Solar panel output predictions?

Discussion in 'All Things Boats & Boating' started by zimbodave, Apr 27, 2016.

  1. zimbodave
    Joined: Jan 2016
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    Location: Zimbabwe

    zimbodave Junior Member

    Like many people, I'm interested, and having a good look at powering a boat with solar panels.
    Current efficiencies are sitting at about 20-22%
    That is what Solar City are claiming their latest panels produce actually coming out the wire.
    Panasonic have test cells they claim are around the 40% mark but these will not be available for some time.

    I haven't found much on Google. Does anyone have a good idea of where solar panel conversion efficiency will be in ten years time?

    Currently 220W / m2 is pretty good. I wonder if we'll be at 400W / m2 in ten years?

    Your thoughts? Can anyone point me to an online resource that makes any kind of accurate predictions regarding power output in the future?

  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Sun radiation is the limiting factor. The maximum is about 1KW/square meter. That assumes the panel being perpendicular to the solar radiation, and there being not clouds, fog or dust in the air. Are you talking about peak production for a few minutes a day, or average?
  3. zimbodave
    Joined: Jan 2016
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    Location: Zimbabwe

    zimbodave Junior Member

    Hi Gonzo,

    At the moment talking about peak production. Wondering where peak production is likely to be in ten years time.
    Realise the max possible is 1kW /m2 as that's all that comes through the atmosphere.
    It would be great if we were up to 40 or 50% efficiency in ten years time, it would make a big difference to viability of solar electric powered boats. Just wondering if anyone has an accurate idea where the industry is likely to be?


  4. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    I am thinking mid 40's % efficiency will be the common standard.
    And 60 to 70% for the most efficient cells.

    I actually think the future of a road engines is no piston engines.
    They will be electric motor with gasoline fuel cells with efficiency of 80 to 90% versus 30% or less today and they will also have batteries maybe. But if the gas fuel cell which directly turns gas into electricity works well, then why bother with the extra expense of batteries.

    Gasoline is never going away. The gasoline fuel cell will run at an elevated temp like a SOFC.
    The future of diesel is less certain. it is perceived still as very dirty fuel and hard to prevent pollution and smog. It is falling from political favor for pollution reasons.

    This earth will never run out of oil that is affordable to most people in developed countries. Some real poor person, well they can not hardly afford to buy food or a place to stay.

  5. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    The published efficiency figures come from tests done at standard 25°C air temperature and wind speed of 1 m/s.
    Everything else being equal, at other temperatures the efficiency will vary according to the formula:
    Eff(T) = Eff(25°)*[1-0.004*(T-25°)]
    The V-I curve will also accordingly undergo a shift:
    PV voltage drop.gif

    Hence, at air temperatures higher than 25°C the voltage drops (for the same current) and so does the efficiency. For air temperatures lower than 25°C the opposite happens.

    For example, if a nominally 22% efficient solar panel (Eff(25°)=0.22) is placed at 35°C air temperature at 1 m/s the efficiency will drop to Eff(T)=0.22(1-0.045)=0.21 or 21%.
    However, when the panel is exposed to a direct sunlight or is placed in an area of stagnant air, cells will be washed by a film of hot air (like 40-50°, and up to 65°C). In that case the efficiency will have a further drop, down to approx. 19%.

    That's an important thing to bear in mind when calculating the actual peak power output of a PV module.
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