Experts Outline Pathway for Generating Up to Ten (10) Terawatts of Power from Sunlight by 2030: NREL – GA SERI


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The annual potential of solar energy far exceeds the world’s energy consumption, but the goal of using the sun to provide a significant fraction of global electricity demand is far from being realized.

Scientists from the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL), their counterparts from similar institutes in Japan and Germany, along with researchers at universities and industry, assessed the recent trajectory of photovoltaics and outlined a potential worldwide pathway to produce a significant portion of the world’s electricity from solar power in the new Science paper, Terawatt-Scale Photovoltaics: Trajectories and Challenges.NREL I download

Fifty-seven experts met in Germany in March 2016 for a gathering of the Global Alliance of Solar Energy Research Institutes (GA-SERI), where they discussed what policy initiatives and technology advances are needed to support significant expansion of solar power over the next couple of decades.

“When we came together, there was a consensus that the global PV industry is on a clear trajectory to reach the multi-terawatt scale over the next decade,” said lead author Nancy Haegel, director of NREL’s Materials Science Center. “However, reaching the full potential for PV technology in the global energy economy will require continued advances in science and technology. Bringing the global research community together to solve challenges related to realizing this goal is a key step in that direction.”

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Photovoltaics (PV) generated about 1 percent of the total electricity produced globally in 2015 but also represented about 20 percent of new installation. The International Solar Alliance has set a target of having at least 3 terawatts – or 3,000 gigawatts (GW) – of additional solar power capacity by 2030, up from the current installed capacity of 71 GW. But even the most optimistic projections have under-represented the actual deployment of PV over the last decade, and the GA-SERI paper discusses a realistic trajectory to install 5-10 terawatts of PV capacity by 2030.

Reaching that figure should be achievable through continued technology improvements and cost decreases, as well as the continuation of incentive programs to defray upfront costs of PV systems, according to the Science paper, which in addition to Haegel was co-authored by David Feldman, Robert Margolis, William Tumas, Gregory Wilson, Michael Woodhouse, and Sarah Kurtz of NREL.

GA-SERI’s experts predict 5-10 terawatts of PV capacity could be in place by 2030 if these challenges can be overcome:

  • A continued reduction in the cost of PV while also improving the performance of solar modules
  • A drop in the cost of and time required to expand manufacturing and installation capacity
  • A move to more flexible grids that can handle high levels of PV through increased load shifting, energy storage, or transmission
  • An increase in demand for electricity by using more for transportation and heating or cooling
  • Continued progress in storage for energy generated by solar power.

The Fraunhofer Institute for Solar Energy (Germany), the National Institute of Advanced Industrial Science and Technology (Japan), and the National Renewable Energy Laboratory (United States) are the member institutes of GA-SERI, which was founded in 2012.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for the Energy Department by The Alliance for Sustainable Energy, LLC.

Researchers succeed in producing OLED electrodes from graphene


Orange luminous OLED on a graphene electrode. The two-euro coin serves as a comparison of sizes. (Image: Fraunhofer FEP)

Researchers succeed in producing OLED electrodes from graphene

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP from Dresden, together with partners, has succeeded for the first time in producing OLED electrodes from graphene. The electrodes have an area of 2 × 1 square centimeters.

“This was a real breakthrough in research and integration of extremely demanding materials,” says FEP’s project leader Dr. Beatrice Beyer. The process was developed and optimized in the EU-funded project “Gladiator” (Graphene Layers: Production, Characterization and Integration) together with partners from industry and research.


Orange luminous OLED on a graphene electrode. The two-euro coin serves as a comparison of sizes. (Image: Fraunhofer FEP)

Graphene is considered a new miracle material. The advantages of the carbon compound are impressive: graphene is light, transparent and extremely hard and has more tensile strength than steel.

Moreover, it is flexible and extremely conductive for heat or electricity. Graphene consists of a single layer of carbon atoms which are assembled in a kind of honeycomb pattern. It is only 0.3 nanometers thick, which is about one hundred thousandth of a human hair. Graphene has a variety of applications – for example, as a touchscreen in smartphones.

