Hydrogen From Sunlight Through Photoelectrochemical Cell Developed With Record 14% Efficiency

Solar energy is abundantly available globally, but unfortunately not constantly and not everywhere. One especially interesting solution for storing this energy is artificial photosynthesis. This is what every leaf can do, namely converting sunlight to chemical energy. That can take place with artificial systems based on semiconductors as well. These use the electrical power that sunlight creates in individual semiconductor components to split water into oxygen and hydrogen. Hydrogen possesses very high energy density, can be employed in many ways and could replace fossil fuels. In addition, no carbon dioxide harmful to the climate is released from hydrogen during combustion, instead only water. Until now, manufacturing of solar hydrogen at the industrial level has failed due to the costs, however. This is because the efficiency of artificial photosynthesis, i.e. the energy content of the hydrogen compared to that of sunlight, has simply been too low to produce hydrogen from the sun economically.

Photovoltaics (PV) is a method of generating electricity by converting solar radiation (sunlight) into direct current electricity by using semiconductors that exhibit the photovoltaic effect. These semiconductors are also called solar panels and are composed of a group of solar cells containing a photovoltaic material. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent years.

Combining the two processes a photoelectrochemical cell can be produced that will harness sunlight to generate chemical fuel, specifically by splitting water to generate hydrogen.

Scientists Develop Solar Cell Polymer With Double Charge Production

Scientists from the U.S. Department of Energy's Brookhaven National Laboratory and Columbia University have developed a solar cell polymer that doubles its electrical charge carrier per unit of light from one carrier to two.

The process of producing two producing two charges from one unit of light is called singlet fission. This discovery can alter the manufacturing process of solar energy producing materials. Having two charges on the same molecule mans that energy-producing materials don't have to be arrayed as perfect crystals. The self-contained materials work efficiently when dissolved in liquids which opens up new ways to develop solar cells including "printing" solar-energy-producing material like ink.

A polymer is a combination of chemical compounds that is made up of repeating structural units (as in a molecular structure). The structure of the polymer dictates it properties.

Polymers are usually associated with plastics. The material used for credit cards is a polymer, as well as PVC plastics and PET water bottles. But polymers can be in any form. Hairspray and mousse is a polymer. Fabrics like spandex are also polymers. While these are synthetic, there are also natural polymers like rubber and amber.

The image above shows Postdoctoral fellow Erik Busby and Matt Sfeir with optical equipment they used to study charge carrier production in organic photovoltaic polymers at Brookhaven Lab's Center for Functional Nanomaterials.

MIT Solar Thermophotovoltaic System Increase Solar Cell Efficiency Up To 80%

Researchers at MIT have developed a solar cell that is much more efficient than current solar photovoltaic cells. Using nanotechnology and material technology, the new cell captures a broader spectrum of light compared to a regular solar cell and transforms these into energy. This development can increase solar power output past current efficiency limits.

By adding an absorber-emitter device between photovoltaic cell and sunlight, the other undetected wavelengths of light is also converted into electricity through heat. Carbon nanotubes and photonic crystals are used as material for the absorber-emitter device.

Photovoltaic cells are solid state electrical devices that convert the energy of light directly into electricity by the photovoltaic effect (using light to convert to energy).

The present maximum theoretical efficiency of a solar cell is 33.70%. This is known as the Shockley-Queisser limit. With the new developed solar cell, the researchers believe once the technology is fully develop, it can break the limit and hit an efficiency rating of well over 80%.

Nanowire Based Solar Cell Increases Shockley-Queisser Efficiency Limit

The figure shows that the sun's rays are drawn into a nanowire, which stands on a substrate. At a given wavelength the sunlight is concentrated up to 15 times. Consequently, there is great potential in using nanowires in the development of future solar cells.
Credit: Niels Bohr Institute

The development of a nanowire based solar cell that increases sunlight concentration to a a factor of 15 raises the standard efficiency limit of solar cells known as the Shockley-Queisser limit.

One of the most popular and common source of renewable and sustainable energy is the Sun. Solar energy is not dependent on weather conditions such as wind power or need to be near a power source such as geothermal or hydroelectric energy producers.

Solar energy is produced by solar panels or solar cells. These cells, also known as photovoltaic cells, convert sunlight to electrical energy.

