Wireless sensor for devices harvests solar energy

www.designnews.com
14 May 2013

Two Israel-based providers of electronics components have collaborated to provide solar power harvesting technology that can power wireless sensors so they require little or no battery power to operate.

Sol Chip and Cellergy are offering a high-performance energy harvester that combines Cellergy supercapacitors and Sol Chip's solar power harvesting technology and can be integrated into a range of devices and applications to provide power for short-range wireless communication.

The companies envision the technology being used to enable the so-called Internet of Things in which devices can identify and communicate with one another over the Internet or a network. These devices will be used in a number of industries, including agriculture, smart lighting control, smart water management, environmental monitoring, medical, security, and safety.

The Everlasting Solar Battery--Sol Chip's contribution to the collaboration--addresses the needs of remote or mobile devices that operate autonomously by prolonging battery life, reducing environmental hazard and improving battery-charging technology, Zack Sharon, Sol Chip's sales and marketing director, told Design News. "The technology harvests light energy to extend battery life or replace batteries in many applications and reduces system overall cost", he said.

The Sol Chip device is essentially a single-chip solar cell with integrated battery management and charging circuitry. The device can recharge batteries or charge super-capacitors, and has a patent-pending architecture that provides higher efficiency with an extremely lean and cost saving implementation, Sharon told us. The harvester combines the Everlasting Solar Battery with Cellergy's supercapacitor technology to store the energy, which allows for more energy storage than typical capacitors.

Energy harvesting is becoming a method of choice for low-power devices that typically run on batteries but don't need a lot of energy to power them. A number of semiconductor and electronics components companies are building ultra-low-power components or micro energy-harvesting devices that can be embedded in devices like medical sensors, smoke alarms, security systems, and other devices.

According to Sharon, the addressable market for the Sol Chip-Cellergy technology is estimated at 1 billion units in 2022, with many segments growing more than 10% per year. "Initial target segments include wireless sensors and wireless sensor networks, smart power grids, smart cities, and active RFID", he said.

Solar Power: Australian scientists successfully print solar panels

www.policymic.com
21 May 2013

3D printing is all the rage at the moment, from the debate over 3D printed guns to plans to print pizza with a 3D food printer. Scientists in Australia, however, have shown that regular printing can still do amazing things too. Researchers at Australia's Victorian Organic Solar Cell Consortium (VICOSC)--a collaboration between the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the University of Melbourne, Monash University and industry partners--have successfully printed an A3 sheet of photovoltaic cells.

The sheets are the largest flexible, plastic solar cells that have been printed in Australia, having gone from printing cells the size of a finger nail just a few years ago. Research Dr David Jones eventually sees the cells, which produce 10 50 watts of power per m², "being laminated to windows that line skyscrapers [and] we'll also be able to embed cells onto roofing materials". Given the cost of the printer alone, $200,000, and its size (see below), this is not exactly the kind of thing that just anyone can start doing.

New all-solid sulfur-based battery outperforms lithium-ion technology

m.phys.org
5 Jun 2013

(Phys.org) —Scientists at the Department of Energy's Oak Ridge National Laboratory have designed and tested an all-solid lithium sulfur battery with approximately four times the energy density of conventional lithium-ion technologies that power today's electronics.

The ORNL battery design, which uses abundant low-cost elemental sulfur, also addresses flammability concerns experienced by other chemistries. 

"Our approach is a complete change from the current battery concept of two electrodes joined by a liquid electrolyte, which has been used over the last 150 to 200 years," said Chengdu Liang, lead author on the ORNL study published this week in Angewandte Chemie International Edition. 

Scientists have been excited about the potential of lithium sulfur batteries for decades, but long-lasting, large-scale versions for commercial applications have proven elusive. Researchers were stuck with a catch-22 created by the battery's use of liquid electrolytes: On one hand, the liquid helped conduct ions through the battery by allowing lithium polysulfide compounds to dissolve. The downside, however, was that the same dissolution process caused the battery to prematurely break down.

The ORNL team overcame these barriers by first synthesizing a never-before-seen class of sulfur-rich materials that conduct ions as well as the lithium metal oxides conventionally used in the battery's cathode. Liang's team then combined the new sulfur-rich cathode and a lithium anode with a solid electrolyte material, also developed at ORNL, to create an energy-dense, all-solid battery. 

"This game-changing shift from liquid to solid electrolytes eliminates the problem of sulfur dissolution and enables us to deliver on the promise of lithium sulfur batteries," Liang said. "Our battery design has real potential to reduce cost, increase energy density and improve safety compared with existing lithium-ion technologies." 



The new ionically-conductive cathode enabled the ORNL battery to maintain a capacity of 1200 milliamp-hours (mAh) per gram after 300 charge-discharge cycles at 60° Celsius. For comparison, a traditional lithium-ion battery cathode has an average capacity between 140-170 mAh/g. Because lithium sulfur batteries deliver about half the voltage of lithium-ion versions, this eight-fold increase in capacity demonstrated in the ORNL battery cathode translates into four times the gravimetric energy density of lithium-ion technologies, explained Liang. 

