Tiny Solar Cell Could Make a Big Difference

How small can a solar cell be and still be a powerhouse? How about six hundred microns wide — about the diameter of a dot made by a ballpoint pen? The U.S. Department of Energy’s National Renewable Energy Laboratory recently validated greater than 41 percent efficiency at a concentration of 1,000 suns for tiny cells made by Semprius — one of the highest efficiencies recorded at this concentration. The energy conversion efficiency of a solar cell is the percentage of sunlight converted by the cell into electricity.

Seed money from DOE, together with the experts at the NREL-based SunShot Incubator Program, lifted Semprius from a small electronics start-up with a novel idea to a real difference-maker in the solar cell world.

Semprius’ triple-junction cells are made of gallium arsenide. Low-cost lenses concentrate the sun light onto the tiny cells 1,100 times. Their tiny size means they occupy only one-one thousandth of the entire solar module area, reducing the module cost. In addition, the use of a large number of small cells helps to distribute unwanted heat over the cell’s structure, so there’s no need for expensive thermal management hardware such as heat fins.

Semprius engineers use the company’s patented micro-transfer printing process to allow the micro-cells to be transferred from the growth substrate to a wafer. In a massive parallel process, thousands of cells are transferred simultaneously. This allows the original substrate to be used again and again, dramatically cutting costs. It also provides a way to handle very small cells.

This low-cost approach, which Semprius executives say can cut manufacturing expense by 50 percent, caught the eye of energy giant Siemens, which this year took a 16 percent stake in Semprius, as part of a $20 million investment from venture capitalists.

Sunshot Incubator Program Spurs Private Investment

Since 2007, DOE has invested $50 million for 35 solar start-ups to participate in the PV Incubator program — now the SunShot Incubator — at NREL. Private investment in those firms now totals more than $1.3 billion, a 25-to-1 multiple.

DOE and NREL selected Semprius to be one of their PV Incubator companies in 2010. Incubator companies get $1 million to $3 million to develop their concepts into actual working prototypes or pilot projects. And they also get the expertise of NREL scientists to help overcome obstacles and test for reliability and validity.

Transfer Printing Technology Evolves to Innovative Solar-Cell Use

Semprius’ back story, though, begins at the University of Illinois where Professor John Rogers and his team developed the transfer-printing process initially intended for flexible electronics.

Soon, Rogers realized that applying the technology to a concentrated photovoltaic (CPV) design could be much more lucrative.

Semprius grows a temporary layer on the original gallium-arsenide substrate, and then grows the multi-junction solar cell structure on top of that layer. Then, after the wafer is processed, the transfer printing process is used to remove the cells from the gallium-arsenide substrate and transfer them to an interposer wafer.

“We’re using a completely different approach to what has been practiced,” said Kanchan Ghosal, CPV Applications Engineering Manager and the principal investigator for Semprius’ PV Incubator Award. “This approach uses micro-cells and transfer printing to significantly reduce the use of materials in highly concentrated PV modules. And it provides a highly parallel method to manufacture the module, based on established microelectronics processes and equipment.”

Demand for Concentrated PV Expected to Double Each Year

Semprius broke ground on a manufacturing plant in Henderson, N.C., this year. The state of North Carolina and local agencies kicked in $7.9 million for the 50,000-square foot plant, which is expected to employ 256 people at full build-out.

North Carolina Gov. Bev Perdue cited her state’s “investments in education and job training” as the reason the company chose to locate there. The plant is expected to start operating next year, with an initial capacity of 5 megawatts, eventually growing to 35 megawatts.

The available market for highly-concentrated photovoltaics is expected to double or more each year over the next nine years, reaching greater than 10 gigawatts of power by 2020, according to Semprius CEO Joe Carr.

Partnership with DOE and NREL Proves Fruitful

Semprius first looked at using its micro-transfer printing for solar cells in 2007, with the help of a “Next-Gen” grant from DOE’s Office of Energy Efficiency and Renewable Energy.