The focus on solar cell technology is raising the efficiency of the solar cell to convert solar energy to electrical energy. In solar cell production, the value that is used to gauge the efficiency of the solar cell is the Shockley-Quesser limit. This limit refers to the maximum theoretical efficiency of a solar cell using a p-n junction to collect power from the cell.

A p-n junction refers to the boundary of two semiconductors; the p-type and the n-type. The p-type semiconductor contains excess holes while the n-type contains excess free electrons.

The Shockley-Queisser limit puts the maximum solar cell efficiency at around 33.7%. This means that at most, only 33.7% of sunlight can be converted into elecrical energy. Currently, silicon based photovoltaic cells have an efficiency of 22%.

Stanford Researchers Map Out Alternative Energy Plan For New York

In the shadow of the controversial decision whether or not to allow hydraulic fracturing in the State of New York, researchers at Stanford University has laid out a plan on the use of alternative energy.

Hydraulic fracturing is the creation and propagation of fractures in a rock layer. It is a process used to extract petroleum, natural gas and other substances from source rocks.

There have been harsh criticism and environmental concerns with the process of hydraulic fracturing. The State of New York will soon decide whether to approve this process in the state. Supporters of the decision feel that it will bring an economic boom from the resulting jobs and that it will help end dependence on imported oil.

Researchers believe that instead of focusing on hydraulic fracturing, it will be best environmentally and economically to focus on using alternative energy such as solar and wind power instead.

Nanotechnology Research Develops New Photovoltaic Process Using Gold Nanorods

Researchers in Photovoltaic technology have developed a new method in converting sunlight into electrical energy using gold nanorods.

Research into photovoltaic energy (converting solar rays into electrical energy) has benefited a lot from materials technology and nanotechnology. The main process of a photovoltaic cell or solar cell is using the photons from the sun's rays to basically move electrons around to generate electricity.

At this level, nanotechnology can help push the methods to even higher ground since the technology deals with properties and processes at the molecular and even atomic scale. One application that nanotechnology can contribute to photovoltaic research is the nanorod.

Nanorods are nanostructures that are elongated and shaped like a hotdog. These can range in size from 1 nanometer (nm) to 100nm. These structures interact with light, electricity, and magnetic fields that makes it a very good candidate for semiconductors and photovoltaic applications.

Graphene Shows Potential To Be Efficient Photovoltaic Material In Light Detection and Energy Harvest

Graphene research has shown that the material can be used in the development of efficient solar photovoltaic cells.

Much has been written and discussed about graphene. It has opened up a whole litany of advanced applications that it has been described as "The Wonder Material".

One particular property of graphene that many scientists have been focusing on is how electrons behave and interact with graphene. Graphene, being only one atom thick, allows electron to move much more freely along its surface. The electrons travel through the graphene sheet as if they carry no mass, as fast as just one hundredth that of the speed of light. This makes graphene a great conductor, better than even copper.

Also, since graphene is just one atom thick, diodes, transistors, and other electronic components can be developed on a single-layered device architecture. By using nano-scale electronic channels and tailoring the geometrical symmetry, devices can be operated on at very high speeds of up to 1.5 Terahertz (1,500 GHz). This allows for the development of high speed electronics for various applications and devices.

Researchers have discovered a new property of graphene that allows it to convert a single absorbed photon into multiple electrons. This could open up research into the development of efficient solar cells.

Solar Panel Decals Which Can Be Peeled And Applied To Any Surface

Scientists have developed a solar panel that can be applied to anything from cellphones to business cards. These panels resemble decals that can be peeled and applied on to surfaces like helmets, cellphones, roofs, windows, etc.

Solar panels or solar cells convert light energy, particularly light from the Sun, into electrical energy. Solar energy has been the biggest growing trend in renewable energy. In 2011, investments in alternative and renewable energy reached a high of US$ 257 Billion.

Since sunlight is unlimited and constant, it is a viable source for endless amounts of energy. Solar panels gather energy by taking advantage of how electrons behave when energy is added to it.

At the moment, solar cells are the most affordable and available of the technologies around. Solar panels that generate electricity and provide heating are available commercially. Every year, the solar panel technology increases its efficiency and lowers cost making it more and more viable for use in everyday homes.

Recent developments have ranged from solar paint, solar cells that can be painted on to surfaces, to solar cell fibers that can be woven into cloth.

Silicon Based Photovoltaic (Solar Cell) Fiber Leads To Electricity Generating Fabrics

Optical fiber, thinner than human hair, has been developed with photovoltaic properties which may give rise to fabric that can generate electricity. The fiber which is silicon based acts on the principle of solar cells that convert sunlight into electrical energy.

