New Developments July 2017

Japan’s Renewable-Energy Revolution Japan's approach to stewardship of its land and water resources is distinct from that of the U.S. As an island nation with a millennia-long history, the concepts of reuse, repurposing and multiple use are intrinsic to Japanese culture. In 2011, the Tohoku earthquake and subsequent Fukushima nuclear disaster caused Japan to reassess its dependence on nuclear power as a primary source of electricity generation. Building renewable-energy capacity, predominantly in the form of photovoltaic projects, is one answer in the nation's quest for alternatives. These images, from a series of flights over the Tokyo and Kobe/Osaka regions of Japan, show a range of photovoltaic projects on former golf courses, quarries, dams, man-made islands and floating projects on ponds and reservoirs.

Climate change damages US economy, increases inequality Unmitigated climate change will make the United States poorer and more unequal, according to a new study. The poorest third of counties could sustain economic damages costing as much as 20 percent of their income if warming proceeds unabated. States in the South and lower Midwest, which tend to be poor and hot already, will lose the most, with economic opportunity traveling northward and westward. Colder and richer counties along the northern border and in the Rockies could benefit the most as health, agriculture and energy costs are projected to improve. "Unmitigated climate change will be very expensive for huge regions of the United States," said Hsiang, Chancellor's Associate Professor of Public Policy at UC Berkeley. "If we continue on the current path, our analysis indicates it may result in the largest transfer of wealth from the poor to the rich in the country's history." The team of economists and climate scientists computed the real-world costs and benefits: how agriculture, crime, health, energy demand, labor and coastal communities will be affected by higher temperatures, changing rainfall, rising seas and intensifying hurricanes.

Self-powered system makes smart windows smarter Researchers developed a new type of smart window: a self-powered version that promises to be inexpensive and easy to apply to existing windows, with potential to save heating and cooling costs. The window powers itself with a transparent solar cell that harvests near-ultraviolet light. "We wanted the smart window to dynamically control the amount of natural light and heat that can come inside, saving on energy cost and making the space more comfortable." The smart window controls the transmission of visible light and infrared heat into the building, while the new type of solar cell uses near-UV light to power the system. "Using near-UV light to power these windows means that the solar cells can be transparent and occupy the same footprint of the window without competing for the same spectral range or imposing aesthetic and design constraints." In the paper published in Nature Energy, the researchers described how they used organic semiconductors -- contorted hexabenzocoronene (cHBC) derivatives -- for constructing the solar cells. Other researchers have already developed transparent solar cells, but those target infrared energy. However, infrared energy carries heat, so using it to generate electricity can conflict with a smart window's function of controlling the flow of heat in or out of a building. Transparent near-UV solar cells, on the other hand, don't generate as much power as the infrared version, but don't impede the transmission of infrared radiation, so they complement the smart window's task. "Someone in their house or apartment could take these wireless smart window laminates -- which could have a sticky backing that is peeled off -- and install them on the interior of their windows," said Davy. "Then you could control the sunlight passing into your home using an app on your phone, thereby instantly improving energy efficiency, comfort, and privacy."

Wearable electronics: Superstretchable, supercompressible supercapacitors Flexible, wearable electronics require equally flexible, wearable power sources. Scientists have now introduced an extraordinarily stretchable and compressible polyelectrolyte which, in combination with carbon nanotube composite paper electrodes, forms a supercapacitor that can be stretched to 1,000 percent in length and compressed to 50 percent in thickness with even gaining, not losing capacity. Electrolytes in supercapacitors are often based on polyvinyl alcohol gels. To make such gels mechanically more flexible, elastic components like rubber or fibers must be added. Zhi's new electrolyte is based on a different principle: It is composed of a polyacrylamide (PAM) hydrogel reinforced with vinyl-functionalized silica nanoparticles (VSPNs). This material is both very stretchable thanks to the cross-links by the vinyl-silica nanoparticle and highly conductive thanks to the nature of the polyelectrolyte, which swells with water and both holds and transfers ions.

