Solar power remains the most viable option in the fight to replace fossil fuels. Yet, it still accounts for less than two percent of the world’s total electrical output, despite a drastic decrease in the prices of solar panels. In a bid to make solar power more economical, two companies in Germany have developed mobile robots to install solar panels.
The limiting factor in solar power technology is electrical output. Each square meter of solar panel generates around 145 watts of electricity, just enough to power two or three lightbulbs. That means you have to cover over two square kilometers of land with solar panels in order to match the peak capacity of a large fossil-fuel power plant. Each of those panels needs to be manually installed.
PV Kraftwerker and Gerlicher in Germany have developed mobile robots that can install ground-mounted solar panels day and night, in all types of weather. The main purpose is to save money on labor. Installations that previously required 35 workers can now be done with only three workers in less than a quarter of the time.
PV Kraftwerker is a construction company specializing in solar parks. The company estimates that for a 14-megawatt solar plant, the cost of installing the panels would be around $2 million. Using a robot could cut that cost by half.
The robots can be considered investments that cost $900,000 per unit. The company says return of investment is guaranteed with steady use in less than a year.
Automated labor could be an invaluable asset in Germany’s ambitious plans to generate a third of its electricity from renewable sources within eight years and 80 percent by 2050. In 2011 alone, Germany covered around 50 square kilometers of ground and rooftops with panels capable of generating 7.5 gigawatts of electricity.
The PV Kraftwerker robot is fabricated from off-the-shelf-Japanese components. The machinery consists of a robotic arm mounted on an all-terrain vehicle with tank-like tracks. Suction cups are used to grip the glass face of the panels and the arm swings them into place. A camera guides the installation by providing a three-dimensional view of the scene. The robot is designed to assemble power-plant-grade solar panels that are four times the size of typical residential panels.
Markus Gattenlöhner, head of marketing at PV Kraftwerker, says complete automation of the installation process is not yet feasible. Most of the solar power in Germany is generated by rooftop arrays where the shape and orientation of the roofs are too varied for robots to handle. Even for small solar farms and those using ordinary-size panels, human labor is still faster and cheaper than the robots. Christian Hoepfner, scientific director at the Fraunhofer Center for Sustainable Energy Systems, adds that the role of robots will be limited to large, ground-mounted installations.
For now, the robot can only lay panels on metal frames that humans have already installed. Two people walking alongside the robot screw the panels to the frame and make electrical connections.
However, PV Kraftwelker and other companies are looking into new ways to expand automation. Robots are being developed that can pound poles into the ground where panels can be mounted; this would eliminate the need to install frames. Newer solar modules can be snapped or glued into position instead of being screwed. Even electrical connections can be automated using special plugs.
Gattenlöhner says the Japanese government commissioned their company to build a robot that could install a solar power plant near the site of the Fukushima nuclear-plant disaster. The robot will have to be adapted to work independent of humans as much as possible since these areas are radioactive sites. The Japanese wants the robot to be ready in six months.