Posts belonging to Category Solar energy

By 2025 Renewables Will Power 67 Percent Of South Australia

Declining renewables and energy storage costs will increasingly squeeze out gas-fired generation in South Australia as early as 2025, a joint research report conducted by Wood Mackenzie and GTM Research shows. The South Australia experience is noteworthy in a global power mix set to increasingly shift to renewable energy. South Australia retired its last coal plant in 2016 and is projected to have installed renewable energy capacity exceed its peak demand by 2020.

By 2025, wind, solar and battery costs will fall by 15 percent, 25 percent and 50 percent respectively. By then, renewables and batteries could offer a lower cost alternative to combined-cycle gas turbine plants, which are commonly used to manage base load power generation in South Australia. Meanwhile by 2035, renewables and batteries will provide a commercial solution for both base loads and peak loads. As a consequence, gas will increasingly be used just for emergency back-up.

One determining factor is the rate with which battery charging costs declines. By 2025, we expect battery charging cost to decrease as off-peak prices will gradually be set by excess wind generation. Battery storage then becomes a potential solution for managing peak loads,” said Bikal Pokharel, principal analyst for Wood Mackenzie‘s Asia-Pacific power and renewables .
By 2025 it’s expected that 67 percent of South Australia’s power capacity will come from renewables. Gas demand in the power sector will then decline by 70 percent.

Currently, South Australia’s peak loads are managed by open-cycle gas turbine (OCGT) plants. But by 2025, battery storage would be cheaper than OCGTs in managing peak loads even at gas price of A$7/mmbtu. OCGTs would then be relegated as emergency back-ups.”


Cheap, Robust Catalyst Splits Water Into Hydrogen And Oxygen

Splitting water into hydrogen and oxygen to produce clean energy can be simplified with a single catalyst developed by scientists at Rice University and the University of Houston. The electrolytic film produced at Rice and tested at Houston is a three-layer structure of nickel, graphene and a compound of iron, manganese and phosphorus. The foamy nickel gives the film a large surface, the conductive graphene protects the nickel from degrading and the metal phosphide carries out the reactionRice chemist Kenton Whitmire and Houston electrical and computer engineer Jiming Bao and their labs developed the film to overcome barriers that usually make a catalyst good for producing either oxygen or hydrogen, but not both simultaneously.

A catalyst developed by Rice University and the University of Houston splits water into hydrogen and oxygen without the need for expensive metals like platinum. This electron microscope image shows nickel foam coated with graphene and then the catalytic surface of iron, manganese and phosphorus

Regular metals sometimes oxidize during catalysis,” Whitmire said. “Normally, a hydrogen evolution reaction is done in acid and an oxygen evolution reaction is done in base. We have one material that is stable whether it’s in an acidic or basic solution.

The discovery builds upon the researchers’ creation of a simple oxygen-evolution catalyst revealed earlier this year. In that work, the team grew a catalyst directly on a semiconducting nanorod array that turned sunlight into energy for solar water splittingElectrocatalysis requires two catalysts, a cathode and an anode. When placed in water and charged, hydrogen will form at one electrode and oxygen at the other, and these gases are captured. But the process generally requires costly metals to operate as efficiently as the Rice team’s catalyst.

The standard for hydrogen evolution is platinum,” Whitmire explained. “We’re using Earth-abundant materials — iron, manganese and phosphorus — as opposed to noble metals that are much more expensive.

The robust material is the subject of a paper in Nano Energy.


New Solar System Produces 50 Percent More Energy

A concentrating photovoltaic system (CPV) with embedded microtracking can produce over 50 percent more energy per day than standard silicon solar cells in a head-to-head competition, according to a team of engineers who field tested a prototype unit over two sunny days last fall.

Solar cells used to be expensive, but now they’re getting really cheap,” said Chris Giebink, Charles K. Etner Assistant Professor of Electrical Engineering, Penn State. “As a result, 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.