Chemical reaction of copper, methane and hydrogen

The production of the OLED electrodes takes place in a vacuum. In a steel chamber, a wafer plate of high-purity copper is heated to about 800 degrees. The research team then supplies a mixture of methane and hydrogen and initiates a chemical reaction. The methane dissolves in the copper and forms carbon atoms, which spread on the surface. This process only takes a few minutes. After a cooling phase, a carrier polymer is placed on the graphene and the copper plate is etched away.

Gladiator project was launched in November 2013. The Fraunhofer team is working on the next steps until the conclusion in April 2017. During the remainder of the project, impurities and defects which occur during the transfer of the wafer-thin graphene to another carrier material are to be minimized.

The project is supported by the EU Commission with a total of 12.4 million euros. The Fraunhofer Institute’s important industrial partners are the Spanish company Graphenea S.A., which is responsible for the production of the graphene electrodes, as well as the British Aixtron Ltd., which is responsible for the construction of the production CVD reactors.

Applications from photovoltaics to medicine

“The first products could already be launched in two to three years”, says Beyer with confidence.

Due to their flexibility, the graphene electrodes are ideal for touch screens. They do not break when the device drops to the ground. Instead of glass, one would use a transparent polymer film. 
Many other applications are also conceivable: in windows, the transparent graphene could regulate the light transmission or serve as an electrode in polarization filters.

Graphene can also be used in photovoltaics, high-tech textiles and even in medicine.

Source: Fraunhofer Institute for Electron Beam and Plasma Technology FEP

Flower power—photovoltaic cells replicate rose petals


 With a surface resembling that of plants, solar cells improve light-harvesting and thus generate more power. Scientists of KIT (Karlsruhe Institute of Technology) reproduced the epidermal cells of rose petals that have particularly good antireflection properties and integrated the transparent replicas into an organic solar cell. This resulted in a relative efficiency gain of twelve percent. An article on this subject has been published recently in the Advanced Optical Materials journal.

Photovoltaics works in a similar way as the photosynthesis of plants. Light energy is absorbed and converted into a different form of energy. 

In this process, it is important to use a possibly large portion of the sun’s light spectrum and to trap the light from various incidence angles as the angle changes with the sun’s position. Plants have this capability as a result of a long evolution process – reason enough for photovoltaics researchers to look closely at nature when developing solar cells with a broad absorption spectrum and a high incidence angle tolerance.

Scientists at the KIT and the ZSW (Center for Solar Energy and Hydrogen Research Baden-Württemberg) now suggest in their article published in the Advanced Optical Materials journal to replicate the outermost tissue of the petals of higher plants, the so-called epidermis, in a transparent layer and integrate that layer into the front of solar cells in order to increase their efficiency.

First, the researchers at the Light Technology Institute (LTI), the Institute of Microstructure Technology (IMT), the Institute of Applied Physics (APH), and the Zoological Institute (ZOO) of KIT as well as their colleagues from the ZSW investigated the optical properties, and above all, the antireflection effect of the epidermal cells of different plant species.

 These properties are particularly pronounced in rose petals where they provide stronger color contrasts and thus increase the chance of pollination. As the scientists found out under the electron microscope, the epidermis of rose petals consists of a disorganized arrangement of densely packed microstructures, with additional ribs formed by randomly positioned nanostructures.

In order to exactly replicate the structure of these epidermal cells over a larger area, the scientists transferred it to a mold made of polydimethylsiloxane, a silicon-based polymer, pressed the resulting negative structure into optical glue which was finally left to cure under UV light. “This easy and cost-effective method creates microstructures of a depth and density that are hardly achievable with artificial techniques,” says Dr. Guillaume Gomard, Group Leader “Nanopothonics” at KIT’s LTI.

