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Old Posted Aug 26, 2014, 7:21 AM
Allan83 Allan83 is offline
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Originally Posted by Innsertnamehere View Post
hydroelectric storage of power is a great way to store mass amounts of energy, it just takes a special kind of terrain. Use the power generated by solar to pump water up to a reservoir, let it flow down into hydroelectric dam to generate the power through generators.
This is being done in a lot of places. It's obviously not the greenest way to do things, but it is fairly efficient, and I guess the key thing is that it can be used to make use of waste power.
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Old Posted Apr 1, 2015, 8:54 PM
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scalziand scalziand is offline
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Not sure if I entirely trust this reference, since it's uncited, but this article claims less than 50 cents per W panel cost.

Jinko Solar to expand capacity in Malaysia
Sneha Shah wrote on 23 Mar, 2015

Jinko Solar (JKS) is one of the lowest cost producers of solar panels. The company is vertically integrated and amongst the top three shippers in the last year. Jinko Solar gave a strong set of results for 2014, performing well on all fronts. Net profit for the whole year amounted to $100 million. The company has an annual capacity of 2.5 GW for silicon ingots and wafers, 2 GW for solar cells, and 3.2 GW for solar modules, as of December 2014. Now the company is planning to establish new production facility in Malaysia starting by May 2015.

The company’s cost of production is below 50 cents per watt currently. Not only that the company is also a producer of high efficiency solar products. Jinko Solar achieved 306.9 watts as efficiency level for its Eagle+ modules, when industry average is only 255 watts for a 60-cell module. Jinko has a strong project pipeline, with projections of forming a yieldco soon. The company has established its market share not only in China, USA, Europe and Japan but also in emerging markets like Chile, India, Latin America.


Edit: $156/260W here, but the Jinko website doesn't have prices. IF the price stayed the same for the 307 W panel, then $156/307W = $0.51 per W.

Last edited by scalziand; Apr 1, 2015 at 9:11 PM.
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Old Posted Oct 14, 2015, 6:06 PM
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Things have moved fast this year.

SolarCity Unveils World’s Most Efficient Rooftop Solar Panel, To Be Made in America
New module that generates more power per square foot than any rooftop solar panel in production will also be the highest-volume solar panel manufactured in the U.S.

Oct 02, 2015

SAN MATEO, Calif. – SolarCity (NASDAQ: SCTY) has built the world’s most efficient rooftop solar panel, with a module efficiency exceeding 22 percent. The new SolarCity panel generates more power per square foot and harvests more energy over a year than any other rooftop panel in production, and will be the highest volume solar panel manufactured in the Western Hemisphere.

SolarCity will begin producing the first modules in small quantities this month at its 100 MW pilot facility, but the majority of the new solar panels will ultimately be produced at SolarCity’s 1 GW facility in Buffalo, New York. SolarCity expects to be producing between 9,000 - 10,000 solar panels each day with similar efficiency when the Buffalo facility reaches full capacity.

SolarCity’s panel was measured with 22.04 percent module-level efficiency by Renewable Energy Test Center, a third-party certification testing provider for photovoltaic and renewable energy products. SolarCity’s new panel—created via a proprietary process that significantly reduces the manufacturing cost relative to other high-efficiency technologies—is the same size as standard efficiency solar panels, but produces 30-40 percent more power. SolarCity’s panel also performs better than other modules in high temperatures, which allows it to produce even more energy on an annual basis than other solar panels of comparable size.

Panasonic Quickly Beats SolarCity’s Solar Module Efficiency Record

October 9th, 2015 by Steve Hanley

Originally published on Solar Love.

Recently, SolarCity announced it will begin manufacturing the “world’s most efficient solar panels” at its factory in Buffalo, New York, starting in 2016. It claims it has designed a panel that converts 22.1% of sunlight into electricity.

Now, less than a week later, Panasonic says it has trumped that achievement. A Panasonic solar panel has established a new world record module conversion efficiency of 22.5% on a commercial sized prototype using solar cells based on mass production technology. The test results were confirmed by the renowned Japanese National Institute of Advanced Industrial Science and Technology. The 72-cell, 270-watt prototype incorporates newly developed enhanced technology that will eventually be scaled into volume production.

