Pasadena Water and Power
Impacts on Power Distribution and
the City's Response During the Recent
Excessive Heat Event
City Council
September 16, 2024
Pasadena Water and Power
Extreme Heat Conditions in Southern
California Impacted Utilities Region-wide
• Record-breaking to near
record-breaking extended
heat conditions
> Wed 9/4 through Mon 9/9
> Peak on Friday, 9/6
• Extreme heat conditions
caused power outages
across the region
2 Pasadena Water and Power
Pasadena Also Impacted by
Extreme Heat Wave
• During extent of 6-day extreme heat event, Pasadena
experienced 11 localized outages
> Crews on standby allowing for prompt response to outages > Power restored to affected customers within hours or overnight • Pasadena critically impacted on Fri 9/6
> 115 degrees ambient temperature at Glenarm Power Plant > New all-time system high peak load of 330.8 MW
> Extreme heat conditions triggered power plant system component shutdowns and automatic preventive measures to safeguard critical equipment from significant damage
3 Pasadena Water and Power
Pasadena Provided Critical and Immediate
Response for Overall Continued Reliability
4 • Emergency preparedness
> Crews and equipment available, ready to respond
> Early measures taken, including installing additional cooling systems at power plant
> Protocols in place for emergency response
> Communication systems established
• Quick action taken to protect the system,
communicate with customers, and restore
power
> Implemented immediate load shedding (rotating
outages): maintained safe thresholds and prevented
potential cascading system-wide equipment failure
> Sent system-wide customer notifications
> Safely restored power plant equipment, restarted units, and stabilized the system within 1.5 hours
> Concluded rotating outages, restored power to
impacted customers, and continued to meet loads
through remainder of extreme heatwave event
PWP website front page during heat wave
Rotating one-hour outages implemented,
preventing system equipment damage
Pasadena Water and Power
Extreme Heat Impacts and Response
Additional Details
5 Pasadena Water and Power
Ready to Supply Power System Demands with
Imported and Locally Produced Energy
*GT-5 out for repairs (66 MW)
GLENARM
POWER PLANT
IMPORTED ENERGY
Four generators*
available with total
generation capacity
up to 132 MW
Imported through SCE
transmission system
Import Capacity: 280 MW
Available Capacity to Meet Demands
Pasadena Water and Power
Glenarm Power Plant Supplies Electricity to
Meet Load Above Import Capacity
~330
GLENARM
POWER PLANT
IMPORTED ENERGY
Import Capacity: 280 MW
Power Supply Balance Prior to Units Going Offline
9/6/2024
~271 MW ~59 MW
GT-3 & GT-4 Online
Pasadena Water and Power
Glenarm Power Plant Supplies Electricity to
Meet Load Above Import Capacity
~330
GLENARM
POWER PLANT
IMPORTED ENERGY
Import Capacity: 280 MW
Extreme Heat Conditions Tripped Units Offline
Demand Greater than Import Capacity
Risk of System Equipment Failure
0 MW
~50 MW
over import
capacityGT-3 & GT-4 Offline
330 MW
GT-3 & GT-4 offline as main gas compressor tripped due to high heat, and redundant gas compressor failed to start due to cooling system issues Pasadena Water and Power
Glenarm Power Plant Supplies Electricity to
Meet Load Above Import Capacity
~330
GLENARM
POWER PLANT
IMPORTED ENERGY
Import Capacity: 280 MW
Immediately Worked to Bring Units Online
to Avoid Load Shedding
~21-58 MW
GT-1 Online
GT-2 Offline
GT-3 Briefly Online
GT-4 Offline
272-309 MW
GT-2 unable to synchronize due to voltage out of phase issues; GT-1 generated power for 53 minutes until extreme high heat tripped the unit ~0-29 MW
over import
capacity
Pasadena Water and Power
Glenarm Power Plant Supplies Electricity to
Meet Load Above Import Capacity
~330
GLENARM
POWER PLANT
IMPORTED ENERGY
Import Capacity: 280 MW
Full Loss of Glenarm Power Plant Production (3:54pm)
Required Immediate Load Shedding (4:02pm)
Preventing Potential System Equipment Failure
0 MW
~50 MW
over import
capacityAll Units Offline
330 MW
Rotating outages implemented for 1-hr periods;
Approximately 12,000 customers impacted (between 15 min to 1 hr max) Pasadena Water and Power
Glenarm Power Plant Supplies Electricity to
Meet Load Above Import Capacity
GLENARM
POWER PLANT
IMPORTED ENERGY
Import Capacity: 280 MW
0-54 MW 280-266 MW
Rotating outages concluded at 5:21 p.m. after steady production verified Continued to generate power to meet loads through extreme heatwave 4:02 p.m. – 5:21 p.m.
Rotating Outages (Load Shed) ~50 MW
Restoring GT-1,3,4
Pasadena Water and Power
12 Continued Communications throughout
Extreme Heat Event
• Promoted emergency preparedness and energy
conservation prior to extreme heat event
> Working closely with City PIO
• Quickly notified customers
> When critical load shedding was required, staff implemented "robo-calls" and emails to all PWP customers via Everbridge Due to critical time constraints, initial notification sent shortly after rotating outages implemented
> Follow up notification sent when rotating outages concluded • Coordinated emergency messaging with City PIO
> Immediate and ongoing communication with PIO
> Coordinated responses to multiple news media requests > Social media support
PIO team posted to City social media (X/Twitter, Facebook, Instagram) PWP team posted to department's social media (X/Twitter & Facebook) > PWP front webpage changed to direct customers to outage map
Pasadena Water and Power
Continue to Enhance Systems for Reliability
• Cooling systems at Power Plant
> Installed mister/sprinkler system for gas compressor
> Created shade for the emissions control load center and used a fan for cooling > Augmented evaporative cooling system with purchase of 2 additional large units > Considering installing a HVAC system for the gas compressor building and permanent shade structure for emissions control load center
• Improving communication systems
> Developing customer notification messaging system to incorporate multiple languages and proactive messaging
> Continue outreach for medical device registration.
Recent activity:
Bill inserts (Mar/Apr, Sep/Oct), advertising (print/digital) social media, City Manager newsletter, PWP newsletter
• City and community continue to step up
> Crews continue to maintain reliable services and remain ready to respond > Thank you to the community and other city departments! 13