This changing economic landscape has put a premium on high efficiency. In contrast to silicon solar panels, which currently dominate the market at 15 to 20 percent efficiency, concentrating photovoltaics focus sunlight onto smaller, but much more efficient solar cells like those used on satellites, to enable overall efficiencies of 35 to 40 percent. Current CPV systems are large — the size of billboards — and have to rotate to track the sun during the day. These systems work well in open fields with abundant space and lots of direct sun.

What we’re trying to do is create a high-efficiency CPV system in the form factor of a traditional silicon solar panel,” said Giebink.


SuperPowerful Tiny Device Converts Light Into Electricity

In today’s increasingly powerful electronics, tiny materials are a must as manufacturers seek to increase performance without adding bulk. Smaller also is better for optoelectronic devices — like camera sensors or solar cells —which collect light and convert it to electrical energy. Think, for example, about reducing the size and weight of a series of solar panels, producing a higher-quality photo in low lighting conditions, or even transmitting data more quickly.

However, two major challenges have stood in the way: First, shrinking the size of conventionally used “amorphousthin-film materials also reduces their quality. And second, when ultrathin materials become too thin, they are almost transparent — and actually lose some ability to gather or absorb light.

Now, in a nanoscale photodetector that combines both a unique fabrication method and light-trapping structures, a team of engineers from the University at Buffalo (UB) and the University of Wisconsin-Madison (UW-Madison) has overcome both of those obstacles. The researchers — electrical engineers Qiaoqiang Gan at UB, and Zhenqiang (Jack) Ma and Zongfu Yu at UW-Madison — described their device, a single-crystalline germanium nanomembrane photodetector on a nanocavity substrate, in the July 7, 2017, issue of the journal Science Advances.

This image shows the different layers of the nanoscale photodetector, including germanium (red) in between layers of gold or aluminum (yellow) and aluminum oxide (purple). The bottom layer is a silver substrate

We’ve created an exceptionally small and extraordinarily powerful device that converts light into energy,” says Gan, associate professor of electrical engineering in UB’s School of Engineering and Applied Sciences, and one of the paper’s lead authors. “The potential applications are exciting because it could be used to produce everything from more efficient solar panels to more powerful optical fibers.”

The idea, basically, is you want to use a very thin material to realize the same function of devices in which you need to use a very thick material,” says Ma, the Lynn H. Matthias Professor and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison, also a lead author. Nanocavities are made up of an orderly series of tiny, interconnected molecules that essentially reflect, or circulate, light.

The new device is an advancement of Gan’s work developing nanocavities that increase the amount of light that thin semiconducting materials like germanium can absorb. It consists of nanocavities sandwiched between a top layer of ultrathin single-crystal germanium and a bottom, reflecting layer of silver.


How To Power The U.S. With Solar

Speaking recently at the National Governors Association Summer Meeting in Rhode Island, Elon Musk told his audience — including 30 United States governors — that it’s possible to power the nation with solar energy.

If you wanted to power the entire U.S. with solar panels, it would take a fairly small corner of Nevada or Texas or Utah; you only need about 100 miles by 100 miles of solar panels to power the entire United States,” Musk said. “The batteries you need to store the energy, to make sure you have 24/7 power, is 1 mile by 1 mile. One square-mile. That’s it.”

Why solar? Well, as Musk explained, as far as energy sources go, we can count on solar to come through for us: “People talk about fusion and all that, but the sun is a giant fusion reactor in the sky. It’s really reliable. It comes up every day. If it doesn’t we’ve got bigger problems.”

At present, about 10 percent of the U.S. is powered by renewable energy sources. To achieve a complete renewable energy power, Musk thinks solar is the way to go.

To start, he suggested combining rooftop solar and utility-scale solar plants. The former would be on the rooftops of houses in the suburbs, while the latter could power other areas. As we’ve seen with Tesla’s new rooftop solar unit, and efforts in other countries, like Australia, to build large-scale solar plants, this is a goal well within reach.

