Reply #18: This might be better for home use [View All]

[iconoclastNYC]

The SunBall™ rooftop solar system.



Incorporates a high efficiency (>30%) solar energy concentrator (Fresnel lens), an automatic dawn to dusk sun tracking system and solar cells.

"The company's goal is to reduce the delivered cost of rooftop generated photovoltaic (PV) kWhs to below that available from the grid. Solar PV then becomes a sensible financial and logical choice for domestic and commercial electricity users."

The Sunball uses Spectrolab 35-38% efficiency triple junction solar cells similar to those used in the Mars rovers.

Using "Max kWh Tracking"™ the the sun is continually tracked to ensure the best power generation. This is done by continuously searching the sky to obtain the maximum PV current. The internal microprocessor can also command an increasing spiral sky scan to find and lock onto the sun or brightest sky spot if the sun is obscured by clouds.

Their website shows a map of the US with cost of electricity per kW for various regions. This shows a cost per kWh of $0.072 to $0.084 in the sunniest southwestern states and $0.126 to $0.168 in the upper Midwest and northeast for four 1 m2 , 1.3 Wp SunBall's at $6000 25 year life and no rebates. (the second site listed gives the cost as $6,400 plus inverter).


http://thefraserdomain.typepad.com/energy/2005/09/sunball_rooftop.html