The city of Durango plans to install a solar array at its water treatment plant on College Mesa to offset electrical consumption there, but some area residents expressed concerns.

They fear the installation could cause eye injuries, affect scenic views and slash property values.

A city notice dated July 28 was sent to residents who live within 300 feet of the project site. It describes the proposed solar array as a 147-kilowatt ground-mounted solar array to be placed immediately west of the water treatment plant’s reservoir. The solar array’s footprint would be about 9,000 square feet and would offset over half the treatment plant’s electrical consumption.

A separate statement from Durango Community Development states the solar array would offset 37-40% of electricity consumption.

The notice says the project doesn’t require public hearings with the Durango Planning Commission or approval from City Council, but residents were informed of potential impacts and the city accepted feedback through Aug. 14.

George Bracksieck, who lives with his family on Jenkins Ranch Road just south of the proposed site, received a copy of the city notice.

“There’s concern that intense, blinding, possibly high-damaging light could be directed directly at us,” he said.

He also said the solar array would “probably be an eyesore.” With that combined with the possible glare issue, he suspects the project would cause his property value to take a hit because prospective homebuyers would be less interested in purchasing his home.

Residents have some reason to be worried about glare. City planner Dan Armentano said a study conducted by Forge Solar found the angle of the sun and the angle of the would-be solar panels could reflect glare into some residents' homes.

However, the study rated the potential glare as “green,” comparable to sunlight reflecting off the surface of a lake, Armentano said.

Glare ratings range from “green” to “yellow” to “red” based on severity, he said. “Yellow,” in layman’s terms, indicates the potential of a glare to burn an image into a person’s retina. If one has stared into a bright light for a moment before looking away, he or she has probably experienced a temporary afterimage caused by the retina burn.

The “red” rating refers to physical eye damage caused by glare, Armentano said.

He said the city is considering planting trees where glare would be the strongest to reduce or eliminate the glare reaching homes, although it might take several years for the trees to grow and have the desired effect.

More analysis is being performed for specific sites between 467 and 522 Jenkins Ranch Road, Kennebec Drive and the southern end of La Questra Drive.

Durango sustainability manager Marty Pool replied to an inquiry from Backsieck about how observation points were chosen. He said they were picked randomly to show how glare impacts different locations.

Pool said the analysis at an observation point, two houses west of Backsieck’s, says that point has zero hours of glare.

“This is due to the angle of the tilt of the solar panels and the sun's angle in the sky throughout the course of the year. Because there is a limit to how far north of due-west the sun sets in the summer, different locations south of the array are affected differently,” he said. “Traveling from east to west along the southern property line of the water treatment plant, there reaches a point at which low-angle evening sun rays will no longer reflect to a location on the ground.”

Pool said in an interview with The Durango Herald there is more to deciding where to place a solar array than some people realize. Solar plants can’t be built just anywhere because they need to be associated with electrical consumption while aligning with La Plata Electric Association’s policies.

LPEA has a power supply contract with Tri-State Generation and Transmission Association, Inc. Also, wholesale power is much less expensive than what the electric cooperative charges customers.

“If you were just to install solar somewhere that’s not connected to a load, you’re only getting like four cents per kilowatt hour. You’re getting wholesale power rates, essentially,” Pool said.

It makes the most sense to install solar arrays where the city is consuming the most power, he said.

Armentano said in an email responding to concerned Jenkins Ranch Road and Hillcrest Estates residents that the water treatment plant was chosen because a solar array stands to offset between 37-40% of the plant’s electricity consumption and because it’s the fourth largest energy consumer among city facilities.

If solar panels were simply attached to the roof of the water treatment plant, it would only offset electrical consumption by less than 10%, he said.

The proposed solar array is attached to the city’s energy performance contract, which is meant to save long-term costs while funding solar projects, maintenance and equipment upgrades with a focus on renewable energy solutions.

cburney@durangoherald.com

A previous version of this story incorrectly stated the approximate footprint of the proposed solar array, which is 9,000 square feet according to the city.