Looking Back at Recent PV InnovationsEnergy. The lifeblood of modern civilization. Finding clean sources of it is very high on the green movement's priority list, and one very promising field is solar photovoltaics (PV). We, at TreeHugger, have been covering the field for a while now, and we think it's time to look in the rearview mirror at some of the top PV solar innovations from our archives.
Thin Film Solar Record: 19.9% EfficiencyA shortage of silicon in the past few years and the demand for thin and flexible panels has helped increase the focus on thin film solar recently, and a lot of progress is being made. The US National Renewable Energy Laboratory (NREL) has created thin film solar panels that are very close to competing with their more traditional silicon-based cousins. "The copper indium gallium diselenide (CIGS) thin-film solar cell recently reached 19.9 percent efficiency in testing at the lab, setting a new world record."
CoolEarth Inflatable Solar BalloonsSolar photovoltaic cells are still relatively expensive, so many companies are trying to find ways to reduce the PV surface area that they use. One way to do that is to use concentrators to direct more sunlight to smaller (but usually more efficient) solar panels. But even if you do that, you still have high costs for support materials and the concentrators themselves.
That's the problems that CoolEarth is trying to solve with its inflatable solar collectors. The balloons themselves are said to be 400 times cheaper than a concentrator of the same size made of polished aluminum, and they can be mounted on wires, reducing costs further. Maintenance is also easier: You can repair them with tape, and replace one unit in about 15 minutes. Read on for more details and a promo video.
Sunrgi Xtreme Concentrated Photovoltaics: Solar Power Competitive With Fossil Fuels?Sunrgi recently made an impressive claim: They say that their system will soon be able to "produce electricity at a wholesale cost of 5 cents per kWh (kilowatt hour)." (!) They do it by concentrating the Sun's light close to 2,000 times (!!!) into extremely efficient solar photovoltaic cells. Part of Sunrgi's patent-pending technology has to do with the cooling of the solar cells, dual-axis sun tracking, and the way the whole system is optimized for mass-production. Find out more about it in our post about Sunrgi's concentrated solar power.
'Hairy' Thin Film Solar Panels Using NanowiresWe often hear about new exotic materials and strange shapes, but this could be the weirdest announcement yet: Researchers at McMaster University (coolest name ever) have succeeded in 'growing' light-absorbing nanowires made of high-performance photovoltaic materials on carbon-nanotube fabric. In other words, hairy solar panels.
The aim is to produce flexible, affordable solar cells that, within five years, will achieve a conversion efficiency of 20%. Longer term, it's theoretically possible to achieve 40% efficiency!
Moth Eyes Biomimicry for Solar PanelsSilicon is reflective, so a lot of light that could be turned into electricity is bounced back and lost. Anti-reflective coating is used, but its effectiveness is limited and it has downsides too. So while looking for a solution, researchers noticed that moths have very non-reflective eyes ("most likely an evolutionary defense against nocturnal predators"). The moth-eye process creates panels that reflect less than 2% of light. That's a vast improvement over the 35 to 40% reflection rate seen without the anti-reflection coating layers.
Solaria: 90% of the Power with 50% of the SiliconSolaria's solar cells produce about 90% of a conventional solar panel's power, while using half as much silicon, thus reducing costs. "Ordinarily, the silicon in a solar panel spans its surface, collecting light from as much area as possible. But Solaria slices the silicon into thin strips and spaces them apart so that they only account for about half the panel's area. A clear molded plastic cover collects light from the entire panel and funnels it to the strips of silicon." For more information, including images, see our post about Solaria's solar panels.
1366 Technologies: Bringing Solar Power Closer to $1/WattThese guys are really clever. 1366 Technologies, a company named after the solar constant (there are 1366 watts of solar radiation hitting each square meter of the Earth on average) is working on improving multi-crystalline silicon solar panels. Three different innovations allowed them to make their prototype 27% more efficient than conventional multi-crystalline silicon solar cells, bringing its total efficiency to 19.5%, about the same as single-crystal silicon solar cells (which are more expensive). For more details on these three innovations, see our post about 1366 Technologies' solar panels.
Day4 Energy's Innovation: 25% Cheaper Solar PanelsBeating solar PV efficiency records in the lab is great but in the short-term, what matters most is what makes it to market. That's why Day4 Energy's recent innovation is so interesting: It should cut the cost of panels by 25% by increasing the efficiency of their cells to 17-18%, and the new panels should be on the market within 18 months. For more details on how they do it, see our post on Day4 Energy's solar panels.
Nanosolar: Driving Down Costs by 'Printing' Solar PanelsNanosolar is a company based in Palo Alto, California, which uses an innovative technique to produce a kind of "solar film". To make the film, Nanosolar prints CIGS (copper-indium-gallium-selenium) onto a thin polymer using machines that look like printing presses. There is no costly silicon involved in the process, and, ultimately, a solar cell from Nanosolar will cost about one-fifth to one-tenth the cost of a standard silicon solar panel. Nanosolar has raised a lot of money, including from Sergey Brin and Larry Page, and from France's EDF with investments of $50 million, and they are now ramping production as fast as possible. See more in our post about Nanosolar and in the video below.
General Electric: Printing OLEDs and Solar Panels
Not strictly a solar panel innovation, GE's process to print out rolls of OLEDs could also be applied to solar panels, according to the company. This could help reduce costs and simplify manufacturing processes. Read more about it in our post about GE's "major milestone": printing organic LEDs like paper, also applicable to solar panels.
Converting Infrared Light to ElectricityBy adding titanium and vanadium into the semiconducting material of a solar panel, you can alter it so that it can use the infrared spectrum of light as well as the visible. Because of this, such solar panels have a theoretical absorption limit of 63%, which compares to about 40% for ordinary solar cells. Read more about it in our post about using the infrared spectrum in solar panels.
First Solar's Cadmium Telluride Solar PanelsSome experts are speculating that First Solar might beat over 80 competitors to achieve manufacturing costs low enough to market solar panels at less than $1 per Watt, the target considered necessary for solar to compete with coal-burning electricity on the grid. Read more about it in our post about First Solar's Cadmium Telluride solar panels.
AVA Solar: Cadmium Telluride Thin Film at $1/WattAnother company working on cadmium telluride thin film is AVA Solar. They claim the panels will cost about $1/watt to manufacture, and will cost customers about $2/watt, which is about half what regular panels cost these days. Read more in our post about AVA Solar's Cadmium Telluride solar panels.
Japan Hopes to Have Solar Power Station in Space by 2030f and when this project is completed, it is envisioned that it will have to be physically massive, let alone costly: the orbiting solar portion could stretch for kilometers and weight 10,000 tonnes; the laser portion could be as long as 10 kilometers; the ground-based receiving unit could be up to two kilometers long. Read more in our post about Japan's plans for a solar power station in space.
EMCORE Solar Cell Sets Efficiency RecordDeveloped in conjunction with the National Energy Research Laboratory and the US Air Force Research Laboratory, EMCORE's Inverted Metamorphic Multi-Junction Solar Cell Technology (IMM) has set a world record for in-orbit conversion efficiency of 33%. When adapted to use in the company's terrestrial-based concentrator photovoltaic systems (CPV), efficiencies between 42-45% (!) are expected to be achieved. Read more in our post about EMCORE solar panels.
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