New Developments August 2017

Where we start the clock for climate change makes a big difference Carbon emissions at the start of the Industrial Revolution are often unaccounted for but may have significant consequences, an analysis published last week in Nature Climate Change finds. According to the study, the small increase in temperature that may have resulted from these early emissions dramatically shrinks the global carbon budget – the amount of greenhouse gases that we can collectively produce in the future while still avoiding harmful increases in global average temperature. The problem is, just what “pre-industrial” means is often poorly defined. The most commonly used baseline is the period between 1850 and 1900. But the Industrial Revolution was already well underway by then. What if temperatures had already begun to increase? Analyses suggest that it’s possible that temperature hadn’t yet begun to increase in the late nineteenth century, making this a reasonable baseline period. But it’s equally plausible that human activities had already increased global average temperature by roughly 0.2 °C by then. If we manage to implement steep reductions in emissions, the choice of baseline period matters a lot. If 1850-1900 was already 0.2 °C warmer than a true pre-industrial baseline, then the chance of avoiding the 1.5 °C threshold drops from 40% to about 12% even with extreme emissions cuts. The chance of avoiding 2 °C drops from 75% to 70%.

How 139 countries could be powered by 100 percent wind, water, and solar energy by 2050  Such a transition could mean less worldwide energy consumption due to the efficiency of clean, renewable electricity; a net increase of over 24 million long-term jobs; an annual decrease in 4-7 million air pollution deaths per year; stabilization of energy prices; and annual savings of over $20 trillion in health and climate costs. The analyses specifically examined each country's electricity, transportation, heating/cooling, industrial, and agriculture/forestry/fishing sectors. Of the 139 countries -- selected because they were countries for which data were publically available from the International Energy Agency and collectively emit over 99% of all carbon dioxide worldwide -- the places the study showed that had a greater share of land per population (e.g., the United States, China, the European Union) are projected to have the easiest time making the transition to 100% wind, water, and solar. The most difficult places to transition may be highly populated, very small countries surrounded by lots of ocean, such as Singapore, which may require an investment in offshore solar to convert fully. The changes in infrastructure would also mean that countries wouldn't need to depend on one another for fossil fuels, reducing the frequency of international conflict over energy. The researchers intentionally exclude nuclear power because of its 10-19 years between planning and operation, its high cost, and the acknowledged meltdown, weapons proliferation, and waste risks. "Clean coal" and biofuels are neglected because they both cause heavy air pollution, which Jacobson and coworkers are trying to eliminate, and emit over 50 times more carbon per unit of energy than wind, water, or solar power.

From greenhouse gas to 3-D surface-microporous graphene

Tiny dents in the surface of graphene greatly enhances its potential as a supercapacitor. Even better, it can be made from carbon dioxide in a novel approach. The process uses a heat-releasing reaction to dig micropores into 3-D graphene and could be a useful supercapacitor material. The supercapacitive properties of the unique structure of 3-D surface-microporous graphene make it suitable for elevators, buses, cranes and any application that requires a rapid charge/discharge cycle. Supercapacitors are an important type of energy storage device and have been widely used for regenerative braking systems in hybrid vehicles. Current commercialized supercapacitors employ activated carbon using swaths of micropores to provide efficient charge accumulation. However, electrolyte ions have difficulty diffusing into or through activated carbon's deep micropores, increasing the charging time. "The new 3-D surface-microporous graphene solves this," Hu says. "The interconnected mesopores are channels that can act as an electrolyte reservoir and the surface-micropores adsorb electrolyte ions without needing to pull the ions deep inside the micropore."  The material exhibited an ultrahigh areal capacitance of 1.28 F/cm2, which is considered an excellent rate capability as well as superb cycling stability for supercapacitors. 

Engineers produce long lasting, energy density battery A new generation of manganese dioxide-zinc batteries with unprecedented cycle life and energy density has now been revealed by scientists. The discovery has made the common household battery suitable for large grid storage applications. this is the first time a novel calcium hydroxide interlayer is used to block the poisonous zinc ions through complexation. This in turn allows the battery to maintain its high energy density over 900 cycles. A recent trend in the energy storage field has been to replace unsafe and expensive lithium-ion batteries with zinc-anode versions as zinc is cheap, abundant and much safer. Until now, the only detriment of this version has been the latter's relatively short cycle life, which has not allowed it to be successfully commercialized as a rechargeable battery.

