Enel deploys robots to ‘dry clean’ solar PV systems

Robot cleaning solar panels with mountains in the background
REIWA's solar cleaning robot 'dry cleans' PV panels (Image: Enel Green Power)

A Sicilian startup has developed an autonomous and sustainable robotic system for cleaning photovoltaic panels without the use of water for global renewables firm Enel Green Power.

When it comes to photovoltaics, dust is the enemy. This is not a trivial concept, even if it may seem so at first glance; actually, the problem of soiling—the accumulation of dust, dirt or sand on PV panels—can decrease, sometimes significantly, the performance of solar power systems.

It’s an issue that’s particularly important in desert areas, areas with low rainfall, and those characterised by the presence of very dusty soil, where soiling can have a heavy impact on energy yield, but in any case, it’s something that concerns solar power everywhere, because regardless of location, cleaning the panels still involves costs, including environmental ones.

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The approach normally adopted involves cleaning the surfaces with pressure washers or tractors equipped with hydraulic brushes; both cases entail water consumption and gas emissions from the motor vehicles used.

To develop a different, more sustainable solution that can also be adopted in large solar parks, Enel Green Power—in collaboration with REIWA, a Sicilian startup already active in the study and development of robotic technology solutions—has perfected SandStorm, an advanced cleaning robot that uses a system of specially designed and manufactured brushes, but most importantly, capable of moving along the rows of panels autonomously and recharging autonomously, returning to its docking station at the end of its task.

Sturdy and versatile, SandStorm adapts, when necessary, even to the uneven alignment of the panel trackers, managing to move autonomously from one row of panels to the next, crossing distances greater than 50cm.

This solution offers advantages across the board:

Operation: robotic cleaning can take place at night, during unproductive hours, which also avoids shading the panels, which can cause electrical imbalances and damage to the panels.

Safety: no human assistance is necessary, so there’s no risk to the operators.
Plant efficiency: the panels can be cleaned—at low cost—every day, minimising soiling.
Sustainability: no water or diesel is consumed , thus eliminating the associated CO2 emissions.

Training: this solution promotes the training of more qualified personnel (for example, for onsite maintenance of robotic devices), leading to the creation of more specialized jobs.
After winning a challenge launched by Enel Green Power through the Enel Open Innovability platform, the cleaning system was successfully tested first in the EGP Innovation Lab at Passo Martino (Catania) and then on an industrial scale in a section (1MW) of the Enel Green Power plant in Totana (Spain).

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Enel Green Power is scaling up the application of this technology with an initial contract for the implementation of around 150 robots in two Spanish PV plants, Totana and Las Corchas, for a total capacity of 135MW.

A collaborative rover has just been tested at the EGP facility in Passo Martino: capable of moving autonomously within a solar park, this robot on wheels will allow the SandStorm robots (the ‘cleaners’) to move between rows of panels to be cleaned, reducing the number of robots required for each plant, and as a result, the operational complexity and the initial investment as well.

So the SandStorm case has turned out to be a success story, with all the right ingredients: a collaboration between complementary businesses; reduced costs and increased renewable production; the development of an efficient, competitive made-in-Sicily technology; the activation of a real industrial supply chain; and, most importantly, the reduction of environmental impacts.

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