7:45 p.m., June 29
Water Authority considering hydroelectric power at San Vicente
The San Diego County Water Authority and the City of San Diego are considering adding a 240-to-500-megawatt hydroelectric generating system to San Vicente Reservoir, the Water Authority announced yesterday (July 8).
The power project, which would only be used during times of peak demand, would involve the construction of a 10,000 acre-foot secondary reservoir in the hills above San Vicente, which will soon have a storage capacity of 242,000 acre feet. During times of peak demand (and high power prices), water would be released from the upper reservoir, pass through electric-generating turbines, and spill into the lake below. The water would then be pumped back uphill overnight, when energy demand dropped.
A similar, but much smaller in scale 40-megawatt project was completed at Lake Hodges in September 2012. If the San Vicente plan is implemented at the largest scale, it could provide enough energy to power 325,000 homes in the region, authorities say.
“Given the closure of the San Onofre plant, it makes sense for us to determine whether we can leverage our experience with hydroelectric power to help meet the region’s need for clean energy,” said Frank Belock, a Water Authority deputy general manager in a release.
San Vicente has been closed to public recreation since 2009, when a $568 million project to expand the dam and double the lake’s water capacity got underway. It was originally expected to reopen sometime between 2014 and 2017, though construction of the electric project is expected to take at least five years. It’s unclear whether this would postpone the lake’s re-opening for public use.
The Water Authority says it has already identified four potential sites for the auxiliary reservoir, and will proceed to spend up to $150,000 on a feasibility study to be completed by next spring. The study will compare anticipated power rates during peak and off-peak hours to the cost of constructing and operating the power system to determine if such an undertaking would prove profitable.