Rocky Mountain Power's plans to reconstruct and expand its substation at 144 S. 1100 East have sparked opposition from neighbors.

Roughly 100 people who live near the power substation turned out for a Salt Lake City Planning Commission meeting this month to voice opposition to the proposed changes, citing concerns ranging from its effect on children's health to negative impacts on views and property values.

Rocky Mountain Power wants to put in two 46,000-volt transformers to replace the one that has been operating at the site since 1974, said Alene Bentley, the company's customer and community manager.

The substation, which serves about 5,100 customers, has reached 93 percent of its capacity, largely due to increased power usage of existing customers, Bentley said. Nearly 4,700 of those customers are residential, she said.

"This substation has reached its capacity limits," Bentley told the Planning Commission. "We need the additional capacity now."

The power company plans to reconstruct the substation to handle the "eventual upgrade" to 138,000 volts, she said, likely within 10 years.

"We do not believe it's a prudent investment to put something in today knowing that in the near future we're going to have to convert that to (138,000 volts)," Bentley said. "In order for this system to operate with the reliability that our customers expect of us, an upgrade is expected."

The two new transformers and upgrades for future capacity would require the structure to be larger and roughly twice as tall — from 30 feet to about 60 feet. The expected upgrade to 138,000 volts would be able to utilize existing power poles, company officials said.

Changes to the substation primarily will be visual, said Dave Eskelsen, Rocky Mountain Power spokesman.

"When we do upgrade a substation, the change from a visual standpoint is fairly dramatic," Eskelsen said.

Rocky Mountain Power has offered to use mature trees in landscaping around the substation to help minimize the visual impact.

That doesn't go far enough for some substation neighbors who worry the changes will harm the historic character of the neighborhood.

"The view is one of the reasons we enjoy our neighborhood so much," said Spencer Hogan, a 30-year resident of the area. "We have incredible sight lines that are going to go away."

"It will stick out like a sore thumb," added Sarah Brenna, who lives in a nearby condominium complex with a view of the substation.