Companies such as PV Kraftwerker and Gehrlicher in Germany are developing mobile robots that can automatically install ground-mounted solar panels day and night, in all sorts of weather, Technology Review reports.

The main idea is to save money on labor, which accounts for a growing fraction of the cost of solar power as panels get cheaper.

According to PV Kraftwerker, a construction firm specializing in solar parks, installations that used to require 35 workers can now be done with just three workers in an eighth the time.

For a 14-megawatt solar plant, the company estimates, it might cost about $2 million to install the panels manually. Using the robot could cut that cost by nearly half. The company says that the robot, which lists for $900,000, could pay for itself in less than a year of steady use.

PV Kraftwerker built its robot from off-the-shelf Japanese components. The machinery consists of a robotic arm mounted on an all-terrain vehicle with tanklike tracks. Suction cups grip the glass face of the solar panels and the arm swings them into place, guided by cameras that give the robot a three-dimensional view of the scene.