Substantial technology advances in power electronics, battery price/performance, efficiency and significantly lower maintenance cost are driving Transportation Electrification forward. While personal vehicle choices are influenced by many factors, fleet managers focus on total cost of ownership considering both the capital and operational impact of aggregated charging facilities. As transit, freight, logistics, taxi, ride share and a growing list of high vehicle utilization applications reach technical viability and exceed cost parity with conventional fuels, fleet operators must understand infrastructure requirements of Electrification and associated project risks. Historically fleet facilities have not had to accommodate the large loads that are needed to support fleets of electrified vehicles. Differences in location, scale, charging equipment and charging behaviors can have profound impact on capital and operational costs. This briefing describes various scenarios for electrical supply required to support fleet facilities and notes the likely development durations for power delivery.

1. UNDERSTANDING AND DE-RISKING
EV CHARGING POWER DELIVERY
Transformative Technologies Briefing
PREPARED FOR
High Power EV Charging Facilities
5 MAY 2017
©Black&VeatchHoldingCompany2018.Allrightsreserved.

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Power Delivery Overview for High Power EV Charging
Demand for High Power EV Charging
Substantial technology advances in power electronics, battery price/performance, efficiency and
significantly lower maintenance cost are driving Transportation Electrification forward. While personal
vehicle choices are influenced by many factors, fleet managers focus on total cost of ownership
considering both the capital and operational impact of aggregated charging facilities. As transit, freight,
logistics, taxi, ride share and a growing list of high vehicle utilization applications reach technical viability
and exceed cost parity with conventional fuels, fleet operators must understand infrastructure
requirements of Electrification and associated project risks. Historically fleet facilities have not had to
accommodate the large loads that are needed to support fleets of electrified vehicles. Differences in
location, scale, charging equipment and charging behaviors can have profound impact on capital and
operational costs. This briefing describes various scenarios for electrical supply required to support fleet
facilities and notes the likely development durations for power delivery.
Understanding Power Delivery and Schedule Risks
Early Electrification pilot programs provided essential feedback on vehicle capabilities, duty cycle,
energy requirements, integration with operations. As business reaches commercialization scale, taking
these lessons to the next level in preparation for broad fleet wide rollouts requires deep understanding
of Power Delivery and Schedule Risk across an operator’s entire facility portfolio. Fleet managers used
to control over their fuel supply and facility projects will now need to navigate a new maze of delivery
voltage choices, rate impacts, transformer upgrades, switchgear configurations and service entrance
updates. Beyond the facility, new charging loads may exceed feeder capacity requiring upgraded or new
utility feeders, substation updates, and even new substations.
High Power EV Charging - Power Delivery Schedule Impacts
A utility’s distribution network distributes electricity from high power transmission down to the end
consumer. At the substation power is converted from high to medium voltage and split among many
feeder circuits. Supply taps along the feeders connect customers to the circuit either directly (Primary
Service, higher power) or via a service transformer (Secondary Service, lower power). Key equipment in
power delivery from a distribution substation to a Secondary Service supply customer is shown below in
Figure 1.

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Figure 1: Typical Distribution Network to Secondary Service Customer Sitei
Depending on the site selection, existing property supply and location on the distribution network, the
addition of high power EV charging load may require equipment upgrades to either grid elements or
building facilities. Because power levels tend to decrease down the network, upgrades are more likely to
be required as EV load size increases. As additional upgrades are required upstream on the network, the
cost and duration of time from order to power delivery will generally also increase.
While upgrade requirements of a specific project are highly dependent on existing equipment capacity
and load of the connected site, circuits and substation, the following scenarios outline “rules of thumb”
for possible power delivery upgrades and schedule impacts that may occur at various EV load sizes. The
following descriptions summarize power upgrade scenarios from least to most complex. Specific site
constraints or conditions may result in deviations from typical schedule timeframes.
Local Facility Upgrade Descriptions & Schedule Factors
Base Case Deployment: Secondary Service Upgrade, No Distribution Circuit Upgrades (up to 1 MW)
Serving sites with new loads below one megawatt can often be supported with a new service
transformer connected to the local distribution grid. This falls within typical Commercial & Industry load
expansions up to the capacity of the local feeder based on existing load profiles. The scenario assumes
the utility scope would be limited to replacement of the service transformer and service entrance
conductor to the main switchboard requiring minimal structural elements. These sites can often proceed
without major delays subject to the utility’s work queue, engineering, permitting and construction
resources.ii
Many utilities keep inventory of commonly used transformers which helps to minimize
schedule impact of secondary service upgrades. The Engineering / Design stage is highly dependent
upon Utility engagement, their design approval processes, and the availability of sufficient detail for the
utility design to be finalized. Frequently, completing required permitting and utility applications with
new products and technologies can be challenging as specifications and certifications are finalized.
Utilization forecasts and other planning information may be required to commence Utility design.