According to Neils Bohr, using the model of a hydrogen atom, an electron (-) orbits a stationary proton (+) in certain fixed orbits held by an electric force . When an electron jumps to a higher or lower orbit (called a quantum leap), it expends or absorbs energy (in the form of light).

Energy is needed for the electron to jump to a higher orbit where it has higher energy levels. When the electron moves to an orbit closer to the proton, energy is released.

Using this principle, a simplified explanation of how a silicon solar cell works would be that when a silicon solar cell absorbs light from the sun, the electron jumps from a higher orbit to a lower orbit which in turn gives off electrical energy.

A more detailed explanation is featured in the embedded video.

For years, the solar cell has been used to harness the suns energy to produce electrical energy. As technology evolves, solar cells have become much more efficient and cost effective in the alternative-energy industry. In 2011, solar power accounted for a total US$147 billion in investments and generated around 69.7 Gigawatts of energy globally.

Biohybrid Solar Cell Based On Spinach Delivers Optimum Electrical Power

This is a biohybrid solar cell that uses the photosynthetic protein from spinach made by Vanderbilt students based on a previous design.
Credit: Amrutur Anilkumar, Vanderbilt University

A biohybrid device is a device that utilizes biological components such as cells and tissues to carry out certain functions or capabilities. Biohybrid devices are usually found in the medical field especially in organ transplant technology. But now, a group of researchers have adopted this technology and used it to produce a biohybrid solar cell.

A solar cell is a solid state electrical device that converts light energy into electrical energy. Sunlight is converted into direct current electricity. This is done through the photovoltaic effect (using light to convert to energy) using semiconductors grouped into solar panels.

These solar panels made up of a group of solar cells containing a photovoltaic material which is usually silicon based. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide.

The combination of biohybrid technology and solar cell technology is also called organic photovoltaics.

Spinach power gets a big boost

An interdisciplinary team of researchers at Vanderbilt University have developed a way to combine the photosynthetic protein that converts light into electrochemical energy in spinach with silicon, the material used in solar cells, in a fashion that produces substantially more electrical current than has been reported by previous "biohybrid" solar cells.

The research was reported online on Sep. 4 in the journal Advanced Materials and Vanderbilt has applied for a patent on the combination.

"This combination produces current levels almost 1,000 times higher than we were able to achieve by depositing the protein on various types of metals. It also produces a modest increase in voltage," said David Cliffel, associate professor of chemistry, who collaborated on the project with Kane Jennings, professor of chemical and biomolecular engineering. "If we can continue on our current trajectory of increasing voltage and current levels, we could reach the range of mature solar conversion technologies in three years."

The researchers' next step is to build a functioning PS1-silicon solar cell using this new design. Jennings has an Environmental Protection Agency award that will allow a group of undergraduate engineering students to build the prototype. The students won the award at the National Sustainable Design Expo in April based on a solar panel that they had created using a two-year old design. With the new design, Jennings estimates that a two-foot panel could put out at least 100 milliamps at one volt – enough to power a number of different types of small electrical devices.

US$ 257 Billion Global Investment in Renewable Energy for 2011 With Solar Energy On Top

Renewable energy comes from sources that are naturally replenished. Resources such as sunlight, wind, rain, ocean tides, and geothermal heat (geysers) can be utilized to provide energy.

Fossil fuels such as oil, coal, and natural gas are finite and will eventually run out. Procurement of these materials are becoming too expensive and can damage the environment as seen in the BP Deepwater Horizon Oil Spill at the Gulf of Mexico or the Fukushima nuclear accident in Japan.

Modern renewable energy can be substituted for fossil fuels in four areas: power generation, heating and cooling, transport fuels, and rural/off-grid energy services. The last 5 years technology behind renewable energy grew rapidly with solar energy growing the fastest. Solar photovoltaic (PV) cells has been the focus of most industries as the most promising and fastest rising technology in this sector with operating capacity increasing at a rate of 58% annually.