Oil fields: Alternative to wasteful methane flaring Researchers say they have a solution to the oil field flares wasting 3.5 percent of the world's natural gas: an inexpensive reactor that can convert methane to electricity. Oil and gas fields burn off methane, producing as much greenhouse gas in a year as 1 million cars. "It's a big problem because not only do you waste energy, but you produce CO2," says Su Ha. Piping methane from remote areas is expensive, so energy companies burn off about one-third of the gas they produce in bright flares that can be seen from space. Ordinarily, methane is such a tightly bonded molecule that breaking it apart requires a lot of water and temperatures of about more than 1,800 F. But McEwen and Ha found that they could use much lower operating temperatures and an inexpensive nickel catalyst in the presence of an electrical field to orient methane and water in a way that makes them easier to break apart. At the end of the process, the researchers end up with carbon monoxide and hydrogen, the ingredients of syngas, or synthetic gas. The product can be used to make gasoline, or the reactor could be attached to fuel cells that convert and store the energy as electricity.

Energy storage solution combines polymers, nanosheets A new, lightweight composite material for energy storage in flexible electronics, electric vehicles and aerospace applications has been experimentally shown to store energy at operating temperatures well above current commercial polymers, according to a team of scientists. "Prior to this work we had developed a composite of boron nitride nanosheets and dielectric polymers, but realized there were significant problems with scaling that material up economically." Scalability -- or making advanced materials in commercially relevant amounts for devices -- has been the defining challenge for many of the new, two-dimensional materials being developed in academic labs. "From a soft materials perspective, 2D materials are fascinating, but how to mass produce them is a question," Wang said. "Plus, being able to combine them with polymeric materials is a key feature for future flexible electronics applications and electronic devices." Hexagonal boron nitride is a wide band-gap material with high mechanical strength. Its wide band gap makes it a good insulator and protects the PEI film from dielectric breakdown at high temperatures, the reason for failure in other polymer capacitors. At operating temperatures above 176 degrees Fahrenheit, the current best commercial polymers start to lose efficiency, but hexagonal-boron-nitride-coated PEI can operate at high efficiency at over 392 degrees Fahrenheit. Even at high temperatures, the coated PEI remained stable for over 55,000 charge-discharge cycles in testing.

Solar glasses generate solar power Organic solar cells are flexible, transparent, and light-weight -- and can be manufactured in arbitrary shapes or colors. Thus, they are suitable for a variety of applications that cannot be realized with conventional silicon solar cells. The solar cell lenses, perfectly fitted to a commercial frame, have a thickness of approx. 1.6 millimeters and weigh about six grams -- just like the lenses of traditional sunglasses. The microprocessor and the two small displays are integrated into the temples of the Solar Glasses. They show the illumination intensity and the ambient temperature as bar graphs. The Solar Glasses also work in indoor environments under illumination down to 500 Lux, which is the usual illumination of an office or a living area. Under these conditions, each of the "smart" lenses still generates 200 milliwatt of electric power -- enough to operate devices such as a hearing aid or a step counter.

Vertical axis wind turbines can offer cheaper electricity for urban and suburban areas Small vertical axis wind turbines (VAWTs) possess the ability to effectively operate in the presence of high turbulent flow, which makes them ideal energy harvesting devices in urban and suburban environments. A VAWT is a wind turbine design where the generator is vertically oriented in the tower, rather than sitting horizontally on top. While there are many VAWT designs, the one used in this study is called the straight-blade Darrieus type or H-rotor turbine. According to the researchers, small VAWTs possess the ability to effectively operate in the presence of high turbulent flow, which makes them ideal energy harvesting devices in urban and suburban environments. An optimally designed VAWT system can financially compete with fossil-fuel based power plants in urban and suburban areas, and even spearhead the development of a net-zero energy building or city. The optimal design configuration at this site produced electricity at a cost 10 percent lower than the average national electricity unit price.