In 2010, Semprius earned one of four spots in what is now the SunShot Incubator, which is funded by DOE and run out of NREL.

Ghosal laughs when he remembers the frantic moments finishing the application for the PV Incubator.

“We barely met the criteria,” Ghosal said. “The rules said that you had to have a module ready to be eligible, but we only had small squares with a couple of cells, not a real module.”

So, the Semprius engineers “worked feverishly day and night to make our first module.”

“Two days before the deadline, we were able to get good results from that first module,” Ghosal said. “We applied for the Incubator grant with the results from this module and a scale-up plan.”

When Ghosal asked the company’s engineers about whether they could meet the hard deadlines and aggressive goals laid down by NREL, “I was met with a lot of apprehension,” he recalled. “NREL was asking for a lot of deliverables that had not been done before.”

But it all worked out, and Semprius became the latest Incubator company to achieve more than it thought it could via the strict dictates of the NREL contract.

“It looked like a tall order, but we met all our goals,” Ghosal said.

Kaitlyn VanSant, NREL’s technical monitor for Semprius, said the company is being too modest.

“They actually met the goals a lot faster than originally anticipated,” VanSant said. “The goals were definitely aggressive, but they accomplished them quicker than the timeline.”

The modules to be made in the North Carolina plant starting next year will be 24 inches by 18 inches, and about 2 and a half inches deep, have a concentration of more than 1,100 suns and an efficiency of more than 31 percent. These modules would be cost competitive with fossil fuel technology at high volume.

NREL’s role was critical, Ghosal said.

“A lot of the early benefits were from the testing NREL could do. NREL has an internationally recognized testing program,” Ghosal said. “It’s one thing to claim a particular output, but something different to say that it was validated at NREL. It gives that stamp of credibility.

“Also, we learned from NREL how vigorous we had to be in terms of the materials we are using,” Ghosal said. “We got an understanding of how it would perform in the field and got some important pointers of what to watch for.”

China and Russia Team Up to Launch the World’s Largest Lithium Ion Battery Plant

Lithium ion batteries currently power everything from laptops to electric cars, and Russia and China are gearing up to dominate the industry by launching the world’s largest Li-ion battery plant. Planned for Novobirsk, Russia, the facility will be a joint venture between Chinese firm Thunder Sky and RUSNANO (a Russian state-run corporation) and it will be able to produce up to 500,000 batteries (of all sizes) per year.

The collaborative facility, named Liotech, will have an area exceeding 40,000 square feet – making it the largest lithium-ion battery factory in the world. It will be able to produce big automotive and bus batteries as well as batteries for smaller gadgets and emergency power supplies.

The Russian and Chinese firms have reportedly signed multiple contacts to supply the batteries to countries around the world, and 500 people are set to get new jobs at the plant. RUSNANO Managing Director Sergey Polikarpov told CleanTechnica: “The new factory is an outstanding example of the local impact of transferring the foreign high technology. It has led to construction of modern production facilities. When plant capacity has been met, more than 500 individuals will be employed. In realizing a program to replace imports, we are creating an entire cluster of new high-tech production for materials and components related to the batteries and also an engineering center which is an excellent synergy”.

Liotech CEO Alexander Erokhin added, “Implementation of public electric transport equipped with our lithium-ion batteries will significantly improve the environment in large cities in Russia. Use of the batteries in combination with alternative sources of energy will promote the development of ‘green technology’ and increase the energy efficiency of the Russian economy. We are already seeing interest in our storage batteries from Russian Railways, the Moscow Metro, electric power networks and power generating companies, businesses in the military industrial complex, the public utilities sector, and telecommunications companies.”

Apple files patents for hydrogen fuel cell technology to power mobile devices

Batteries as you know them may become a thing of the past for your Apple products as the company hopes to use hydrogen cells to produce lighter batteries that could last for weeks.

The company is staying on the cutting edge as they have recently submitted applications for patents to create new energy sources for their products.

The filings that the company submitted seem to have rather bold promises of allowing electronics to run for days or weeks without having to be recharged.

