Lexicon: Single & Dual Axis Solar Trackers

photo: Concentrix Solar

Nevermind Single or Dual Axis varieties, what are solar trackers?

In the broadest sense solar trackers move the solar panel so that it is position as close to optimum as possible in relation to the angle of the sun, across seasons and time of day. Compared to just laying a panel flat, correct positioning can boost the panels output by up to 15%, but by using a motorized tracker gains due to efficiency of between 27-40% can be achieved.

Currently, there exist two types: Single Axis and Dual Axis. Single axis trackers move on one axis over the course of the day, following the sun; doing so can boost output by about one-third. Dual axis trackers on the other hand move both east and west but also vertically; this can increase output by 35-40% as compared to a flat panel.

Single-axis tracking is one of the most straightforward ways to improve the potential performance and economics of a commercial solar installation. By using relatively simple equipment, considerably more performance can be expected. Tracking system manufacturer RayTracker, for example, says its systems have been proven to improve energy yield over fixed angle modules by up to 23% and over flat modules by 38%.

Manufacturers of the simpler, single-axis devices have claimed that the additional net energy yield delivered by a dual-axis system over a single-axis system is frequently lost as a result of additional installation, permitting and on-going maintenance costs. And, such systems are at greater risk of failure, having more moving parts than a single-axis tracker. Furthermore, single-axis trackers tend to have a lower profile, sometimes half the height of dual-axis trackers, and are therefore more likely to receive planning permits.

$467 Million in Stimulus Money Released for Solar Power & Geothermal

photo: David Blaikie via flickr.

Solar power and geothermal power have finally gotten their portion of money allocated in the American Reinvestment and Recovery Act, to the tune of $467 million. President Obama announced this by touting the usual rhetoric of decreasing dependency on foreign oil and putting people back to work in through green energy jobs. Energy Secretary Stephen Chu too talked up green jobs, plus the role renewable energy can play in combatting climate change Frankly, absolutely nothing new or novel was said, but it is great that solar and geothermal have finally been shown some federal stimulus love. This is how all that money is being divided up:

Geothermal to Get Most of the Funding
All told geothermal is getting $350 million: $140 million is going toward Geothermal Demonstration Projects; $80 million towards Enhanced Geothermal Systems Technology Research and Development; $100 million towards Innovative Exploration Techniques; $30 million towards a National Geothermal Data System, Resource Assessment, and Classification System.

Solar Power Gets One-Third of Geothermal
Solar power has been allocated $117.6 million: $51.5 million for Photovoltaic Technology Development; $40.5 for Solar Energy Deployment (“Projects in this area will focus on non-technical barriers to solar energy deployment, including grid connection, market barriers to solar energy adoption in cities, and the shortage of trained solar energy installers.”); Concentrating Solar Power Research and Development brings up the rear with $25.6 million.

More: Department of Energy

World’s Largest Solar Tower Now Powers 10,000 Homes

Photo via Abengoa

The world’s largest solar power tower just began operating outside Seville, Spain—and it marks a historic moment in the saga of renewable energy. The solar tower PS20, seen above right next to its smaller sister PS10, produced even more power than expected over the course of its trial testing. It’s been confirmed that the groundbreaking solar tower generates 20 megawatts of electricity: and it’s now powering 10,000 homes with renewable energy.

The tower, built and operated by Abengoa Solar, is one of the more innovative examples of solar technology. Though we’ve seen similar solar towers before, we’ve never seen it executed on such a scale.

How the World’s Largest Solar Tower Works
Here’s how it works, according to Abengoa:

PS20 consists of a solar field made up of 1,255 mirrored heliostats designed by Abengoa Solar. Each heliostat, with a surface area of 1,291 square feet, reflects the solar radiation it receives onto the receiver, located on the top of a 531 feet-high tower , producing steam which is converted into electricity generation by a turbine.

As for the energy benefits? Well, of course there are many: by Abengoa’s calculations, the plant will prevent over 12,000 tons of CO2 from entering the atmosphere. And combined with PS10, which generates 10 megawatts of power, both stations combined are a renewable energy force to be reckoned with.

This is yet another sign that the renewable energy revolution is ramping up—Spain has long been a leader in alternative power, and this is yet another clean energy victory. But what’s even more encouraging is that Abengoa Solar now has a presence in 70 countries around the world—will we be seeing massive solar power towers springing up all over?

