  The open ocean is an immense, untapped region for collecting solar energy.  Giant kelp does not grow naturally in the open ocean because kelp normally needs an attachment at about 10-20 meters of depth and also needs key nutrients that are available in deep ocean water or near shore but not at the surface in the open ocean.  This concept proposes an economical system to provide a grid for attachment and access to nutrients, making it possible to farm kelp in the extensive regions of the open ocean.

If successful, this patented approach will grow kelp attached to large grids in the open ocean, each grid towed by inexpensive underwater drones.  These drones will maintain the grids near the surface during the day to gather sunlight for photosynthesis.  At night, the drones will take the grids down to the deeper, cold water where the kelp can absorb nutrients that are not adequate in the warmer surface waters.  These kelp farms will also be taken to deeper water during storms or to avoid passing ships.  Every three months, the drones will move the kelp farms to scheduled locations to rendezvous with harvesters.

Why grow giant kelp on farms in the open ocean?

• does not compete with food production for agricultural land.
• will not harm environmentally-sensitive areas, such as deserts or marine reserves.
• does not use fresh water, pesticides, or artificial fertilizers (using, instead, abundant nutrients in deep water).
• stores nutrients when they are available and uses them when needed.
• is relatively easy to process into drop-in fuels because it has no lignin and little cellulose.
• is one of the fastest-growing primary producers with elongation rates ~30 cm/day, and average photosynthetic efficiency in the range of 6-8%, much higher than terrestrial plant production at 1.8-2.2%.
• stores over 1 Watt/m2 (averaged 24/7/365) of sunlight as chemical energy (~2.8 kg ash-free, dry weight per m2-year) , as observed in natural beds.
• continues to grow year round especially if adequate nutrients are available, and the harvest is non-destructive so farms can be productive for years without replanting.

Why grow giant kelp on farms in the open ocean guided by underwater drones?

• near shore areas with natural upwelling of nutrients won’t produce enough biomass to make a significant
   impact on the nation’s energy needs.
• many natural kelp beds are in marine reserves, or in recreational or commercial areas.
• the production underwater drones will be less expensive than one might expect because they will be made out of reinforced concrete and numerous subsystems are already available in production quantities (automated guidance & control, communications, batteries, pumps, sensors).
• most importantly, kelp grown in the open ocean can utilize massive open ocean areas to supply an energy feedstock sufficient for the projected peak world population at the current U.S. per capita rate of energy consumption of ~9500W/person.

The Pacific Ocean offshore of the Western U.S. represents an immense, untapped solar collecting area and, if this effort is successful, will be the first deployment region for the commercial farm systems.  Fast-growing kelp produces biomass year round and could provide a transformational solution to the need for millions of tons of feedstock per year.

Osaka Metropolitan University scientists have developed a process using artificial photosynthesis to successfully convert more than 60% of waste acetone into 3-hydroxybutyrate, a material used to manufacture biodegradable plastic. The results were obtained using low-concentration CO2, equivalent to exhaust gas, and powered by light equivalent to sunlight for 24 hours.

The researchers expect that this innovative way of producing biodegradable plastic could not only reduce CO2 emissions but also provide a way of reusing laboratory and industrial waste acetone. Their findings have been published in the journal Green Chemistry.

Poly-3-hydroxybutyrate—a biodegradable plastic—is a strong water-resistant polyester often used in packaging materials, made from 3-hydroxybutyrate as a precursor. In previous studies, a research team led by Professor Yutaka Amao from the Research Center for Artificial Photosynthesis at Osaka Metropolitan University found that 3-hydroxybutyrate can be synthesized from CO2 and acetone with high efficiency, but this was only demonstrated at higher concentrations of CO2 or sodium bicarbonate.

This new study aimed to reuse waste acetone from permanent marker ink and low concentrations of CO2—equivalent to exhaust gas from power plants, chemical plants, or steel factories. Acetone is a relatively inexpensive and reasonably harmless chemical used in many different laboratory settings, either for reactions or as a cleaning agent, which produces waste acetone. The acetone and CO2 acted as raw materials to synthesize 3-hydroxybutyrate using artificial photosynthesis, powered by light equivalent to sunlight.