The primary sources for renewable energy are:

• Solar: Solar photovoltaic cells can convert sunlight to electricity. Sunlight can also be used to heat water and buildings.
• Wind: Can be harnessed to operate wind turbines that generate energy.
• Biomass: These are biological matter that makes up plants. It can be used to produce fuel that can power vehicles or can generate electricity and others.
• Hydrogen: The most abundant element on Earth. It can be burned as a fuel or converted into electricity.
• Geothermal: Using the Earth's internal heat to produce energy, heating, and cooling.
• Ocean: Using tidal energy and oceanic thermal energy for energy production
• Hydropower: Using flowing water to turn mechanical machines to produce energy

Global investment in renewable energy powers to record $257 billion

Solar generation surged past wind power to become the renewable energy technology of choice for global investors in 2011.

Solar attracted nearly twice as much investment as wind, driving the renewable energy sector to yet another record-breaking year, albeit one beset with challenges for the industry, according to two new reports on renewable energy trends issued today by the United Nations Environment Programme (UNEP) and the Renewable Energy Policy Network for the 21st Century (REN21).

Global Trends in Renewable Energy Investment 2012 is the fifth edition of the UNEP report, based on data from Bloomberg New Energy Finance, and has become the standard reference for global clean energy investment figures.

This year it shows that despite an increasingly tough competitive landscape for manufacturers, total investment in renewable power and fuels last year increased by 17% to a record $257 billion, a six-fold increase on the 2004 figure and 94% higher than the total in 2007, the year before the world financial crisis.

New Low Cost And Effective Dye Sensitized Solar Cells Being Developed For Cheap Readily Available Solar Energy

A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect (using light to convert to energy)

Dye sensitized solar cells are low cost thin film solar cells based on a semiconductor formed between a photo-sensitized anode and an electrolyte (photoelectrochemical system). The Grätzel cell is an example of a dye sensitized solar cell.

Gratzel cells are named after Michael Grätzel who invented them. Instead of silicon, the Swiss scientist used titanium dioxide (TiO2), a cheap and widely available material.

Grätzel cells work when particles of TiO2, coated with a dye that absorbs sunlight, are placed between two electrodes in an electrolyte solution containing iodine ions. The cells generate electrical energy when the energy captured by the dye makes the electrons in the dye molecules jump from one orbital to another. The electrons then jump onto the TiO2 particles and diffuse towards one electrode, while the iodine ions carry electrons from the other electron to regenerate the dye.

Because of the low cost and general availability of materials in producing Grätzel cells, it is feasible that this technology can be implemented even in the poorest countries.

New inexpensive, environmentally friendly solar cell shines with potential

The limitations of conventional and current solar cells include high production cost, low operating efficiency and durability, and many cells rely on toxic and scarce materials. Northwestern University researchers have developed a new solar cell that, in principle, will minimize all of these solar energy technology limitations.

In particular, the device is the first to solve the problem of the Grätzel cell, a promising low-cost and environmentally friendly solar cell with a significant disadvantage: it leaks. The dye-sensitized cell's electrolyte is made of an organic liquid, which can leak and corrode the solar cell itself.

Grätzel cells use a molecular dye to absorb sunlight and convert it to electricity, much like chlorophyll in plants. But the cells typically don't last more than 18 months, making them commercially unviable. Researchers have been searching for an alternative for two decades.

MIT NEWS: Building Cubes and Towers In 3D To Extend Solar Panel Efficiency

MIT RESEARCH: A new dimension for solar energy

Innovative 3-D designs from an MIT team can more than double the solar power generated from a given area.

CAMBRIDGE, Mass. -- Intensive research around the world has focused on improving the performance of solar photovoltaic cells and bringing down their cost. But very little attention has been paid to the best ways of arranging those cells, which are typically placed flat on a rooftop or other surface, or sometimes attached to motorized structures that keep the cells pointed toward the sun as it crosses the sky.

Now, a team of MIT researchers has come up with a very different approach: building cubes or towers that extend the solar cells upward in three-dimensional configurations. Amazingly, the results from the structures they’ve tested show power output ranging from double to more than 20 times that of fixed flat panels with the same base area.

The biggest boosts in power were seen in the situations where improvements are most needed: in locations far from the equator, in winter months and on cloudier days. The new findings, based on both computer modeling and outdoor testing of real modules, have been published in the journal Energy and Environmental Science.

“I think this concept could become an important part of the future of photovoltaics,” says the paper’s senior author, Jeffrey Grossman, the Carl Richard Soderberg Career Development Associate Professor of Power Engineering at MIT.

The MIT team initially used a computer algorithm to explore an enormous variety of possible configurations, and developed analytic software that can test any given configuration under a whole range of latitudes, seasons and weather. Then, to confirm their model’s predictions, they built and tested three different arrangements of solar cells on the roof of an MIT laboratory building for several weeks.