Thermal Photovoltaics Breakthrough Boasts Theoretical Efficiency of 85%

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Theoretical Efficiency of 85%!
Thermal photovoltaics has been around since the 1960s, but it never produced enough power to compete with solar thermal using steam turbines, or more traditional photovoltaic solar panels. However, recent breakthroughs at MTPV Corp. (which stands for Micron-Gap Thermal Photovoltaics, the name of the technology they’re using) supposedly deliver “an order of magnitude” more power than regular thermal photovoltaics.

What’s the difference between conventional solar panel and photovoltaics from thermal photovoltaic systems?

A conventional solar panel absorbs light from the entire spectrum, but it only converts certain colors efficiently. Much of the energy in the other wavelengths of light goes to waste. As a result, the maximum theoretical efficiency of a conventional solar cell is 30 percent, or 41 percent if the sunlight is first concentrated using a mirror or lens. In a thermal photovoltaic system, light is concentrated onto a material to heat it up. The material is selected so that when it gets hot, it emits light at wavelengths that a solar cell can convert efficiently.As a result, the theoretical maximum efficiency of a thermal photovoltaic system is 85 percent.

-Technology Review

Using “micron-gaps” between the heated part and the photovoltaic part (instead of the traditional bigger gaps), they claim to have increased the flow of photons to the solar panel by 10 times compared to traditional TPV technology, which not only makes the whole thing less expensive (coupled with the fact that 1/10 as much solar-cell material as traditional TPV is used), but also lowers its working temperature significantly.

The 85% efficiency theoretical figure mentioned above is of course very hard to reach, but MTPV’s computer models show that 50% efficiency should be possible. So far the company has reached 10 to 15%, which is similar to many other solar panels on the market (not bad). With a bit more progress (it probably hasn’t been getting much R&D effort compared to silicon and thin film solar cells), this technology could become a big player in the solar power world.

Via Technology Review, MTPV

IKEA Puts $U.S. 75 Million Toward Cheap Solar

Johan Stenebo is chief of an IKEA susidiary called Greentech, and a man with a dream. Stenebo wants to invest in the “cheapest, best” PV roof panels available in order to sell them in IKEA stores in the next two to four years.

Low-cost solar a tall order
Of course, that’s a very tall order. But IKEA founder Ingvar Kamprad‘s son Peter is an avowed green tech believer, and Stenebo’s Greentech will put about US$75 million into at many as ten companies in five different areas: solar technology, energy conservation, water saving products, alternative lighting, and new product materials. Scandinavian companies are Greentech’s first focus. Nearly all of these areas are ones we would welcome the IKEA low-cost approach to, although setting up solar roof panels with just the simplistic diagrams and little Allen keys that accompany IKEA’s usual do-it-yourself furniture seems something of a stretch. Then there’s the problem than many installations require building and other permits. But IKEA’s fabulous distribution network of 270 global superstores would mean green tech for the global masses, a welcome development.

Solar supermarkets in four years?
Up until now, IKEA has held itself to interior decoration rather than pursuing the constructing and building sector that is dominated (at least in the U.S.) by players such as Lowe’s and Home Depot. But these megastores haven’t tried to sell green solutions in any organized fashion, so IKEA sees little current competition for its plans to get products to stores in three to four years. Via ::Miljö Aktuellt (Swedish)

Read more on IKEA:
IKEA Bans Plastic Bags For Good
IKEA Gives Out 60,000 Free CFLs
IKEA Lighting The Way To Warmer LED Lamps

Source:

“IKEA Puts $U.S. 75 Million Toward Cheap Solar”, treehugger.com, Business & Politics, April Streeter, 14th Aug 2008

General Motors Factory to Host World’s Largest Rooftop Solar Array

photo courtesy of General Motors

General Motors has partnered with Clairvoyant Energy, Veolia Environmental and the Government of Aragon to install what will be the world’s largest rooftop solar array on its Zaragosa, Spain assembly plant.

According to GM, the array will be 12 MW in size and cover two million square feet and consist of approximately 85,000 panels. Installation is expected to be completed this fall. The space for the project will be leased from General Motors by Veolia Environment and Clairvoyant Energy, who will operate and maintain the installation. According to GM the project will help the corporation reduce costs, while at the same time providing green power to the local electric grid.

General Motors already opeates rooftop solar arrays on two of its California warehouses, which provide up to 50% of electricity used in these facilities.

The previous record holder in this fast changing category, and the reigning US champion, is the solar array on Atlantic City’s convention center, which is a mere 2.36 megawatts.

