A new design for inverters invented by Ideal Power Converters, in Spicewood, Texas, could significantly lower the cost of solar power and make it practical in more places.

Ideal Power Converters cuts solar installation costs by cutting the size of inverters, the devices that convert the DC power made by solar panels into the AC power needed for households, or the grid. Ordinarily, 30 kilowatt inverters are about the size of refrigerators and too big to fit inside existing mechanical rooms in many buildings. In many cases, installers have to build small outbuildings to house them, and use cranes or forklifts to move them into place.

Ideal’s inverters are as small as a suitcase and weigh 42 kilograms, so they can be easily mounted on a wall. The ease of installation is enough to shave 15 cents per watt from an installation, says CEO Bill Alexander, which adds up to thousands of dollars for the large rooftop installations the company’s inverter is designed for. 

Such a savings can make more solar installations affordable and speed up the growth of solar power capacity. Installation and the cost of inverters and other equipment besides solar panels can account for up to 80 percent (about $2 to $4 a watt) of the total cost of solar power.

The technology is a new inverter design that makes use of a technique called soft switching, which allows conventional silicon transistors to switch at very high speeds. This makes possible circuits that replace the heavy transformers and electronic filters used in conventional inverters with inexpensive and lightweight switches and capacitors. Alexander says the company expects to start selling the inverters in May.