Carbon conversion New carbon dioxide experiments may lead to artificial, renewable fuels, outlines new research. In chemical reactions performed in the lab, a research team has identified a new additive that helps selectively convert carbon dioxide into fuels containing multiple carbon atoms -— a step toward ultimately making renewable liquid fuels that are not derived from coal or oil. Fuels with multiple carbon atoms are more desirable because they tend to be liquid -- and liquid fuels store more energy per volume than gaseous ones. For instance, propanol, which is liquid and contains three carbon atoms, stores more energy than methane, which is a gas and only has one carbon atom. The goal of chemists like Peters, Agapie, and their colleagues working at the Joint Center for Artificial Photosynthesis (JCAP), a U. S. Department of Energy (DOE) Energy Innovation Hub, is to artificially create multi-carbon liquid transportation fuels using the widely available ingredients of sunlight, water, and CO2. To find the ideal combination for making the multi-carbon fuels, the team experimented with a mix of different chemicals in the lab. They used an aqueous solution and a copper electrode, which served as both a catalyst and source of energy in place of the sun. The group added CO2 to the solution, as well as a class of organic molecules called N-substituted arylpyridiniums, which formed a very thin deposit on the electrode. This film, for reasons that are not understood yet, dramatically improved the fuel-making reaction, selectively producing the desirable chemicals ethanol, ethylene, and propanol. Ultimately, this information may help lead to alternate fuels made efficiently from sunlight, CO2, and water -- instead of oil.

Real greenhouse gas footprints of reservoirs revealed When hydropower reservoirs traps organic matter, it leads to higher local greenhouse gas emissions. But the emissions are not increased but displaced. A new tool calculates the real greenhouse gas footprints of reservoirs. "Greenhouse gases that are emitted in a reservoir may well have been emitted anyway. It is a displacement, not an increase, and this was not accounted for in earlier calculations. You must also consider the prior land use and the processes in the whole river basin," says Atle Harby. "A hydropower reservoir does not add any new carbon dioxide to the atmosphere, unlike fossil-fuel power plants," said Tormod Schei. A study from EDF and SINTEF published in the journal Science of the Total Environment in 2011 found that the 40-year-old Nam Ngum reservoir behaves as a carbon sink, with negative net greenhouse gas emissions because of low methane production and a high CO2 uptake by phytoplankton. The IPCC are now going to revise their guidelines for national greenhouse gas inventories with the help of Atle Harby and 15 other lead authors. The chapter on how to handle freshwater reservoirs (flooded land) will be revised following the new findings.

Smart electrical grids more vulnerable to cyber attacks Electricity distribution systems in the USA are gradually being modernized and transposed to smart grids, which make use of two-way communication and computer processing. This is making them increasingly vulnerable to cyber-attacks. Such attacks affect both customers and distribution companies and can take various forms, such as stealing customer data (allowing a burglar to determine if a residence is unoccupied, for instance), taking power from particular customers (resulting in increased power bills), disrupting the grid and denying customers power on a localized or widespread basis. "The most devastating scenario involves a computer worm traversing advanced metering infrastructures and permanently disabling millions of smart meters," noted Dr. Shenoi. Such attacks already occur: in December 2015, for example, the Russian hacker group Sandworm successfully attacked the Ukrainian power grid, disrupting power to more than 225,000 customers. Plant operators restored power within six hours by manually resetting the circuit breakers, but in the case of disruption in major US cities, this would take much longer. "Damaging a few million smart meters would cause a power outage in a large geographic area that may last anything from several months to over a year," said Dr, Shenoi. This is "because of the limited production and inventories of smart meters and availability of technicians."

Engineers charge ahead on zinc-air batteries Researchers have found a solution for one of the biggest stumbling blocks preventing zinc-air batteries from overtaking conventional lithium-ion batteries as the power source of choice in electronic devices. Due to the global abundance of zinc metal, these batteries are much cheaper to produce than lithium-ion batteries, and they can also store more energy (theoretically five times more than that of lithium-ion batteries), are much safer and are more environmentally friendly. Their widespread use has been hindered by the fact that, up until now, recharging them has proved difficult. This is due to the lack of electrocatalysts that successfully reduce and generate oxygen during the discharging and charging of a battery. "Up until now, rechargeable zinc-air batteries have been made with expensive precious metal catalysts, such as platinum and iridium oxide. In contrast, our method produces a family of new high-performance and low-cost catalysts," he said. These new catalysts are produced through the simultaneous control of the: 1) composition, 2) size and 3) crystallinity of metal oxides of earth-abundant elements such as iron, cobalt and nickel. Trials of zinc-air batteries developed with the new catalysts had demonstrated excellent rechargeability -- including less than a 10 percent battery efficacy drop over 60 discharging/charging cycles of 120 hours.

