SFPUC Commission Meeting
July 28, 2026
Approve Increase to Construction Cost and Duration Contingencies for Contract No. DB-121R2
Moccasin Powerhouse Generator Rehabilitation
Presented by: Javad Mirsaidi, Project Manager
1 2
Project Location Map within Hetch Hetchy Regional Water System
3 Project Background
On May 11, 2021, by Resolution No. 21-0078, the
Commission awarded Contract No. DB-121R2,
Moccasin Powerhouse Generator Rehabilitation, to
General Electric Renewables US LLC.
The scope of the Contract was to upgrade aging
generator components originally installed in 1969. The
work included the design, manufacturing, and
installation of numerous components, including:
• Stator Frame
• Stator Core
• Windings
• Rehabilitation work on the rotor
• Relay protection upgrades
Shaft Alignment Issue
During the rehabilitation process, it was
discovered that the Generator Unit No. 1
shaft was out of alignment due to a
slight bend at the top of the shaft. The
resulting eccentricity caused excessive
vibration during operation.
On May 27, 2025, by Resolution No. 25-
0085, the Commission approved an
increase in the cost and duration
contingencies to address the shaft
alignment issues.
4 5
Recommendation
The corrective measures were appropriate and cost-effective, they also underscored the need for an enhanced vibration monitoring system to improve detection of instability, and support safe operation.
Staff therefore requests Commission approval of an addition of • $400,000 in cost contingency, and
• 212 calendar days in duration contingency
to accommodate procurement of a new vibration monitoring system.
DEPARTMENT
Infrastructure Division
AGENDA NO.
12 MEETING DATE
July 28, 2026
AGENDA ITEM
Public Utilities Commission
City and County of San Francisco
Calendar: Regular Calendar
Project Manager: Javad Mirsaidi
Approve Increase to Construction Cost and Duration Contingencies for Contract No. DB-121R2, Moccasin Powerhouse Generator Rehabilitation
Summary of Proposed
Commission Action:
Approve an increase of $400,000 to the existing cost contingency and an increase of 2 12 calendar days to the existing duration contingency for Contract No. DB-121R2, Moccasin Powerhouse Generator Rehabilitation, with General Electric Renewable s US LLC, for a revised cost limit of $33,048,985, and a revised duration limit of 2,110 consecutive days (approximately five years and nine months), to address cost and schedule impacts of the procurement and installation of a new vibration monitoring system.
Background: The San Francisco Public Utilities Commission (SFPUC) Hetch Hetchy Water and Power operates the Moccasin Powerhouse , which was completed in 1969 with the installation of Generator Unit No. 1 and No. 2. T ogether these two units generate a combined maximum output of 110 megawatts. The average generation from Moccasin Powerhouse is approximately 430 gigawatt hours per year or 25 percent of the total generation from the Hetch Hetchy Water and Power system. The generator units at Moccasin Powerhouse have exceeded their life expectancy by 20 years. The generator units are in critical need of repair to continue operating.
The Hetch Hetchy water system serves 2.7 million people in the Bay Area, with approximately one-third of the delivered water going to retail customers in San Francisco. As the water flows through the Moccasin Powerhouse, its generators also function as flow- regulating facilities. Reliable water delivery depends on both generators being operational. If one generator fails, the SFPUC can continue deliveries using the remaining generator but this significantly reduces system redundancy, and places added stress on the remaining unit, increasing the risk of failure. Each generator is equipped with a bypass system designed to divert a limited flow of water around the generator. These bypasses, however, were not intended for prolonged use and may fail before the generator rehabilitation is completed . If both generators and their bypass systems fail, water deliveries from the Tuolumne River to the Bay Area would cease until the facilities are restored.
Agenda Title: DB-121R2, Moccasin Powerhouse Generator Rehabilitation Commission Meeting Date: July 28, 2026
On May 11 , 2021, by Resolution No. 21 -0078, th is Commission awarded Contract No. DB-121R2, Moccasin Powerhouse
Generator Rehabilitation, to General Electric Renewables US LLC.
The original contract amount was $26,271,805 and the original contract duration was 1,093 consecutive calendar days.
On June 13, 2023, by Resolution No. 23- 0108, this Commission approved a n increase of 365 calendar days to the duration contingency due to delays in the supply chain for long lead items , for a total revised duration limit of 1,567 consecutive calendar days, with no change to the contract amount.
On August 13, 2024, by Resolution No. 24- 0169, this Commission approved an increase of $2,150,000 to the cost contingency to cover the improvements to the generator fire protection system and other unforeseen modifications that were required to complete the second generator rehabilitation work, for a total revised cost limit of $31,048,985 (including the original 10% contingency) , with no change to the contract duration.
