Keeping wind and solar plants generating at full capacity requires continuous, costly and time-consuming monitoring and maintenance — but a growing number of startups are using new technologies, including drones, robots and other high-tech gizmos, to boost renewable energy providers’ productivity and reduce their operating costs. While the technology remains in its infancy, it’s expected to grow into a multi-billion dollar sector, and to help a wide range of investor-friendly energy companies to boost their bottom line.

One of the most promising approaches uses drone-mounted cameras to inspect turbine blades for damage caused by hail, bird strikes, bugs, and other environmental hazards. That can save plant operators hundreds of dollars apiece on annual inspections that would otherwise need to be carried out by workers dangling precariously from ropes. “Technicians only need to climb the assets that require attention, and the requirement to work at height is reduced, if not eliminated in many cases,” explains Craig Roberts, CEO of Cyberhawk Innovations, which this year launched a drone inspection service for wind turbines. 

With upwards of 800,000 blades now deployed on turbines around the world, there’s a big potential market for drone-inspection technologies. Navigant Research forecasts that annual revenues for wind-industry drone equipment and services could hit $1.6 billion annually by 2024. “The use of drones for wind turbine blade inspection is proving to be more than a novelty,” says Navigant analyst Jesse Broehl. “Current inspection techniques … will increasingly be augmented by drone inspections.” 

Solar plant operators are experimenting with similar technologies, chiefly by using drone-mounted  thermal imaging to identify hot spots that suggest a PV array is malfunctioning. Duke Energy (NYSE:DUK) this summer partnered with California’s AeroVironment for a series of tests using quadcopter and fixed-wing drones to monitor its PV arrays, while Google (NASDAQ:GOOG)-backed drone startup Skycatch is testing its technology in partnership with First Solar and SolarCity.

And drones and other robotic devices aren’t just being used for inspections. Some plant operators are mulling using drones as flying scarecrows to keep migrating birds away from their turbines, or as a means of spotting endangered species that could wander near to solar panels and wind farms. “Drones can do just about anything the energy companies don’t want to send people to do,” says Michael Blades, an analyst for the research firm Frost & Sullivan. 

In the solar sector, drones and robots are increasingly playing an important role in streamlining plants’ panel installation and cleaning operations. Alion Energy has developed a rail-mounted robotic solar installation machine that it claims can build out utility-scale PV arrays at twice the speed and half the cost of human workers, and a similar rail-mounted device that can scrub panels and trim nearby foliage to keep solar panels operating at maximum efficiency. Other startups are testing similar technologies: Swiss outfit Serbot has developed robots that squirt PV panels with water and compressed air to clean off dust and debris, while Aerial Power’s drone-based cleaning system can scrub clean PV arrays without requiring the installation of additional equipment.

While cleaning ‘bots are typically more expensive than drone-based inspection tools, they can yield sizable and direct bottom-line benefits for plant operators. Serbot estimates that its cleaning tech can boost productivity at a typical U.S. or European plant by about 20 percent, and in drier, dustier areas such as the Middle East, well-cleaned panels can increase plants’ output by as much as 40 percent. “If you can boost electricity production by 20 percent at a solar plant, that’s huge for an operator or utility,” says Michael Butler, a veteran clean-tech investor who runs Cascadia Capital.

Direct investment opportunities in the sector remain relatively scarce, with most startups currently in the pre-IPO phase. Still, a handful of publicly listed drone manufacturers, such as Parrot (EPA:PARRO) and IXYS Corporation (NASDAQ:IXYS), offer opportunities for fairly undiluted investment in the technology, and are expected to benefit from booming demand in coming years. “With the possible burgeoning set of opportunities to use drones in the energy industry and other areas, IXYS is likely to be a big winner in the space over time,” writes's Michael McDonald.

For now, robotics and drone startups remain a fairly risky niche play, and investors should carefully weigh potential long-term efficiencies against the sector’s high up-front costs. One cautionary tale: QBotix, a well-funded startup developing robots capable of adjusting utility-scale PV arrays to track the sun, shuttered its doors in August after failing to gain traction in an increasingly cost-conscious sector. “The industry is unwilling to embrace novel, but more expensive and unproven, technologies,” warns Fortune’s Katie Fehrenbacher.

In the long run, though, “The opportunities are in the billions -- with a B,” says Lux Research analyst Maryanna Saenko.


Companies to watch

*   It’s not just drones that are shaking up the sector: Helical Robotics specializes in creating magnetic wheeled robots that can drive straight up the vertical walls of turbine towers, allowing operators to capture close-up images and carry out maintenance work remotely.

*   Grand Forks startup EdgeData, founded in May with $450,000 in public research funding, focuses on developing software that can collate photos from drone surveys, reducing the complexity of the inspections. "Instead of looking at 900 pictures, we're only looking at five," explains director of operations Greg Thorsteinson.

*   Texas startup HoverStat is working on technology that uses off-the-shelf, low-budget drones and cameras to measure roofs ahead of solar-panel installations, allowing initial surveys to be done in as little as 10 minutes.


Ben Whitford is the U.S. correspondent for The Ecologist. He has written for the Guardian, Newsweek, Mother Jones, Slate, and many other publications.