Surprise discovery in the search for energy efficient information storage Today almost all information stored on hard disc drives or cloud servers is recorded in magnetic media, because it is non-volatile and cheap. For portable devices such as mobile phones and tablets, other forms of non-magnetic memory are used because the technology based on magnetism is impractical and is not energy efficient. The main benefit of using magnetism is the fact that the magnetic state remains stable when power is removed from the device, enabling non-volatile storage of information. By contrast, most processors and random access memory (RAM) chips store information using electrical charge which is fast, but dissipates when the device is powered down. Magnetic random access memory (MRAM) is a promising form of non-volatile RAM based on magnetism which has recently found applications in some niche markets. In MRAM information is written using electrical current which generates heat and stray magnetic fields. The researchers have discovered a way to control the chirality of the vortex domain wall using an electric field.

New ultrathin semiconductor materials exceed some of silicon's 'secret' powers Chip makers appreciate what most consumers never knew: silicon's virtues include the fact that it 'rusts' in a way that insulates its tiny circuitry. Two new ultrathin materials --hafnium diselenide and zirconium diselenide -- share that trait and outdo silicon in other ways that make them promising materials for electronics of the future. The new materials can also be shrunk to functional circuits just three atoms thick and they require less energy than silicon circuits. 

New battery is activated by your spit Researchers have developed the next step in microbial fuel cells (MFCs): a battery activated by spit that can be used in extreme conditions where normal batteries don't function. Binghamton University Electrical and Computer Science Assistant Professor Seokheun Choi has focused on developing micro-power sources for the use in resource-limited regions to power point-of-care (POC) diagnostic biosensors; he has created several paper-based bacteria-powered batteries. "On-demand micro-power generation is required especially for point-of-care diagnostic applications in developing countries," said Choi. "Typically, those applications require only several tens of microwatt-level power for several minutes, but commercial batteries or other energy harvesting technologies are too expensive and over-qualified. Also, they pose environmental pollution issues." "Now, our power density is about a few microwatts per centimeter square. Although 16 microbial fuel cells connected in a series on a single sheet of paper generated desired values of electrical current and voltage to power a light-emitting diode (LED), further power improvement is required for other electronic applications demanding hundreds of milliwatts of energy," said Choi.

New battery material goes with the flow In this type of battery, called nonaqueous redox flow, energy is stored in negatively and positively charged solutions inside large tanks. We want the stability of the molecules to be high so the battery doesn't break down prematurely, but we also want it to be able to hold a lot of energy. The two are at odds. The researchers were able to shut down a common energy-sucking side reaction using a process called bicyclic substitution, which protects the most reactive parts of the molecule's atomic scaffolding, somewhat like using insulation to cover exposed wires. The researchers discovered that the battery suffered only a minimal loss of capacity after 150 cycles of charging and draining the battery, proving the high stability of the molecule.

The unintended consequences of cool roofs Widespread adoption of “cool roofs” – typically made of light-colored materials that reflect a large fraction of the sun’s rays – has the potential to increase certain types of air pollution. Cool roofs are known to be a good strategy for mitigating the urban heat island effect, the tendency of cities to be several degrees warmer than surrounding areas because buildings and pavement tend to trap heat. And cooler cities can reduce demand for air conditioning and therefore greenhouse gas emissions. The lower temperature on land is likely to weaken sea breezes and alter the mixing of air from different levels of the atmosphere. In turn, these changes will slightly increase PM2.5 concentrations throughout the basin. Past studies have assumed that cool roofing materials don’t alter reflection of ultraviolet (UV) wavelengths. The researchers tested various cool roofing materials and found that in fact some products do reflect more UV rays than traditional roofs. When they incorporated this information into their models, they found that widespread installation of cool roofs is likely to increase the concentration of ozone. The increase in ozone could mostly be prevented by requiring cool roofing materials to minimize reflectance of UV rays.

Climate inaction will leave our kids a trillion dollar debt Unless we drastically cut our carbon emissions, today’s young people will have to pay up to US$535 trillion to clean up the atmosphere, according to a new study. That’s how much it would cost them to remove carbon dioxide emissions from the air using negative emissions technologies to avoid the worst effects of climate change. The study is part of a lawsuit filed against the US Government by 21 children who claim that federal policies are violating their constitutional right to living in a healthy climate.