Their patent applications detail their plans for hydrogen fuel cells

The new energy sources would be sued for many or all Apple products

‘Such fuel cells and associated fuels can potentially achieve high volumetric and gravimetric energy densities, which can potentially enable continued operation of portable electronic devices for days or even weeks without refuelling,’ the filings report.

Not only would their plan to use hydrogen fuel cells get rid of ‘the need for a bulky and heavy battery’ but it would also help the environment.

Lighter and longer: The proposed hydrogen fuel batteries would allow Apple products to weigh less and last for weeks without being recharged

By switching from standard batteries which use toxic chemicals to hydrogen, the by-products of the new technology would only be water and electrical energy.

‘Our country’s continuing reliance on fossil fuels has forced our government to maintain complicated political and military relationships with unstable governments in the Middle East, and has also exposed our coastlines and our citizens to the associated hazards of offshore drilling,’ the company wrote in it’s patent application.

‘These problems have led to an increasing awareness and desire on the part of consumers to promote and use renewable energy sources,’ it continued.

The idea of hydrogen fuel technology isn’t new, but this is the clearest indication of exactly what the company intends to do to improve users experiences with the iPod or iPhone.

Apple Insider reported that the first round of patent applications on the subject came in October when they filed papers that mentioned ‘lighter and more efficient hydrogen fuel cells’. 

While the iPhone 4S was released after the death of legendary Apple founder Steve Jobs in October, a technological breakthrough like an entirely different battery would be a massive upswing for the company.

The new iPhone 5 is still on the imminent horizon, as initial predictions put its release date at sometime in late December.

Stunning Origami Solarcell Lamps Are Made From Folded Photovoltaic Panels!

Korea-born, Eindhoven-based Joon & Jung‘s Origami Solarcell is a polygonal low-energy LED lamp that is completely powered by the sun’s energy. The pendant lights are made from a flexible photovoltaic material that is folded into a 3D lamp using origami techniques. The flat-pack multi-faceted lights are still in the prototype stage, but we hope to see these innovative, energy-efficient designs hit store shelves in the near future.

Researchers develop cheap and easy to mass-produce “solar-paint”

A team of researchers from the University of Notre Dame in Indiana is reporting the creation of a “solar paint” that could mark an important milestone on the road to widespread implementation of renewable energy technology. Although the new material is still a long way off the conversion efficiencies of commercial silicon solar cells, the researchers say it is cheap to make and can be produced in large quantities.

In an effort to find an alternative to silicon-based solar cells, the Notre Dame researchers turned to quantum dot materials. They started with nanoparticles of titanium dioxide (TiO2) and coated them with either cadmium sulfide or cadmium selenide – both compounds that can absorb photons. A photon of the right energy hitting the cadmium compounds causes an electron to escape, which is absorbed by the TiO2.

The resultant particles were then suspended in a water-alcohol mixture to create a paste. The cadmium sulfide mixture produced a yellow paste, while the cadmium selenide mix produced a dark brown. The most efficient was a mixture of the two that produced a light brown paste.

When the paste was brushed onto a transparent conducting material and exposed to light, it created electricity. To replenish the electrons lost by the cadmium and test the conversion efficiency of the paint-on electrode, cathodes made from other materials and additional compounds were used.

“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 Prashant Kamat, an investigator in Notre Dame’s Center for Nano Science and Technology (NDnano). “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.”

Kama and his team have christened the new paint “Sun-Believable” and plan to study ways to increase its conversion efficiency and improve its stability. The Notre Dame team’s paper is published in the journal ACS Nano.

Power from Trees

Currently a team of MIT researchers are using platinum electrodes and ficus plants to discover the truth of feeble electric currents from trees. They have come up with an answer. They state that the pH difference between the soil and the living tree is the cause of creating electric currents. Now scientists are debating over how to use this power source for human benefits.

