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Utilities Advisory Commission
Staff Report
From: Dean Batchelor, Director Utilities
Lead Department: Utilities
Meeting Date: February 7, 2024
Staff Report: 2401-2508
TITLE
Discussion of Electric Grid Modernization Plan
RECOMMENDATION
This memorandum and presentation are for discussion purposes only; no action is requested at
this time.
EXECUTIVE SUMMARY
The City of Palo Alto’s Electric Grid Modernization for Community-Wide Electrification Project
(Grid Mod Project) was developed to enhance the distribution system’s grid resiliency and
reliability in a manner that will continue to accelerate the City’s clean energy and decarbonization
goals. Palo Alto’s grid must be modernized to reach the capacity required to electrify all homes
and cars. The modernized system will be designed to fully accommodate energy received from
local generation such as rooftop solar and battery storage, an important element in
decarbonization goals. There will be an upgrade to the distribution system to incorporate local
generation, allow two-way power flow, meet projected capacity needs, enhance voltage
regulation and system protection requirements, and provide a high level of resiliency and
reliability.
The Project’s three main objectives are:
•Increase capacity on the Electric Grid to allow for the addition of new electrical load from
the electrification of heating load, electric vehicles, and battery storage.
•Enhance system reliability and resiliency by installing advanced distribution network
protection schemes.
•Implement distribution system control technologies to allow for high levels of solar
penetration, battery storage, distributed energy resources, and electric vehicles.
To meet the expected increase in demands, this Project will increase network capacity. Capacity
increases will include the following work:
•Converting 4kV systems to 12kV.
•Installing more distribution transformers with greater capacity.
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•Rebuilding secondary networks by increasing the conductor size and creating more
secondary networks.
•Replacing four distribution substation transformers at two substations with larger
transformers having greater capacity.
BACKGROUND
The City established its first Climate Protection Plan in 2007, which is now the Sustainability and
Climate Action Plan (S/CAP). This plan has been periodically updated and aligned with current
conditions to provide a comprehensive roadmap to reducing greenhouse gas (GHG) emissions.
In 2013, Palo Alto became one of the first cities in the nation to source 100% carbon-neutral
electricity. In 2020, the City launched an update to reduce GHG emissions 80 percent below 1990
levels, i.e., reduce 624,095 metric tons of greenhouse gases by 2030 (the “80 x 30 goal"). This
goal exceeds even the state of California's world-leading reduction goal of 80% by 2050; the
California Global Warming Solutions Act of 2006 (AB32) requires the state to reduce its GHG
emissions 40% below 1990 levels by 2030 and set an aspirational goal to reduce emissions 80%
by 2050.
One major initiative in the S/CAP is to promote the transition to all-electric homes and electric
vehicles (EVs) to reduce greenhouse gas emissions. A 2021 impact analysis showed to meet the
“80 x 30 goal”, the City must electrify all of its roughly 15,000 single-family homes, replacing
natural gas equipment with efficient electric alternatives. Also, currently, one in six Palo Altans
drive an electric car, and EVs now account for more than 30% of new car sales in Palo Alto - the
highest adoption rate in the country. One of three newly registered vehicles in Palo Alto is an EV.
This transition, or “electrification,” will require an extensive upgrade to the electric distribution
network due to a large increase in electrical energy needed to replace gas heating equipment
with electrical equipment and support EVs.
As a result, the Grid Mod Project was developed to enhance the distribution system’s grid
resiliency and reliability in a manner that will continue to accelerate the City’s clean energy and
decarbonization goals. Palo Alto already supplies customers electricity from a 100% carbon
neutral portfolio and has been in the forefront of efforts to design programs allowing customers
to easily utilize clean energy through EVs and electric appliances.
Palo Alto’s grid must be modernized to reach the capacity required to electrify all homes and
cars. The modernized system will be designed to fully accommodate energy received from local
generation such as rooftop solar and battery storage, an important element in decarbonization
goals. There will be an upgrade to the distribution system to incorporate local generation, allow
two-way power flow, meet projected capacity needs, enhance voltage regulation and system
protection requirements, and provide a high level of resiliency and reliability.
