I wrote a little something about Cool Earth Solar over a year and a half ago, but lately there’s been some recent developments. To recap, the Cool Earth Solar concept is to make solar concentrators that are essentially big balloons. They are made of cheap plastic (basically consisting of the same stuff that’s used to make those metal foil coated party balloons – by making one half of the balloon transparent, and the other side of the balloon shiny, their concentrators can focus sunlight at 400 to 500 times its normal intensity on to a water cooled solar cell mounted in the center of the balloon. The concentrator also tracks the movement of the sun.
Using this technology, each Cool Earth Solar balloon can generate about 1 kilowatt of power at peak sunlight, and the company feels that they can deliver solar energy at about $1 per installed watt, which would make the cost about the same as the installed watt cost for a large coal-fired power plant. While one drawback is that the balloons won’t last very long – estimates are for about a year before the balloon will need to be replaced – the company says that the cost of replacement will be very low.
Next month, Cool Earth Solar plans to install a number of its solar concentrating balloons at its headquarters located in Livermore, California. Using data from the prototype, early in 2009 the company plans to build a 1.5 megawatt plant that will consist of 1,000 of these balloons placed over 12 acres of land. In 2010, Cool Earth Solar says that it has plans to build an even larger solar plant.