The scientists then integrated the transparent replica of the rose petal epidermis into an organic solar cell. This resulted in power conversion efficiency gains of twelve percent for vertically incident light. At very shallow incidence angles, the efficiency gain was even higher. The scientists attribute this gain primarily to the excellent omnidirectional antireflection properties of the replicated epidermis that is able to reduce surface reflection to a value below five percent, even for a light incidence angle of nearly 80 degrees.

 In addition, as examinations using a confocal laser microscope showed, every single replicated epidermal cell works as a microlense. The microlense effect extends the optical path within the solar cell, enhances the light-matter-interaction, and increases the probability that the photons will be absorbed.

“Our method is applicable to both other plant species and other PV technologies,” Guillaume Gomard explains. “Since the surfaces of plants have multifunctional properties, it might be possible in the future to apply multiple of these properties in a single step.” The results of this research lead to another basic question: What is the role of disorganization in complex photonic structures? Further studies are now examining this issue with the perspective that the next generation of solar cells might benefit from their results.

 Explore further: Light propagation in solar cells made visible

More information: Ruben Hünig et al. Flower Power: Exploiting Plants’ Epidermal Structures for Enhanced Light Harvesting in Thin-Film Solar Cells, Advanced Optical Materials (2016). DOI: 10.1002/adom.201600046 

Ultra-thin solar cells can easily bend around a pencil


Scientists in South Korea have made ultra-thin photovoltaics flexible enough to wrap around the average pencil. The bendy solar cells could power wearable electronics like fitness trackers and smart glasses. The researchers report the results in the journal Applied Physics Letters (“Ultra-thin Flexible GaAs Photovoltaics in Vertical Forms Printed on Metal Surfaces without Interlayer Adhesives”).

 

Bend solar Cells id43736Ultra-thin solar cells are flexible enough to bend around small objects, such as the 1mm-thick edge of a glass slide, as shown here. (Image: Juho Kim, et al/ APL)

 

Thin materials flex more easily than thick ones – think a piece of paper versus a cardboard shipping box. The reason for the difference: The stress in a material while it’s being bent increases farther out from the central plane. Because thick sheets have more material farther out they are harder to bend.

“Our photovoltaic is about 1 micrometer thick,” said Jongho Lee, an engineer at the Gwangju Institute of Science and Technology in South Korea. One micrometer is much thinner than an average human hair. Standard photovoltaics are usually hundreds of times thicker, and even most other thin photovoltaics are 2 to 4 times thicker.
The researchers made the ultra-thin solar cells from the semiconductor gallium arsenide. They stamped the cells directly onto a flexible substrate without using an adhesive that would add to the material’s thickness. The cells were then “cold welded” to the electrode on the substrate by applying pressure at 170 degrees Celcius and melting a top layer of material called photoresist that acted as a temporary adhesive. The photoresist was later peeled away, leaving the direct metal to metal bond.
The metal bottom layer also served as a reflector to direct stray photons back to the solar cells. The researchers tested the efficiency of the device at converting sunlight to electricity and found that it was comparable to similar thicker photovoltaics. They performed bending tests and found the cells could wrap around a radius as small as 1.4 millimeters.
The team also performed numerical analysis of the cells, finding that they experience one-fourth the amount of strain of similar cells that are 3.5 micrometers thick.
“The thinner cells are less fragile under bending, but perform similarly or even slightly better,” Lee said.
A few other groups have reported solar cells with thicknesses of around 1 micrometer, but have produced the cells in different ways, for example by removing the whole substract by etching.
By transfer printing instead of etching, the new method developed by Lee and his colleagues may be used to make very flexible photovoltaics with a smaller amount of materials.
The thin cells can be integrated onto glasses frames or fabric and might power the next wave of wearable electronics, Lee said.
Source: American Institute of Physics

 

U of Toronto breakthrough promises more efficient solar cells


QDOTS imagesCAKXSY1K 8TORONTO, ON – A new technique developed by University of Toronto Engineering Professor Ted Sargent and his research group could lead to significantly more efficient solar cells, according to a recent paper published in the journal Nano Letters.

