Solar Farm Mowing Robot: Where ABB Robots Fit

Grass grows between and under the rows of a solar farm, and overgrown vegetation can block the panels and cut their power output. A solar farm mowing robot is one way to keep it down: an electric, self-driving mower that works the rows on its own, sometimes at night. Sheep are the other way, and some operators now use both. This post looks at how grass was kept short before robots, from sheep on the White House lawn to the first solar-powered robot mower, what flocks and robot fleets are doing on solar sites this autumn, and where ABB's robots fit, which today is mostly in the factories that build outdoor machines.

Sheep at the La Ola Solar Farm on Lanai, Hawaii, in 2011, where they kept weeds and grass trimmed between and under the panels. Photo: Merrill Smith, U.S. Department of Energy via Wikimedia Commons (public domain)

From sheep and scythes to the first robot mower

Lawn mowers began as an alternative to the scythe and to grazing animals. Edwin Budding's mower, patented in Britain on 31 August 1830, was designed for sports grounds and large gardens. Petrol mowers followed in 1914 from the Ideal Power Mower Co. of Lansing, Michigan, and today the biggest gang mowers ride on tractors to cut golf courses and parks. Grazing animals kept some of the work: from 1918 to 1920, during the First World War, a flock of sheep lived on the White House lawn. White House maid Lillian Rogers Parks recalled that the wool was auctioned for the Red Cross, two pounds for each state, and raised many thousands of dollars.

Sheep grazing on the White House lawn during Woodrow Wilson's presidency, 1918. Photo: unknown photographer, Library of Congress via Wikimedia Commons (public domain)

The first robot mowers came from inventors. In 1969 S. Lawrence Bellinger introduced and patented the MowBot, which weighed 125 pounds and ran for three hours. In 1992 André Collens patented the first fully solar-powered robotic mower and sold it to Husqvarna, which put it on the market in 1995. Most home robot mowers still follow a border wire laid around the lawn, while newer ones steer by RTK satellite positioning or cameras, and the largest can look after about 25 acres. In October 2024, FireFly Automatix's electric autonomous reel mowers kept the fairways for the PGA Tour's Black Desert Championship in Utah.

A Husqvarna Automower robotic lawn mower on a lawn in 2007. Photo: Denoir / Wikimedia Commons (public domain)

On solar farms, sheep came back. A US Department of Energy photo from March 2011 shows sheep at the La Ola Solar Farm on Lanai, Hawaii, where they kept weeds and grass trimmed in the hard to reach places between and under the panels. The deal pays twice: solar companies pay farmers for the vegetation management, and the farmers can still sell their lambs to grocers and restaurants at the end of the season. Sheep need shepherds, though, and farmers who graze solar sites check their flocks two to three times a week.

Sheep among the panels of a large Belgian solar park in 2015, described by the photographer as the biggest in the Benelux. Photo: Antalexion / Wikimedia Commons (CC BY-SA 4.0)

Flocks and robot fleets on solar sites this autumn

New research is helping the graziers. On 15 October Cornell described a new spreadsheet tool, published on 28 September in Manufacturing & Service Operations Management, that helps farmers decide how many sheep to buy and sell for a given solar site; if a farmer does not have enough sheep, the grass has to be cut some other way. United Agrivoltaics already uses it to bring new graziers on board. A second Cornell study found that grazing in the right numbers raises populations of bees and lady beetles compared with mowing. In New York, Josh Pierce, who started with five sheep in 2018, now runs about 300 on nine solar contracts.

Sheep under the panels at the Kassø solar park in Denmark, May 2025. Photo: Hjart / Wikimedia Commons (CC BY-SA 4.0)

Robot fleets are growing too. Renu Robotics in San Antonio says more than 100 of its all-electric autonomous mowers are working in the field, that they typically save solar and energy sites 30 to 50 percent, and that they let operators switch to mowing at night. Swap Robotics, a 2019 University of Waterloo spinout, has dozens of robots in Canada and the US and has raised more than $15 million. One investor, Silicon Ranch, which keeps its own flock of sheep, said in 2025 that Swap's robots complement its grazing. On 21 October RC Mowers unveiled RECONX, an autonomous mower for properties including solar fields, with one operator running up to three machines.

FireFly AMP electric autonomous reel mowers on a fairway at Black Desert in Ivins, Utah, which they kept for a PGA Tour event in October 2024. Photo: Lawnjunkie / Wikimedia Commons (CC0)

ABB does not make mowers, and we found no ABB robot working on a solar farm. Its robots appear one step back, on the assembly lines of outdoor equipment makers. At Husqvarna, the company that sold that first solar robot mower, an ABB YuMi dual-arm cobot picks screws and fastens the starter on chainsaws, more than 400 per shift. Since 2020 an ABB IRB 1600 with SafeMove software and laser scanners has fitted the handle and chain catcher on the same line, working beside people partly without fences. A cell like that could assemble mowing robots too, though no such project has been announced.

An ABB YuMi dual-arm cobot fastening starters onto chainsaws on Husqvarna's assembly line. Photo: ABB

Where solar site mowing goes next

For homes, this autumn's news is about rules. On 9 September the US Federal Communications Commission gave Husqvarna conditional approval for four foreign-made Automower models, the 305V iQ, 310V iQ, 420V iQ and 440V iQ, a month after it published a list of equipment it deems an unacceptable security risk. They are due to launch in the US in 2027. Husqvarna says it already serves more than 500 US golf courses with professional robotic mowing, while home use is still limited. Our post on garden and lawn robots covers the home side.

An ABB industrial robot at work on a chainsaw body in Husqvarna's assembly line. Photo: ABB

On large solar sites, robots and sheep are already being mixed. Silicon Ranch pairs Swap's robots with its flock, and Cornell's model assumes farmers will cut whatever the sheep cannot keep down. New York wants 70% of its electricity from renewables by 2030, and the Solar Energy Industries Association estimates that less than 1% of the state's prime farmland hosts solar panels today. Our autonomous tractor post covers driverless machines on farmland. Building mowing robots in numbers is a factory job, and our post on lawn mower manufacturing looks at where ABB welding and assembly robots could fit on those lines.

Sheep grazing at Shortheath Solar Park, November 2025. Photo: Ian Calderwood / Wikimedia Commons (CC BY-SA 2.0)

Most of the cost figures come from the sellers. Renu's 30 to 50 percent saving is the company's own number, and RECONX, due in production in spring 2027, still burns fuel in a 40 horsepower Vanguard engine with a 14 gallon tank. Safety is part of the pitch: Renu says its robots spare operators from overseeing mowing crews and the accidents that come with them, yet RECONX still needs one operator for every three machines. Flocks have limits too. Cornell economist Todd Schmit warns that "a small sheep farm is not going to be able to service a large array on its own," although fellow Cornell researcher Vincent Slaugh sees room for US shepherds to grow, since about half of the lamb and mutton eaten in the US is imported.

A worker holds a chainsaw part next to the ABB YuMi on Husqvarna's assembly line. Photo: ABB

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