Next, while in transition from fossil fuel to solar, it’d be necessary to rely on other renewables. “We’ll need to be a combination of utility-scale solar and rooftop solar, combined with wind, geothermal, hydro, probably some nuclear for a while, in order to transition to a sustainable situation,” Musk explained.

Finally, the U.S. has to build more localized power sources, like the rooftop solar setups. “People do not like transmission lines going through their neighborhood, they really don’t like that, and I agree,” Musk said. “Rooftop solar, utility solar; that’s really going to be a solution from the physics standpoint. I can really see another way to really do it.”

When this happens, the U.S. would eliminate about 1,821 million metric tons of carbon dioxide (CO2) emissions generated by the country’s current electric power sector — 35 percent of the overall CO2 energy-related emissions in the U.S.


Solar Nanotechnology-based Desalination

A new desalination system has been developed that combines membrane distillation technology and light-harvesting nanophotonics. Called nanophotonics-enabled solar membrane distillation technology, or NESMD for short, the development has come from the Center for Nanotechnology Enabled Water Treatment (NEWT), based at Rice University. The system works whereby hot salt water is flowed across one side of a porous membrane and cold freshwater is flowed across the otherWater vapor is naturally drawn through the membrane from the hot to the cold side, and because the seawater doesn’t need to be boiled, the energy requirements are less than they would be for traditional distillation, according to the researchers. However, the energy costs are still significant because heat is continuously lost from the hot side of the membrane to the cold.

Unlike traditional membrane distillation, NESMD benefits from increasing efficiency with scale,” said Rice’s Naomi Halas, a corresponding author on the paper and the leader of NEWT‘s  nanophotonics research efforts. “It requires minimal pumping energy for optimal distillate conversion, and there are a number of ways we can further optimise the technology to make it more productive and efficient.

The distillation membrane in the chamber contained a specially designed top layer of carbon black nanoparticles infused into a porous polymer. The light-capturing nanoparticles heated the entire surface of the membrane when exposed to sunlight. A thin half-millimeter-thick layer of salt water flowed atop the carbon-black layer, and a cool freshwater stream flowed below.

Rice scientist and water treatment expert Qilin Li said the water production rate increased greatly by concentrating the sunlight: “The intensity got up 17.5 kilowatts per meter squared when a lens was used to concentrate sunlight by 25 times, and the water production increased to about 6 liters per meter squared per hour.”

In the PNAS study, researchers offered proof-of-concept results based on tests with an NESMD chamber about the size of three postage stamps and just a few millimeters thick.


Sion, The Solar-Powered Car

What has room for 6 passengers, an all-electric range of up to 155 miles (250 kilometers), and a body covered in solar panels that can add as many as 18 miles (30 kilometers) of driving a day from sunlight? That would be the Sono Motors Sion, an innovative solar-powered car from a team of German entrepreneurs that is scheduled to have its world debut on July 27 (2017).

The Sion project was able to move forward thanks to an Indiegogo crowdfunding campaign last year that raised over a half million dollars. More than 1,000 people have participated so far.

The car will have two versions. The Urban comes with a 14.4 kilowatt-hour battery pack. It has a range of about 75 miles (121 kilometers) and will cost $13,200. The Extender version has a 30 kilowatt-hour battery and a range of 155 miles (250 kilometers). Its target price is $17,600. Neither price includes the battery. Like the Renault Zoe, customers will either buy the battery separately or lease it. The leasing option gives owners the flexibility to upgrade the battery later as improvements in battery technology become available.

The hood, roof, and rear hatch of the Sion are covered with monocrystalline silicon cells that are 21% efficient. On a sunny day, they can generate enough electricity to add 18 miles of range. The solar cells are 8 millimeters thick and embedded in a polycarbonate layer that is shatterproof, weather resistant, and light in weight. The Sion can also be 80% charged using an AC outlet in about 30 minutes, according to company claims. No DC charging option is available. The car also comes with an outlet that can power electronic devices.