The most practical thing is fire alarm for forest department, originating from the trees itself. Trees electric power can charge a battery. This battery in turn will be connected to a small sensor. This sensor will power a brief radio transmission. That radio signal will transport daily soil and air condition measurements to a network of much larger, solar powered Forest Service environmental monitoring stations. Those sensors will also give out a crisis signal in the event of a sudden rise in air temperature that might indicate the outbreak of a forest fire.

“I truly believe it has potential,” said Victoria Henderson, branch chief for equipment and chemicals at the Forest Service’s National Interagency Fire Center. “If this can enhance our existing technology to a degree that would gain us a lot more fire protection, then we’d look at a plan to purchase it for our nationwide infrastructure, which is huge.”

Scientists have also discovered that the greater the pH difference between the tree and soil the more the energy will be produced. It is estimated that five to 300 nanowatts of current can be tapped from every tree every time. The device is being designed and marketed by Voltree Power. It is a recently formed subsidiary of MagCap, an electronic components maker. Voltree is collaborating with Netherlands-based GreenPeak Technologies. They have set up similar low power wireless sensors for companies such as Honeywell and Kronos. But deploying such a mesh network of radio-linked sensors on a large scale will be first of its kind. These sensors will be much smaller than the Forests Service’s monitoring stations. This will help Forest Department in quickly pinpointing the location and time of the fire.

Solar-Powered Air Conditioning for Cars

 

Solar Powered Car (Corvair) — not a car using the solar-powered air conditioning system discussed below.

PolyU’s department of electrical engineering, in collaboration with Green Power Industrial, has developed an air conditioning system for cars that utilizes a photovoltaic solar panel to power the air conditioning system when the engine is off.

The solar panel is made of a flexible material so that it can conform to the shape of the car roof, and it charges a battery which, in turn, powers the standalone air conditioning system.

Traditional vehicles use the engine to turn the air conditioner compressor on via a clutch, and the alternator to power the fans. When the air conditioning system is turned on, the clutch (which is attached to the compressor’s rotor) is pressed by an electromagnet against a wheel that is always being turned by the engine (via a belt) and the clutch then turns,… and the clutch finally turns the engine.

One of the touted benefits of this solar-powered setup is reduced air pollution and reduced fuel consumption, because people tend to keep their engines on (in order to keep the A/C on) when waiting in parking lots for their child to get out of school, or maybe while a friend is grabbing a few things in a store, and so on.

Of course, when idling, your fuel economy is actually 0 mpg, since you are burning gas but not actually going anywhere, so all of it (except what is used for the air conditioning) is wasted and lowers your average fuel efficiency.

This system received two awards from the 39th International Exhibition of Inventions of Geneva this year and the developers of the system claim that they expect widespread deployment of it.

Wind Mapping of Costal Areas of Pakistan

Phase-I of project is completed successfully and based on this survey, potential areas for installing wind power farms have been indicated. These areas having coverage of 9700 sq. km in Sindh have a gross wind power potential of 43000 MW. Keeping in view the area utilization constrains etc.
 the exploitable electric power potential of this area in Sindh is about 11000 MW

Range of Photovoltaic technologies

Insulating thermal and acoustic glass

Onyx Solar has developed a wide range of photovoltaic glass specifically designed for installation in buildings. The photovoltaic properties allow this glasses to generate electricity even in those buildings where the orientation and inclination is not at its optimum (for example: north façade).

1. It is not a traditional photovoltaic module designed for ground installation. It has been designed specially as safety glass for buildings in order to comply with the Technical Code of the Building.
2. It is available in different thicknesses, sizes and grades of transparency.
3. It works in all weather conditions, including low light and cloudy conditions.
4. It produces low cost electricity (kWh), allowing lower capital investment and increased output per rated watt.
5. It is environmentally friendly and has a shorter energy payback period (the amount of time it takes to generate enough energy to equal the energy used to produce it) than traditional photovoltaic modules.
6. It is frameless and has a uniform colour that is aesthetically appealing. It is ideal for building integrated photovoltaics (BIPV) and other high-visibility applications.