The Idaho Public Utilities Commission, in a Sept. 15 final order, granted Idaho Power’s November 2016 application, issuing the company a certificate of public convenience and necessity (CPCN) to build a new (second) 138-kV transmission line and related facilities “to provide redundant service from the Wood River substation near Hailey into the Ketchum substation.”
As noted in the order, Idaho Power applied for a CPCN to build the second line, asserting that the line is necessary to secure reliable and adequate service to its customers. The company asserted that the existing line serves more than 9,000 customers in the North Valley, including the resort communities of Ketchum and Sun Valley, and the Sun Valley ski resort. The commission added that according to the company, while its sole existing radial transmission line has a good record of reliability, the line has experienced sustained outage line events, is aging, and requires reconstruction.
Idaho Power stated that it typically initiates and builds a second transmission source and transformer in an area when peak load for the area’s substations is projected to surpass 40 MW, thus exceeding NERC’s reliability standard. The commission added that the winter 2007 peak load for the Ketchum and Elkhorn substations serving the North Valley was 63 MW.
Idaho Power in 1974 obtained a certificate to build a second transmission line to the North Valley and related facilities, and in 1995, the company participated in public meetings about the proposed construction of a second line, the commission said.
There was considerable public opposition to the proposal, and the company concluded that the line was no longer needed nor feasible. The commission added that at the company’s request, it cancelled the certificate. In 2007, the company initiated a Community Advisory Committee (CAC) to develop the Wood River Valley Electrical Plan, a comprehensive plan for future transmission facilities in the Wood River Valley, including the North Valley area. The CAC in 2011 recommended that Idaho Power build the second 138-kV line, and took additional input from the community from 2012-2014, the commission added, noting that the CAC reaffirmed the need for a second energy path into the North Valley.
The company selected an underground transmission option with undergrounding at Elkhorn Road as the proposed configuration for its requested CPCN, the commission said. The company asked that the commission grant its requested CPCN authorizing the company to build a redundant transmission line to ensure reliable and adequate service to the North Valley, with the line extending overhead from the Wood River substation, then transitioning underground near Elkhorn Road, and continuing underground to the Ketchum substation.
The commission also noted that the company examined three potential points where the line would transition from overhead to underground transmission, and that the company’s preferred transition point was Elkhorn Road, which is the lowest-cost option at $30m.
“Having reviewed the record, we find that the company has demonstrated the need for a redundant line from the Wood River substation to the Ketchum substation,” the commission said.
The redundant line is justified by the company’s own planning standard, supports national reliability standards, and will increase resiliency in the North Valley, the commission said.
The company provided evidence that a major outage could take days or weeks to repair, particularly given the line’s mountainous terrain and access limitations, the commission said, adding that an outage of days or weeks could have devastating impacts, particularly if it occurred in the middle of winter. The hospital may be unable to provide full services, emergency responders may be hampered in their ability to do their jobs, and the public may be without power to heat their homes, the commission said.
Noting that many parties and participants called for additional analysis of alternative solutions, including distributed local generation and energy storage systems, the commission said that it does not believe that those options are effective stand-alone alternatives to a redundant line at this time.
For example, the commission said, parties and participants suggested those options could be used – and need only be used – to meet just a portion of the North Valley’s load.
“We do not believe an option that only meets a small part of the load is an effective solution for providing adequate and reliable service, when the redundant line option would be capable of serving all of the load,” the commission said. “That being said, we agree that these options should continue to be explored, particularly as the North Valley’s load increases and as the alternatives become more cost-effective.”
The commission said that it approves the company’s requested route of overhead transmission line from the Wood River substation to the transition point near Elkhorn Road, then underground transmission to the Ketchum substation.
Noting that parties and participants questioned the need for that route and its cost, the commission said that the company explained why an overhead transmission configuration along the whole route is not feasible. As an example, the commission said, siting an overhead transmission line through the downtown Ketchum area could require placing large steel poles in the sidewalks or the edge of the road, which could impair drivers’ and pedestrians’ sight lines in intersections and would be a detriment to public safety.
Among other things, the commission noted that Sierra Club filed the sole petition for intervenor funding in the case, requesting $14,850 for attorney fees. The commission said that Sierra Club materially contributed to its analysis and decision, and granted the organization’s petition. The amount of $14,850 will be chargeable to the company’s residential and small commercial customers, the commission said.
The commission also said that the order does not constitute approval of any cost of the line for ratemaking purposes, and that the company will be required to apply to the commission for inclusion of the costs of the line in its rates at a later date.
As noted in a Sept. 15 commission statement, interested parties may petition the commission for reconsideration of the order by Oct. 6.
Idaho Power’s parent company is IDACORP (NYSE:IDA).