While the cost of a given amount of energy generated by such 3-D modules exceeds that of ordinary flat panels, the expense is partially balanced by a much higher energy output for a given footprint, as well as much more uniform power output over the course of a day, over the seasons of the year, and in the face of blockage from clouds or shadows. These improvements make power output more predictable and uniform, which could make integration with the power grid easier than with conventional systems, the authors say.

Creating Hydrogen Fuel Using Solar Energy Through Artificial Photosynthesis

Aside from electricity produced by solar energy, scientists are studying a new way of using the sun in producing hydrogen fuel.

Photosynthesis is the process of converting light energy to organic compounds such as sugar that acts as a storage for chemical energy. This is the primary process for plants and some bacteria in manufacturing their own food. The process starts when energy from sunlight is absorbed by proteins called "photosynthetic reaction centers" that contain chlorophylls (the green pigment in plants). In plants, these proteins are held inside organelles called chloroplasts, while in bacteria they are embedded in the plasma membrane. Some of the light energy gathered by chlorophylls is stored in the form of adenosine triphosphate (ATP). The rest of the energy is used to remove electrons from a substance such as water.

Photovoltaics (PV) is a method of generating electricity by converting solar radiation (sunlight) into direct current electricity by using semiconductors that exhibit the photovoltaic effect. These semiconductors are also called solar panels and are composed of a group of solar cells containing a photovoltaic material. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent years.

Combining the two processes, Cal Tech have produced a photelectrochemical cell that harness sunlight to generate chemical fuel, specifically by splitting water to generate hydrogen.

CERN News: Solar Thermal Panels Made With CERN Technology

A solar thermal collector is a solar collector designed to collect heat by absorbing sunlight.

Solar Thermal Panels are usually refers to hot water panels but the term could also be associated with more omplex installations such as solar parabolic, solar trough and solar towers or simpler installations such as solar air heat. These complex collectors are generally used in solar power plants where solar heat is used to generate electricity by heating water to produce steam which drives a turbine connected to an electrical generator. The simpler collectors are typically used for supplemental space heating in residential and commercial buildings.

Photovoltaics (PV) is a method of generating electricity by converting solar radiation (sunlight) into direct current electricity by using semiconductors that exhibit the photovoltaic effect. These semiconductors are also called solar panels and are composed of a group of solar cells containing a photovoltaic material. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent years.

At Geneva International Airport, SRB Energy delivered the first of the solar panels that will form one of the largest solar energy systems of Switzerland. Ultimately, some 300 high-temperature solar thermal panels will cover a surface of 1200 square metres on the roof of the airport’s main terminal building. The panels, which will be used to keep the buildings warm during the winter and cool in the summer, are derived from vacuum technology developed at CERN for particle accelerators.

“We are delighted that Geneva International Airport has opted for this technology,” says Cristoforo Benvenuti, the inventor of the panels, who has been working on vacuum technology at CERN since the 1970s. “The panels emerged from vacuum technologies that were developed for fundamental physics purposes, and it is highly gratifying to see them put to use for renewable energy.”

"This new generation of solar panels is an innovative green technology that is the fruit of a partnership between CERN and industry", explains Enrico Chesta, head of the Technology Transfer Section of CERN's Knowledge Transfer Group. “Like medicine and information technology, energy is becoming a domain in which accelerator and detector technology is finding successful applications.”

Engineers Discover New Way To Produce Economic and Efficient Solar Panels

Photovoltaics (PV) is a method of generating electricity by converting solar radiation (sunlight) into direct current electricity by using semiconductors that exhibit the photovoltaic effect.

These semiconductors are called solar panels and are composed of a group of solar cells containing a photovoltaic material. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent years.

Photovoltaic is derived from the word "photo" meaning light and "voltaic" which refers to the production of electrical power. Solar based electricity is slowly entering the mainstream market evidenced by the number of solar panels sprouting up on the rooftops of many houses. With the advent of cheaper materials and more efficient technology, in ten years or less, solar energy can be up to par with traditional coal generated electricity.

As proof, scientists have recently discovered a way to economize the production of these solar panels and increase the power output.

New Developments in Solar Cells Increases Efficiency

A photovoltaic cell or a solar cell is a device that converts light energy (typically sunlight) into electricity.

