Greenbotics, which was snapped up by the US panel giant SunPower last November...

A gadget that looks a bit like a large flat-bed office scanner claims it could hold the key to cheaper solar energy.

Made by Greenbotics, which was snapped up by the US panel giant SunPower last November, the solar-panel cleaning robot is an example of how the industry is turning to standardised operations and maintenance (O&M) techniques as a way of keeping PV power prices down.

The Greenbotics CleanFleet machine uses less than half a cup of water to clean a solar panel, which is about 90% less than traditional cleaning methods, SunPower says.

“The robots can be configured for use with a variety of solar panels and mounting types, including fixed-tilt arrays and single-axis trackers, and offer a less costly and greener alternative to manual cleaning methods, pressure washers and sprayer trucks,” a press release reveals.

“Regularly cleaning solar panels located in dry, dusty regions can increase annual energy production by up to 15%.”

Solar panels

SunPower boss Tom Werner added: “Greenbotics and its CleanFleet robots will allow us to further maximise the proven system performance of our high efficiency, most reliable solar panels, which is critical to a project’s economics and levelised cost of electricity.”

Matthew Feinstein, of Lux Research, says the advent of tolos, such as panel-cleaning robots, has been slow coming to the PV industry because of the diversity of applications and environments involved.

“Standardising O&M is difficult due to both differences in application segments, rooftop versus utility-scale, and geography,” he says. “Water availability-cost for a utility-scale project in Saudi Arabia might be very different from that in California. The same goes for labour costs.”

Furthermore, he says: “If costs aren’t prohibitive, there’s not much incentive to standardise processes or seek new materials.”

Yaniv Kalish, who leads business development for commercial and industrial solar at Urban Green Energy, a manufacturer of distributed energy systems, says the lack of a focus on O&M standardisation is perhaps understandable given the youthfulness of the solar industry.

Full lifespan

“Unfortunately, because solar is so new to many customers, they tend to look at only the short term costs of a project, rather than the full lifespan of the system,” Kalish says.

“Because of this, they choose modules with the lowest sticker price without taking into account the possibility of higher maintenance costs once the system is installed.”

Nevertheless, Kalish says: “This view is changing as the industry matures. Quality and long-term investment is becoming more significant for developers, and module makers and component companies will follow suit.”

One major step forward for the industry is that at this point most PV panels have become fairly standardised.

“These standard sizes for the panel frames and output help drive more uniformity in other solar components, such as racking and inverters, that have to be compatible with the panels,” Kalish notes.

System design

“This, in turn, helps streamline system design, as engineers can quickly find compatible components. At this point, PV modules are pretty much a commodity, so hopefully the rest of the equipment will also follow this pattern.”

Greater equipment standardisation should hopefully open the door for greater standardisation, and lower costs, for O&M.

Feinstein says there are a number of areas that solar engineering, procurement and construction (EPC) companies or other maintenance providers could investigate.

One is after-market anti-reflective coatings, which can help cut bare silicon’s 30%-plus surface reflection and ensure more sunlight is converted to energy.

“These would be applied in the field, rather than at the site of module production, to prevent losses from dust or moisture that brushes up onto the panels,” Feinstein comments.

“They might need re-application every five or 10 years, but that’s certainly fewer trips to the site than EPCs take for typical cleaning. Large chemical companies and start-ups alike offer these coatings.”

Energy output

AGC Solar, which has an anti-reflective coating called SPARC, says: “This coating offers high solar transmission which allows an increase in the energy output of the PV panels by up to 5%, which is equivalent to gaining two extra weeks of sun each year.”

Kalish also believes increased standardisation of processes other than O&M could help reduce maintenance costs by freeing up resources. For example, he says: “Standardizing the permit process would ultimately lower project cost and reduce timelines.

“Currently, every municipality has its own process and regulations regarding solar permits, which impacts the timeline for project implementation.

“Because of this lack of standardization, project developers have to stay up to date on all of the various permitting procedures, putting a strain on resources.”

Overall, the fact that there appear to be many potential avenues for further cost reduction can only be good news for the industry. As Feinstein concludes: “The interesting thing about O&M innovations is the different ways they attack the problem.

“Undoubtedly, a few other interesting solutions will pop up in the near future.”