Transmission owners in the Northwest are committed to building 39 new projects over the next decade with a combined estimated price tag of roughly $1.6 billion, according to ColumbiaGrid. The Pacific Northwest-focused transmission planning group — which includes Avista Corp. the Bonneville Power Administration, Puget Sound Energy Inc., Seattle City Light and several public utility districts — detailed the projects in an annual report, released Aug. 2.
The assessment explores grid reinforcements needed in the Northwest in coming years and also includes projects proposed by major Northwest transmission owners that are not members of the nonprofit planning group, including Portland General Electric Co., Berkshire Hathaway Energy's PacifiCorp subsidiary and others.
One major project identified in the report, Bonneville's proposed $772 million I-5 Corridor Reinforcement Project, a 500-kV line between Castle Rock, Wash., and Troutdale, Ore., was recently canceled, reducing the Northwest's currently planned 10-year transmission outlays from the group's identified $2.4 billion in proposed grid investments. That continued a downward revision of the region's transmission investment plans. Just a year-and-a-half ago, Columbia Grid's board adopted a 10-year plan that laid out 56 projects totaling $2.56 billion. In 2013, the group published a draft transmission plan identifying at least $2.8 billion of projects.
At the same time, regional peak demand considered in this year's assessment fell compared to last year's report, with winter peak load in the Northwest forecast at 31,829 MW
in the 10-year base case, down from the 32,572 MW in last year's report. Projected summer peak load in the 2017 report's 10-year base case was reduced to 27,115 MW from 27,390 MW.
The assessment highlights common areas of concern among regional transmission owners related to voltage problems, unsolved outages and facility overloads, and identifies resolved issues from previous reports, as well as reoccurring and new challenges. With Bonneville no longer pursuing the I-5 Corridor project, by far the largest of the projects considered in the report is IDACORP Inc. subsidiary Idaho Power Co.'s long-planned $840 million, 500-kV Boardman-Hemingway line, between Melba, Idaho, and Boardman, Ore., scheduled to come online in 2020.