First battery-free cellphone makes calls by harvesting ambient power Engineers have designed the first battery-free cellphone that can send and receive calls using only a few microwatts of power, which it harvests from ambient radio signals or light. It's a major step forward in moving beyond chargers, cords and dying phones. The team of UW computer scientists and electrical engineers eliminated a power-hungry step in most modern cellular transmissions -- converting analog signals that convey sound into digital data that a phone can understand. This process consumes so much energy that it's been impossible to design a phone that can rely on ambient power sources. Instead, the battery-free cellphone takes advantage of tiny vibrations in a phone's microphone or speaker that occur when a person is talking into a phone or listening to a call. An antenna connected to those components converts that motion into changes in standard analog radio signal emitted by a cellular base station. This process essentially encodes speech patterns in reflected radio signals in a way that uses almost no power. “If every house has a Wi-Fi router in it, you could get battery-free cellphone coverage everywhere." The battery-free phone does still require a small amount of energy to perform some operations. The prototype has a power budget of 3.5 microwatts. The UW researchers demonstrated how to harvest this small amount of energy from two different sources. The battery-free phone prototype can operate on power gathered from ambient radio signals transmitted by a base station up to 31 feet away. Using power harvested from ambient light with a tiny solar cell -- roughly the size of a grain of rice -- the device was able to communicate with a base station that was 50 feet away.

Why rising temperatures don’t make solar power rise That’s because solar panels actually become less efficient as the mercury rises. High temperatures can decrease a photovoltaic cell’s output by between 10 and 25 percent. At high temperatures, the resting state of the electrons goes up. As a result, the difference between the resting state and excited state is smaller, producing less power. The effect is more pronounced for homeowners who have installed rooftop solar arrays, since those rarely have built-in cooling. A study in the United Kingdom found that once a panel exceeds 107 degrees (Fahrenheit), its output drops by 1.1 percent for every 1.8 degree rise in temperature.

City plants can actually decrease air quality during heat waves Research from the metropolis of Berlin shows that green spaces, from forests to public parks, can intensify ozone pollution in cities, an effect that is pronounced during heat waves. During a bad hot spell in 2006, plants in Berlin contributed to as much as 60% of the observed ozone pollution, with potential risks for the health of city-dwellers. The problem, the researchers report in Environmental Science & Technology, comes down to a class of chemicals called volatile organic compounds, or VOCs. Plant leaves pump out VOCs naturally. But some of these gases can also kick off chemical reactions in the air that form ground-level ozone—a pollutant that is harmful to people, especially those with preexisting respiratory disease. It’s hard to say what impact this upswing had on Berliners. The heat wave caused mortality rates around the city to climb by 20%, and ozone pollution could worsen the health impacts of hot weather, the researchers write. They don’t, however, recommend purging the city of green life. Trees bring a lot of benefits to an urban area. They cool cities down and pull other unwanted gases, such as carbon dioxide, out of the air.

Reducing air pollution will improve renewable energy production Particulate matter includes airborne dust as well as microscopic pollution from burning of biomass, trash, and fossil fuels. Particulate matter in the air reduces the amount of solar radiation that reaches the Earth – in fact, this effect is so well known that it is even incorporated into climate change models. They found that power generation leaps by about 50 percent when a solar panel is cleaned after 20 to 30 days of particulate matter accumulation. In China and northern India, particulate matter diminishes solar energy production by about 17 percent. This amounts to an annual loss of about 780 megawatts of electricity in India and 7,400 megawatts in China. The Arabian Peninsula sees a 25 percent reduction in solar energy production due to particulate matter, but this is mostly due to dust in this desert region. However, ounce for ounce, human-caused particulate matter from burning fossil fuels causes a much greater loss of solar capacity than plain old dust.