Inside, all the seats of the 5 door hatchback fold flat, offering multiple configurations for carrying passengers and cargo. There is a 10 inch center display and smartphone connectivity via WiFi or Bluetooth. The ventilation system is called breSono and incorporates a dollop of moss, which is said to act as a natural filter when an electrical charge is applied.

The company will offer an online maintenance and repair system it calls reSono. It allows owners to order parts online and comes with a video that shows them how to install the parts when they arrive.  Or they can take the car and the parts to any local auto repair shop facility to get them installed.


Perovskite Solar Cells Conversion Efficiency Rises Up To 20%

A new low-temperature solution printing technique allows fabrication of high-efficiency perovskite solar cells with large crystals intended to minimize current-robbing grain boundaries. The meniscus-assisted solution printing (MASP) technique boosts power conversion efficiencies to nearly 20 percent by controlling crystal size and orientation.

The process, which uses parallel plates to create a meniscus of ink containing the metal halide perovskite precursors, could be scaled up to rapidly generate large areas of dense crystalline film on a variety of substrates, including flexible polymers. Operating parameters for the fabrication process were chosen by using a detailed kinetics study of perovskite crystals observed throughout their formation and growth cycle.

We used a meniscus-assisted solution printing technique at low temperature to craft high quality perovskite films with much improved optoelectronic performance,” said Zhiqun Lin, a professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. “We began by developing a detailed understanding of crystal growth kinetics that allowed us to know how the preparative parameters should be tuned to optimize fabrication of the films.”

The new technique is reported in the journal Nature Communications.


Solar Energy Transforms Salt Water Into Fresh Drinking Water

A federally funded research effort to revolutionize water treatment has yielded an off-grid technology that uses energy from sunlight alone to turn salt water into fresh drinking water. The desalination system, which uses a combination of membrane distillation technology and light-harvesting nanophotonics, is the first major innovation from the Center for Nanotechnology Enabled Water Treatment (NEWT), a multi-institutional engineering research center based at Rice University.

NEWT’s “nanophotonics-enabled solar membrane distillation” technology, or NESMD, combines tried-and-true water treatment methods with cutting-edge nanotechnology that converts sunlight to heat. More than 18,000 desalination plants operate in 150 countries, but NEWT’s desalination technology is unlike any other used today.

Direct solar desalination could be a game changer for some of the estimated 1 billion people who lack access to clean drinking water,” said Rice scientist and water treatment expert Qilin Li, a corresponding author on the study. “This off-grid technology is capable of providing sufficient clean water for family use in a compact footprint, and it can be scaled up to provide water for larger communities.”

The technology is described online in the Proceedings of the National Academy of Sciences.


Nano-based Material Is 60 Times More Efficient To Produce Hydrogen

Global climate change and the energy crisis mean that alternatives to fossil fuels are urgently needed. Among the cleanest low-carbon fuels is hydrogen, which can react with oxygen to release energy, emitting nothing more harmful than water (H2O) as the product. However, most hydrogen on earth is already locked into H2O (or other molecules), and cannot be used for power.

Hydrogen can be generated by splitting H2O, but this uses more energy than the produced hydrogen can give back. Water splitting is often driven by solar power, so-called “solar-to-hydrogenconversion. Materials like titanium oxide, known as semiconductors with the wide band-gap, are traditionally used to convert sunlight to chemical energy for the photocatalytic reaction. However, these materials are inefficient because only the ultraviolet (UV) part of light is absorbed—the rest spectrum of sunlight is wasted.

Now, a team in Osaka University has developed a material to harvest a broader spectrum of sunlight. The three-part composites of this material maximize both absorbing light and its efficiency for water splitting. The core is a traditional semiconductor, lanthanum titanium oxide (LTO). The LTO surface is partly coated with tiny specks of gold, known as nanoparticles. Finally, the gold-covered LTO is mixed with ultrathin sheets of the element black phosphorus (BP), which acts as a light absorber.

