A herd of sheep keep the grass trimmed at OCI Solar Power's 4.4-megawatt solar farm, Alamo 2. Photo Courtesy of CPS Energy.

What do solar power and sheep have in common?

They’re both good for the environment: solar panels generate clean, carbon-free electricity, while sheep eat grass – lots of it. They’re now working together at Alamo 2, a 4.4-megawatt solar farm off Binz-Engleman Road.

A herd of about 90 sheep keep the grass trimmed around and under the panels, meaning no gas-powered mowers rumbling across the 45-acre site. It’s one of seven OCI Solar Power is building as part of its agreement with CPS Energy to bring 400 MW of renewable sun power to San Antonio. Check out more photos of the fuzzy lawnmowers, and watch this video of them hard at work:

“OCI decided to use sheep as a ‘greener’ means of vegetation control than mowers and traditional machinery,” said F. Lee Samaie, asset manager with OCI Solar Power. “A few solar farms in California have successfully used sheep on their sites for the same reason.”

Sheep grazing isn’t yet a widespread practice on Texas solar farms, but in addition to California, it’s also used in parts of Europe, according to the Texas Tribune, which first wrote about the woolly groundskeepers on July 11:

“Contracting with a local breeder to bring sheep to a solar installation is cheaper than hiring two-legged groundskeepers, companies say, and easier than trying to maneuver lawn equipment in tight spaces. Sharing the land also helps the local agricultural economy, industry leaders say.”

The sheep arrived at Alamo 2 in April and have done a great job of keeping grass low and out of the way of the solar panels, Samaie said. OCI Solar Power is keeping an eye on the farm to determine whether it will use sheep at future sites.

The breed of sheep at the farm, Barbados Cross, can withstand extreme temperatures better than other breeds because of its ability to find shelter. The nearly 18,000 dual-axis solar panels at the farm, which follow the sun as it moves across the sky during the day, provide plenty of shade for the rams and ewes at the site. They’re also better at finding their own food and so don’t require supplemental feeding to survive – and there’s plenty of native grass on the farm to keep these sheep satisfied.

This solar farm is also unusual in its proximity to development. Solar sites are often located out in the country, far from urban areas. Alamo 2 was developed with the San Antonio River Authority on land near the Upper Martinez Creek Wastewater Treatment Facility. The solar farm is surrounded on two sides by homes while a school abuts the property on another side.

“Alamo 2 is a great neighbor to San Antonio and Converse residents,” said OCI Solar Power President and CEO Tony Dorazio. “Solar farms are an all-around win because of their passive nature but positive environmental impacts.”

As you might expect, the sheep are good neighbors – passive and “ba-a-ashful” to visitors who may find their way on to the fenced site. OCI Solar Power brought in two herding dogs, both Great Pyrenees mixes, to keep a watchful eye on the property and deter unwanted visitors.

We’re looking for a suitable name for the working pups who patrol at the Solar farm. You can help us choose by casting a vote in our Name that Solar Sheepdog Poll.

*This article has been republished with permission from Energized, the CPS Energy blog.

Full disclosure: The Arsenal Group LLC, which publishes the Rivard Report provided consulting services to CPS Energy in 2012. Monika Maeckle, who co-founded the Rivard Report, now works for CPS Energy as director of integrated communications.

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Scott Wudel

Scott Wudel is a communications manager for CPS Energy.