New material may help cut battery costs for electric cars, cellphones A novel manganese and sodium-ion-based material might become a contender, offering a potentially lower-cost, more ecofriendly option to fuel next-generation devices and electric cars. As manufacturers -- and consumers -- push for more electric vehicles (EVs), lithium production may have a hard time keeping up with increasing demand, Cho said. According to a recent report by the International Energy Agency, the global electric car stock surpassed 2 million vehicles in 2016 after crossing the 1 million mark in 2015. The report notes that, depending on the policy environment, there is a good chance that it will range between 9 million and 20 million by 2020 and between 40 million and 70 million by 2025. "Lithium is a more expensive, limited resource that must be mined from just a few areas on the globe," Cho said. "There are no mining issues with sodium -- it can be extracted from seawater. Unfortunately, although sodium-ion batteries might be less expensive than those using lithium, sodium tends to provide 20 percent lower energy density than lithium." In the design developed by Cho and his colleagues, sodium replaces most of the lithium in the cathode, and manganese is used instead of the more expensive and rarer elements cobalt and nickel. "Our sodium-ion material is more stable, but it still maintains the high energy capacity of lithium," Cho said. "And we believe this is scalable, which is the whole point of our research. We want to make the material in such a way that the process is compatible with commercial mass production."

We need to talk about the most effective ways to reduce our carbon footprint Today, the average person living in the United States is responsible for emissions of greenhouse gases equivalent to 16.4 tons of CO2 every year. Per-capita annual emissions are equivalent to 16.3 tons of CO2 in Australia, 13.5 tons in Canada, and 6.7 tons in the European Union. In order to keep the global average temperature increase under 2 °C, per capita annual emissions must fall to the equivalent of 2.1 tons CO2 by 2050. When the researchers surveyed previously published literature to determine which actions make the greatest difference in reducing an individual’s carbon footprint, they found four high-impact strategies: eating a plant-based diet (saves 0.8 tons CO2 per year), avoiding air travel (saves 1.6 tons CO2 per round-trip transatlantic flight), living car-free (saves 2.4 tons CO2 per year), and – the really big one – having one fewer child (saves 58.6 tons CO2 per year). But the new study has its own blind spots. One of them is the “have fewer children” strategy. It’s based on calculations from a 2009 study that assigned projected carbon emissions from future generations to people living now (a parent is responsible for half the lifetime emissions of each child, one quarter of the emissions of each grandchild, and so on – all divided over the years of the parent’s lifetime). But “crediting” people today for emissions avoided many decades in the future is deeply misleading about how to achieve the massive near-term emissions cuts necessary to keep climate change in check. For example, if the average person in the United States is responsible for 16.4 tons of CO2 emissions per year, the idea that having “one fewer child” saves 58.6 tons of CO2 per year suggests that avoiding procreating yields negative carbon emissions to the tune of 42.2 tons of CO2. This framing risks letting people with fewer children than average off the hook for their carbon emissions in the here and now. A second misleading piece has to do with urban living. Although the researchers acknowledge that structural factors may affect people’s ability to make lifestyle changes, they frame their high-impact behaviors as choices largely within an individual’s control. We need to be honest about not just the behavioral changes that will make the biggest difference in reducing emissions, but about what it will take to get there.

Lithium could hold key to sustainable ammonia synthesis A hundred years on from its development, the Haber–Bosch process remains the primary industrial route to make ammonia. Ammonia’s importance as a fertiliser is without question, but so is the Haber–Bosch process’ impact on the environment. Haber–Bosch breaks the triple bond in molecular nitrogen with high pressures and temperatures, and the hydrogen gas it requires to turn nitrogen into ammonia mainly comes from burning natural gas. As a consequence, industrial ammonia synthesis is reportedly responsible for up to 3% of global CO2 emissions. Now, scientists from Stanford University have proposed an electrochemical lithium cycling process to make ammonia, achieving an efficiency of 88.5% in lab-scale tests. The process uses electricity – which can have a renewable source, such as wind or solar energy – to electrolyse lithium hydroxide and produce lithium metal. Exposing this lithium to a flowing nitrogen atmosphere gives lithium nitride and to complete the cycle, this lithium nitride is combined with water in a hydrolysis reaction. Using water as the hydrogen source, rather than hydrogen gas itself, is another beneficial aspect of the process. This generates the desired product of ammonia, and regenerates the lithium hydroxide used up in the initial stage. 