SolarCity & Panasonic Announcements May Mark Beginning Of Solar Without Subsidies

October 12th, 2015 by Guest Contributor

Originally published on The Handleman Post.
By Clayton Handleman

Not so long ago, Sunpower’s 20+% efficiency modules were seen as high end niche products. Last week SolarCity announced that it had leapfrogged that benchmark with its 22% modules currently rolling off of its 100 MW lines and soon to be rolling off its 1 GW line at Elon Musk’s ‘other’ gigafactory. With multiple vendors at GW scale with above 20% efficient modules, PV has reached the point of commoditizing high efficiency modules, and the ripple effect on system level costs has profound implications.

Adding fuel to the fire, in a recent Cleantechnica post, Panasonic shot back with its announcement of production prototypes testing at 22.5% efficiency. And the longtime leader, Sunpower, is in the process of upping its game with 23% efficient modules planned for production in 2017 in its Fab 5, which at a planned 800MW (.8GW) is also at the GW scale and rivaling SolarCity’s fab in capacity.

PERC Solar Cells Could Achieve 24% Conversion Efficiency Using Current Technologies

September 30th, 2015 by James Ayre

Monocrystalline solar cells utilizing a PERC (Passivated Emitter and Rear Cell) design could achieve conversion efficiencies as high as 24% via the use of technologies already on the market, according to the Institute for Solar Energy Research Hameln (ISFH).

The assertion was supported via a simulation that the ISFH presented at the recent EU PVSEC in Hamburg, Germany. The simulation showed that, via the use of a number of specific technologies (a wafer possessing a high charge carrier lifetime of 1000µs rather than 400µs, selective emitters, boron-doped aluminum paste for the local back surface field, 10 µm thin contact fingers rather than 60 µm, multi-wires rather than bus-bars), conversion efficiency could be boosted to 24% from the ~20.5% that it stands at today.

Commenting on the future of PERC solar cells, and thus the motives behind the simulation, ISFH presenter Byungsul Min commented: “The PERC (solar) cell will set a moving target and dominate the market for some time to come.”


Last edited by scalziand; Oct 14, 2015 at 6:26 PM.
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Old Posted Nov 11, 2015, 9:35 PM
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Perovskite Solar Cell Boost From Brown
October 10th, 2015 by Tina Casey

Originally published on Solar Love.

We’ve been spilling a lot of ink over perovskite solar cells recently, and here comes Brown University with yet another breakthrough. Along with researchers from the National Renewable Energy Laboratory, the Brown team has figured out a way to grow larger perovskite solar cells while keeping the conversion efficiency at a fairly high level. (h/t James Wimberley)

The Promise Of Perovskites

Solar researchers are all over perovskites, a class of synthetic crystals that mimic the unique structure of naturally occurring perovskite. Perovskites could become a low-cost, easy-to-manufacture substitute for silicon in solar cells, and researchers have been slowly breaking down the barriers to achieving that.

One problem, according to the Brown team, is that while relatively high solar conversion efficiencies of more than 20% have been reported in the laboratory, those are based on very small samples, typically 1/10 of a square centimeter.

Conventional processes for producing larger perovskite solar cells have fallen short in the quality department, with defects that interfere with efficiency.

“Glue” For Bigger, Better Perovskite Solar Cells

The new study can be found in the journal Advanced Materials under the title “Square-Centimeter Solution-Processed Planar CH3NH3PbI3 Perovskite Solar Cells with Efficiency Exceeding 15%.”

It’s based on a perovskite fabrication process previously developed at Brown, in which a solvent containing perovskite precursors is spread out on a substrate. An “anti-solvent” is then applied to get rid of the first solvent, leaving a nice smooth film of perovskite crystals.

The beauty of this method, aside from yielding a high-quality product, is its potential for scaling up to a commercial rate while keeping costs down, one factor being its ability to produce perovskite solar cells under room temperature conditions.

Scaling that process up is the challenge tackled by the new perovskite study. Here’s the rundown from Brown:

“The trick is to add excess organic precursor that initially “glues” the small perovskite crystals and helps them merge into larger ones during a heat-treatment, which then bakes away the excess precursor.”

Initial results for the new perovskite solar cells show an efficiency of 15%, which is not bad considering the potential to churn them out quickly and cheaply.

The team is pretty confident that this method, or one closely resembling it, could eventually get up to the 20% range and higher.

Another Boost For Hot-Carrier Perovskite Solar Cells
October 31st, 2015 by Tina Casey

Originally published on Solar Love.

Perovskite solar cells have been getting a lot of attention for their potential to reach new heights of efficiency and new lows of cost. In the latest development, our friends over at the National Renewable Energy Laboratory have revealed a critical “bottleneck” in perovskite solar conversion that has huge implications for third-generation, super-efficient, hot-carrier solar cells.

