Saudi Arabia wants to spend over $100 billion to build vast solar arrays and reduce its dependency on oil to generate electricity. But desert sandstorms pose a major challenge to keeping solar panels clean and efficient.

Japanese startup Miraikikai is developing a solution to getting rid of this pesky dust and grit: a cleaning robot that doesn't need water.

The firm has produced the Wall Walker wall and ceiling robot, and recently unveiled a prototype solar panel cleaner built with researchers at Kagawa University.

It weighs about 24 pounds -- light enough to be carried by one person -- and measures about 22 inches across.

It cleans with a rotating brush and can operate for up to two hours on a battery charge.

The robot's efficacy has been demonstrated in arid regions, Miraikikai said in a release, and the machine can clean panels as well as human workers.

Making optimal use of the device would result in low-cost cleaning even in areas with relatively cheap labor costs.