The team's all-solid design also increases battery safety by eliminating flammable liquid electrolytes that can react with lithium metal.

Chief among the ORNL battery's other advantages is its use of elemental sulfur, a plentiful industrial byproduct of petroleum processing. 

"Sulfur is practically free," Liang said. "Not only does sulfur store much more energy than the transition metal compounds used in lithium-ion battery cathodes, but a lithium sulfur device could help recycle a waste product into a useful technology." 

Although the team's new battery is still in the demonstration stage, Liang and his colleagues hope to see their research move quickly from the laboratory into commercial applications. A patent on the team's design is pending.

John Laing plans $76 million investment in wind and solar energy

www.bloomberg.com
25 Apr 2013

John Laing Plc, a U.K, developer of hospitals, schools and roads, estimates it will spend about 50 million pounds ($76 million) this year on onshore wind and photovoltaic power projects in Britain and Sweden.

The company plans to invest in five developments this year, using debt to fund 50% to 70% of each plant, Ross McArthur, head of renewable energy for London-based John Laing, said in an interview. It wants to invest in areas with different regulatory structures to reduce reliance on one kind, he said.

The company completed three wind and two solar deals last year. While it's currently focused on northern European markets including the UK, John Laing is able to access the Australian and North American markets through locally based teams, said Andy Harmer, head of waste and energy. This may bring opportunities over the next year to 18 months, he said.

Sweden plans to get half of its energy from clean sources by 2020, from 47% now, and the U.K, is aiming for 15%, up from about 9.4%. Both subsidize renewable energy by placing an obligation on electricity suppliers to buy a certain portion of their power from low-carbon sources.

Wind-solar hybrid plants up to twice as efficient

www.pv-magazine.com
22 Apr 2013

Combining wind turbines and photovoltaic systems results in up to twice the amount of electricity being generated across the same surface area, while shading losses caused by wind turbines amount to a mere 1 to 2%-much less than previously thought.

As an additional benefit, the construction of hybrid power plants does not require grid expansion because the plants generate wind and solar power at different times of day and during complementary seasons, ensuring the level of energy fed into the grid is more steady than that of wind or photovoltaic power plants alone.

"Until now, it was thought that the shadows cast on solar plants by wind turbines led to high yield losses. The study shows, however, that these shading losses are much lower than expected, provided the hybrid power plant is well designed", said Alexander Woitas, head of the engineering department at Solarpraxis AG, parent company of pv-magazine.com. Various scenarios were simulated for the study and detailed shading analyses were carried out.

"Initial requests to create yield reports as well as technical and economic system planning have given us cause to hope that the more efficient utilization of space and infrastructure created by hybrid power plants has excellent prospects for the future", said Dr. Christian Breyer, managing director of the Reiner Lemoine Institut. "We also calculated what effects combining photovoltaic and wind power plants will have on power grids on both a global and regional level. The fact that wind and photovoltaic power supply the grid with much more stable levels of energy when working together has a positive effect on grid stability", he added.

While wind turbines produce a lot more electricity during the colder parts of the year, due to greater levels of wind over the winter months, solar power plants generate more solar power in the summer, compensating for the lower wind power production at this time of the year.

Next year, a photovoltaic system at Templin, near Berlin, is set to be retrofitted with wind turbines as part of the German government's Zwanzig20 research initiative. Data from the pilot plant will be analyzed by Solarpraxis, the Reiner Lemoine Institut and project partners.

Nanowires boost efficiency of solar cells

www.compoundsemiconductor.net
19 Apr 2013

ZnO quantum dots could translates fabrication of large-area films making solar panels Solar cells made from quantum dots could be low-cost, flexible, and easy to make. But the efficiency with which they convert light into electricity remains too low for practical use. Capitalising on this, researchers' at the Massachusetts Institute of Technology have combined nanowires with quantum dot solar cells.

The cell's efficiency increases the cells' efficiency by 35%. Quantum dots are semiconductor nanocrystals that absorb different wavelengths of light depending on their size. Solar cells made from different-sized crystals should absorb light over a much wider range of colours than silicon devices.

What's more, because quantum dots are made in solution, they could be easily printed or painted onto flexible surfaces. Scientists have calculated that quantum dots could be used to make thin-film solar cells that could convert light to electricity with 15% efficiency, the same as commercial silicon devices.

The best-performing quantum dot solar cells consist of a lead sulphide quantum dot layer butted up against a zinc oxide or titanium dioxide layer. The quantum dots absorb light, and electrons created in the process travel to the metal oxide layer to reach the electrical circuit.