Climate change will bring us less nutritious crops–and rising global protein deficiency Crops like wheat, barley, and rice are staple foods for millions around the globe, and are responsible for the bulk of dietary protein in many countries. With the rising carbon dioxide emissions that accompany climate change, the nutritional value of these staple crops will decline. That’s expected to place 148 million more people at risk of protein deficiency by 2050–with the worst impacts felt in sub-Saharan Africa and South Asia. Increasing carbon dioxide levels are believed to affect plants’ ability to absorb nutrients, resulting in declining protein levels. The researchers found that in 18 countries–including India, Turkey, and Iraq–protein availability is expected by 2050 to decline by more than five percent. Three staple crops in particular were worst-affected: barley would experience a 14.1 percent protein decline under rising CO2 levels; wheat, a decline of 7.8 percent; and in rice, of 7.6 percent. Since wheat and rice are staple foods for a striking 71 percent of the planet’s population, this is particularly worrying. By 2050, even if carbon dioxide emissions stay at today’s levels, 15 percent of the world population–that’s 1.4 billion people–will be at risk of protein deficiency. If CO2 emissions steadily increase, however, it’s expected that an additional 148 million people would also become newly protein-deficient by 2050. In India, for instance, that would leave 53 million people without enough protein in their diets.

Turning homes into power stations could cut household fuel bills by more than 60 percent Energy bills could be cut by more than 60 percent -- saving the average household over £600 a year -- if homes were designed to generate, store and release their own solar energy, a report has revealed. The concept has already been proven and is operating successfully on a building in the UK.  The UK's first energy-positive classroom combines an integrated solar roof and battery storage with solar heat collection on south-facing walls. Over 6 months of operation the Active Classroom has generated more energy than it has consumed. Technologies include solar roofs, shared battery storage and the potential for charging points for electric vehicles. Water heating comes from a solar heat collector on south facing walls. Waste heat is captured and recycled within the building. “The technology works, so what we need now is to build on our partnerships with industry and government and make it happen.” “The technology can be retrofitted or incorporated into new build.”

Annual wind report confirms tech advancements, improved performance, low wind prices "Wind energy prices -- particularly in the central United States, and supported by federal tax incentives -- are at all-time lows, with utilities and corporate buyers selecting wind as the low-cost option," said Berkeley Lab Senior Scientist Ryan Wiser. Low wind turbine pricing continues to push down installed project costs. Wind turbine equipment prices have fallen from their highs in 2008, to $800-$1,100/kilowatt(kW), and these declines are pushing down project-level costs. The average installed cost of wind projects in 2016 was $1,590/kW, down $780/kW from the peak in 2009 and 2010.

Distributed wind power keeps spinning, growing America's use of distributed wind -- which is wind power generated near where it will be used -- continues to grow, according to the 2016 Distributed Wind Market Report. Distributed wind can range from a small, solitary turbine at a remote cabin to several large turbines powering an entire neighborhood. Third-party financing and leasing options are enabling companies and individuals to generate wind power on their properties. These options provide flexibility that eases the financial and logistical burdens of installing and operating wind turbines. The average levelized cost of energy produced by distributed wind projects installed in 2016 ranged from 5 to 24 cents per kilowatt-hour, with power produced by larger turbines costing the least. In comparison, the average residential power rates in the U.S. range from 9.3 to 20 cents per kilowatt-hour while average commercial power rates range 7.5 to 15 cents per kilowatt-hour.

aCar -- the electric 'all-rounder' An electric car for Africa, custom-designed for the needs of the population there, that strengthens rural structures and helps drive the economy: scientists have been working intensively towards this goal for four years. The new prototype, the aCar, is designed for passenger and cargo transportation and is also interesting for the European automotive market. access to a vehicle of any kind is hardly a given for many people in Africa. For farmers who live far from urban centers, this means that they have no direct access to medical care, education or to political processes. They are dependent on transport contractors who bring their products to the next city for sale in order to make a living. As a result, many people are leaving rural areas in search of better living conditions in the city. The 20 kWh battery capacity gives the vehicle an electric range of 80 kilometers. The battery can be loaded from an ordinary 220 volt household wall socket within 7 hours. Solar modules mounted on the roof of the aCar gather energy throughout the day. Optional solar collector sheets can be unrolled to significantly increase the amount of solar energy produced for self-contained battery charging.  In future, as many of the aCar's components as possible are to be manufactured on location, in order to strengthen local economies. In order to make the automobile affordable for people on location, the price for the basic vehicle in Africa is to be kept under 10,000 Euros on a long-term basis. Another important point was testing the impact of the higher temperatures and air humidity on the electric systems. The first vehicles are to be manufactured in a model factory in Europe. "We'll have to master all the technical procedures before the car can be made in Africa. Then we can train people from Africa who can in turn pass on their knowledge there."

