Introduced by Sustainable Technologies (SusTech), the VariSun Controller uses captured sunlight to power irrigation pumps. While the product is targeted to California because of an approaching deadline for replacing diesel-powered motors, it can be shipped out of state. The controller is part of a solar-powered mobile unit that can be connected to an electrical grid or work off-grid in remote locations. The system uses DC power to control the speed of three-phase AC motors. Depending on pump size and energy needs, SusTech can custom-design solutions for farmers. Without the three-phase pump, the 1-hp VariSun Mobile Solar System costs about $7,200 with a four-panel, 1,080-watt system. The 2-hp to 3-hp VariSun Mobile Solar System costs $11,500 with a 10-panel, 2,700-watt system, without the three-phase pump. The 5-hp VariSun Mobile Solar System ranges from $18,200 to $19,700 with 16 to 20 panels and a 4,300- to 5,300-watt system. The 2- to 3-hp VariSun control panel, ready to connect to a solar array, costs $3,000. Larger systems are also available. For more information, call SusTech at (510) 523-1125 or e-mail VariSun@sustainabletech.cc.