Solar Power links by treehugger.com
Intel Invests in Solar Power, Forms New Company
Duke Energy Announces 20 Megawatt Solar Power Project in North Carolina

Investment in Solar Cells to Equal Semiconductors by 2010

by Matthew McDermott, Brooklyn, NY on 24th June ’08 for treehugger.com

photo by Jørgen Schyberg

As if we didn’t hit you every day with more evidence that the solar industry is booming…

Market research group iSuppli is reporting that worldwide investments in the production of solar cells will equal those for semiconductor manufacturing by 2010. Global production is expected to rise from 2007 levels of 3.5 GW to up to 12 GW in that time. Production lines capable of manufacturing 1 MW or more of PV cells will increase from the 90 to 100 which existed in 2007, to perhaps 400 by 2010. Factories capable of1 GW of PV production annually also will be established in the future, the report says.

“The market for PV cells is estimated to grow by 40% annually until 2010, and 20% beyond,” said Dr. Henning Wicht, an iSuppli analyst. He went on to say the heavy investments will be required to finance this production: “Each PV factory will require an investment of $500 million and more, will employ as many as 1,000 workers per site, and will generate annual revenue of $1 billion per year or more.”

via :: Earth2Tech

Solar Power by treehugger.com
Solar Power to Reach Parity by 2015, New Study Claims
New Thin-film Solar Cell Coater Reaches 1GW Annual Output
Intel Invests in Solar Power, Forms New Company

My Input:

WOAH!

New Thin-film Solar Cell Coater Reaches 1GW Annual Output

by Matthew McDermott, Brooklyn, NY on 19th June ’08 for treehugger.com

What you’re watching above is a new thin-film coater from Nanosolar in action. The San Jose-based company calls the machine a “milestone in solar technology” and while usually such language is standard PR hyperbole, considering that 10-30MW in annual production through other methods is usual, the 1 gigawatt annual throughput of this coater really is a cut above.

Nanosolar says the way in which it can achieve such high levels of production is through its proprietary nanoparticle ink, which allows them simply print their highly efficient (up to 14.5%) solar cells at rates up to 100 feet per minute.

The cost of the coater is $1.65 million, which is significantly less expensive that vacuum process tools, as well as being much faster in operation.

Nanosolar began shipping its first panels last December.

:: Nanosolar

Other Links by treehugger.com
EDF Energies Nouvelles Invests $50M in Nanosolar
Nanosolar: Printing Solar Film Like Paper
19.9%: New Thin Film Solar Efficiency Record
Sharp Invests $725 Million in 480 MW Thin-Film Solar Plant

See Also from The Green Guy Blog:

New Solar Cell Rivals Silicon-Based Ones

(Another article on Thin-film Solar Cells except from another company. Tells you a lot about the competition in this field yea?)

New Solar Cell Rivals Silicon-Based Ones

 

Photo Credit: straylight6 on flickr

Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory have moved closer to creating a thin-film solar cell that can compete with the efficiency of the more common silicon-based solar cell. 

The copper indium gallium diselenide (CIGS) thin-film solar cell recently reached 19.9 percent efficiency, setting a new world record for this type of cell. Multicrystalline silicon-based solar cells have shown efficiencies as high as 20.3 percent. The energy conversion efficiency of a solar cell is the percentage of sunlight converted by the cell into electricity.

“This is an important milestone,” said NREL Senior Scientist Miguel Contreras. “The thin film people have always looked for matching silicon in performance, and we are reaching that goal.”

CIGS cells use extremely thin layers of semiconductor material applied to a low-cost backing such as glass, flexible metallic foils, high-temperature polymers or stainless steel sheets. Thin-film cells require less energy to make and can be fabricated by a variety of processes.  Because of this, they provide a promising path for providing more affordable solar cells for residential and other uses. The CIGS cells are of interest for space applications and the portable electronics market because of their light weight. They are also suitable in special architectural uses, such as photovoltaic roof shingles, windows, siding and others.

Researchers were able to set the world record because of improvements in the quality of the material applied during the manufacturing process, boosting the power output from the cell, Contreras said.

Members of the record-setting team at the National Center for Photovoltaics include Contreras, Ingrid Repins, Brian Egaas, John Scharf, Clay DeHart and Raghu Bhattacharya.

NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for DOE by Midwest Research Institute and Battelle.

So watch this space.

References:

National Renewable Energy Laboratory, News Releases, 24th March 2008

Record Makes Thin-Film Solar Cell Competitive with Silicon Efficiency