We focused our attention on the importance of using CO2 created by exhaust gas from thermal power plants and other sources to demonstrate the practical application of artificial photosynthesis," explained Professor Amao. After 24 hours, more than 60% of acetone had been successfully converted to 3-hydroxybutyrate. "In the future, we aim to develop artificial photosynthesis technology further, so that it can use acetone from liquid waste and as well as exhaust gas from the laboratory as raw materials," stated Professor Amao.

Rice chemist James Tour and co-lead authors Rice alumnus Wala Algozeeb, graduate student Paul Savas and postdoctoral researcher Zhe Yuan reported in the American Chemical Society journal ACS Nano that heating plastic waste in the presence of potassium acetate produced particles with nanometer-scale pores that trap carbon dioxide molecules. These particles can be used to remove CO2 from flue gas streams, they reported.

"Point sources of CO2 emissions like power plant exhaust stacks can be fitted with this waste-plastic-derived material to remove enormous amounts of CO2 that would normally fill the atmosphere," Tour said. "It is a great way to have one problem, plastic waste, address another problem, CO2 emissions."

A current process to pyrolyze plastic known as chemical recycling produces oils, gases and waxes, but the carbon byproduct is nearly useless, he said. However, pyrolyzing plastic in the presence of potassium acetate produces porous particles able to hold up to 18% of their own weight in CO2 at room temperature.

In addition, while typical chemical recycling doesn't work for polymer wastes with low fixed carbon content in order to generate CO2 sorbent, including polypropylene and high- and low-density polyethylene, the main constituents in municipal waste, those plastics work especially well for capturing CO2 when treated with potassium acetate. The lab estimates the cost of carbon dioxide capture from a point source like post-combustion flue gas would be $21 a ton, far less expensive than the energy-intensive, amine-based process in common use to pull carbon dioxide from natural gas feeds, which costs $80-$160 a ton.

Like all amine-based materials, the sorbent can be reused. Heating it to about 75 degrees Celsius (167 degrees Fahrenheit) releases trapped carbon dioxide from the pores, regenerating about 90% of the material's binding sites. Because it cycles at 75 degrees Celsius, polyvinyl chloride vessels are sufficient to replace the expensive metal vessels that are normally required. The researchers noted the sorbent is expected to have a longer lifetime than liquid amines, cutting downtime due to corrosion and sludge formation.

To make this type of material, waste plastic is turned into powder, mixed with potassium acetate and heated at 600 C (1,112 F) for 45 minutes to optimize the pores, most of which are about 0.7 nanometers wide. Higher temperatures led to wider pores. The process also produces a wax byproduct that can be recycled into detergents or lubricants, the researchers said.

Farms could hold the key to meeting humanity's energy demands and ushering in a greener, more sustainable future. Research from Oregon State University published last week showed that covering just one percent of the world’s farmland with solar panels would be enough to meet global electricity needs.

Research from Oregon State University that was published last week shows that covering just one percent of the world’s farmland with solar panels would be enough to meet global electricity needs. The findings, which looked at five Tesla-supplied setups in the area to model a global solution, have been published in the journal Scientific Reports.

“There’s an old adage that agriculture can overproduce anything,” Chad Higgins, an associate professor in OSU’s college of agricultural sciences, said in a statement. “That’s what we found in electricity, too. It turns out that 8,000 years ago, farmers found the best places to harvest solar energy on Earth.”

The setup, known as both “agrivoltaics” or “agrophotovoltaics,” has been shown in previous research as a more efficient way of using the same farmland. It could benefit crops and provide power for both the farm itself and the broader community.

Agrivoltaics: How It Works

Crops take up land. Solar panels also take up land. But solar doesn’t need to sit directly on the ground like the crops, so why not place them over the crops to better use the land? That’s the thinking behind agrivoltaics. One of the first to outline the idea was Adolf Goetzberger and Armin Zastrow, who wrote a 1981 paper in the International Journal of Solar Energy calling for solar panels to be placed two meters above crops.

The University of Hohenheim in Germany explored the idea in 2017, and found that it could hold great benefits. They studied 720 solar panels covering a number of crops to see the change in yields. Clover grass yields dropped 5.3 percent, and others like potatoes and wheat by 18 percent, but the energy could match the farm load and send surplus energy to a nearby utility company.

Rice University's solar-powered approach for purifying salt water with sunlight and nanoparticles is even more efficient than its creators first believed.