The problem is that the quantum dot layer has to be thick enough to absorb light efficiently, but thin enough for the electrons to quickly traverse it. The MIT researchers, led by electrical engineering and computer science professor Vladimir Bulovic, overcame that trade off by replacing the flat ZnO layer with an array of vertical zinc oxide nanowires.

Nanowires penetrate the quantum dot layer, providing conductive paths for the electrons to follow out to the electrical circuit, says Joel Jean, a graduate student in Bulovic's group. The researchers published their results in the journal Advanced Materials.

The researchers start with glass substrates that are coated with indium tin oxide transparent electrodes. They deposit a ZnO layer on top and float the entire susbtrate upside down in an aqueous solution of zinc precursors.

An array of aligned nanowires grows downwards from the ZnO layer. After about an hour, the researchers rinse the substrates. Finally, they deposit PbS quantum dots, which fill up the space between the nanowires, and top it off with a gold electrode.

The nanowires boost the output current of the devices by 50% and the efficiency by 35% over planar ZnO devices. The overall light-to-electricity conversion efficiency of the new devices is 4.9%, among the highest reported for ZnO-based quantum dot solar cells, Jean says.

The researchers believe the efficiency could be further enhanced by using thicker light-absorbing layers and longer nanowires, as well as by controlling the spacing between nanowires to better accommodate quantum dots.

The idea of using ZnO nanowires to increase efficiency in quantum dot solar cells is not new, but this is the first significant implementation of the concept, says Matthew Beard, a senior scientist at the National Renewable Energy Laboratory. "The observed efficiency boost is promising and significant", he says. "The efficiencies for these types of solar cells are increasing rapidly and this work demonstrates that the improvements in efficiency will continue".

A key advantage of the nanowire-quantum dot cells, says Jean, is that they could be made on large areas. "One of the main benefits of quantum dots is that they're grown in and deposited from solution", he adds.

"This translates to fabrication of large-area films, which is necessary for making solar panels. Zinc oxide nanowires are also grown in an aqueous solution process. Scalability should be one of the primary practical advantages of this type of solar cell".

Portugal provides 70% of electricity using renewable energy

designbuildsource.com.au
19 Apr 2013

Figures from Portugal's electricity network operator indicate that 70% of all electricity consumed in the country during the first quarter of this year was derived from renewable energy sources, leading to a marked decline in the usage of conventional fossil fuels for power generation purposes.

The record-breaking levels of renewable energy usage were heavily abetted by favourable weather conditions, expediting generation by hydroelectric power facilities and wind turbines and bringing about declines in electricity consumption by Portuguese citizens.

Hydro was the biggest power provider throughout the quarter, supplying 37% of all electricity consumed in Portugal for a staggering 312% year-on-year increase.

Wind power came in second, supplying 27% of total electricity and achieving a record-breaking generation level for Portugal. wind turbine power generation levels increased 60% year-on-year and were 37% greater than average.

In stark contrast to the prominence of hydroelectric power and wind in Portugal's energy portfolio, however, solar power makes only a negligible contribution to nationwide power generation. While figures on solar power generation for the first quarter of 2013 are not yet available, in 2012 photovoltaics only supplied 0.7% of total energy demand, equivalent to 225.5 MWs.

The frugal energy consumption habits of the Portuguese no doubt also contributed to the increased prominence of renewables. While a warm winter and fewer working days contributed to a marked decline in energy usage of 2.3% during the first quarter, power consumption in Portugal has fallen steadily over the past several years and currently stands at 2006 levels.

The increased usage of renewable energy has conversely led to a sharp decline in the consumption of conventional fossil fuels, which the small Iberian nation can only import. Portugal used 29% less coal and 44% less gas for electricity generation in the first quarter compared to 2012 figures.

Portugal has undertaken concerted efforts to transition toward renewable energy sources since the middle of last decade, in order to reduce the country's reliance on imported fossil fuels as well as harness its rich climate resources as a peninsular nation state.

In 2011, Portugal even managed to use renewable energy sources to provide for all the country's power needs for a period of several hours. The March quarter of 2013 marks the first occasion, however, that the country has managed to supply so much of its energy needs from renewable sources over such a protracted time frame.

Silex opens Australia's largest CPV plant

www.businessspectator.com.au
15 Apr 2013

Silex Systems has commenced operation of Australia's largest concentrating photovoltaic (CPV) solar power station in Victoria's north-west.

The Mildura development, run by Silex subsidiary Solar Systems, will have a capacity of 1.5 MWs when fully operational-enough to power up to 500 average sized homes. A power purchase agreement for power off-take onto the local Mildura grid was signed with Diamond Energy in December last year.

"The commencement of operations at our Mildura Demonstration Facility is a significant milestone in the commercialisation of Solar Systems' unique 'Dense Array' CPV technology", Silex CEO Dr Michael Goldsworthy said.

"The first array consisting of 10 dish systems has been successfully commissioned and is operational, with the remaining three arrays of 30 dishes to be brought online progressively over the next few weeks".

