The Idaho Public Utilities Commission on Dec. 2 approved a Certificate of Public Convenience and Necessity (CPCN) for Idaho Power for its share of the costs to install selective catalytic reduction (SCR) on the coal-fired Jim Bridger Units 3-4.
“Based upon our review of the Application, the direct and rebuttal testimony of the parties, legal briefs, and public participation through testimony and comments, the Commission grants in part and denies in part the Application of Idaho Power for a Certificate of Convenience and Necessity regarding its investment in Selective Catalytic Reduction (SCR) controls in Jim Bridger Units 3 and 4,” said the PUC order.
Idaho Power owns one-third of the four-unit Jim Bridger coal-fired plant located near Rock Springs, Wyo. PacifiCorp owns the remaining two-thirds and is the operator of the plant. Idaho Power maintained that Jim Bridger is the “workhorse” of Idaho Power’s thermal fleet.
Each SCR system would be comprised of two separate universal reactors, with multiple catalyst levels; inlet and outlet ductwork; a shared ammonia reagent system; an economizer upgrade; structural reinforcement of the boiler and flue gas path ductwork and equipment; and extension of the existing plant’s distributed control system. An induced draft fan upgrade and an associated auxiliary power system variable frequency drive insertion are required on Unit 4 only.
Much of the need for the SCRs is due to regional haze mandates from the U.S. Environmental Protection Agency. On May 23, EPA recommended approval of the Wyoming Regional Haze SIP for installation of SCR on Units 3 and 4 in 2015 and 2016, respectively.
The total cost of the project (before allowance for funds used during construction – AFUDC) is $353.8m. Idaho Power’s one-third share is $117.9m. Idaho Power’s commitment estimate for its portion of the project is $129.8m – which includes $11.9m in AFUDC.
Idaho Power relies on 174 MW and 177 MW of net dependable baseload capacity from Units 3 and 4, respectively, based on its one-third ownership shares of those units.
The commission noted that environmental groups opposed putting more money into an aging coal plant. “We acknowledge the public’s concerns about unnecessarily extending the life of the Bridger coal plant. The detrimental effects of long-term coal use on human health, the climate, wildlife, land, and water are well-documented. However, Idaho Power’s analysis presented, and Staff’s investigation confirmed, that an investment in selective catalytic reduction controls is presently the least-cost, least-risk alternative to both reduce environmental effects and allow reliable electric service to continue.”
The commission told Idaho Power to report back if alternatives to this capacity present themselves during the process of installing the SCRs. It also refused to grant binding ratemaking treatment at this time. “We find that granting a CPCN pursuant to [Idaho Code] and denying binding ratemaking treatment pursuant to [Idaho Code] maintains a fair, just and reasonable balance of interests between the Company and the Company’s ratepayers,” the commission wrote.