Lithium in tap water may cut dementia Lithium is naturally found in tap water, although the amount varies. The findings, based on a study of 800,000 people, are not clear-cut. The results, published in JAMA Psychiatry, showed moderate lithium levels (between 5.1 and 10 micrograms per litre) increased the risk of dementia by 22% compared with low levels (below five micrograms per litre). However, those drinking water with the highest lithium levels (above 15 micrograms per litre) had a 17% reduction in risk. The lithium in tap water is at much lower levels than is used medicinally. Experiments have shown the element alters a wide range of biological processes in the brain. Prof Simon Lovestone said there should now be studies to see if regular, small doses of lithium could prevent the onset of dementia. The problem with this style of study - which looks for patterns in large amounts of data - is it cannot prove cause-and-effect. Prof Tara Spires-Jones, from the Centre for Discovery Brain Sciences, at the University of Edinburgh, said: "This association does not necessarily mean that the lithium itself reduces dementia risk. "There could be other environmental factors in the area that could be influencing dementia risk.

Zeroing in on the carbon cycle Joos, a professor of physics at the University of Bern in Switzerland, sat down with Future Earth to talk about the upcoming event. He also discussed what scientists have learned about the carbon cycle since the inaugural International Carbon Dioxide Conference was held in 1981. At that time, he says, researchers depended on relatively simple calculations, called box models, to investigate the ins and outs of carbon dioxide in the atmosphere. Today, they use complex simulations, called Earth System Models, to more accurately study how carbon flows between various parts of the planet – research that has shown the magnitude by which humans are now shifting the climate. Fossil-fuel CO2 emissions have almost doubled in the less than 40 years since 1981 when the first conference was held in Bern. There are still improvements needed in what is known about extreme events, in terms of how multiple stressors affect the marine and terrestrial carbon cycle. I’m thinking of marine and atmospheric heatwaves, droughts on land, ocean acidification and deoxygenation of the ocean, and how these extreme events will affect ecosystems and human systems – food production, for example. Also, we are still struggling to quantitatively explain the evolution of the carbon cycle over past abrupt events. We know from paleodata that the climate has shifted over years and decades, as well as on glacial-interglacial time scales. This has implications for our understanding of the evolution of peat and permafrost carbon. Another area where more research is needed is the link between human activities and the carbon cycle. That includes the consequences of land management and the use of resources.

Breakthrough in magnesium batteries Magnesium batteries offer promise for safely powering modern life -- unlike traditional lithium ion batteries, they are not flammable or subject to exploding -- but their ability to store energy has been limited. "Magnesium ion is known to be hard to insert into a host," said Yoo, first author on the paper. "First of all, it is very difficult to break magnesium-chloride bonds. More than that, magnesium ions produced in that way move extremely slowly in the host. That altogether lowers the battery's efficiency." The new battery stores energy by inserting magnesium monochloride into a host, such as titanium disulfide. By retaining the magnesium-chloride bond, Yao said, the cathode demonstrated much faster diffusion than traditional magnesium versions. The researchers report the new battery has storage capacity of 400 mAh/g, compared with 100 mAh/g for earlier magnesium batteries. Commercial lithium ion batteries have a cathode capacity of about 200 mAh/g. Voltage of the new battery remains low at about one volt. That compares to three to four volts for lithium batteries. As an earth-abundant resource, magnesium is cheaper and does not form dendrites.

More solar power thanks to titanium With the help of a catalyst, sunlight can drive the oxidation of water to oxygen and the release of electrons for current generation, a process also called artificial photosynthesis. Iron oxide in the form of hematite is a convenient and cheap catalyst candidate, but the electrons set free by the chemical reaction tend to be trapped again and get lost; the electricity flow is inefficient. As a solution, Jinlong Gong from Tianjin University, China, introduced a nanometer-thin passivation layer of titania. Not only does this prevent charge recombination between the hematite electrode structure and the substrate, but it also provides the iron oxide with a considerable doping source to increase its charge-carrier density, a highly promising effect for photoelectric applications. Both effects, passivation and doping, indeed produced a more than four times higher photocurrent under standardized conditions. The addition of an iron hydroxide co-catalyst pushed the photocurrent density even further to a value more than five times above that of the undoped system. This design combining cheap materials, few preparation steps, and enhanced electrical performance may be exemplary for improved systems in green artificial photosynthesis.