EVs could compete with gasoline-powered cars by 2022 Earlier this month, Volvo became the first carmaker to announce that every car it makes starting 2019 will be electric or hybrid. The researchers led by Oliver Schmidt at Imperial’s Centre for Environmental Policy wanted to analyze the potential cost reductions for various energy storage technologies. They looked at 11 technologies, including pumped hydro, lead-acid and lithium-ion batteries. The team gathered data on historic product prices and installed storage capacity from peer-reviewed literature, research and industry reports, energy storage databases, and interviews with manufacturers. Next, they created curves to predict how fast costs may fall as installed capacity increases. Taking into account the uncertainty of falling battery costs, they predict that EVs could be cost-competitive with gas-powered vehicles as soon as 2022 or as late as 2034. Bloomberg forecasts that plug-in hybrids and all-electric vehicles will make up 54 percent of new light-duty vehicle sales globally by 2040, surpassing sales of fossil fuel engines.

Unbalanced wind farm planning exacerbates fluctuations The expansion of renewable energy has been widely criticised for increasing weather-dependent fluctuations in European electricity generation. A new study shows that this is due less to the variability of weather than from a failure to consider the large-scale weather conditions across the whole continent: many European countries are unilaterally following national strategies to expand wind energy capacities without looking beyond their own backyard. It would be better, however, for individual countries to work together and to promote the expansion of wind capacity in other European regions that are currently making very little use of wind power. Balancing capacity across the continent would effectively minimise the extreme fluctuations caused by the varied weather conditions that currently affect wind speeds. Today’s wind farms are distributed irregularly across Europe, mostly in countries bordering the North Sea. This results in uneven wind electricity generation, because most capacity is installed in neighbouring countries with similar weather conditions. This means that if a stable high-pressure system causes a lull for a few days or even weeks over the North Sea, as happened in the winter of 2016/17, Europe-wide wind electricity generation drops dramatically. The difference between high production in favourable wind conditions and low production during a lull could be as much as 100 gigawatts -- roughly the same capacity as 100 nuclear power plants -- and would have to be made available or held back within the course of only a few days. If European countries were to cooperate and set up future wind farms based on understanding of the continent-scale weather regimes, fluctuations in future wind energy could be stabilised at the current level of around 20 gigawatts. The Balkans, Greece, the western Mediterranean, and northern Scandinavia are all potential sites. The authors say that it would be difficult to store electricity for several days to balance these multi-day fluctuations -- with batteries or pumped-storage lakes in the Alps, for example -- since the necessary amount of storage capacity will not be available in the foreseeable future. Current storage technologies are more suited to compensating for shorter fluctuations of a few hours or days. Moreover, a wider geographical distribution of wind farms also requires the expansion of the transmission grid. However, such a pan-European renewable energy system could still provide Switzerland with the opportunity to use its hydropower capacities more economically in order to compensate for short-term fluctuations.

Aging U.S. power plants provide risks and opportunities Power plant retirement trends will complicate achieving long-term carbon dioxide (CO2) emission reduction targets and require a significant increase in capital investments. Additionally, a shift in investment emphasis from adding megawatts of generating capacity at low cost to reducing tons of CO2 emissions is creating an imbalance that may pressure grid reliability over the next two decades. The U.S. also stands to lose a substantial amount of zero-emitting power plants when the vast majority of the existing nuclear power plant fleet retires between 2030 and 2040, if not before. "Some 90 percent of every megawatt ever built is still in operation and now is more than 28 years old on average," said Fischbeck, professor of social and decision sciences and engineering and public policy and a world renowned risk expert. "One of the interesting results from our study was that younger coal plants have tended to retire earlier than older coal plants. As these younger plants generally have lower emissions, their retirement tends to be less environmentally beneficial than initially thought." "A key factor in meeting these objectives -- or any future national ones -- will be the retirement of existing zero-emitting facilities," said Rode.