The planning phase for the next stage, the 100MW Mildura Solar Power Station Project, remains on track, the company said, with construction commencement expected late in 2014. This timeline is reliant on the successful operation of the demonstration facility and finalisation of funding arrangements.

THE Desert Kingdom; desalination from oil power to solar power?

www.saudigazette.com.sa
15 Apr 2013

Saudi Arabia finds itself in an interesting economic cleft stick. While blessed with oil that it can currently sell at around $104 per barrel on the world market, it is compelled to burn a sizable proportion of that potential income to produce desalinated water. Cost of production of water fluctuates, but a fair guess is between 40 and 90¢ a barrel, depending on fuel price.

To produce water, the Kingdom uses approximately 1.5 million barrels of oil a day across its 30 or so desalination plants to meet the demand for domestic and industrial water. Little of this water--if any is used for agriculture. The water for agriculture--some 85 to 90% of the total water use in the Kingdom--comes from non-replaceable resources, underground aquifers that are drying out rapidly. For every 100 liters per annum withdrawn, only one liter or less finds itself back into the aquifer.

The government has wisely decided that food security, once an unquestionable shibboleth of policy, is no longer worth the use of resources and has taken up the idea of virtual water. This refers to the hidden flow of water if food or other commodities are traded from one place to another.

Virtual water is best defined as "the volume of freshwater used to produce the product, measured at the place where the product was actually produced". It refers to the sum of the water use in the various steps of the production chain. It is 'virtual' for when the product arrives at its destination, the water is no longer contained in it, and was used only to produce it. An example of the saving of such imports is wheat, which takes 1,600 tons of water on average to produce one ton of grain.

It has resolved that the Kingdom will rely entirely on imports for food by 2016. Starting in 2008, the government has been reducing wheat purchases from local farmers by 12.5% a year and plans eventually to withdraw all agricultural subsidies to these farmers. Having addressed the issue of water supply and use and effectively engaged the biggest user of water, agriculture, positively, desalination for the balance of life in the Kingdom remains a huge challenge on several levels.

A major issue, the use of expensive oil that could produce income for making water, has spawned a slew of projects based on solar power for water production. The Kingdom might, and probably is, considering nuclear power as another option, but this introduces the political aspect of the importation of nuclear fuels and technology to the region, which is already under the baleful gaze of the West.

Happily, Saudi Arabia is one of the sunniest places on earth, averaging between 200 and 300 hours per month. Solar power therefore is an environmentally friendly, infinitely renewable (well, for the next seven billion years or so and the earth will have dried out and life gone in 3.5 billion) and very available alternative. Moreover it is harmless, both politically and environmentally.

The Kingdom seems to have opted so far for the expensive option of photovoltaic cell electricity generation to run the new solar desalination plants rather than the simpler, longer lasting and lower maintenance Concentrated Solar Power (CSP) alternative. Commercially viable CSP plants are already in operation in California, France and Spain--all with lower sunshine hours--and are feeding electricity into the grid.

The government is tackling the building of desalination capacity actively and has allocated $6.4 billion for water and sanitation projects in 2013.

Saline Water Conversion Corp. SWCC, (which supplies 50% of the municipal water in the Kingdom and produces 18% of the global total) for example plans to build the world's largest water desalination plant in Rabigh and will have the ability to pump 600,000 cubic meters of desalinated water per day. The conventionally fueled plant should be completed by 2018. State-owned National Water Co, plans to spend $66 billion on plants and upgrades over the next 10 years.

In October 2012, Abdul Rahman Al-Ibrahim, governor of SWCC announced plans to establish three new solar-powered desalination plants in Haqel, Dhuba and Farasan in addition to the one under construction in Khafji.

The Khafji solar desalination project will be the first large-scale solar-powered seawater reverse-osmosis (SWRO) plant in the world. It was due for completion at the end of 2012 and designed with a capacity of 30,000 cubic meters of water per day for the 100,000 customers.

The Khafji desal plant is the first step in King Abdullah City for Science and Technology's solar power program to reduce desalination costs. Phase two of the project is the construction of a new plant to produce 300,000 cubic meters of water per day is planned by 2015, and phase three will involve Haqel, Dhuba and Farasan by 2018.

The Kingdom is not alone in the search for a clean, effective and cheap means of producing water. The UN classifies around 700 million people in 43 countries as suffering from water scarcity today. By 2025 the figure is forecast to rise to 1.8 billion.

With the global population expected to reach nine billion by 2050 and the US secretary of state openly discussing the threat of water shortages leading to wars, the production of desalinated water has never been more important.

Materials scientists make solar energy chip 100 times more efficient

phys.org
20 Mar 2013

Scientists working at the Stanford Institute for Materials and Energy Sciences (SIMES) have improved an innovative solar power device to be about 100 times more efficient than its previous design in converting the sun's light and heat into electricity. "This is a major step toward making practical devices based on our technique for harnessing both the light and heat energy provided by the sun", said Nicholas Melosh, associate professor of materials science and engineering at Stanford and a researcher with SIMES, a joint SLAC/Stanford institute.