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Table 1: Base Case Power Delivery Schedule
Base Case Deployment – Alt 1: Supply Conductor Upgrade, No Grid Upgrades (up to 1 MW)
Often utility supply conductor from the main grid to the utility service transformer is sized for maximum
service load. As the service transformer size increases there is also a possibility that the supply
conductor must be replaced. If the distribution circuit is located a short distance from the service
transformer, replacement of the supply conductor should have minimal schedule impact, though there
is additional permitting risk if new “service drop” or right of way is required to connect to the feeder.
It’s possible that other utility customers may be affected by this conductor upgrade, requiring additional
time for notification and scheduling of work.
Base Case Deployment – Alt 2: Medium Voltage Service, No Grid Upgrade (over 2 MW)
If the load required at a site exceeds standard service transformer and low voltage switchboard ratings
(typically around 3000 A) the customer may seek or be required to take primary service at medium
voltage to allow for multiple service transformers (customer owned) behind the meter. Under this
scenario, the utility would install a new primary service entrance conductor from the primary
distribution circuit. If the distribution circuit is located a short distance from the service transformer,
replacement of the supply conductor should have minimal schedule impact, though there is additional
time and permitting risk if new “service drop” or right of way is required to connect to the feeder.
Note: Medium voltage switchgear equipment is typically custom built and lead times can be significantly
longer than low voltage (480v) switch gear.
Grid Upgrade Descriptions & Schedule Factors
Dependent upon site selection, one or more upstream power delivery and / or distribution grid
upgrades may be required including: re-conductoring / upgrading the conductors on the circuit
supplying the site, adding one or more conductors to the existing feeder pathway from the substation,
installing a new feeder, substation upgrades and building a new substation.
Project Phase Typical Ranges (Months)
Engineering / Design 0.50 - 2.00
Permitting / Land Use 0.50 - 3.00
Construction 1.75 - 2.50
Commissioning 0.25 - 0.50
Total Project Schedule 3.00 - 8.00

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Table 2: Power Delivery Upgrade Scenarios
Grid Upgrade Deployment - Re-Conductor or New Line Equipment (over 1 MW)
As loading decreases along a distribution circuit, the end of the line may utilize smaller conductor. If
expanded load results in overload along the distribution circuit, the replacement of overhead or
underground wire to a larger size to increase the load capacity of and or improve voltage regulation on a
feeder or section of feeder may be required. Reconductor will require engineering design and
construction and outage sequencing to remove and replace existing equipment. Furthermore, the
length of reconductor will determine the duration of the schedule.
Grid Upgrade Deployment - New Feeder (over 5 MW)
Distribution feeders have varying degrees of utilization based on the existing connected load and time of
use. If a proposed project exceeds the line capacity and line upgrades cannot address overloads, a new
circuit must be installed from the substation to project site. New feeders require significant planning,
engineering and construction and involve major infrastructure upgrades such as installing a new feeder
position at the medium voltage substation bus and permitting right of way over the full circuit path.
Substation Upgrade - New Transformer Bank (over 10 MW)
Transformer banks serve multiple feeders. When overloaded, a new transformer bank is added or the
overloaded transformer is replaced with a larger bank. This equipment requires physical space in the
substation and may also impact the electrical capacity of connected equipment such as the medium
voltage bus and relaying. Significant planning, engineering and construction is required at the substation
and significant equipment lead time may be required for the new transformer. Some substations may
not have sufficient area available to accommodate new transformer banks.
New Substation (over 20 MW)
For very large installations a new utility or dedicated high voltage substation may be required. This will
require land acquisition and significant design and construction. Furthermore, new substations are
required to be integrated into the sub transmission or transmission network which requires additional
studies and may trigger further upstream upgrades, environmental studies, community outreach and
permit approvals. The timeline for development of new substations can be measured in years.
Power Delivery, Trigger MW, Upgrade Locations MW Customer Right of Way Utility
Supply Conductor (Service Extension) 0 - 1 n n
Medium Voltage (Service Provisioning) 3 - 5 n n
Feeder Re-Conductor 1 - 5 n
Feeder Additional Conductor 3 - 5 n
New Feeder 5 - 10 n
Substation Upgrade Required 5 - 10 n
New Substation Required 10 - 20 n

