Construction of a new energy transmission line in Beaver County was officially marked Monday in a signing ceremony in Milford. The new line replaces one of the poorest performing systems in the state that was seen as a potential deterrent to growth.

SALT LAKE CITY — The head of the Utah Bureau of Land Management and the president of Rocky Mountain Power took part in a celebratory signing ceremony Monday marking construction of a critical energy transmission line.

The event featuring Juan Palma and Richard Walje at the Milford City Offices marks start of a project to put in the new Cameron to Milford 138,000-volt line to shore up vulnerabilities in the grid and more than double existing capacity that has long been overwhelmed.

Bemoaned as one of the poorest performing power systems in the state, the electrical load in west Beaver County and Milford has experienced more than 3 million customer minutes lost in a three-year period, according to an environmental analysis performed by the Bureau of Land Management.

PacifiCorp ties into the geothermal source of power at the Blundell plant, which fluctuates and impacts the amount of energy available to customers in that area. When additional generation from Blundell is not available, the result is outages to customers. In 2008, for example, there were 17 outages lasting 431 hours.

Officials estimate that the unreliability of the system zaps 2,000 households of about 500 minutes, or more than eight hours of power per year, leading to concerns over public safety.

The existing line can provide about 21.1 megawatts of energy without tying into Blundell, but during irrigation season, demand outstripped supply five months out of the year in 2008.

The analysis says the system is being stretched beyond its capacity, with existing customers using 26 percent more electricity than they did 20 years ago.

Industrial customers can't take their full, contracted load of power without jeopardizing the system in western Beaver County, the analysis says.

"Beaver County economic development officials and county commissioners have voiced their concerns on several occasions about the possibility of opportunities being lost, or companies being deterred from developing in this area because of the lack of electrical facilities to support their operations," the document said.

The analysis said PacifiCorp can't meet requests for load increases from existing customers, and two cement and lime companies that are considering building plants in the area could see their efforts derailed.

Development and expansion of any renewable energy projects in the area are being hampered as well because of the need for additional transmission capacity, the analysis said.

The project, which includes a single-circuit overhead line about 25 miles long, also shores up backup power supply. As it exists now, use of a line at one of the substations would result in "thermal overload," essentially causing a voltage collapse in Milford and wiping out the power to 90 percent of residential and business customers.

BLM officials say the new line will more than double the existing capacity in the area, taking it from 21.1 megawatts to a projected 48.2 megawatts.

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