ANALYSIS
The City conducted an electrification study to evaluate the impacts of projected electrification
loads on Palo Alto’s distribution and substation transformers, primary/secondary distribution
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circuits, and to propose upgrades needed to mitigate overloads. The estimated cost to construct
the necessary electric system upgrades for a 100% electrification scenario is between $220
million to $306 million, depending on the approach. Of the nine substations in Palo Alto, the
study recommends major design and equipment upgrades at two of the nine substations, and
minor to moderate upgrades at four substations to meet projected loads to support 100%
electrification.
The Grid Mod Project requires bringing online more transformers, replacing deteriorating wires
and connectors, upgrading or replacing poles, and providing battery storage and solar system
support to the interconnected grid. Specifically, the Project involves replacing the current 1,413
single phase pole top transformers rated less than 50kVA with the same type of transformers
rated 50kVA or larger. Additionally, there are currently 261 single-phase pad mount transformers
and 231 single-phase underground transformers installed on the distribution system. Based on
the projected average peak load of 6kVA per customer, 341 of these transformers (including all
231 underground transformers) will need to be replaced with 75kVA or larger transformers to
mitigate overloads. In order to limit the maximum number of customers per transformer to 15
(90kVA), an additional 83 transformers will need to be installed. Furthermore, 296,300 circuit
feet of open wire secondary conductors in the distribution system will be replaced with
aluminum aerial cable. These design aspects will accommodate 100% residential electrification
of end uses in the Palo Alto community, aligning with the City’s primary goal of decarbonization.
For future housing development, the City will perform new analysis and make appropriate
electric distribution network changes as needed for electrification.
Capacity increases on the network are needed to meet the additional load that will be placed on
the distribution network. The estimated average diversified electric energy demand for
households at the current time is approximately 2-3 kVA per home. When homes are electrified,
the diversified electric demand is expected to increase to approximately 6 kVA per home. This
increased load will exceed the capacity of the existing distribution network. Most of the impacts
of the increased load will be on the distribution transformers and the secondary networks serving
homes. In addition, some substation transformers will need to be replaced and upgraded to
support the new distribution network.
Capacity increases included in this Project are comprised of the following work:
•Converting remaining 4kV systems to 12kV.
•Installing more distribution transformers with greater capacity.
•Rebuilding secondary networks by increasing the conductor size and creating more
secondary networks.
•Replacing four distribution substation transformers at two substations with larger
transformers having greater capacity.
Grid resiliency and reliability are key factors in delivering a service to meet customer needs. As
electrification loads increase and customers become more dependent upon electricity to meet
household and transportation needs, the grid will need to be more reliable and have limited
downtime. To help facilitate meeting resiliency and reliability goals, the City’s dark fiber network
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is currently being expanded to provide services to the community and connectivity to electric
distribution switches and protection equipment.
To meet the need for greater reliability and resiliency, the Project includes the following:
•Additional circuit ties will be installed to improve the ability to pick up load during
outages.
•Automated restoration schemes that can be used to isolate faults and restore customers
will be installed where they are practical to deploy.
•Advanced distribution protection schemes will be installed to decrease the size of the
outages on the feeders.
Due to the high penetration of solar generation, battery storage, and EVs in this community,
there will be opportunities to test technologies to control input into the grid, maintain the voltage
regulation of the system, and control customer behavior through price signals. Palo Alto is
connected to the system operated by the California Independent System Operator (CAISO).
Currently the state electricity grid is undergoing a transformation to a grid that relies on
renewables. As a result, there are situations where the grid has too much supply, and at other
times it is short on supply. Palo Alto will implement technologies that can support the two-way
needs of the larger grid. These technologies include solar inverters that regulate power factor
and load output, vehicle to grid power supply, and demand management technologies. Palo Alto
developed low, mid, and high electric load forecasts through 2045 including the total expected
additional data center load, EV load, and building electrification load.
In addition to enhancing reliability and resiliency of the electric grid, electrification will benefit
the community by saving money, improving qualify of life, and helping the environment. While
electrification will typically result in higher electric bills, significant savings can be achieved
elsewhere, such as customers’ vehicle fuel and natural gas bills. EV owners can save about $1,000
per year on fuel and thousands of dollars more in maintenance over the life of an EV. As more
Low, Mid, and High Load Forecasts through 2045
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people switch from fossil fuel to electricity, there will be significant reduction in carbon emissions
which helps Palo Alto reach the “80 x 30 goal” to ensure the quality of life for future generations.
