The process required decommissioning of the existing hydroelectric generating facility. Decommissioning involved nearly three years of construction to permanently disable the 73-year-old plant’s hydroelectric functions, and required maintaining the ability to provide for water supply releases from the dam.
The decommissioning process was initiated in December 2011 with a written application to FERC requesting authorization to permanently cease hydroelectric generation operations at the facility. To meet FERC requirements for surrender, the BRA was directed to permanently disable generation capability. This was accomplished by dismantling the project’s two penstocks (large water pipes) that conveyed water from the reservoir to the turbines located inside the powerhouse. In addition, two 6,900-volt circuits which connected the project’s generators to the electrical distribution grid were removed. In accordance with the FERC approved decommissioning process, these actions rendered the facility permanently incapable of generating or delivering power.
Included in the decommissioning project was installation of a controlled outlet conduit.
This conduit is an 86-inch diameter pipe that allows BRA to release water from the reservoir without the necessity of opening the dam’s floodgates in order to provide water for beneficial uses throughout the basin.
The facility, put into service in 1941, ceased power production in 2007 after evaluation by several engineering firms identified safety issues with the electric generating infrastructure. In light of the extensive upgrades necessary to restore the aging facility for future use, BRA began evaluating the feasibility of maintaining the hydroelectric capability. Ultimately, the BRA Board of Directors voted to apply for decommissioning after conducting extensive economic analysis which concluded that the required renovation, re-licensing and continued operation of the facility was no longer viable.