HomeMy WebLinkAbout10/05/1999, C9 - STENNER CANYON HYDROELECTRIC PLANT FEASIBILITY STUDY council '°Oct.Oct5, 1999
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CITY OF SAN LUIS 0 B I S P 0
FROM: John Moss, Utilities Director/4�
Prepared By: Bob Hamilton,)Water Supply Supervisor
SUBJECT: Stenner Canyon Hydroelectric Plant Feasibility Study
CAO RECOMMENDATION
Authorize staff to request proposals for a feasibility study for the Stenner Canyon Hydroelectric
Plant, and authorize the City Administrative Office to execute an agreement with the selected
consultant if proposals are within the approved budget amount.
DISCUSSION
The Stenner Canyon Hydroelectric Plant was constructed in the mid-1980's at the old water
treatment plant site adjacent to Reservoir 42. The facility utilized the raw water supplied from
Salinas Reservoir to generate power which was sold back to Pacific Gas and Electric Company
(PG&E). The plant was designed to generate 640 kilowatts per hour (kwh) but only achieved
approximately 520 kwh maximum output due to pipeline losses and other system constraints.
In June of 1998, the City was notified by the Federal Energy Regulatory Commission (FERC) that
maintenance must be performed on the hydrogenerator to keep it operational, or surrender of the
operating permit would be required. Since the original construction of the power generation
facility, changes have occurred which impact the operation of the hydroplant. Changes that may
affect operation of the facility include;
1. Modifications at the Water Treatment Plant for the use of ozone as the primary disinfectant.
2. Modification of the Cuesta Tunnel by the State Water Project.
3. Operational safety issues.
Staff presented a preliminary analysis of the benefits associated with continued operation of the
hydroelectric plant to Council on February 16`h, 1999. The analysis recommended abandonment
of the hydroelectric facility and surrender of the FERC operating license. Council directed staff to
initiate a more thorough study of the operating benefits and associated costs. The Request for
Proposal for additional analysis of the hydroplant will include the following:
• Safety issues
• Potential to use power generated by the hydroplant to operate the Water Treatment Plant.
• Hydraulics review.
• Water supply valving.
• Telemetry control issues.
• Water quality concerns.
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Council Agenda Report—Abandonment of Stenner Canyon Hydroelectric Plant
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• System safety analysis.
• Water Treatment Plant operational impacts.
• Projected annual revenues.
• Cost/benefit analysis.
• Potential for use of less expensive power from Cal Poly.
FISCAL IMPACT
A total of$20,000 was approved as a part of the 1999-00 budget to support the hydroelectric
generator study (1999-01 Financial Plan, Appendix B,page 73-74).
ALTERNATIVES
♦ Initiate Action to Reinstate Operation of the Hydroelectric Plant. This alternative would
require staff to locate qualified technicians to perform maintenance necessary to make the
hydrogenerator operational. It is unknown whether the facility can be operated properly due
to modifications at the Cuesta Tunnel which serves as the control point for the hydroplant
operation. Based on operational and safety constraints, staff does not recommend pursuing
this alternative.
♦ Defer any action relative to the hydroplant. This is essentially what has been done for the
last several years. FERC will require that the City provide maintenance of the facility or
abandon the license granted by FERC for the continued operation. Staff does not recommend
this alternative.
♦ Abandon Facility. This alternative was the original staff recommendation to Council,
however, as directed by Council, a thorough cost / benefit evaluation of the operation of the
hydroplant could reveal long-term benefits for the City.
* RFP available in Council reading file
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