The paper, “Jointly-tuned plasmonic-excitonic photovoltaics using nanoshells,” describes a new technique to improve efficiency in colloidal quantum dot photovoltaics, a technology which already promises inexpensive, more efficient solar cell technology. Quantum dot photovoltaics offers the potential for low-cost, large-area solar power – however these devices are not yet highly efficient in the infrared portion of the sun’s spectrum, which is responsible for half of the sun’s power that reaches the Earth.

The solution? Spectrally tuned, solution-processed plasmonic nanoparticles. These particles, the researchers say, provide unprecedented control over light’s propagation and absorption.

The new technique developed by Sargent’s group shows a possible 35 per cent increase in the technology’s efficiency in the near-infrared spectral region, says co-author Dr. Susanna Thon. Overall, this could translate to an 11 per cent solar power conversion efficiency increase, she says, making quantum dot photovoltaics even more attractive as an alternative to current solar cell technologies.

“There are two advantages to colloidal quantum dots,” Thon says. “First, they’re much cheaper, so they reduce the cost of electricity generation measured in cost per watt of power. But the main advantage is that by simply changing the size of the quantum dot, you can change its light-absorption spectrum. Changing the size is very easy, and this size-tunability is a property shared by plasmonic materials: by changing the size of the plasmonic particles, we were able to overlap the absorption and scattering spectra of these two key classes of nanomaterials.”

Sargent’s group achieved the increased efficiency by embedding gold nanoshells directly into the quantum dot absorber film. Though gold is not usually thought of as an economical material, other, lower-cost metals can be used to implement the same concept proved by Thon and her co-workers.

She says the current research provides a proof of principle. “People have tried to do similar work but the problem has always been that the metal they use also absorbs some light and doesn’t contribute to the photocurrent – so it’s just lost light.”

More work needs to be done, she adds. “We want to achieve more optimization, and we’re also interested in looking at cheaper metals to build a better cell. We’d also like to better target where photons are absorbed in the cell – this is important photovoltaics because you want to absorb as many photons as you can as close to the charge collecting electrode as you possibly can.”

The research is also important because it shows the potential of tuning nanomaterial properties to achieve a certain goal, says Paul Weiss, Director of the California NanoSystems Institute.

“This work is a great example of fulfilling the promise of nanoscience and nanotechnology,” Weiss says. “By developing the means to tune the properties of nanomaterials, Sargent and his co-workers have been able to make significant improvements in an important device function, namely capturing a broader range of the solar spectrum more effectively.”

Nano-rod solar cell generates hydrogen


QDOTS imagesCAKXSY1K 8A new type of solar collector that uses gold nano-rods could convert sunlight into energy without many of the problems associated with traditional photovoltaic solar cells.

24 February 2013 Will Parker

 

The developers of the new technique, from the University of California – Santa Barbara, say it is “the first radically new and potentially workable alternative to semiconductor-based photovoltaic devices to be developed in the past 70 years.” They provide details of the new solar hydrogen generator in the journal Nature Nanotechnology.

In conventional photovoltaic cells, sunlight hits the surface of semiconductor material, one side of which is electron-rich, while the other side is not. The photon excites the electrons, causing them to leave their positions, and create positively-charged “holes.” The result is a current of charged particles – electricity.

In the new technique, it is not semiconductor materials that provide the electrons and venue for the conversion of solar energy, but a “forest” of gold nano-rods operating in water. Specifically, gold nano-rods capped with a layer of crystalline titanium dioxide and platinum, and a cobalt-based oxidation catalyst deposited on the lower portion of the array.

“When nanostructures, such as nano-rods, of certain metals are exposed to visible light, the conduction electrons of the metal can be caused to oscillate collectively, absorbing a great deal of the light,” explained Martin Moskovits (pictured front center), a professor of chemistry at UCSB. “This excitation is called a surface plasmon.”

