The Federal Energy Regulatory Commission has approved Grant County Public Utility District’s proposal to upgrade generators at 1,125-MW Wanapum, one of two developments in the 1,980-MW Priest Rapids project on the mid-Columbia River in Washington.
FERC issued an order amending the project license Nov. 7, increasing the total authorized capacity of Wanapum and the second development, Priest Rapids, to 1,980 MW from 1,893 MW. The new figure is based on 1,125 MW for the Wanapum development and 855 MW for the Priest Rapids development.
FERC issued a relicense order for the Priest Rapids project (No. 2114) earlier this year, authorizing the publicly owned utility to continue to operate the project for 44 more years. (HNN 8/26/08)
Devine Tarbell &Associates Inc. is providing professional engineering services for the generator upgrade program under a $1 million contract awarded earlier this year that extends through the end of 2018. (HNN 1/16/08) Grant County PUD also is in the process of selecting a contractor to do the actual upgrade work; proposals to perform that work are due Nov. 20.
Wanapum houses ten generating units. FERC previously amended the license to authorize installation of new advanced turbines rated at 112.5 MW. The new turbines will increase total rated capacity to 1.5 million horsepower from 1.2 million hp, and increase the total hydraulic capacity to 188,000 cubic feet per second from 178,000 cfs.
Despite the turbine upgrade, the generators’ total nameplate capacity remained unchanged at 1,038 MW. However, each upgraded generator will have a nameplate rating of 122 MW. With the completion of all ten turbine replacements and the upgrade of the ten generators, the authorized capacity will be limited by the total turbines capacity of 1,125 MW.
The new order states Grant County PUD will continue with installation of the remaining six advanced hydro turbines at Wanapum in addition to performing upgrades of the ten generators at Wanapum.