Slashdot Mirror

← Back to Stories (view on slashdot.org)

Bigger, Cheaper Solar Cells

Posted by Soulskill on from the not-quite-DIY dept.

Phenombecile800 writes "First Solar, a start-up from Arizona, is making photovoltaic cells at a fraction of the usual cost. Their secret: increasing the light-catching area 'from postage-stamp to traffic-sign dimensions,' reducing the manufacturing time to 1/10th of the competition's, and thinning the active element to 1/100th the usual thickness over a glass substrate, which enables the production of large panels. IEEE Spectrum provides some technical details about the production process. 'Glass is placed on rollers and fed into the first chamber, where it is heated to 600 C. Then it is transferred into the second chamber, which is full of cadmium sulfide vapor, formed by heating solid CdS to 700 C. The vapor forms a submicrometer deposit on the glass as it moves through this cloud, after which a similar process in a third chamber adds a layer of micrometers-thick CdTe in about 40 seconds. Then a gust of nitrogen gas rapidly cools the panels to 300 C in a fourth chamber, strengthening the material so that it can withstand hail and high winds.'"

3 of 370 comments (clear)

  1. The old green question by gilgongo · · Score: 5, Interesting

    It's probably unanswerable, but I wonder how much energy it takes to make these cells, and how long it takes for them to offset that?

    --
    "And the meaning of words; when they cease to function; when will it start worrying you?"
    1. Re:The old green question by Anonymous Coward · · Score: 5, Interesting

      It's probably unanswerable, but I wonder how much energy it takes to make these cells, and how long it takes for them to offset that?

      We can answer anyway without even RTFA. The summary says that the cells are made out of glass (not hewn out of a crystalline ingot of silicon). Assuming 10% efficiency and 20% availability of sunlight (due to weather and geometry), you get approx 20W/m^2, or 1 kWh every two days.

      Given that glass beer bottles cost a few cents each, a square meter of glass probably takes no more than a few dozen kWh of energy to produce. Even if the vapor deposition doubles or triples that, you still would end up with an energy surplus after just a couple of months of operation.

  2. Re:The old black question by dubbayu_d_40 · · Score: 4, Interesting

    What's a better use of oil, making persistent sources of energy, or driving to 7-11 for nachos?