Background
The Upper Gorge Power Plant (UGPP) currently releases low flow water to the Owens River as part of the LADWP agreement with the California Department of Fish and Game (DFG). Eventual negotiations with the DFG allowed an average flow of 48 cubic feet per second (cfs) on the Owens River of which 16 cfs comes from upstream sources at UGPP. A net flow of 32 cfs will have to come thru the plant. This net of 32 cfs was not adequate to spin the UGPP turbine which requires a minimum of 40 cfs.
The low flow release was accomplished when an energy dissipation structure (EDS) and a Tailbay release structure were installed in 1995 and allowed water to bypass the plant. These low flow releases averaged 6,785 hours per year over the last 5 years. An economic analysis conducted in 2006, indicated this project will have attractive returns and will contribute to our efforts in increasing renewable generation.
Project Description
A bypass plant, able to generate a maximum of 4 megawatts (MW) of power, is planned in order to capture the energy of the water released to the Owens River and generate power. The unit will be on-line when the UGPP is off-line. The unit will be located on the north side of the existing EDS unit and will discharge water to the Owens River on the same location as the EDS. The existing EDS and its discharge structure will be kept and operated to continue the flow of water when the 4 MW bypass plant is out of service. The power house will contain all the turbine, switchgears, control centers, and auxiliaries which will be tied electrically to the existing transformers of the UGPP. An option is currently being considered to upgrade the existing 34.5 kilovolt transmission line and connect the new unit. New foundations for new power house will be constructed.
During construction and commissioning there should be no interruption to the continuous operation of the plant and release of water to the Owens River.