The new device is based on the photon-enhanced thermionic emission (PETE) process first demonstrated in 2010 by a group led by Melosh and SIMES colleague Zhi-Xun Shen, who is SLAC's advisor for science and technology. In a report last week in Nature Communications, the group described how they improved the device's efficiency from a few hundredths of a percent to nearly 2%, and said they expect to achieve at least another 10 fold gain in the future.

Concentrated sunlight heats up the device's semiconductor cathode to more than 400° Centigrade. Photoexcited hot electrons (blue dots) stream out of the cathode's nanotextured underside down to the anode, where they are collected as direct electrical current. Additional solar and device heat is collected below the anode to run electricity-generating steam turbines or Stirling Engines.

Conventional photovoltaic cells use a portion of the sun's spectrum of wavelengths to generate electricity. But PETE uses a special semiconductor chip to make electricity by using the entire spectrum of sunlight, including wavelengths that generate heat. In fact, the efficiency of thermionic emission improves dramatically at high temperatures, so adding PETE to utility-scale concentrating solar power plants, such as multi-MW power tower and parabolic trough projects in California's Mojave Desert, may increase their electrical output by 50%. Those systems use mirrors to focus sunlight into superbright, blazingly hot regions that boil water into steam, which then spins an electrical generator. "When placed where the sunlight is focused, our PETE chips produce electricity directly; and the hotter it is, the more electricity it will make," Melosh said.

The heart of the improved PETE chip is a sandwich of two semiconductor layers: One is optimized to absorb sunlight and create long-lived free electrons, while the other is designed to emit those electrons from the device so they can be collected as an electrical current. A cesium oxide coating on the second layer eases the electrons' passage from the chip. Future research is aimed at making the device up to an additional 10 times more efficient by developing new coatings or surface treatments that will preserve the atomic arrangement of the second layer's outer surface at the high temperatures it will encounter in the concentrating solar power plant.

"We expect that other materials, such as those incorporating barium or strontium, will make the surface much more stable up to at least 500° Celsius", said Jared Schwede, a Stanford graduate student who performed many of the PETE experiments. An additional challenge will be to engineer the device to withstand the dramatic 500 degree daily temperature swings at solar power plants, as their systems heat up during the day and then cool down at night.

Colourful 'solar glass' means entire buildings can generate clean power

www.guardian.co.uk
12 Feb 2013

A solar power company capable of "printing" colourful glass that can generate electricity from the sun's energy announced a £2m funding boost on Tuesday. Oxford Photovoltaics, a spin-off from the University of Oxford, said the investment from clean-tech investors MTI Partners will help its solar glass, which can be dyed almost any colour, take a step closer to the commercial market.

"What we say here is rather than attach [solar] photovoltaics to the building, why not make the building the photovoltaics?" Kevin Arthur, the company's founder and CEO, told the Guardian. "If you decide to build a building out of glass, then you've already decided to pay for the glass. If you add this, you're adding a very small extra cost. [The solar cell treatment] costs no more than 10% of the cost of the facade". These generally cost between £600 and £1,000 per m², meaning the new cell treatment wouild cost just £60 £100 extra per m².

The technology works by adding a layer of transparent solid-state solar cells at most three microns thick to conventional glass, in order to turn around 12% of the solar power received into low-carbon electricity. The power can then be exported to the national grid or used for the running of a building.

"Within reason we can print any colour, there's a wide range of dyes, blues and greens and reds and so on. But different colours have different efficiencies: black is very high, green is pretty good and red is good, but blue is less good", said Arthur.

The £2m investment will pay for equipment and recruiting staff for the company's new base on the Begbroke Science Park near Oxford. The company is looking to build a much larger manufacturing facility next year, with full size panels available for sampling and trials at the end of 2014. A4 sized samples will be ready by the end of 2013. While the company is mostly targeting customers planning new buildings, it also "very interested" in retrofits on the facades of existing buildings.

Separately, a team at the University of Sheffield and University of Cambridge this week said they had succeeded in developing a process to 'spray paint' solar cells on to surfaces and, potentially in the future, roofs and buildings. The teams believe the process could significantly cut the cost of solar in the future, but currently only works on "very smooth" surfaces and is less efficient than conventional solar panels.

Professor David Lidzey from the University of Sheffield said: "Spray coating is currently used to apply paint to cars and in graphic printing. We have shown that it can also be used to make solar cells using specially designed plastic semiconductors. Maybe in the future surfaces on buildings and even car roofs will routinely generate electricity with these materials".

Solar power worldwide reached 100GW installed capacity last year for the first time, up from 71GW in 2011 and just 40GW in 2010, according to recent trade body figures.