New electric-powered equipment and appliances are much more energy-efficient than the
devices they replace. Heat pump efficiency has risen from 10 SEER (seasonal energy efficiency
ratio) to close to 20 SEER — that’s 500% efficient — for cooling, and from 6 HSPF (heating
seasonal performance factor) to 10 FSPF — 250% efficient — for heating in a couple of decades.
Natural gas furnaces are 92% efficient.1
Customer benefits of grid modernization and electrification include:
•Reduced greenhouse gas emissions
•Grid-connected or smart appliances
•Reduced fire risk and avoid the risks of gas leaks
•Increased efficiency and lower energy costs from electric-powered equipment
•Reduced power outages
•Lower operating and maintenance costs for vehicles, equipment and appliances
HIGH-LEVEL ESTIMATED TIMELINE
Year 1 – 2024
Task 1.0: Overhead Distribution System Upgrade Pilot Project
Subtask 1.1 - Prepare design
Subtask 1.2 - Order and delivery of transformers
Subtask 1.3 - Material order and delivery
Subtask 1.4 - Construction
Task 2.0: Design Resource Acquisition
Subtask 2.1 - Prepare RFP for Design Services
Subtask 2.2 - Evaluate Proposals and Select Consultant
Task 3.0: Phase 1 Overhead System Improvements
Upgrade 10% of Overhead Distribution System
Subtask 3.1 - System Design
Subtask 3.2 - Order and delivery of transformers
Year 2 – 2025
Task 3.0 (continued): Phase 1 Overhead System Improvements
Subtask 3.3 - Material order and delivery
Subtask 3.4 - Construction
Task 4.0: Phase 2 Overhead System Improvements
Upgrade 40% of Overhead Distribution System
Subtask 4.1 - System Design
Subtask 4.2 - Order and delivery of transformers
Subtask 4.3 - Material order and delivery
1 https://www.questline.com/blog/beneficial-electrification-energy-utility-customers/
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Subtask 4.4 - Construction
Task 5.0: Transformer Upgrades – Colorado Substation
Subtask 5.1 - Substation Transformer Expansion Design
Subtask 5.2 - Order long-lead time material
Year 3 – 2026
Task 6.0: Phase 3 Overhead System Improvements
Upgrade 70% of Overhead Distribution System
Subtask 6.1 - System Design
Subtask 6.2 - Order and delivery of transformers
Subtask 6.3 - Material order and delivery
Task 7.0: Feeder Ties and Circuit Outlets – Colorado Substation
Subtask 7.1 - Design Circuits
Subtask 7.2 - Order long-lead time material
Task 8.0: Phase 4 Overhead System Improvements
Upgrade 100% of Overhead Distribution System
Subtask 8.1 - System Design
Year 4 – 2027
Task 5.0 (cont.): Transformer Upgrades – Colorado Substation (re-ordered)
Subtask 5.3 - Substation Construction
Task 6.0 (cont.): Phase 3 Overhead System Improvements
Subtask 6.4 - Construction
Task 7.0 (cont.): Feeder Ties and Circuit Outlets – Colorado Substation
Subtask 7.3 - Construction
Task 8.0 (cont.): Phase 4 Overhead System Improvements
Subtask 8.2 - Order and delivery of transformers
Subtask 8.3 - Material order and delivery
Task 9.0: Phase 1 Underground System Improvements
Upgrade 33% of Underground Distribution System
Subtask 9.1 - System Design
Task 10.0: Transformer Upgrades – Hopkins Substation
Subtask 10.1 - Substation Transformer Expansion Design
Subtask 10.2 - Order long-lead time material
Year 5 – 2028
Task 8.0 (cont.): Phase 4 Overhead System Improvements
Subtask 8.4 - Construction
Task 9.0 (cont.): Phase 1 Underground System Improvements
Subtask 9.2 - Order and delivery of transformers
Subtask 9.3 - Material order and delivery
Subtask 9.4 - Construction
Task 11.0: Phase 2 Underground System Improvements
Upgrade 66% of Underground Distribution System)
Subtask 11.1 - System Design
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Year 6 – 2029
Task 10.0 (cont.): Transformer Upgrades – Hopkins Substation
Subtask 10.3 - Substation Construction
Task 11.0 (cont.): Phase 2 Underground System Improvements
Subtask 11.2 - Order and delivery of transformers
Subtask 11.3 - Material order and delivery
Task 12.0: Phase 3 Underground System Improvements
Upgrade 100% of Underground Distribution System)
Subtask 12.1 - System Design
Year 7 – 2030
Task 11.0 (cont.): Phase 2 Underground System Improvements
Subtask 11.4 - Construction
Task 12.0 (cont.): Phase 3 Underground System Improvements
Subtask 12.2 - Order and delivery of transformers
Subtask 12.3 - Material order and delivery
Subtask 12.4 - Construction
FISCAL/RESOURCE IMPACT
High level estimated costs including labor and material by activity. The following unit costs are
from the 2021 CPUC PG&E Unit Cost Guide, except for pole top transformer and substation
transformer/switchgear costs which are provided by Utilities engineering staff. City will
continue to pursue grant funding opportunities as they arise.