Solar cells are commonly grouped together as modules to form a solar panel to convert enough electrical energy to practically run a device or group of devices. These solar panels convert light to electricity thru the process known as the photovoltaic effect.

By tweaking the smallest of parts, a trio of University at Buffalo engineers is hoping to dramatically increase the amount of sunlight that solar cells convert into electricity.

With military colleagues, the UB researchers have shown that embedding charged quantum dots into photovoltaic cells can improve electrical output by enabling the cells to harvest infrared light, and by increasing the lifetime of photoelectrons. Quantum dots are tiny particles, or “nanoparticles”, made of a semiconductor material. These quantum dots display unique optical and electrical properties. The most immediately apparent of these is the emission of photons under excitation, which are visible to the human eye as light

The research appeared online last May in the journal Nano Letters. The research team included Vladimir Mitin, Andrei Sergeev and Nizami Vagidov, faculty members in UB's electrical engineering department; Kitt Reinhardt of the Air Force Office of Scientific Research; and John Little and advanced nanofabrication expert Kimberly Sablon of the U.S. Army Research Laboratory.

Mitin, Sergeev and Vagidov have founded a company, OPtoElectronic Nanodevices LLC. (OPEN LLC.), to bring the innovation to the market.

MIT Research: Here Comes The Sun

A new sunflower-inspired pattern increases concentrated solar efficiency.

CAMBRIDGE, Mass. -- Just outside Seville, in the desert region of Andalucia, Spain, sits an oasis-like sight: a 100-meter-high pillar surrounded by rows of giant mirrors rippling outward. More than 600 of these mirrors, each the size of half a tennis court, track the sun throughout the day, concentrating its rays on the central tower, where the sun’s heat is converted to electricity — enough to power 6,000 homes.

The sprawling site, named PS10, is among a handful of concentrated solar power (CSP) plants in the world, although that number is expected to grow. CSP proponents say the technology could potentially generate enough clean, renewable energy to power the entire United States, provided two factors are in ample supply: land and sunlight.

Now researchers at MIT, in collaboration with RWTH Aachen University in Germany, have come up with a design that reduces the amount of land required to build a CSP plant, while increasing the amount of sunlight its mirrors collect. The researchers found that by rearranging the mirrors, or heliostats, in a pattern similar to the spirals on the face of a sunflower, they could reduce the pattern’s “footprint” by 20 percent and increase its potential energy generation. The sunflower-inspired pattern allows for a more compact layout, and minimizes heliostat shading and blocking by neighboring mirrors. The researchers published their results in the journal Solar Energy, and have recently filed for patent protection.

Lightweight Solar Power Generator Enters Full Production For Military Use

The U.S. Department of Navy, through funding from the Office of Naval Research (ONR) has entered into full production its solar generator, the Ground Renewable Expeditionary ENergy System (GREENS).

GREENS is a portable, 300-watt, hybrid battery generator that uses the light from the sun to produce electricity. It was developed to provide Marines with continuous power in the battlefield. In fact, several GREENS are already being used in the field.

Cliff Anderson is the logistics program officer in ONR's Expeditionary Maneuver Warfare & Combating Terrorism Department. He says that GREENS significantly reduces the amount of fuel that has to be delivered to the field. With less fuel to deliver, it minimizes the number of warfighters on the roads, convoys and hazards. It also lowers the cost of logistics associated with distributing fuel.

"That was really the objective: to get warfighters out of harm's way and reduce the cost of transporting fuel."

The GREENS project was conceived in 2008 when a Universal Needs Statement was submitted from Iraq for an expeditionary renewable power system. Approval for this project was expedited and technical execution took less than six months with the first unit tested in July 2009.

The system transitioned from the ONR to the Marine Corps Systems Command (MCSC). From there, GREENS went into production. The solar powered generator provided Marines with power to use various military devices. Several small Marine Corps outposts have even used GREENS as their sole energy source.

Video: Ground Renewable Expeditionary ENergy System

The overall goal for GREENS is that it will reduce the logistics burden for providing power to remote locations. It provides the military the AC and DC power it needs to charge typical communication, targeting, and computing devices. GREENS also reduces fossil fuel use otherwise needed for typical generators, and will lessen the need for fuel resupply, reducing the associated threats to vehicle convoys in Afghanistan and Iraq.

Justin Govar, chemical engineer and program manager, Expeditionary Power Sources Office, says, "GREENS is important because within the Marine Corps we are fighting in areas that are remote, that require very difficult logistical trains to get to."