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Summary of Grid Upgrade Power Delivery Schedules
Each utility maintains queues for interconnection and requisite design, permitting, right of way
agreements and construction to support power delivery for customers in their service territories. While
fleet load profiles, site specifics and available distribution grid power make each scenario different, fleet
operators need to understand potential schedule impacts. To assist understanding timing and project
planning Black & Veatch recommends consideration of these typical ranges of potential schedule
impact.
Table 3: Power Delivery Schedules
Indicative schedule below reflects the typical site focused activities along with the relative duration
required for distribution grid upgrade for discussion purposes rather than actual project delivery. As
noted on in the chart, additional commissioning and testing is typically conducted once full power has
been delivered to the site.
Figure 2: Distribution Grid Upgrade Schedule Impacts
Potential Power Delivery Upgrades Typical Ranges (Months)
Supply Conductor (Service Extension) 0 - 2
Medium Voltage (Service Provisioning) 0 - 5
Feeder Re-Conductor 6 - 36
Feeder Additional Conductor 6 - 36
New Feeder 9 - 48
Substation Upgrade Required 18 - 36
New Substation Required 24 - 48

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Conclusions & Recommendations
▪ Access to less than 1 MW or 2MW of capacity is often available, however will typically require
service extensions to the property. Service extensions are relatively common for commercial
utility customers; however, work can run into unanticipated roadblocks based on updated city
requirements, right of way/easements and/or excessive costs.
▪ As requirements grow beyond 2MW of power, bringing power may entail upgrading to medium
voltage service. In this scenario service extensions are brought to medium voltage switchgear
where metering takes place. The customer is then responsible for distributing and transforming
the power to low voltage for use on premise. Scheduling risks and additional upfront site and
equipment costs must be planned for and accounted.
▪ With increased power levels, the scope and location of distribution grid upgrades increases, so
does the intensity of land use, right of way and permitting requirements. Existing overhead and
underground feeder pathways provide significantly faster approval cycles vs. new pathways -
however existing pathways may be fully subscribed. Similarly, upgrading a substation versus
constructing a new substation with requisite transmission lines service will have significantly less
impact on costs and schedules.
▪ Utilities will generally not release site specific power delivery capabilities without expressed
intent to develop a location. Therefore, early engagement and utility coordination at an account
and engineering level is highly encouraged to fully understand requirements and feasible power
delivery schedules.
▪ An important aspect of utility coordination is the ability to leverage existing relationships.
Relationships, combined with knowledge of utility engineering and business practices can
reduce utility service fees and significantly accelerate service delivery for high-power electric
vehicle charging.
▪ Anticipating future needs along with today’s power requirements is a cornerstone in successful
power delivery design and engineering to minimize costs and schedule delays in building electric
vehicle charging infrastructure deployments.
▪ Fleet facilities are meant to be in service for a long time. Design decisions can have lasting
effect on the total lifecycle cost of operations. Given the potential for lengthy and expensive
service modifications, begin utility engagement as early as possible in the design process.
Qualified, experienced power consultants, like those at Black & Veatch, can provide valuable
analysis and design services which can positively affect cost and timeframes for power delivery.

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About the authors:
Paul Stith - Director of Strategy & Innovation for Black & Veatch’s Transformative Technologies
business. He specializes in sustainable transportation and distributed clean energy solutions. He works
with vehicle OEMs, utilities, transit agencies, cities and emerging transportation service providers to
plan and build infrastructure for electrification and automation of light, medium and heavy-duty vehicle
fleets. StithP@bv.com | +1 913-458-8747 P | +1 408-384-9455 M
Elizabeth Waldren – Electrical Engineer for Black & Veatch’s Renewable Energy and Energy Storage
business. She specializes in medium and high voltage design and planning for interconnection of
distributed and utility scale resources to the electric grid.
WaldrenE@bv.com | +1 913-458-7761 P
i
Icons for the distribution towers and transformers made by Freepik from www.flaticon.com.
ii
Equipment procurement and engineering/permitting/construction delays are not included in this analysis.