MILAN/FRANKFURT (Reuters) - Flying robots that can travel dozens of kilometers without stopping could be the next big thing for power companies.

Workers operate a drone to survey high-voltage power lines of electric company Westnetz near Wilnsdorf, Germany, July 11, 2018. REUTERS/Ralph Orlowski

Utilities in Europe are looking to long-distance drones to scour thousands of miles of grids for damage and leaks in an attempt to avoid network failures that cost them billions of dollars a year. However the technology faces major safety and regulatory hurdles that are clouding its future in the sector.

Snam (SRG.MI) and EDF's (EDF.PA) network subsidiary RTE have tested prototypes of long-distance drones that fly at low altitudes over pipelines and power lines.

Italy's Snam, Europe's biggest gas utility, told Reuters it is trialing one of these machines - known as BVLOS drones because they fly 'beyond the visual line of sight' of operators - in the Apennine hills around Genoa. It hopes to have it scouting a 20 km stretch of pipeline soon.

France's RTE has also tested a long-distance drone, which flew about 50 km inspecting transmission lines and sent back data that allowed technicians to virtually model a section of the grid. The company said it would invest 4.8 million euros ($5.6 million) on drone technology over the next two years.

At present, power companies largely use helicopters equipped with cameras to inspect their networks. They have also recently started occasionally using more basic drones that stay within sight of controllers and have a range of only about 500 meters.

However an industry-wide shift toward renewable energy, and the need to monitor the myriad extra connections needed to link solar and wind parks to grids, is forcing utilities to look at the advanced technology.