The installation of grid-tied solar systems by businesses or individuals reduces reliance on fossil fuels and whittles away at electric bills.
Numbers show the popularity of such systems in La Plata Electric Association territory.
The cooperative, which had 672 net-metered accounts as of Tuesday, approved 180 of those in 2014 and 95 the year before.
But as more people make a commitment to solar, their installations can get in the way of each other or hamper the functioning of the electrical grid itself.
Electrical grids are designed to distribute power, said Ron Meier, manager of engineering, at La Plata Electric Association. The potential for problems arises when energy isn’t needed immediately where it’s generated by a private producer, Meier said.
“The energy leaves the house (or business) looking for a place to be used,” Meier said.
As it goes up back into the grid – up the down staircase as it were – the reverse flow can be tolerated for a time. But eventually the increased voltage damages the grid itself or damages appliances or electronic gadgetry.
Any equipment with a digital display can be affected, he said. A volt meter at an outlet would indicate if voltage is too high.
Some solar arrays switch themselves off when their output no longer is needed, Meier said. But not all of them.
As a result, all applications for solar installations get close scrutiny, with a computer-model analysis of the impact on the system, Meier said.
The potential for damage has forced engineers to more closely examine installation of solar arrays in certain neighborhoods, typically those that installed solar early and have clustering, Meier said.
He also is monitoring the area around Mayday, north of U.S. Highway 160 in La Plata Canyon, because of abundant solar installations.
A large solar project or many small ones in close proximity can lock out further installation of solar systems in the same neighborhood.
A case in point is a plan by the city of Durango to invest in enough solar to light buildings and power office equipment.
The city is assessing location, size and the economics of the plan, Mary Beth Miles, assistant to City Manager Ron LeBlanc, said Wednesday.
The city is looking at city-owned sites for ground-mounted solar arrays near its water-treatment plant east of Fort Lewis College and near the recycling center on Tech Drive, Miles said.
A project could come together in the next few months when the city plans to bid on the project, Miles said.
A project of such magnitude near the water-treatment plant could preclude further solar installation in the Hillcrest or SkyRidge neighborhoods, Meier said.
Damage from reverse flow can be averted by a bank of batteries to store energy not immediately needed.
If an application for solar installation poses an undue burden on the grid, the applicant can get around the problem by disconnecting from the power line serving the neighborhood and hooking up to the main power line, Meier said.
“But it will cost the applicant,” Meier said. “It can be expensive, and it isn’t always possible.”
Individuals or a utility such as LPEA could turn to banks of storage batteries to save electricity for when it’s needed, Meier said. LPEA has no such plans now, he said.
Absent battery storage, grid infrastructure upgrades and advances in voltage-regulation technology can solve the reverse-flow problem, Meier said.
“But that’s in the future,” Meier said.
daler@ durangoherald.com