Rooftop concentrating photovoltaics win big over silicon in outdoor testing A concentrating photovoltaic system with embedded microtracking can produce over 50 percent more energy per day than standard silicon solar cells in a head-to-head competition. “The solar cell is no longer the dominant cost of the energy it produces. The majority of the cost increasingly lies in everything else -- the inverter, installation labor, permitting fees, etc. -- all the stuff we used to neglect.” The researchers embed tiny multi-junction solar cells, roughly half a millimeter square, into a sheet of glass that slides between a pair of plastic lenslet arrays. The whole arrangement is about two centimeters thick and tracking is done by sliding the sheet of solar cells laterally between the lenslet array while the panel remains fixed on the roof. An entire day's worth of tracking requires about one centimeter of movement, which is practically imperceptible. The CPV system reached 30 percent efficiency, in contrast to the 17 percent efficiency of the silicon cell. All together over the entire day, the CPV system produced 54 percent more energy than the silicon and could have reached 73 percent if microcell heating from the intense sunlight were avoided.

Enhancing the resilience of the American electricity system With growing risks to the nation's electrical grid from natural disasters and as a potential target for malicious attacks, the U.S. Department of Energy (DOE) and the U.S. Department of Homeland Security (DHS) should work closely with utility operators and other stakeholders to improve cyber and physical security and resilience, says a new congressionally mandated report by the National Academies of Sciences, Engineering, and Medicine. The committee that conducted the study and wrote the report recommended ways to make the grid more resilient through the development and demonstration of technologies and organizational strategies that minimize the likelihood that outages will happen, reduce the impacts and speed recovery if they do, all the while developing mechanisms for continual improvements based on changing threats. In this report, the committee focused on reducing the nation's vulnerability to large blackouts that extend over several service areas or states and last three days or longer. Events that can lead to such outages include hurricanes, earthquakes, solar storms, cyber and physical attacks, and major operational errors. Although the possibility of such long-duration outages cannot be totally eliminated, the report identifies many steps that can be taken to make the power system more resilient. No single entity is responsible for planning, operating, or regulating the grid, and increasing its resilience will require coordinated actions by state, federal, private, and public groups, the report states.

Creating lithium-ion batteries for extreme environments Lithium-ion batteries are popular power sources for cellphones and other electronics, but problematic in extreme heat or cold. The Rice team was most interested in seeing how batteries perform in temperatures from minus 60 to 150 degrees Celsius (minus 76 to 302 degrees Fahrenheit), knowing that current batteries are designed to operate near room temperature and within a narrow temperature range. At best, lithium-ion batteries lean toward either hot or cold operations, which is less than optimal for an electric car driven from the hot desert to snowy peaks. The Rice team built a comprehensive map of both standard and promising new materials in commercial batteries and detailed their typical energy densities and temperature ranges for each component. "We compared stabilities of materials with respect to each other and against a temperature scale," Ajayan said. "This will help researchers cherry-pick a required combination for their needs." Performance in current lithium-ion batteries requires compromise, the researchers wrote. For example, water-based electrolytes like lead-acid and nickel-metal hydride operate only between minus 50 and 50 C, while molten salt batteries work fine only at temperatures above 90 C. Batteries with lithium thionyl chloride operate between minus 60 and 150 C, but only at peak between 20 and 55 C.

A new optimization model could bring higher solar-power integration Demand response (DR) is one promising way to increase operational flexibility and energy efficiency. Researchers at the Universiti Teknikal Malaysia Melaka (UTeM) in Malaysia incorporated DR scenarios in simulated comprehensive network case studies based on 100 urban low-voltage network samples. DR initiatives, through the use of advanced building controls or manually reducing power during hours of peak demand, encourage consumers to reduce their electricity use in exchange for lower electric bills and other incentives. DR applications with 100 percent PV penetration (in the third case study) provided the best use of solar energy and influenced network performance the most, reducing energy consumption at peak demand by 32 percent, reducing network losses by 42 percent and improving network utilization by 12 percent. Gan said that these benefits would be even greater with the integration of energy storage systems and other smart-grid technologies, such as building sensors and smart meters. "Although demand response provides notable benefits to the network, it cannot by itself fully unleash benefits of intermittent renewable energy, particularly when the output of generation is higher than the demand."

