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Cheaper Solar Concentrators

Skyline Solar, a new startup, is combining conventional technologies to lower solar-power costs.

By Kevin Bullis

Monday, May 04, 2009

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Skyline Solar, a startup that today announced its existence to the world, has developed a cheaper way to harvest energy from the sun. The company's solar panels concentrate sunlight onto a small area, reducing the amount of expensive semiconductor material needed to generate electricity.

Sun collectors: Skyline Solar combines conventional silicon solar cells with reflective parabolic troughs (shown here).
Credit: Skyline Solar

The technology will bring the cost of solar power in line with the average cost of electricity, at least in sunny areas, says Ben Eiref, Skyline Solar's director of product management. Currently, solar power can be far more expensive than electricity from conventional sources; many governments have resorted to subsidies to increase its use.

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Skyline Solar has raised $24.6 million to date and has been awarded $3 million by the Department of Energy to speed up production. It has also installed a pilot power plant that can produce 24 kilowatts of electricity, and has started production of its solar panels with the goal of selling them later this year. They are designed for commercial installations in the 1-to-10-megawatt range, such as on food-processing and water-treatment facilities at the edges of cities or in rural areas.

The startup isn't the first company to attempt to reduce costs by concentrating sunlight onto smaller solar cells. But Skyline Solar says that it can better compete with other energy sources by combining two technologies that can be produced in high volume using existing equipment and that have been demonstrated in the field for decades: conventional silicon solar cells and reflective parabolic troughs, which are used now in solar thermal plants. In these thermal plants, the long, curved troughs concentrate light on tubes, heating up a fluid inside them that, in turn, is used to drive power-generating turbines. Skyline Solar has replaced those tubes with narrow solar panels, adding a heat sink to keep them from getting too hot. The troughs concentrate the light by about a factor of 10, increasing the power output of the panels by about the same amount as conventional solar panels without concentrators. (To compensate for the increased power output, the company has incorporated larger electrical contacts into the panels.)

Comments

  • Why not a system needing no tracking?
    Solyndra's model uses a tubular collector that needs no aiming. Would a hybrid of the "Cheaper Solar Concentrator" covered in this article be able to lower cost using a Solyndra-like collector, perhaps a larger tube to handle light reflected from a wider angle distribution plane needing no tracking system?
    Rate this comment: 12345

    ROQ
    05/04/2009
    Posts:3
    Avg Rating:
    3/5
    • Re: Why not a system needing no tracking?
      By its very nature, concentrators need tracking. there is no way a concentrator can work without tracking, as it has to be always pointed towards the sun for it to work.  In fact that is the main challenge of high concentrators (100+ suns)in that a little off-sight and the cells stop to produce electricity.  The best as of this time is the low concentrators 2-10x like our 5x concentrators.  Visit our website at www.solar-trackers.com.
      Manny Bade
      Rate this comment: 12345

      mannybade
      10/27/2009
      Posts:5
  • Excess heat
    Would it be possible to provide the cooling with water pipes that would provide domestic heat?
    Rate this comment: 12345

    boustrephon
    05/04/2009
    Posts:17
    Avg Rating:
    4/5
    • Re: Excess heat
      Silacon Corporation of Woodbury, MN recently launched production of concentrated solar multi-hybrid containing solar panels, hot water sourcing, and novel tracking that avoids the complexity of popular two-axis trackers.  A major goal was very low cost kit like construction for off-grid electricity, water heating, water purification, mineral extraction, and other features.  Solar energy focused on popular PV and energy absorbers concurrently in mixed ratios permit very high efficacy of available solar over longer sun-hour periods from tunable 0-2 suns. Main trough concentration is more than 20:1 and employs Cassegrain options. Common electronic variety extruded heat sinks modified for high absorption low emission function as excellent absorbers, heat exchangers, and hosts for concentrated solar PV arrays. Work guided by NREL and 3M Co. research permits new reflector options and trough efficiencies. Interested parties might want to check the size of the backyard first. Most work!
      Rate this comment: 12345

      Silacon
      05/06/2009
      Posts:47
      Avg Rating:
      2/5
  • Hot Spots
    Parabolic troughs create 'hot spots' on the receiver. Tube warping is an issue with conventional solar thermal due to hot spots and there are likely to be bigger issues with a PV receiver. The Compact Linear Fresnel Reflector (CLFR) route is probably better due to uniform irradiance on the receiver.
    Rate this comment: 12345

    asogan
    05/04/2009
    Posts:9
    Avg Rating:
    4/5
    • Re: Hot Spots
      3M Co. claims very good mirror films. Combined with careful attention to detail in fabrication the new films make concentrators practical. Silacon reviewed Fresnel lens finding them worthwhile yet expensive and not fault free. They work, however, for many applications. Silacon can apply both technologies as can many others. 
      Rate this comment: 12345

      Silacon
      06/08/2009
      Posts:47
      Avg Rating:
      2/5
  • 1D tracking is cheap
    These are 1D trackers, so one motor, and very little extra structural support is needed to allow a lot of panel to track. 
    In contrast, 2d trackers would be much more expensive because the entire weight and wind load gets concentrated on a column and mechanism which needs to be very robu$t right down to the foundation.
    Rate this comment: 12345

    carlp
    05/04/2009
    Posts:3
    Avg Rating:
    5/5
  • Solar Search
    Entering various terms "Solar cell, quanta/quantum, fresnel, heat and frequency" into the Wolfram/Alpha search engine (when available) should be fun.
    Rate this comment: 12345

    Phineas
    05/05/2009
    Posts:93
    Avg Rating:
    4/5
  • Heatsinks
    Concentrator solar arrays are not new, I think they are approaching 40% efficiency or more by now.

    Heatsinks?  These concentrated PV cells get very hot. It would be better to recover the heat and maybe use it in a stirling-cycle generator to produce even more electricity.
    Rate this comment: 12345

    zeddy
    05/05/2009
    Posts:5
    Avg Rating:
    5/5
    • Re: Heatsinks
      Problem with Stirling system is there's too much talk but I still have to see a stirling engine being offered for producing electricity for home comsumption.  Hey, I may be wrong, so please direct me to a site or a dealer where I could buy one.
      Manny Bade
      Rate this comment: 12345

      mannybade
      10/27/2009
      Posts:5
  • Better Solar Panels with 2X  Concentrators
    I feel this technology might be suatainable in short-term in hot places like India with average summer temprature around 45 degree celcius. Reflectors life i smore important than solar panels with considering its replacement and maintenance cost. Solar panel looses efficiency by about 0.05% with every degree rise from its standard operating temp of 25 degree C.

    Passive Heat sinks themselves will be very hot at such place and active heat dissipation will lead to high fabrication cost.

    We have developed 2X Concentrator Solar Panels with about 22% lesser cost than flat monocrystalnie solar panels. Additionally, our design doesnt requies tracking since it naturally captures wider sun horizon with inbuilt passive heat dissipation.

    Now we are trying to make easy to installl user friendly installation with on site assembly kit.

    Gaurav
    exgaurav@yahoo.com
    Rate this comment: 12345

    exgaurav
    06/13/2009
    Posts:1
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    5/5
  • Cheaper Solar Concentrators
    They have not indicated their price, so how can we evaluate if it's indeed cheap.  Our 5x concentrators are now in the market.  The technology raised production by a factor of 3x. Each unit produces 2.8 kW.  They have already been installed all over Europe.  Please visit our website at www.solar-trackers.com then call or email me for comments and more info.
    Manny Bade
    Rate this comment: 12345

    mannybade
    10/27/2009
    Posts:5

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