No batteries required: Energy-harvesting yarns generate electricity Scientists have developed high-tech yarns that generate electricity when they are stretched or twisted. 'Twistron' yarns have many possible applications, such as harvesting energy from the motion of ocean waves or from temperature fluctuations. In order to generate electricity, the yarns must be either submerged in or coated with an ionically conducting material, or electrolyte, which can be as simple as a mixture of ordinary table salt and water. Stretching the coiled twistron yarns 30 times a second generated 250 watts per kilogram of peak electrical power when normalized to the harvester's weight. "Harvesting electrical energy from human motion is one strategy for eliminating the need for batteries. Our yarns produced over a hundred times higher electrical power per weight when stretched compared to other weavable fibers reported in the literature." "If our twistron harvesters could be made less expensively, they might ultimately be able to harvest the enormous amount of energy available from ocean waves," Baughman said. "However, at present these harvesters are most suitable for powering sensors and sensor communications. Based on demonstrated average power output, just 31 milligrams of carbon nanotube yarn harvester could provide the electrical energy needed to transmit a 2-kilobyte packet of data over a 100-meter radius every 10 seconds for the Internet of Things."

Trash to treasure: The benefits of waste-to-energy technologies Using landfill waste to produce energy generates less greenhouse gases than simply letting the waste decompose. The study highlights the benefits of food waste as a potential source of energy. Organic waste such as yard trimmings, paper, wood and food produces millions of tons of methane emissions at landfills every year in the U.S., but it could produce renewable natural gas and liquid fuels such as gasoline and diesel. Landfill gas from waste contains high concentrations of methane, which has about 30 times higher global warming impact compared to carbon dioxide. Although the operators of large landfills are required to combust landfill gas, it is impossible to perfectly collect the gas and there is still a large amount of non-captured methane escaping into the atmosphere.

Nanoparticles pollution rises 30 percent when flex-fuel cars switch from bio to fossil When ethanol prices at the pump rise for whatever reason, it becomes economically advantageous for drivers of dual-fuel vehicles to fill up with gasoline. However, the health of the entire population pays a high price: substitution of gasoline for ethanol leads to a 30% increase in the atmospheric concentration of ultrafine particulate matter, which consists of particles with a diameter of less than 50 nanometers (nm). "These polluting nanoparticles are so tiny that they behave like gas molecules. When inhaled, they can penetrate the respiratory system's defensive barriers and reach the pulmonary alveoli, so that potentially toxic substances enter the bloodstream and may increase the incidence of respiratory and cardiovascular problems," said Paulo Artaxo, Full Professor at the University of São Paulo's Physics Institute (IF-USP) and a co-author of the study. According to him, between 75% and 80% of the mass of nanoparticles measured in this study corresponds to organic compounds (carbon in different forms) emitted by motor vehicles. Levels of ultrafine particulate matter in the atmosphere are neither monitored nor regulated by environmental agencies not only in Brazil but practically anywhere in the world, Artaxo stressed.

Oil company tells two different climate change stories: One to scientists and one to the public The oil company ExxonMobil has misled the public about climate science over the last several decades, according to a study by Harvard University researchers Geoffrey Supran and Naomi Oreskes published last week in Environmental Research Letters. The findings are based on a close reading of 187 documents produced by ExxonMobil (as well as Exxon and Mobil prior to the two companies’ merger in the late 1990s) between 1977 and 2014. For example, 83% of peer-reviewed papers and 80% of internal documents acknowledge that climate change is real and caused by human actions. But 80% of advertorials express doubt about this. Similarly, of the documents that address whether climate change is serious, 60% of peer-reviewed publications conclude that it is, while 62% of advertorials communicate doubt. Of the documents that take a position on whether climate change is solvable, 64% of advertorials promote doubt – that is, they suggest that it’s either too hard or too expensive to stop climate change. But only 3% of peer-reviewed papers and 9% of internal company documents take this view.

Silicon solves problems for next-generation battery technology Silicon -- the second most abundant element in the earth's crust -- shows great promise in Li-ion batteries, according to new research. By replacing graphite anodes with silicon, it is possible to quadruple anode capacity. "We now have a good understanding of the material properties required in large-scale use of silicon in Li-ion batteries. However, the silicon we've been using is too expensive for commercial use, and that's why we are now looking into the possibility of manufacturing a similar material from agricultural waste, for example from barley husk ash," Professor Vesa-Pekka Lehto explains.