As the “hot” electrons in these plasmonic waves are excited by light particles, some travel up the nano-rod, through a filter layer of crystalline titanium dioxide, and are captured by platinum particles. This causes the reaction that splits hydrogen ions from the bond that forms water. Meanwhile, the holes left behind by the excited electrons head toward the cobalt-based catalyst on the lower part of the rod to form oxygen.

The researchers say that hydrogen production was clearly observable after about two hours. Importantly, the nano-rods were not subject to the photo-corrosion that often causes traditional semiconductor materials to fail and Moskovits says the device operated with no hint of failure for “many weeks.”

Though still in its infancy, the research promises a more robust method of converting sunlight into energy. “Despite the recentness of the discovery, we have already attained ‘respectable’ efficiencies. More importantly, we can imagine achievable strategies for improving the efficiencies radically,” Moskovits said.

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Related: Discuss this article in our forum Stanford announces peel-and-stick solar panels Solar steam generator outshines photovoltaic solar cells Solar power’s dirty secret: skyrocketing lead pollution Much simpler catalyst could fast-track hydrogen economy

See Summary of article here: http://www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2013.18.html

Source: University of California – Santa Barbara

University of British Columbia Files Patent on Unique Battery Type Solar/Light Conversion Cell


SOURCE: University of British Columbia

University of British Columbia

November 02, 2012 11:30 ET

VANCOUVER, BC–(Marketwire – Nov 2, 2012) – The University of British Columbia (UBC)announces the international patent filing for a Battery type Solar/Light conversion cell. This unique generator and storage approach allows both solar power generation and storage within a single cell. Based on photosynthesis, it can be implemented using abundant and readily replenished and renewable biomaterials.

This invention aims to allow industry to install solar photovoltaic (PV) systems with a built in energy storage component. This type of system addresses the natural intermittency of Solar (PV) systems due to the movement of clouds over modules and the need for night time power, and it provides a built-in solution for reducing the total demand on the electrical grid. This unit is anticipated to provide a simple effective method for energy arbitrage by storing direct and indirect Solar/Light energy for later use should the peak energy demands fall several hours after the peak solar generation is available, such as at night. The commercialization of this technical achievement would allow for a much larger penetration of solar PV into the total energy supply and management system and therefore the invention has the potential to increase the value and market for both grid-connected and off-grid solar PV systems worldwide.

The invention is the result of an interdisciplinary venture led by Professor J. Thomas Beatty, who studies photosynthesis in micro-organisms, and Professor John D. Madden in Electrical & Computer Engineering. “We began by asking whether we can learn from nature and make use of natural materials to create useful solar energy harvesting approaches. What we found is an approach that integrates two key components of energy supply: generation and storage”.

The new approach involves the use of a light absorbing battery-like cell complete with two electrodes and an electrolyte. Light is absorbed by light harvesting molecules in the electrolyte. Charges are then transferred between the excited light harvesting molecules and mediator molecules, also in the electrolyte, with nearly perfect quantum efficiency. The mediators store the harvested energy, which can then be extracted at the electrodes on demand. Essential to the effectiveness of this technology is the development of highly selective electrodes, each of which primarily reacts with only one type of mediator.

“Unlike photovoltaic technologies, which rely on very thin absorbing layers, and transparent electrodes, this new technology operates with light arriving parallel to the surface of the electrodes, allowing for thicker devices with volume for energy storage,” says Madden. “With the new architecture one can envision the creation of solar ponds for harvesting and storage. This is a very general new approach.”

The UBC team is supported by Natural Sciences and Engineering Research Council of Canada. Researchers from the University of South Florida and the Australian Centre of Excellence in Electro materials Science are also involved.

The University of British Columbia, located in Vancouver, BC, is a global centre for research and teaching, consistently ranked among the top 40 universities of the world. UBC attracts $550 million per year in research funding from government, non-profit organizations and industry through more than 8,000 projects. It ranks in the top ten universities in North America for commercializing research and has spun off 149 companies. It is a place where innovative scientific ideas are transferred effectively to industry through a globally connected research community.