Researchers in Rice's Laboratory for Nanophotonics (LANP) this week showed they could boost the efficiency of their solar-powered desalination system by more than 50% simply by adding inexpensive plastic lenses to concentrate sunlight into "hot spots." The results are available online in the Proceedings of the National Academy of Sciences.

"The typical way to boost performance in solar-driven systems is to add solar concentrators and bring in more light," said Pratiksha Dongare, a graduate student in applied physics at Rice's Brown School of Engineering and co-lead author of the paper. "The big difference here is that we're using the same amount of light. We've shown it's possible to inexpensively redistribute that power and dramatically increase the rate of purified water production."

In conventional membrane distillation, hot, salty water is flowed across one side of a sheetlike membrane while cool, filtered water flows across the other. The temperature difference creates a difference in vapor pressure that drives water vapor from the heated side through the membrane toward the cooler, lower-pressure side. Scaling up the technology is difficult because the temperature difference across the membrane—and the resulting output of clean water—decreases as the size of the membrane increases.

Rice's "nanophotonics-enabled solar membrane distillation" (NESMD) technology addresses this by using light-absorbing nanoparticles to turn the membrane itself into a solar-driven heating element.

Stanford researchers have devised a way to generate hydrogen fuel using solar power, electrodes and saltwater from San Francisco Bay. Hongjie Dai and his research lab at Stanford University have developed a prototype that can generate hydrogen fuel from seawater.

The findings, published March 18 2019 issue in Proceedings of the National Academy of Sciences (USA), demonstrate a new way of separating hydrogen and oxygen gas from seawater via electricity. Existing water-splitting methods rely on highly purified water, which is a precious resource and costly to produce.

Theoretically, to power cities and cars, “you need so much hydrogen it is not conceivable to use purified water,” said Hongjie Dai, J.G. Jackson and C.J. Wood professor in chemistry in Stanford’s School of Humanities and Sciences and co-senior author on the paper. “We barely have enough water for our current needs in California.”

Hydrogen is an appealing option for fuel because it doesn’t emit carbon dioxide, Dai said. Burning hydrogen produces only water and should ease worsening climate change problems.

Dai said his lab showed proof-of-concept with a demo, but the researchers will leave it up to manufacturers to scale and mass produce the design.

MIT engineers have come up with a conceptual design for a system to store renewable energy, such as solar and wind power, and deliver that energy back into an electric grid on demand. The system may be designed to power a small city not just when the sun is up or the wind is high, but around the clock.

The new design stores heat generated by excess electricity from solar or wind power in large tanks of white-hot molten silicon, and then converts the light from the glowing metal back into electricity when it's needed. The researchers estimate that such a system would be vastly more affordable than lithium-ion batteries, which have been proposed as a viable, though expensive, method to store renewable energy.

They also estimate that the system would cost about half as much as pumped hydroelectric storage—the cheapest form of grid-scale energy storage to date. "Even if we wanted to run the grid on renewables right now we couldn't, because you'd need fossil-fueled turbines to make up for the fact that the renewable supply cannot be dispatched on demand," says Asegun Henry, the Robert N. Noyce Career Development Associate Professor in the Department of Mechanical Engineering.

"We're developing a new technology that, if successful, would solve this most important and critical problem in energy and climate change, namely, the storage problem." Henry and his colleagues have published their design today in the journal Energy and Environmental Science.

Since the first airplane took flight over 100 years ago, virtually every aircraft in the sky has flown with the help of moving parts such as propellers, turbine blades, and fans, which are powered by the combustion of fossil fuels or by battery packs that produce a persistent, whining buzz.

Now MIT engineers have built and flown the first-ever plane with no moving parts. Instead of propellers or turbines, the light aircraft is powered by an “ionic wind” — a silent but mighty flow of ions that is produced aboard the plane, and that generates enough thrust to propel the plane over a sustained, steady flight. Unlike turbine-powered planes, the aircraft does not depend on fossil fuels to fly. And unlike propeller-driven drones, the new design is completely silent.

“This is the first-ever sustained flight of a plane with no moving parts in the propulsion system,” says Steven Barrett, associate professor of aeronautics and astronautics at MIT. “This has potentially opened new and unexplored possibilities for aircraft which are quieter, mechanically simpler, and do not emit combustion emissions.”

He expects that in the near-term, such ion wind propulsion systems could be used to fly less noisy drones. Further out, he envisions ion propulsion paired with more conventional combustion systems to create more fuel-efficient, hybrid passenger planes and other large aircraft. Barrett and his team at MIT have published their results today in the journal Nature.