On May 27, 2025, by Resolution No. 25 -0085, th is Commission approved an increase of $1,600,000 to the cost contingency, and an increase of 331 calendar days to the duration contingency, for a total revised cost limit of $32,648,985, and a total revised duration limit of 1,898 consecutive calendar days , to address increased costs and schedule impacts due to shaft alignment issues discovered during reassembly of Generator Unit No. 1.
Scope of Contract: The contract work location is in Moccasin, California.
The contract work consists of design, manufacture, and installation of:
• Stator Frame;
• Stator Core;
• Windings;
• Rehabilitation work on the rotor; and
• Relay protection upgrades for two hydro-generation units at the Moccasin Powerhouse.
Modifications to the
Contract:
Design Phase Modification Nos. 1-3: Staff issued Design Phase Modification Nos. 1-3 to administratively encumber the full contract value with no changes to the contract amount or contract duration.
Construction Phase Modification Nos. 1 -17: Staff issued Construction Phase Modification Nos. 1- 17, as authorized under Resolution No s. 21-0078 and 24- 0169, increasing the contract amount by $3,229,612, and increasing the contract duration by 365 calendar days ,
to replace surface air coolers and bearing oil
coolers, re -rating and inspection of gantry crane, changes to the Agenda Title: DB-121R2, Moccasin Powerhouse Generator Rehabilitation Commission Meeting Date: July 28, 2026
protection and control design, add additional cable to provide proper length for future upcoming project repairs to the turbine shaft collars, perform single unit retardation testing, design and installation of the new fire suppression system, ensure that the protection engineer be available onsite during the Unit 2 Blackout Outage, Unit 2 alignment and cooling water system, bearing pad rebabbit, lead abatement, and Operations and Maintenance manual modifications, for a total contract amount of $29,501,417, and a total contract duration of 1,458 consecutive calendar days.
Construction Phase Modification Nos. 18 -24: Staff issued Construction Phase Modification Nos. 18- 24, as authorized by Resolution Nos . 21-0078, 24- 0169, and 25 -0085, increasing the contract amount by $2,406,205, and increasing the contract duration by 204 consecutive calendar days to address Unit 1 thrust block inspections, Unit 1 shaft alignment and repairs to thrust collar and shims, compensable delay costs and addit
ional duration for
field iterations to achieve alignment with newly machined parts for a total contract amount of $31,907,622, and a total contract duration of 1,662 consecutive calendar days.
Proposed Increase to Cost and Duration Contingencies: Staff recommends the Commission approv e an additional increase of $400,000 to the existing cost contingency, and 212 calendar days to the existing duration contingency, for a revised cost limit of $33,048,985 and a revised duration limit of 2,110 consecutive calendar days, to accommodate equipment procurement and installation. The work performed under Contract Modification Nos. 18–24, which included inspections, shaft alignment, and repairs to the Unit 1 thrust block assembly, addressed the immediate conditions encountered during reassembly. While these corrective measures were appropriate and cost-
effective, they also
underscored the need for enhanced, ongoing monitoring to manage future performance risks for both units. To support this, staff recommends procuring and installing a new vibration monitoring system for both units.
Funding and Costs: Funding Source: Hetch Hetchy Capital Improvement Program , Project No. 10014086, Moccasin Powerhouse and Generator Step- Up Rehabilitation
Original Contract Amount: $26,271,805
Original 10% Cost Contingency: $2,627,180
Approved Increase in Cost Contingency: $3,750,000
Modified Increases to Contract Amount: $5,635,817
Total Current Contract Amount: $31,907,622
Current Cost Contingency: $741,363
[Proposed] Additional Cost Contingency: $400,000
Total [Proposed] Contract Cost Limit: $33,048,985
Agenda Title: DB-121R2, Moccasin Powerhouse Generator Rehabilitation Commission Meeting Date: July 28, 2026
Schedule: Notice-to-Proceed Date: June 21, 2021
Original Contract Duration: 1,093 consecutive calendar days Original 10% Duration Contingency: 109 calendar days
Approved Increase to Duration Contingency: 696 calendar days Modified Increases to Contract Duration: 569 calendar days Total Current Contract Duration: 1, 662 consecutive calendar days
Current Duration Contingency: 236 calendar days
[Proposed] Additional Duration Contingency : 212 calendar days
Total [Proposed] Duration Limit : 2,110 consecutive calendar days
Environmental
Review:
On August 4, 2014, the Planning Department determined the Project to be categorically exempt from environmental review under the California Environmental Quality Act ( CEQA) Guidelines Section 15301, Class 1 (Existing Facilities) (Case No. 2014.1184E).
The proposed modifications are within the scope of the Project evaluated in the exemption.
View the CEQA exemption determination.
Local Business
Enterprise Utilization
and Non-
Discrimination in
Contracting:
Pursuant to Chapter 14B of the San Francisco Administrative Code, the Contract Monitoring Division has waived subcontracting goals for this construction contract due to the specialized nature of the work.
