Wednesday, July 22, 2009

Solar Design Spotlight

shadow knowsWe’re talking hot stage lights and big, bright bulbs streaming sharp shafts of white light into the night sky. It may seem illogical to juxtapose solar energy with the metaphor of such a luxuriant glare. Yet, in this case, the metaphor’s juxtaposition tempts with a delicious, irresistible irony.

Rate Crimes has presented critiques of energy policy that are based on economic analyses of solar energy. These critiques have focused on the repressive and obscure policies of the electric utilities, government, and other bodies of influence in Arizona. The purpose of these analyses and commentary is to expose how and to understand why the rapid adoption of solar energy in the sunniest climes has been delayed, if not defeated. Policy makers certainly have earned criticism, but others have also contributed to the defeat of solar energy. In a survey of culpable parties, it would be remiss to omit mention of the foibles and failings of the solar industry. The first to gain mention deserves the ‘spotlight’ unlike any other.

The sun defeats the flame of any spotlight. Apparently, a fool can still make a spotlight defeat the sun.
spotlight shaded solar array

Yes, you are correctly seeing that. Someone actually designed a set of high-intensity lamps so that they shade a solar array. This solar array is losing significant energy. It is also possible that the life of the shaded modules will be shortened.

Normally, one might assume that the solar energy company that designed and installed this system was unaware of what must have been a later, unexpected ‘modification’ by another party. However, in this case, this image was published on the solar energy company’s website homepage as one of a series of images advertising their portfolio!


  1. This comment has been removed by a blog administrator.

  2. Apologies for my previous flippancy. My point is that, although an engineer may see an ill-conceived arrangement here, to the layperson this represents a well-intentioned and effective step in the right direction for sensible energy. Why denounce what appears to be a reasonably ambitious project for a minor design flaw?

  3. Thank you for continuing the conversation. Your contributions are much appreciated.

    What may appear to be a minor design flaw is actually quite egregious for technological, economical and policy reasons.

    Technologically, the crystalline modules employed in this design are particularly susceptible to shading. The shadows being cast by the lighting assembly are large enough to diminish current from a solar cell. Shading even a single cell can diminish the output of a crystalline module by as much as 75%. The cells are connected in series within the module, just as the modules are connected in series within each string in the array. This arrangement results in a cascade effect where even a single shaded cell will dramatically diminish the output of the entire string within the array.

    This diminished output multiplied over the decades-long life of the system may well cancel the economic benefits of an investment in solar energy. As is explained here on Rate Crimes, the value of solar electric energy in Arizona is more than economically competitive with the traditional, toxic fuels.

    It is crucial that the full value of solar energy be realized. If even supposedly experienced solar energy companies are incapable of delivering sustainable solar solutions, then architects, engineers, designers, and contractors unfamiliar with solar energy can hardly be expected to perform any better.

    The current economic troubles and the increased awareness of environmental challenges have inspired many neophytes to explore solar energy in Arizona. It is particularly important now to provide these initiates with examples of both excellent designs, and dramatic failures. The example presented in this ‘spotlight’ is a dramatic failure.

    This example is even more so a failure because it was produced by a solar energy company that has a very long record and should be more responsible. By promoting such a poor example of solar energy system design they do a great disservice to the industry.

    Good intentions alone will not pave the road to sustainability.