Solar Panel Makers Need Equipment Upgrades to Survive Shakeout


With overcapacity of 82%, companies need innovative tools to differentiate from cheaper Chinese rivals, says Lux Research.

English: Thin-film PV array

English: Thin-film PV array (Photo credit: Wikipedia)

BOSTON, Oct 25, 2012 (BUSINESS WIRE) — Reeling from a glut of production capacity, makers of solar panels need to acquire innovative production equipment in order to cut costs, increase margins, and offer differentiated products, according to Lux Research.

This year, global capacity utilization is at 55% for crystalline silicon (x-Si) module production, 70% for cadmium telluride (CdTe) and 80% for copper indium gallium (di) selenide (CIGS). Consequently, cell and module manufacturers are turning to core product differentiation to revamp margins and fend off low-cost Chinese competition.

“Across the industry there is recognition that innovation is needed to survive a shakeout,” said Fatima Toor, Lux Research Analyst and the lead author of the report titled, “Turning Lemons into Lemonade: Opportunities in the Turbulent Photovoltaic Equipment Market.” “Equipment suppliers have a vital role to play in enabling that innovation.”

Lux Research analysts examined the PV production equipment landscape to identify opportunities for innovation. Among their findings:

— There’s opportunity in reducing silicon costs. Current wafer sawing techniques waste silicon; in contrast, technologies, such as direct solidification and epitaxial silicon eliminate the need for wafer sawing. Emerging quasi-monocrystalline silicon (qc-Si) ingot growth enables 40% cheaper c-Si wafers.

— In CIGS, standardization is key. CIGS thin-film PV relies on custom equipment today. However, off-the-shelf tools and improved throughput will drive higher efficiencies, performance and yield – lowering capex and helping manufacturers attain scale and competitive production costs.

— New cell designs lead to equipment upgrades. Emerging cell designs, such as selective emitter (SE) and heterojunction with intrinsic thin layer (HIT) present potential for high efficiencies. However, they require new tools, and as a result, 60% to 70% of new equipment sales are for the cell production equipment.

The report, titled “Turning Lemons into Lemonade: Opportunities in the Turbulent Photovoltaic Equipment Market,” is part of the Lux Research Solar Components Intelligence service.

About Lux Research

Lux Research provides strategic advice and on-going intelligence for emerging technologies. Leaders in business, finance and government rely on us to help them make informed strategic decisions. Through our unique research approach focused on primary research and our extensive global network, we deliver insight, connections and competitive advantage to our clients. Visit http://www.luxresearchinc.com for more information.

SOURCE: Lux Research

Note To Readers: We have been following a ‘disruptive nanotechnology’ company, researching and developing a ‘3rd Generation’ of solar cells based in part on low-cost quantum dots and reduced input cost printing techniques. Below is a short excerpt from a website, a link also provided below. Perhaps, with innovation such as this, the U.S. Solar industry can become the clear leader in providing grid competitive renewable energy. Perhaps ….        Cheers!  – BWH-

Solterra Renewable Technologies  

http://www.solterrasolarcells.com/corporate_vision.php?ID=11

“Solterra will be producing and distributing a Thin Film Quantum Dot PV Solar Cell which is differentiated from other PV cells by a unique technology that results in lower cost, higher efficiency, and broader spectral performance.  Solterra’s Quantum Dot Solar Cell achieves a dramatically lower manufacturing cost per watt because no vacuum equipment is required, no expensive silicon is required and low-cost screen printing and/or inkjet techniques are used on inexpensive substrates. Secondly, the Solterra Thin Film Quantum Dot Solar Cell has the potential to generate multiple excitons from each proton providing the potential for exponential improvements in conversion efficiency. Third, Solterra’s PV cell is not only more efficient in the early morning and late afternoon compared to crystalline silicon PV cells, but it also has the potential to harvest light energy in the infrared and ultraviolet spectra.