Hobby crafts

Barrett says the inspiration for the team’s ion plane comes partly from the movie and television series, “Star Trek,” which he watched avidly as a kid. He was particularly drawn to the futuristic shuttlecrafts that effortlessly skimmed through the air, with seemingly no moving parts and hardly any noise or exhaust. “This made me think, in the long-term future, planes shouldn’t have propellers and turbines,” Barrett says. “They should be more like the shuttles in ‘Star Trek,’ that have just a blue glow and silently glide.”

About nine years ago, Barrett started looking for ways to design a propulsion system for planes with no moving parts. He eventually came upon “ionic wind,” also known as electroaerodynamic thrust — a physical principle that was first identified in the 1920s and describes a wind, or thrust, that can be produced when a current is passed between a thin and a thick electrode. If enough voltage is applied, the air in between the electrodes can produce enough thrust to propel a small aircraft.

For years, electroaerodynamic thrust has mostly been a hobbyist’s project, and designs have for the most part been limited to small, desktop “lifters” tethered to large voltage supplies that create just enough wind for a small craft to hover briefly in the air. It was largely assumed that it would be impossible to produce enough ionic wind to propel a larger aircraft over a sustained flight.

“It was a sleepless night in a hotel when I was jet-lagged, and I was thinking about this and started searching for ways it could be done,” he recalls. “I did some back-of-the-envelope calculations and found that, yes, it might become a viable propulsion system,” Barrett says. “And it turned out it needed many years of work to get from that to a first test flight.”

Buying enough clean energy to make up for your dirty energy is one thing; using all clean energy 24/7 is another, and it could signal a new approach.

Saudi Arabia has a plan to wean its economy off oil. In the biggest sign of what the future of the Gulf state would look like, Saudi Arabia’s crown prince, Mohammed Bin Salman, has signed a memorandum of understanding with Japanese multinational Softbank to build 200 GW of solar power by 2030 at a cost of $200 billion.

These are eye-popping numbers. If built, that solar-power plant will be about 200 times the size of the biggest solar plant operating today. It would more than triple Saudi Arabia’s capacity to produce electricity, from about 77 GW today. With current technology, solar panels capable of generating 200 GW would likely cover 5,000 sq km—an area larger than the the world’s largest cities, And, yet, these are not unrealistic figures.

Based on data from Bloomberg New Energy Finance (BNEF), the global solar industry produced about 100 GW worth of solar panels last year, and production capacity is ramping up quickly.

But memorandums like the one signed by Bin Salman often don’t turn into reality. “I’ve probably made more binding agreements to grab a coffee,” Jenny Chase, a solar analyst with BNEF, joked on Twitter.

Still, the crown prince stands to damage his reputation if he doesn’t at least ramp up Saudi Arabia’s solar-power contribution. Though the country has talked about investing in clean energy for quite some time, it was only in 2017 that it began taking bids to build solar-power plants. And if any country could build a solar plant of this scale, it’s Saudi Arabia: the country gets plenty of sun, has vast areas of empty desert, and possibly has the financial power to pull it off.

A solar panel that can generate electricity from falling raindrops has been invented, enabling power to flow even when skies cloud over or the sun has set. Solar power installation is soaring globally thanks to costs plunging 90% in the past decade, making it the cheapest electricity in many parts of the world. But the power output can plummet under grey skies and researchers are working to squeeze even more electricity from panels.

The new device, demonstrated in a laboratory at Soochow University in China, places two transparent polymer layers on top of a solar photovoltaic (PV) cell. When raindrops fall on to the layers and then roll off, the friction generates a static electricity charge.

“Our device can always generate electricity in any daytime weather,” said Baoquan Sun, at Soochow University. “In addition, this device even provides electricity at night if there is rain.”

Other researchers have recently created similar devices on solar panels, known as triboelectric nanogenerators (Tengs), but the new design is significantly simpler and more efficient as one of the polymer layers acts as the electrode for both the Teng and the solar cell.

“Due to our unique device design, it becomes a lightweight device,” said Sun, whose team’s work is published in the journal ACS Nano. “In future, we are exploring integrating these into mobile and flexible devices, such as electronic clothes. However, the output power efficiency needs to be further improved before practical application.”