It's something in the water: Scientists extract hydrogen as potential fuel source Extracting hydrogen from water using electricity is a fairly straightforward process, but it is inefficient and usually takes a lot of energy. The efficiency can be improved using catalysts, which are often made of expensive precious metals, such as platinum. The Lawrence Livermore team sought to come up with a cheaper way to efficiently split the water molecules. Wood and lead author Yuanyue Liu -- a Livermore summer intern with Wood -- turned to a class of catalysts based on transition-metal dichalcogenides (MX2), which have generated a great deal of interest for water splitting. The issue with the MX2 materials that currently are used (based on molybdenum and tungsten) is that only the exposed edges of the catalysts are active. Instead, Wood, Liu and colleagues used quantum-mechanical calculations to reveal underlying electronic factors that would make the entire surfaces of the MX2 materials active for catalysis. These "descriptors" were then used to computationally screen MX2 candidates that could make better water-splitting catalysts.

Explaining why perovskite solar cells are more efficient Experimenters with a powerful 'electron camera' have discovered that light whirls atoms around in perovskites, potentially explaining the high efficiency of these next-generation solar cell materials and providing clues for making better ones.  "We recorded movies that show that certain atoms in a perovskite respond to light within trillionths of a second in a very unusual manner. This may facilitate the transport of electric charges through the material and boost its efficiency." "Previous studies have mostly explored the role of the methylammonium ions and their motions in transporting electric charge through the material," Wu said. "However, we've discovered that light causes large deformations in the network of lead and iodine atoms that could be crucial for the efficiency of perovskites." The researchers first hit a perovskite film, less than two millionths of an inch thick, with a 40-femtosecond laser pulse. One femtosecond is a millionth of a billionth of a second. To determine the atomic response, they sent a 300-femtosecond pulse of highly energetic electrons through the material and observed how the electrons were deflected in the film. This technique, called ultrafast electron diffraction (UED), allowed them to reconstruct the atomic structure. The team expected that the light pulse would affect atoms evenly in all directions, causing them to jiggle around their original positions. "But that's not what happened," Lindenberg said. "Within 10 trillionths of a second after the laser pulse, the iodine atoms rotated around each lead atom as if they were moving on the surface of a sphere with the lead atom at the center, switching each octahedron from a regular shape to a distorted one." The surprising deformations were long-lived and unexpectedly large, similar in size to those observed in melting crystals.

Model developed to predict, prevent power outages using big data High-speed winds during a thunderstorm may cause trees around an electric grid to crash into the distribution system feeders causing an outage in that area. Currently, most utility companies diminish such accidents by scheduling regular tree-trimming operations. This effort is costly and is based on a rotational approach to different service areas, which may take months and sometimes years before all trees are trimmed. By analyzing the impact of a potential vulnerability and weather impacts on power system outages, the researchers can predict where and when outages can occur. Predicting an optimal tree trimming schedule that would minimize the risk of vegetation-related outages is only one of the applications. The researchers describe their methodology for the framework as a three-part process. First, they investigate the probability of a potential hazard, such as severe weather. Next, they assess the vulnerability of the utility assets by taking the weather probability and predicting its impact on the assets. The last and most significant step is evaluating the impact of certain events and the calculation of costs of reliability indices and maintenance, replacement and repair.