"Infantry battalions that are far forward do not have immediate access to a wide range of logistics and maintenance equipment; therefore, any source of power that requires no [military-grade fuel], low maintenance and no special skills to operate becomes an instant success," said Maj Sean Sadlier, a logistics analyst with the Marine Corps Expeditionary Energy Office, who trained users on and tested GREENS in the field with India Company, 3rd Battalion, 5th Marine Regiment. Additionally, "GREENS is modular, portable, rugged and intuitive enough to deploy in a combat environment. Units trained on GREENS as part of pre-deployment training have provided positive feedback."

The Ground Renewable Expeditionary ENergy System supports the Marine Corps' objective of generating all power needed for sustainment and command, control, communications, computers and intelligence equipment in place in the field by 2025. This vision, as laid out in the USMC Expeditionary Energy Strategy, aligns with the Marine Corps Vision and Strategy 2025. The goal is to enable Marines to travel more lightly and quickly by reducing the amount of fuel needed.

GREENS was set up and tested at NSWC Carderock in West Bethesda, Md. It was subjected to a 300-Watt continuous power testing at NAVAIR China Lake during the 2010 Empire Challenge. Ambient temperatures recorded during the China Lake exercise exceeded 116 degrees Fahrenheit and even under these extreme temperature conditions, the system provided an average of 85% of the rated energy. This result exceeded expectations and led to an MCSC request that the product be rapidly developed and readied for acquisition.

Even with the positive feedback, The Naval Surface Warfare Center are still looking into getting the average rated energy up from 85% up to 100%

The solar powered generator is composed of 1600-watt solar arrays and rechargeable batteries combined to provide 300 watts of continuous electricity for Marines in remote locations. Additionally, there is a toolkit feature that allows Marines to enter their expected mission profile and determine which components from GREENS that they will need to take with them. GREENS can be rapidly deployed and is High Mobility Multipurpose Wheeled Vehicle (HMMWV) transportable.

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Naval Surface Warfare Center Carderock Division
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Solar Paint That Can Generate Electricity

Researchers at the University of Notre Dame has created an inexpensive “solar paint” that uses semiconducting nanoparticles to produce energy.

“We want to do something transformative, to move beyond current silicon-based solar technology,” says Prashant Kamat, John A. Zahm Professor of Science in Chemistry and Biochemistry and an investigator in Notre Dame’s Center for Nano Science and Technology (NDnano), who leads the research.

“By incorporating power-producing nanoparticles, called quantum dots, into a spreadable compound, we’ve made a one-coat solar paint that can be applied to any conductive surface without special equipment.”

They focused on nano-sized particles of titanium dioxide which were coated with either cadmium sulfide or cadmium selenide. The particles were then suspended in a water-alcohol mixture to create a paste. When this paste was brushed onto a conducting material and exposed to light, it created electricity.

The solar cell is easy to assemble because the middle layer can be painted onto a clear electrode. T-butanol, water, cadmium sulfide and titanium dioxide is mixed for thirty minutes. A clear electrode is masked off with office tape. Once the tape is in place, the mixture is spread onto the electrode and annealed with a heat gun. Afterwards, an electrolyte solution is sandwiched between the new electrode and a graphene composite electrode. Once this is done, the solar cell is ready for testing under a beam of artificial light.

Video: Painting Solar Cells with Nanoparticle Paste

Their research is described in the journal ACS Nano.

The best light-to-energy conversion efficiency we’ve reached so far is 1 percent, which is well behind the usual 10 to 15 percent efficiency of commercial silicon solar cells,” explains Kamat.

“But this paint can be made cheaply and in large quantities. If we can improve the efficiency somewhat, we may be able to make a real difference in meeting energy needs in the future.”

“That’s why we’ve christened the new paint, Sun-Believable,” he adds.

“Kamat and his team also plan to study ways to improve the stability of the new material.

NDnano is one of the leading nanotechnology centers in the world. Its mission is to study and manipulate the properties of materials and devices, as well as their interfaces with living systems, at the nano-scale.

This research was funded by the Department of Energy’s Office of Basic Energy Sciences.

RELATED LINKS

University of Notre Dame
Center for Nano Science and Technology
Notre Dame researchers develop paint-on solar cells
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Nanotechnology Electric Car Made From One Molecule
NASA Develops Material That Is Blacker Than Black
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