SunPower Corp. (SPWR), the second-largest U.S. solar manufacturer, bought Greenbotics Inc., maker of robots that clean panels to increase the amount of power they can generate.

The robots clean dirt and dust off of photovoltaic and solar thermal arrays and cut water use by 90 percent, San Jose, California-based SunPower said today in a statement. Terms of the deal, the seventh acquisition SunPower has done since it was formed, weren’t disclosed.

SunPower plans to use the systems at projects it develops, especially in the western U.S., the Middle East and Chile, as an alternative to pressure washers and sprayer trucks. The robots will cut water use, save money and boost annual energy yield in dry, dusty regions by as much as 15 percent, according to the release.

“It’s half the cost of normal cleaning,” SunPower Chief Executive Officer Tom Werner said in an Nov. 1 interview. The technology, which he likened to a Roomba vacuum cleaner, “is one we can scale.”