STAKEHOLDER ENGAGEMENT
December 7, 2022 – Utilities Advisory Commission Meeting – Electric Distribution Infrastructure
Modernization Update https://www.cityofpaloalto.org/files/assets/public/v/2/agendas-
minutes-reports/agendas-minutes/utilities-advisory-commission/archived-agenda-and-
minutes/agendas-and-minutes-2022/12-07-2022/12-07-2022-agenda-and-packet.pdf
Description Qty
Unit of
Measure Unit Cost Extended Cost
60/12 kV s ubstation trans former and switchgear 2 Unit 25,000,000$ 50,000,000$
115/60 kV s ubstation transformer and high s ide breaker 2 Unit 20,000,000$ 40,000,000$
Single phas e pole top trans former including pole make ready/replacement 1,400 Unit 20,000$ 28,000,000$
Single phas e pad mount trans former including s ubstructure 424 Unit 40,000$ 16,960,000$
Underground 12 kV circuit tie including cable, trench and s ubstructures 30,900 Foot 800$ 24,720,000$
Overhead 12 kV circuit tie/reconductor 11,000 Foot 220$ 2,420,000$
Overhead s econdary reconductor with AWAC 296,300 Foot 165$ 48,889,500$
4 kV to 12 kV convers ion including trans formers 381 Unit 23,200$ 8,839,200$
Total Estimate 219,828,700$
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June 7, 2023 – Utilities Advisory Commission Meeting – Electric Distribution Infrastructure
Modernization Update
https://cityofpaloalto.primegov.com/meeting/attachment/1764.pdf?name=Electrification%20
Modernrization%20Plan%206-7-2023
November 30, 2023 - Sustainability and Climate Action Plan Ad Hoc Committee Meeting –
S/CAP Progress and 100% Renewable Energy
https://www.cityofpaloalto.org/files/assets/public/v/1/sustainability/presentations/2023.11.30
-scap-ad-hoc-committee-meeting.pdf
ENVIRONMENTAL REVIEW
This informational report is not a project under CEQA. The overhead distribution system upgrade
pilot project currently in progress is categorically exempt from the California Environmental
Quality Act (CEQA) pursuant to CEQA Guidelines 15301 (repair, maintenance, of existing facilities)
and 15302 (replacement or reconstruction of existing facilities).