U.S. Wind has strongest year ever

www.onlinetes.com
3 Feb 2013

The U.S, wind power industry had its strongest year ever in 2012, according to the American Wind Energy Association, installing a record 13,124MW of electric generating capacity, leveraging $25 billion in private investment,and achieving over 60,000MW of cumulative wind capacity.

The milestone of 60,000MW (60GW) was reached just five months after AWEA announced last August that the U.S, industry had 50,000MW installed. Today's 60,007MW is enough clean, affordable, American wind power to power the equivalent of almost 15 million homes, or the number in Colorado, Iowa, Maryland, Michigan, Nevada, and Ohio combined.

In this historic year of achievement, wind power for the first time became the number one source of new U.S, electric generating capacity, providing some 42% of all new generating capacity; the final tally will be released in April in AWEA's annual report. In fact, 2012 was a strong year for all renewables, as together they accounted for over 55% of all new U.S, generating capacity.

Resulting from 190 projects across 32 states plus Puerto Rico, this new record for annual installations of over 13,000 MW by the U.S, industry far surpasses the previous record of 10,000MW installed in 2010.

AWEA Interim CEO Rob Gramlich says, "It is a real testament to American innovation and hard work that for the first time ever a renewable energy source was number one in new capacity. We are thrilled to mark this major milestone in the nation's progress toward a cleaner energy system". Currently installed wind power will avoid 95.9 million metric tons a year of CO₂ emissions, equal to 1.8% of the entire country's carbon emissions.

In last year's fourth quarter alone, 8,380MW were installed, making it the strongest quarter in U.S, wind power history. This was due in large part to impending expiration of the successful federal Production Tax Credit (PTC). It was slated to end at the end of last year, but was extended by Congress on Jan. 1, as part of the "fiscal cliff package", the American Taxpayer Relief Act of 2012.

Gramlich adds, "What is just as striking as the new records is the expansion of new customers. A total of 66 utilities bought or owned wind power in 2012, up from 42 in 2011. We are also seeing growth in new customers in the industrial and commercial sectors purchasing or owning wind power directly".

New wind power purchasers last year included at least 18 industrial buyers, 11 schools and universities, and eight towns or cities, showing a significant trend toward nontraditional power purchasers from the industrial sector. Manufacturers of everything from plastics to light bulbs, semiconductors, and badges, farms, and medical centers are now directly purchasing wind power.

"The fact that wind power grew by another 28% in 2012 alone and poured $25 billion of private investment into the U.S, last year demonstrates wind's ability to scale up, and continue to serve as a leading source of energy in America", Gramlich says.

Top states for new capacity installations in 2012 include:

1. Texas (1,826MW)
2. California (1,656MW)
3. Kansas (1,440MW)
4. Oklahoma (1,127MW)
5. Illinois (823MW)
6. Iowa (814MW)
7. Oregon (640MW)
8. Michigan (611MW)
9. Pennsylvania (550MW)
10. Colorado (496MW)

Black silicon can take efficiency of solar cells to new levels

www.sciencecodex.com
25 Jan 2013

Scientists at Aalto University, Finland, have demonstrated results that show a huge improvement in the light absorption and the surface passivation on highly absorbing silicon nanostructures. This has been achieved by applying atomic layer coating. The results advance the development of devices that require high sensitivity light response such as high efficiency solar cells.

This method provides extremely good surface passivation. Simultaneously, it reduces the reflectance further at all wavelengths. These results are very promising considering the use of black silicon (b-Si) surfaces on solar cells to increase the efficiency to completely new levels, tells Paeivikki Repo, a researcher at Aalto University.

More effective surface passivation methods than those used in the past have been needed to make black silicon a viable material for commercial applications. Good surface passivation is crucial in photonic applications such as solar cells. So far, the poor charge carrier transport properties attributed to nanostructured surfaces have been more detrimental for the final device operation than the gain obtained from the reduced reflectance.

Black silicon can also be used in other technologies than solar cells. Numerous applications suggested for b-Si include drug analysis.

Black silicon (b-Si) has been a subject of great interest in various fields including photovoltaics for its ability to reduce the surface reflectance even below 1%. However, many b-Si applications-especially solar cells-suffer from increased surface recombination resulting in poor spectral response. This is particularly problematic at short wavelengths.

Nanowires make good solar cells

physicsworld.com
21 Jan 2013

Researchers in Sweden and Germany say they have made an important breakthrough in the development of highly efficient solar cells based on nanowires. They have shown that cells made from tiny wires of the semiconductor indium phosphide (InP) have efficiencies as high as 13.8% while covering only about 12% of the surface of a device. While an efficiency of 13.8% is not as good as the best commercial silicon devices, the team believes that it could be improved significantly by further research.