Hot-Carrier Solar Cells

For those of you new to the topic of hot-carrier solar cells, you can get the lowdown in plain language from SPIE, the International Society for Optics and Phonics. The gist of it is as follows: With conventional solar cells, you only get two choices: simple materials, low cost, and low efficiency (such as single-junction solar cells); or multiple materials, high cost, and high efficiency (that would be multi-junction solar cells). In contrast, with hot-carrier solar cells, you could get simplicity of design, low cost, and high efficiency all in one, kind of like having your cake and eating it too. Here’s the explanation from SPIE:

“Heat production is detrimental to the output of solar cells. It occurs when a material absorbs photons with energies larger than its bandgap. To circumvent this problem, photogenerated charge carriers must be collected through specially designed contacts that are energy-selective. Carriers with large kinetic energies—‘hot carriers’—reach these contacts before losing most of their energy as heat. In principle, efficiencies as high as 86% could be achieved.”

If that sounds too good to be true, it is. Hot-carrier solar cells are a long way from the marketplace, one big challenge is how to rev up the kinetic energy transfer to top speed (as in, subpicoseconds), in order to prevent energy loss.

Nevertheless, the high return on efficiency makes the hot-carrier field full of temptation. When SPIE covered hot-carrier solar cells back in 2011, the high mark for solar conversion was 40%, achieved by multi-junction solar cells. In December 2014, CleanTechnica took note of a new solar conversion record of 46%. Considering that the theoretical limit is about 87%, that still leaves plenty of room for alternative, “third-generation” technologies to elbow in.

The Perovskite Solution For Hot-Carrier Solar Cells

So, finally, that brings us back around to the National Renewable Energy Laboratory (NREL). Just today, the lab announced that researchers have figured out a pathway for tackling the heat loss problem by deploying hot-carrier technology in perovskite solar cells.

Perovskite refers to a class of easily synthesized crystals with a structure based on a naturally occurring mineral, perovskite, that was discovered in the Ural mountains in 1839. Within recent years, researchers have been pursuing perovskites for improving solar conversion efficiency.

The commercial deployment of perovskite in solar cells faces some obstacles, with the use of lead being a particular thorny issue, but according to NREL, successive versions of perovskite solar cells have been “shooting up the efficiency charts faster than almost anything researchers have seen before,” making them juicy targets for further research, lead or no lead (for the record, tin is being explored as one alternative to lead).

When NREL began studying perovskites in 2009, it achieved a 3.8% efficiency rate. Within just a few years, the latest attempts have jumped up to more than 20%.

The new study, published in Nature Photonics under the title “Observation of a hot-phonon bottleneck in lead-iodide perovskites,” provides a pathway for pushing perovskite levels into the stratosphere, possibly as high as 66%. Here’s the rundown from the NREL media team:

“The NREL research determined that charge carriers created by absorbing sunlight by the perovskite cells encounter a bottleneck where phonons (heat carrying particles) that are emitted while the charge carriers cool cannot decay quickly enough. Instead, the phonons re-heat the charge carriers, thereby drastically slowing the cooling process and allowing the carriers to retain much more of their initial energy for much longer periods of time. This potentially allows this extra energy to be tapped off in a hot-carrier solar cell.”

Perovskite Power, Solar Cell Style
November 3rd, 2015 by Tina Casey

Originally published on Solar Love.

Where were we? Oh right, perovskite solar cells. For those of you new to the topic, perovskite actually refers to a class of synthetic crystalline materials based on the unique properties of the naturally occurring mineral perovskite.

Perovskite offer enormous promise in terms of solar cell conversion efficiency, but they also have an enormous Achilles heel, which is their tendency to fall apart when exposed to air, especially humid air.

Just this week we took note of a futuristic new development in the field involving so called hot-carrier perovskite solar cells, but the new perovskite solar cell research from the University of California – Los Angeles (UCLA) is a bit more down to earth in terms of solving the air-phobia problem.

A team from UCLA’s California Nanosystems Institute has figured out a new way to stabilize perovskite, basically by creating a perovskite solar cell sandwich.

The conventional approach is to use an organic material as the top buffer layer, in order to get the solar-generated electricity out of the cell. However, the materials typically in use aren’t all that stable themselves, and provide relatively poor cover for the perovskite layer.