ATTACHMENTS
Attachment A: Presentation
AUTHOR/TITLE:
Dean Batchelor, Director of Utilities
Staff: Dave Yuan, Utilities Strategic Business Manager
Discussion of Electric Grid Modernization Plan
February 7, 2024 www.cityofpaloalto.org
2
Presentation Outline
§Distribution System Topology
§Residential Customer Connections – Past & Future
§Major Projects
-Upgrading Distribution System Hardware (Phase 1)
-Complete 4 kV to 12 kV upgrade (2 substation)
-Integrating new utility technologies
-Integrating with new customer technologies
-Fiber to the premise
§Timeline and Resources
3
CPAU Topology
Generation Transmission
- owned by PG&E
-3 Transmission
Lines, 115 kV
rated
Receiving Substations
- 8 distribution substation
-1 transmission substation
- 60 kV sub transmission
network
Distribution System
Network
- 12.47 kV primary circuit
-4.16 kV primary circuit
-Transformers (TX) range: 5
kVA – 2.5 MVA
CPAU Customers
-120/240 V for residential
-120/208/480V for commercial
4
Existing Customer Connections
§3 KVA Expected peak load demand from residential customer
§For new, relocated, or upgraded 200 A electrical services
§Customer invoiced for standard fee
§For new, relocated, or upgraded >200 A electrical services
§Customer invoiced advance engineering fee
§Customer invoiced for additional expenses determined by
estimators
§Customer is responsible for any substructure work, secondary cabling,
and electric meter panel
§CPAU responsible for infrastructure upgrades & labor of connecting
electrical services
5
Updated Customer Connections - Future
§6 kVA expected peak load demand from residential customer
– up from 3 kVA estimated allocation from the past
§Customers will still receive standard invoice for 200 A service
§In Development: standard connection fee for 400 A service
6
CPAU Strategic Projects
Grid Modernization
for Electrification
•Upgrade current
infrastructure (TXs, cable
sizes, etc.)
•Integrating new technology
(i.e., AMI, fault indicators,
remote switching, fuse savers)
•Customer technologies (solar
PV, ESS, EV, V2X, HPWHs)
Fiber to the Premise
(FTTP)
•CPA new internet service provider
•Goal: to upgrade and expand the existing fiber backbone and FTTP for all homes and businesses
•To build new fiber connections to support CPA Internet services to all Palo Alto homes
7
Upgrading Existing Distribution System Elements
§Overall System Upgrade
o Upgrade 4 kV lines installed in 1967 to 12 kV lines
o Upgrade 4 of 30 substation transformers
o Upgrade 1741 of 3000 distribution system transformers
o Upgrade 56 miles of secondary and 17 miles of primary
distribution lines
§Phase 1
o Complete system upgrades and improvements affecting
6,784 customers
Grid Modernization Phase 1
Pilot Area
Customers: 1,224
Total Poles: 409
Phase 1
Customers: 6,784
Total Poles: 1,650
Overhead Secondary System Design
Upgrade to
50 kVA TX
Up to 8
customers per
50 kVA
transformer
4/0 AL cable to replace
majority of existing
open wire or rack
secondary conductors
Fiber to the house
addition
9
Service drop to be
replaced with 1/0
AL triplex
Overhead Electrification Scope of Work
•Approximately 1400 single phase
pole top TXs will need to be
replaced with a 50 kVA or larger
TX
•A total of 296,300 circuit feet (56
miles) of open wire and rack
secondary conductors will need
to be replaced with aerial cable
(1/0 AL Or 4/0 AL) for the entire
City
10
Underground Secondary System Design
Must be
75 kVA TX
350 AL sec. cable to replace
any smaller cable
Up to 12
customers per
transformer
Up to 12
customers per
transformer
350 AL sec. cable to replace
any smaller cable
Remove all
URD TXs
Replace
with 75
kVA TX
Pad Mount Transformer
System
URD Transformer System
11
Underground Electrification Scope of Work
•Of the 261 single phase
padmount TX in CPA, 110 TX will
need to be replaced with a
75kVA or larger TX
•An additional 52 TXs will need to
be installed
•All 231 single phase URD TX in
CPA will need to be replaced
with a 75KVA or larger TX
•An additional 31 TXs will need to
be installed
12
13
Grid Modernization impact on CPAU Infrastructure
Supply/Resources Transmission Substations
-replace 4 of 30
substations TX with
larger capacity
Distribution System
Network
- Replaced secondary cable
-4.16 kV circuit to be replaced
with 12.47 kV
-upgrade and add TX
-replace service laterals
-remove URD TX
CPAU Customers
-New service fees
-Integrate AMI and other
customer technology
14
§Consultants
§ENTRUST
§Magellen
§Soudi Inc
§Contractors
§MP Next Level
§VIP Powerline Corp
§Davey Tree
§Funding
§Est. Budget of $220-
$306M
§Bond Issuance / Debt
Financing
§CIP Funding
Resource Necessities
15
Fall 2024
Proposed Timeline
Pilot Area Complete
Summer 2025 Phase 1 Complete
Winter 2030 All Phases Complete
16
THANK YOU!
Dean Batchelor, Director of Utilities
Dean.batchelor@CityofPaloAlto.org