It strikes me as common sense that if you need nothing more than a magnifying glass to start a fire, there's free solar power anywhere. Yet concentrating solar power in such a manner is not what ordinary solar collectors do. Until recently, that is. IBM seems to have figured out how to use the magnifying glass principle to dramatically shrink the amount of space and number of components needed to build a solar farm:

By mimicking the antics of a child using a magnifying glass to burn a leaf or a camper to start a fire, IBM scientists are using a large lens to concentrate the Sun's power, capturing a record 230 watts onto a centimeter square solar cell, in a technology known as concentrator photovoltaics, or CPV. That energy is then converted into 70 watts of usable electrical power, about five times the electrical power density generated by typical cells using CPV technology in solar farms.

If it can overcome additional challenges to move this project from the lab to the fab, IBM believes it can significantly reduce the cost of a typical CPV based system. By using a much lower number of photovoltaic cells in a solar farm and concentrating more light onto each cell using larger lenses, IBM's system enables a significant cost advantage in terms of a lesser number of total components.

For instance, by moving from a 200 sun system ("one sun" is a measurement equal to the solar power incident at noon on a clear summer day), where about 20 watts per square centimeter of power is concentrated onto the cell, to the IBM Lab results of a 2300 sun system, where approximately 230 watts per square centimeter are concentrated onto the cell system, the IBM system cuts the number of photovoltaic cells and other components by a factor of 10.

The trick lies in IBM's ability to cool the tiny solar cell. Concentrating the equivalent of 2000 suns on such a small area generates enough heat to melt stainless steel, something the researchers experienced first hand in their experiments. But by borrowing innovations from its own R&D in cooling computer chips, the team was able to cool the solar cell from greater than 1600 degrees Celsius to just 85 degrees Celsius.

The initial results of this project will be presented at the 33rd IEEE Photovoltaic Specialists conference today, where the IBM researchers will detail how their liquid metal cooling interface is able to transfer heat from the solar cell to a copper cooling plate much more efficiently than anything else available today.

While using this techology to build solar farms is commendable, I wonder how soon it will be before they start selling home units.

(And speaking of energy, with the price of gasoline continuing to escalate, I wonder how long it will be before people resort to home distillation or ethanol. Sugar is still cheap, and this unit will produce 35 gallons of car fuel per week, at $1.00 a gallon. More here, and remember, "home ethanol production was advocated and used by Henry Ford when he created the Model T.")