By replacing those layers with metal oxides, the UCLA team achieved a “dramatic” difference in longevity. Specifically, the new perovskite solar cells are composed of layers in this order: glass, indium tin oxide, NiOx (oxidized nickel oxide), perovskite, zinc oxide, aluminum, with the ZnO layer providing protection by keeping the aluminum from the perovskite.

In a 60-day open air test at room temperature, the metal oxide perovskite solar cells retained 90 percent of their original conversion efficiency.

Okay, so that doesn’t solve the entire problem, but it indicates that the way forward is to engineer metal oxide layers that are more dense, providing better protection for the perovskite.

You can read all about it in the journal Nature.com under the title “Improved air stability of perovskite solar cells via solution-processed metal oxide transport layer.” The study includes a relatively plain-language description of the challenges involved in engineering a long-lived perovskite solar cell.

UCLA’s press materials also provide a good snapshot of just how fast the rate of perovskite R&D is accelerating. The team started less than two years ago with a conversion efficiency of less than one percent, and it’s already closing in on the 20 percent mark. In the new study, the relatively stable version clocked in at approximately 14.6 percent plus or minus 1.5 percent, for a maximum of 16.1 percent.

Trina Solar Breaks Solar Record With 21.25% Efficient Cells
November 11th, 2015 by Tina Casey

Originally published on Solar Love.

A new solar cell efficiency record has been set by China’s Trina Solar Limited, which announced that its new p-type multi-crystalline silicon solar cell has achieved a solar conversion efficiency of 21.25 percent according to the results of third-party testing. Greater efficiency does not necessarily translate into lower costs, but the manufacturing method is based on Trina’s existing technology and the company anticipates that its new solar cell will provide an extra push to the steep downward trend for the cost of solar-sourced electricity.

Solar Cell Efficiency Records

Where were we? Oh right, the new solar cell efficiency record. For those of you new to the topic, while complex multi-layer solar cells can already achieve solar conversion efficiencies far greater than 21 percent, relatively low cost and simplicity still provides silicon solar cells with an edge in the marketplace.

Trina Solar had its solar cell efficiency rated by the Fraunhofer ISE in Germany, which just a few days ago issued a report on the current state of solar technology and markets. Here’s what Fraunhofer had to say about solar cell efficiency records for technologies on the market today:

The record lab cell efficiency is 25.6 % for mono-crystalline and 20.8 % for multi-crystalline silicon wafer-based technology.

The highest lab efficiency in thin film technology is 21.0 % for CdTe and 20.5 % for CIGS solar cells.

In the last 10 years, the efficiency of average commercial wafer-based silicon modules increased from about 12 % to 16 %. At the same time, CdTe module efficiency increased from 9 % to 13 %.

In the laboratory, best performing modules are based on mono- crystalline silicon with about 23 % efficiency. Record efficiencies demonstrate the potential for further efficiency increases at the production level.

In the laboratory, high concentration multi-junction solar cells achieve an efficiency of up to 46.0 % today. With concentrator technology, module efficiencies of up to 38.9 % have been reached.

Did you catch that first item where it said the record for multi-crystalline solar cells was *only* 21 percent? Fortunately, the researchers who put together the report prefaced the whole thing by noting that in the fast-paced world of solar cell efficiency development, their information would probably be out of date sooner rather than later.

And, they were right.

The Trina Solar Cell Efficiency Record

That mark of 20.8 percent was probably rounded up from Trina’s earlier record-setting entry for solar cell efficiency, which clocked in at 20.76 percent about one year ago.

If you’re thinking that the difference between 20.76 and 21.25 doesn’t sound all that impressive, consider that even just breaking the 20 percent barrier has been a long, hard slog. Solar cell efficiency for multi-crystalline silicon technology was still hovering around the 19.8 percent mark back in 1999. As described in the solar cell efficiency study we came across, the researchers zeroed in on a “honeycomb” surface, echoing Trina’s Honey Plus brand:

The improved multicrystalline cell performance results [partly] from isotropic etching to form a hexagonally-symmetric “honeycomb” surface texture. This texture, largely of inverted hemispheres, reduces reflection loss and improves absorption of infrared light by effectively acting as a randomizer.

In its solar cell efficiency announcement, Trina notes that it purposefully focused on low-cost, scalable processes to manufacture the record breaking solar cell, leading to high-volume commercial production. Here’s the rundown:

The record-breaking p-type multi-crystalline silicon solar cell was fabricated on a high-quality mc-Si substrate with a process that integrates advanced Honey Plus technologies including back surface passivation and local back surface field. The 156×156 mm2 solar cell reached a total-area efficiency of 21.25%.