Agenda Title: DB-121R2, Moccasin Powerhouse Generator Rehabilitation Commission Meeting Date: July 28, 2026
Project Location Map within Hetch Hetchy Regional Water System
DB-121R2
Project Site
PUBLIC UTILITIES COMMISSION
City and County of San Francisco
RESOLUTION NO.
WHEREAS, On May 11, 2021, by Resolution No. 21- 0078, th e Commission awarded Contract No. DB-121R2, Moccasin Powerhouse Generator Rehabilitation, to General Electric Renewable US LLC; and
WHEREAS, The original contract amount was for $26,271,805 and the original contract duration was 1,093 consecutive calendar days; and
WHEREAS, The contract Notice-to-Proceed date was June 21, 2021; and
WHEREAS, On June 13, 2023, by Resolution No. 23-0108, th e Commission approved an increase of 365 calendar days to the duration contingency , for a total duration limit of up to 1,567 consecutive calendar days, with no change to the contract amount; and
WHEREAS, August 13, 2024, by Resolution No. 24- 0169, the Commission approved an increase of $2,150,000 to the cost contingency, for a total revised cost limit of $31,048,985, with no change to the contract duration; and
WHEREAS, May 27, 2025, by Resolution No. 25-0085, the Commission approved an increase of $1,600,000 to the cost contingency, for a total revised cost limit of $32,648,985, with an increase of 331 calendar days to the duration contingency, for a total duration limit of up to 1,898 consecutive calendar days; and
WHEREAS, Staff issued Design Phase Modification Nos. 1 -3 to administratively encumber the full contract value, with no change to the contract amount or contract duration; and
WHEREAS, Staff issued Construction Phase Modification Nos. 1- 17, as authorized under Resolution Nos. 21-0078 and 24-0169, increasing the contract amount by $3,229,612, and increasing the contract duration by 365 consecutive calendar days to replace surface air coolers and bearing oil coolers, re- rating and inspection of gantry crane, changes to the protection and control desi gn, add additional cable to provide proper length for future upcoming project repairs to the turbine shaft collars, perform single unit retardation testing, design and installation of the new fire suppression system, ensure that the protection engineer be available onsite during the Unit 2 Blackout Outage, Unit 2 alignment and cooling water system, bearing pad rebabbit, lead abatement, and Operations and Maintenance manual modifications, for a total contract amount of $29,501,417, and a total contract duration of 1,458 consecutive calendar days; and
WHEREAS, Staff issued Construction Phase Modification Nos. 18- 24, increasing the contract amount by $2,406,205, and increasing the contract duration by 204
consecutive calendar days, as authorized by Resolution Nos. 21-0078, 24-0169, and 25- 0085, to address Unit 1 thrust block inspections, Unit 1 shaft alignment and repairs to thrust collar and shims, compensable delay costs and additional duration for field iterations to achieve alignment with newly machined parts for a total contract amount of $31,907,622, and a total contract duration of 1,662 consecutive calendar days; and
WHEREAS, Staff recommends this Commission approve an increase of $400,000 to the cost contingency and 212 calendar days to the duration contingency, for additional costs and time to procure and install a new vibration monitoring system for both generator units, for a revised cost limit of $ 33,048,985 and a revised duration limit of 2,110 consecutive calendar days; and
WHEREAS, The Contract Monitoring Division has waived the Chapter 14B of the San Francisco Administrative Code subcontracting goals for this project due to the specialized nature of this work; and
WHEREAS, On August 4, 2014, the Planning Department determined the Project to be categorically exempt from environmental review under the California Environmental Quality Act Guidelines Section 15301, Class 1 (Existing Facilities) ( Case No. 2014.1184E); and
WHEREAS, T he proposed modifications are within the scope of the Project evaluated in the exemption; and
WHEREAS, Funds are available from Hetch Hetchy Capital Improvement Program funded Project No. 10014086 , Moccasin Powerhouse and Generator Step- Up Rehabilitation; now, therefore, be it
RESOLVED, That this Commission hereby approves an increase of $400,000 to the existing cost contingency and an increase of 212 calendar days to the existing duration contingency, for Contract No. DB -121R2, Moccasin Powerhouse Generator Rehabilitation, with General Electric Renewables US LLC , for a total cost contingency amount of $6,777,180 and a total duration contingency of 1,017 calendar days; and be it
FURTHER RESOLVED, That this Commission hereby authorizes the General Manager, or the General Manager’s designee, to consider, and, if appropriate, to approve any future modifications to the contract, up to a total cost limit of $33,048,985 and a total duration limit of 2,110 consecutive calendar days.
I hereby certify that the foregoing resolution was adopted by the San Francisco Public Utilities Commission at its meeting of July 28, 2026.
Director of Commission Affairs
San Francisco Public Utilities Commission