Nanowires-tiny semiconductor wires with a thickness of just a few hundred nanometres or less-show great potential for making solar cells that are more flexible, lightweight and cheaper than conventional planar devices. Nanostructures such as wires are efficient absorbers of light and can act as "antennas", harvesting much more light than a device with a planar surface. This is thanks to collective oscillations of charge carriers-called plasmons-that interact strongly with light. "One consequence of this strong absorption on nanowires is that we observe high light-absorption efficiencies even though only a small part of the device's surface is covered by the nanomaterials", explains team member Magnus Borgstroem of Lund University.

Millions of wires
The devices made by the team measured about a square millimetre and each contains about four million InP nanowires. The researchers grew their nanowires using an established technique called "vapour solid growth". "Our nanowires needed to be uniform, having a certain diameter and length in a certain pitch. From our first working p-n InP junctions, it has taken us four years to reach this result", Borgstroem explains.

The team, which includes scientists from Solid State Physics in Lund, Fraunhofer ISE in Freiburg, the University of Kassel and the start-up company Solvoltaics, also in Lund, chose InP because it has a direct band gap of 1.34 eV, which means that it can absorb light over a range of solar-spectrum wavelengths.

In this latest work, the team was able to identify the ideal diameter of the nanowires-which turned out to be about 180 nm. "The right size is essential for the nanowires to absorb as many photons as possible. If they are just a few tenths of a nanometre too small, their function is significantly impaired", says Borgstroem.

Proof of principle
The cells made by the team have efficiencies as high as 13.8%-which is promising but still significantly less than the best commercial silicon devices, which operate at 15 22%. "Our findings are the first to show that it really is possible to use nanowires to manufacture solar cells", says Borgstroem. However, the highest efficiency ever reported for a conventional InP solar cell is 22% and the team admits that it still remains to be seen whether that record can be broken using smaller amounts of nanowire material.

The researchers also believe that the way forward for nanowire-based solar cells is the multi-junction approach, which boosts efficiency by using several different structures tuned to different wavelengths of light from the Sun. "We believe that the road ahead for solar cell application involves multi-junction technology with nanowires, for which the record is 44% in thin films", says Borgstroem.

The work is reported in Science.

Novel solar photovoltaic cells achieve record efficiency using nanoscale structures

www.scientificamerican.com
17 Jan 2013

Here's how to make a powerful solar cell from indium and phosphorus: First, arrange microscopic flecks of gold on a semiconductor background. Using the gold as seeds, grow precisely arranged wires roughly 1.5 micrometers tall out of chemically tweaked compounds of indium and phosphorus. Keep the nanowires in line by etching them clean with hydrochloric acid and confining their diameter to 180 nanometers. (A nanometer is one billionth of a meter.) Exposed to the sun, a solar cell employing such nanowires can turn nearly 14% of the incoming light into electricity—a new record that opens up more possibilities for cheap and effective solar power.

According to research published online in Science—and validated at Germany's Fraunhofer Institute for Solar Energy Systems—this novel nanowire configuration delivered nearly as much electricity as more traditional indium phosphide thin-film solar cells even though the nanowires themselves covered only 12% of the device's surface. That suggests such nanowire solar cells could prove cheaper—and more powerful—if the process could be industrialized, argues physicist Magnus Borgström of Lund University in Sweden, who led the effort.

The promise starts with the novel semiconductor—a combination of indium and phosphorus that absorbs much of the light from the sun (a property known as its band gap). "Now we absorb 71% of the light above the band gap and we can certainly increase that," Borgström says.

Read More…

Thin-Film photovoltaics market aims to convert on huge potential

news.thomasnet.com
5 Jun 2012

Ultimately, the world will run out of fossil fuels. Meanwhile, as the world fights over fossil fuels, our planet hangs in space a mere 93 million miles from a giant fusion reactor that's 1.4 million km wide. The sun gives us about 1.37 kilowatts per m² of energy. If it were somehow possible to convert 100% of the sun's energy into usable power, we would need only one hour of it to power the Earth for an entire year.

Using the sun for energy is hardly a new concept. Nor are photovoltaics (PV), which convert sunlight into electricity; the technology has been under commercial development since the 1970s, though up until recently, it remained difficult to achieve economies in manufacturing to make PV affordable. To date, solar panels large enough to fulfill significant energy needs have been neither very cheap nor very portable.

While the military has developed folding, semi-portable solar panels for installations in remote locations, few organizations or individuals have the kinds of budgets of the Department of Defense. Not to mention that most solar panels to date have been opaque, rigid and hard to use in places that could use a little supplemental energy from PV: atop a car or a building's windows.

The future practicality of PV--lower price point and putting PV cells onto less rigid surfaces so they can be "wrapped" or molded around buildings, cars and even people, in the form of PV-cell clothing--seems to lie in making PV cells flexible. Enter the plastics industry and the development of thin-film solar cells (TFSC), also called thin-film photovoltaic (TFPV) cells. TFSCs are made by depositing one or more thin layers, i.e., films, of photovoltaic material onto a substrate. The thickness of the layers is small, ranging from a few nanometers to a few tens of micrometers. Existing thin-film processes generally use semiconductor materials such as copper, indium, gallium, cadmium and selenium to create the PV cells.