Climate change poses threat to European electricity production The vulnerability of the European electricity sector to changes in water resources is set to worsen by 2030 as a consequence of climate change. Thermoelectric power stations -- including coal, gas, and nuclear plants -- use significant amounts of fresh water for cooling purposes. A large gas power station can use an Olympic-sized swimming pool of water per minute. If water is not available, or if it is too warm, power stations have to reduce electricity production, or cease production completely.  If one power station ceases production, this can be compensated by increasing production from less vulnerable power station, or by energy produced from renewable sources. But in extended periods of drought this compensation mechanism is not enough, resulting in power disruptions and blackouts. Led by Dr. Paul Behrens, a team of Leiden University researchers analysed over 1,300 power stations, drawing water from 818 different water catchments. Their research showed that the number of regions with a vulnerable electricity network due to water availability will increase significantly by 2030. Furthermore, many new power stations are planned for construction next to bodies of water that are already under pressure. The research showed that the areas at future risk of shortages lie mainly in the Mediterranean region: Spain, Italy, Southern France, and Greece. However, areas along the Rhine in Germany, Bulgaria and Poland will also face increasing pressure on their electricity production. 'Our research shows that cooling with sea water can significantly decrease problems on the Mediterranean coast. But it will cost more as investments are needed to equip plants for the use of saline water.'

Engineers invent the first bio-compatible, ion current battery In our bodies, flowing ions (sodium, potassium and other electrolytes) are the electrical signals that power the brain and control the rhythm of the heart, the movement of muscles, and much more. In traditional batteries, the electrical energy, or current, flows in form of moving electrons. This current of electrons out of the battery is generated within the battery by moving positive ions from one end (electrode) of a battery to the other. The new UMD battery does the opposite. It moves electrons around in the device to deliver energy that is a flow of ions. This is the first time that an ionic current-generating battery has been invented. "Potential applications might include the development of the next generation of devices to micro-manipulate neuronal activities and interactions that can prevent and/or treat such medical problems as Alzheimer's disease and depression." The demonstration battery the research team created looks like two glass tubes with a blade of grass inside, each connected by a thin metal wire at the top. The wire is where the electrons flow through to move from one end of the battery to the other as the stored energy slowly discharges. At the other end of each glass tube is a metal tip through which the ionic current flows.

Natural molecule to boost the performance of electrodes for rechargeable batteries Lab tests show that a novel material based on the organic porphyrin molecule allows to charge batteries within one single minute. Many materials that improve the properties of lithium ion batteries in the lab, however, are no sustainable options because they are rare, expensive, toxic or harmful to the environment. Ideally, high-performance energy storage materials would be based on renewable resources. Functional groups were added to the organic copper porphyrin molecule that produce structural and electro-conductive crosslinking of the material when the battery cell is charged for the first time. This significantly stabilizes the structure of the electrode in lab tests and allows several thousands of charge-discharge cycles. With this material, storage capacities of 130-170 milliamp-hours per gram (mAh/g) were measured in the lab -- at a medium voltage of 3 Volt -- and charging-discharging times of only one minute. Current experiments suggest that the storage capacity can be increased by another 100 mAh/g and that the storage system can be operated not only with lithium, but also with the much more abundant sodium.

Scientists Make the Case for Spraying Saltwater Into Clouds to Help Cool the Planet In a new study, researchers at the University of Washington make the case for a geoengineering method known as marine cloud brightening. The technique calls for spraying saltwater into low-lying marine clouds, where they help create more clouds that reflect heat back into space. Conducting small, controlled marine cloud brightening experiments would provide unprecedented data to understand the effects of aerosols on cloud formation and the resulting reflection of sunlight. The researchers are now developing a nozzle that can turn saltwater into tiny droplets and can spray trillions of these aerosol particles high into the atmosphere per second. This is the first step in their three-year plan. Once the sprayer has been developed, they propose to test it in the lab; do preliminary coastal tests in Monterey Bay; and finally move to offshore tests. If these small-scale tests of the technology work, they hope that larger-scale versions could eventually be deployed over larger swaths of ocean. Deliberately messing with the planet’s atmosphere brings up many technical and ethical questions. Reflecting sunlight could affect farming yields and solar panel outputs, for instance. It could trigger much more dramatic unforeseen side effects.