BP is a wonderful material for solar applications, because we can tune the frequency of light just by varying its thickness, from ultrathin to bulk,” the team leader Tetsuro Majima says. “This allows our new material to absorb visible and even near infrared light, which we could never achieve with LTO alone.”

By absorbing this broad sweep of energy, BP is stimulated to release electrons, which are then conducted to the gold nanoparticles coating the LTO. Gold nanoparticles also absorb visible light, causing some of its own electrons to be jolted out. The free electrons in both BP and gold nanoparticles are then transferred into the LTO semiconductor, where they act as an electric current for water splitting.

Hydrogen production using this material is enhanced not only by the broader spectrum of light absorption, but by the more efficient electron conduction, caused by the unique interface between two dimensional materials of BP and LTO. As a result, the material is 60 times more active than pure LTO.


Super-Efficient Production Of Hydrogen From Solar Energy

Hydrogen is an alternative source of energy that can be produced from renewable sources of sunlight and water. A group of Japanese researchers has developed a photocatalyst that increases hydrogen production tenfold.

When light is applied to photocatalysts, electrons and holes are produced on the surface of the catalyst, and hydrogen is obtained when these electrons reduce the hydrogen ions in water. However, in traditional photocatalysts the holes that are produced at the same time as the electrons mostly recombine on the surface of the catalyst and disappear, making it difficult to increase conversion efficiency.

Professor Tachikawa’s research group from the Kobe University developed a photocatalyst made of mesocrystal, deliberately creating a lack of uniformity in size and arrangement of the crystals. This new photocatalyst is able to spatially separate the electrons and electron holes to prevent them recombining. As a result, it has a far more efficient conversion rate for producing hydrogen than conventional nanoparticulate photocatalysts (approximately 7%).

The team developed a new method called “Topotactic Epitaxial Growth” that uses the nanometer-sized spaces in mesocrystals.
Using these findings, the research group plans to apply mesocrystal technology to realizing the super-efficient production of hydrogen from solar energy. The perovskite metal oxides, including strontium titanate, the target of this study, are the fundamental materials of electronic elements, so their results could be applied to a wide range of fields.

The discovery was made by a joint research team led by Associate Professor Tachikawa Takashi (Molecular Photoscience Research Center, Kobe University) and Professor Majima Tetsuro (Institute of Scientific and Industrial Research, Osaka University). Their findings were published  in the online version of Angewandte Chemie International Edition.


Liquid Storage Of The Sun’s Power

Researchers at Chalmers University of Technology in Sweden have demonstrated efficient solar energy storage in a chemical liquid. The stored energy can be transported and then released as heat whenever needed. ​Many consider the sun the energy source of the future. But one challenge is that it is difficult to store solar energy and deliver the energy ‘on demand’.

The research team from Chalmers University has shown that it is possible to convert the solar energy directly into energy stored in the bonds of a chemical fluid – a so-called molecular solar thermal system. The liquid chemical makes it possible to store and transport the solar energy and release it on demand, with full recovery of the storage medium. The process is based on the organic compound norbornadiene that upon exposure to light converts into quadricyclane.

The technique means that we can store the solar energy in chemical bonds and release the energy as heat whenever we need it,’ says Professor Kasper Moth-Poulsen, who is leading the research team. ‘Combining the chemical energy storage with water heating solar panels enables a conversion of more than 80 percent of the incoming sunlight.’

The research project was initiated at Chalmers more than six years ago and the research team contributed in 2013 to a first conceptual demonstration. At the time, the solar energy conversion efficiency was 0.01 percent and the expensive element ruthenium played a major role in the compound. Now, four years later, the system stores 1.1 percent of the incoming sunlight as latent chemical energy – an improvement of a factor of 100. Also, ruthenium has been replaced by much cheaper carbon-based elements.

We saw an opportunity to develop molecules that make the process much more efficient,’ says Moth-Poulsen. ‘At the same time, we are demonstrating a robust system that can sustain more than 140 energy storage and release cycles with negligible degradation.’

The research is presented on the cover of the scientific journal Energy & Environmental Science.