Photosynthesis discovery could help design more efficient artificial solar cells The researchers studied photosynthetic reaction centers from the freshwater cyanobacterium species Synechocystis, which has the same photosynthetic machinery as plants. "Plants convert solar energy ultra-efficiently, considerably more efficiently than any artificial solar cell," Hastings said. "In photosynthesis, light comes in, an electron moves across a membrane and it doesn't come back. The big problem with artificial systems is the electron does go back much of the time. That's the real heart of why plants are so efficient at converting solar energy. Our work has revealed one design principle that is at play in efficient solar energy conversion in plants, and the hope is that this principle could be utilized in the design of new and better types of artificial solar cells."

Analysis identifies where commercial customers might benefit from energy storage Commercial electricity customers who are subject to high demand charges may be able to reduce overall costs by using battery energy storage to manage demand, according to research by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL). The analysis represents the first publicly available survey of commercial-sector demand charges across the United States. By determining locations where comparatively high demand charges are currently in place and the number of customers that may be paying them, researchers provide insight into commercial battery storage market potential across the United States. The analysis looked at the number of commercial customers potentially eligible for utility rate tariffs that include demand charges of $15 or more per kilowatt, an industry benchmark for economic storage opportunities using current technology and pricing. High-level insights include the fact that some the of the country's highest demand charges -- and therefore potentially viable market environments for utilizing energy storage to reduce peak demand -- were found in states not typically known for having high electricity prices, such as Colorado, Nebraska, Arizona, and Georgia.

Electricity consumption in Europe will shift under climate change Rising temperatures due to greenhouse gas emissions will fundamentally change electricity consumption patterns in Europe. A team of scientists from Germany and the United States now analyzed what unchecked future warming means for Europe's electricity demand: daily peak loads in Southern Europe will likely increase and overall consumption will shift from Northern Europe to the South. Further, the majority of countries will see a shift of temperature-driven annual peak demand from winter to summer by the end of this century. This would put additional strain on European power grids. The response of electricity consumption to temperature changes is similar across European countries' peak and total electricity use seem to be smallest on days with a maximum temperature of about 22°C (72°F), and increases when this daily maximum temperature either rises or falls. There now is ample evidence that when it's hot outside, air quality suffers, people are more stressed, aggressive, violent and less productive, mortality and crime rates rise. All sectors of the economy are affected by thermal stress, from the residential to the commercial, agricultural to the industrial sector. The main adaptation mechanism available to humans to combat high outdoor temperatures is a cooled indoor built environment, which in most settings requires the consumption of significant amounts of electricity. The study is the first to use observed hourly electricity data across 35 European countries -- which are connected by the world's largest synchronous electrical grid -- to estimate how climate change impacts the intensity of peak-load events and overall electricity consumption.

New liquid-metal membrane technology may help make hydrogen fuel cell vehicles viable While cars powered by hydrogen fuel cells offer clear advantages over the electric vehicles that are growing in popularity (including their longer range, their lower overall environmental impact, and the fact that they can be refueled in minutes, versus hours of charging time), they have yet to take off with consumers. One reason is the high cost and complexity of producing, distributing, and storing the pure hydrogen needed to power them, which has hindered the roll-out of hydrogen refueling stations. Virtually all of the hydrogen produced in the United States is obtained from hydrocarbon fuels, primarily natural gas, through steam reforming, a multi-step process in which the hydrocarbons react with high-temperature steam in the presence of a catalyst to produce carbon monoxide, carbon dioxide, and molecular hydrogen (H2). Most of the hydrogen separation membranes currently being developed use the precious metal palladium, which has unusually high hydrogen solubility and permeance (which means that hydrogen easily dissolves in and travels through the metal, while other gases are excluded). But palladium is expensive (it currently sells for about $900 per ounce) and fragile. Datta and his students began to wonder whether liquid metals might overcome some of palladium's limitations -- particularly its cost and fragility -- while also, potentially, offering superior hydrogen solubility and permeance. They decided to insert the metal between two layers of support material to create a sandwiched liquid-metal membrane or SLiMM. A membrane consisting of a thin (two-tenths of a millimeter) layer of liquid gallium between a layer of silicon carbide and a layer of graphite, was constructed in the lab and tested for stability and hydrogen permeance. The results showed that the liquid gallium film was up to 35 times more permeable to hydrogen than a comparable layer of palladium and that diffusion of hydrogen through the sandwiched membrane was considerably higher than for a typical palladium membrane. The test also showed that the membranes were selective, allowing just hydrogen to pass through.