Solar Costs Continue To Plunge Globally
November 11th, 2015 by Giles Parkinson

Originally published on RenewEconomy.

Two stunning auction results in India and Chile in the last week have underscored the extraordinary gains that large-scale solar has made against its fossil fuel competitors.

In both countries, solar is now clearly the cheapest option compared to new coal-fired power stations. In Chile, where the auction was open to all technologies, fossil fuel projects did not win a single megawatt of capacity. And the auction produced the lowest ever price for unsubsidised solar – US6.5c/kWh.

In India, US firm SunEdison won the entire 500MW of solar capacity on auction in the state of Andhra Pradesh, quoting a record low tariff for India of INR 4.63/kWh (US7.1c/kWh). Again, this was unsubsidised. And again, it beats new coal generation, particularly generation using imported coal.

These bids follow an auction in the US last month by the Texas city of Austin, which contracted to build 300MW of large-scale solar PV at a price of less than US4c/kWh. Even after backing out a tax credit, this is still less than US6c/kWh, and still beats gas and new coal plants, if anyone was planning to build one.

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Old Posted Nov 13, 2015, 3:37 AM
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Tandem Perovskite-Silicon Solar Cell Efficiency Record Broken

November 12th, 2015 by Glenn Meyers

Originally published on Solar Love.

A new tandem solar cell featuring monolithic perovskite and silicon has produced electricity with record efficiency, reports Helmholz-Berlin.

“Teams from the Helmholtz-Zentrum Berlin and École Polytechnique Fédérale de Lausanne, Switzerland, have been the first to successfully combine a silicon heterojunction solar cell with a perovskite solar cell monolithically into a tandem device.”

THZB reports this hybrid tandem cell has shown an efficiency of 18%, and while not the highest solar cell efficiency rating, this is the highest reported value for this particular type of cell architecture.

A heterojunction silicon cell provides the base for the tandem cell. A very thin layer of transparent tin dioxide was deposited on this bottom cell, followed by 500 nm of perovskite as well as 200 nm of spiro-OMeTAD hole-conductor material. Thin MO3 serves as a protective layer between this hole conductor and the transparent top electrode of ITO. Image: S. Albrecht / HZB

Explaining Tandem Cell Technology

Perovskite layers are known to efficiently absorb light in the blue region of the spectrum. But combining these with silicon layers, which convert long-wavelength red and near-infrared light, has proven to be difficult.

HZB writes, “This is because for high-efficiency perovskite cells, it is usually required to coat the perovskite onto titanium dioxide layers that must be previously sintered at about 500 degrees Celsius. However, at such high temperatures, the amorphous silicon layers that cover the crystalline silicon wafer in silicon heterojunction degrades.”

The team behind this project was led by Professor Bernd Rech and Dr. Lars Korte from the HZB Institute for Silicon Photovoltaics, working in cooperation with HZB’s PVcomB and a group headed by Professor Michael Graetzel at the École Polytechnique Fédérale de Lausanne (EPFL).

This group is the first to have fabricated this kind of monolithic tandem cell, depositing a layer of tin dioxide at low temperatures — to replace the standard titanium dioxide. A thin layer of perovskite was then spin-coated onto this intermediate layer and covered with hole-conductor material. In addition, a crucial element in the device architecture is the transparent top contact. Typically, metal oxides are deposited by sputtering, but this would destroy the sensitive perovskite layer, as well as the hole-conductor material. Therefore, the team from HZB modified the fabrication process and incorporated a transparent protective layer.

18% and High Open-Circuit Voltage

According to the research, this tandem cell attained an 18% efficiency level — nearly 20% higher than the efficiency of individual cells. The open-circuit voltage is 1.78 volts. “At that voltage level, this combination of materials could even be used for the generation of hydrogen from sunlight,” said Dr. Steve Albrecht, lead author of the paper that has now appeared in the journal Energy & Environmental Science.
Additional light catching structures may increase efficiencies

Right now the perovskite-silicon tandem cell is being fabricated on a polished silicon wafer. Efficiencies may change dramatically, states Dr. Lars Korte, head of the silicon heterojunction solar cell group at the Institute for Silicon Photovoltaics, if the wafer surface is textured using light-trapping features, like random pyramids. “The efficiency might be increased further to 25 or even 30%,” she added.

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