Read More…

New dye will lead to more efficient solar energy technology

insciences.org
12 Dec 2011

A North Carolina State University invention has significant potential to improve the efficiency of solar cells and other technologies that derive energy from light. Dr. Ahmed El-Shafei's research group invented a new "sensitizer", or dye, that harvests more ambient and solar light than any dyes currently on the market for use in dye-sensitized solar cells (DSSCs).

"A third-party solar power company compared our new dye, NCSU-10, against the state-of-the-art dye on the market. Our dye had 14% more power density", says El-Shafei, an assistant professor in the Textile Engineering, Chemistry and Science department. "In other words, NCSU-10 allows us to harvest more energy from the same amount of light".

The new dye should significantly boost the efficiency of DSSCs, which have a host of applications. Indoors, these DSSCs can be used in technology to power cellular phones, laptop computers and MP3 players using ambient light. Outdoors, they could be used in conventional solar arrays or in improved energy-driven applications for building-integrated photovoltaic products including, but not limited to, windows, facades and skylights. Compared to the state-of-the-art dye on the market, NCSU-10 can absorb more photons at lower dye concentrations, and can therefore be used to create more effective solar cells on windows and facades while still allowing the windows to be highly transparent.

DSSCs are made of inexpensive and environmentally benign materials including a dye, an electrolyte and titanium dioxide (TiO2)-the white component used in toothpaste. DSSCs work by absorbing photons, or discrete packets of light energy, from incident light (or direct light that falls on a surface) to create free electrons in nanoporous semiconductors such as TiO2, in the cell. These electrons travel to the outside circuit to generate an electric current. Owing to their independence on the angle of incident light and high response to low level of lighting conditions, DSSCs outperform conventional silicon photovoltaic by 20 to 40% under diffuse light, on cloudy and/or rainy days, and in indoor ambient light, which make DSSCs a unique class of photovoltaics.

A patent is pending on the new dye, and the university is in communication with potential industry partners about licensing use of NCSU-10, as well as funding additional research in this area.

Thousands caught out by solar panel deadline

www.telegraph.co.uk
12 Dec 2011

One of Britain's largest solar panel installers, Homesun, said 2,500 of its customers who had missed today's deadline to avoid a 50pc cut in subsidy for self-generated electricity. In a sudden decision last month, the Government said it would halve the amount it would pay those who generate electricity from photovoltaic panels.

Daniel Green, chief executive of Homesun, said the company would aim to help these people, who will be significantly disadvantaged by the cut. He indicated that they could be offered free or deeply discounted panels. "We have paid a lot to have this relationship with these people and they have invested a lot of time", he said.

Consumers had rushed to register their panels before the deadline expired. The Microgeneration Certification scheme said it had provided installers with up to 9,000 certificates for the panels every day in the past week, compared to volumes of about 500 a day before that. After today, those who install and register solar panels will see a 50pc fall in the amount they receive for every kW generated, with the total per unit falling from 43.3p to 21p per kW. The "export" tariff, which is the additional 3.1p per kW for any electricity sold on to the grid, will not change.

Customers who had already signed contracts for panels have scrambled to register their installations before the date, with some fearing that they will lose out. The timing of the move has been criticised by environmental campaigners and the green energy industry. They claim that the decision will cost thousands of jobs.

Wind farm firm to take permits stoush to VCAT

www.abc.net.au
30 Nov 2011

The proponent of a 15-turbine wind farm in the Moyne Shire will ask the Victorian Civil and Administrative Tribunal (VCAT) to overturn a council decision against extending planning permits for the project. The Moyne council says NewEn Australia will have to reapply for permits for the Salt Creek wind farm, near Woorndoo, and must comply with new shire and State Government planning guidelines.

However, the company's managing director, Ernst Weyhausen, says the Government does not require projects that had already been given planning permission to comply with the new rules. "The State Government said it doesn't apply to existing permits and that existing permits can be extended through to March of next year", he said. "The council introduced its own policy back in August that also requires a two-km exclusion zone. However, that policy was never communicated to us".

Solon wins 5.5MW PV order in Germany

www.newenergyworldnetwork.com
11 Nov 2011

European photovoltaic (PV) manufacturer Solon AG has been contracted by Green Energy 3000 to supply modules for a 5.5MW development in Scheibenberg, Germany. The panels will attach to a fixed ground mount and the facility is expected to be grid connected by the end of the year. Andreas Renker, managing director of Green Energy 3000, said, 'We wanted the best possible quality and service. That's why we decided to choose Solon AG products. Through the use of high-quality system components, we expect an annual yield of around 5.3 million kWh.' At the end of last month, Solon AG unveiled plans to construct a 10MW PV plant in Kingman, Arizona, and sold a facility in the north of Italy to Norwegian investment group EAM Solar.