Solar-to-EV Project FAQ
General
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What is the project?
The Solar to EV project is a joint initiative between Smart City San Diego and the San Diego Zoo.
San Diego Gas & Electric, a Smart City San Diego collaborator, will install a solar photovoltaic
canopy that will charge electric vehicles (EV) in the Zoo parking lot. One of the first of its kind in
the region, the project will use solar energy to directly charge plug-in EVs, store solar power for
future use, and provide renewable energy to the surrounding community. The Solar to EV
project will serve as a new energy infrastructure blueprint that can be replicated throughout the
region and beyond.
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Where will it be located?
The Solar to EV project will be located in the southeast quadrant of the Zoo parking lot.
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When will the project construction start? When will it end?
Project construction will begin following the Labor Day Weekend and is expected to conclude in
late Fall 2012.
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Will I be able to visit the Zoo during construction?
Zoo patrons will absolutely be able to visit the Zoo during construction. Patrons will be asked to
park in the Zoo’s other parking zones and regular parking throughout Balboa Park will continue
to be made available during construction.
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Why is this system being installed at the Zoo?
Located in the heart of San Diego’s world-renowned Balboa Park, the Zoo is visited by more than
3.5 million people each year. Installing this project at the Zoo is an opportunity to showcase San
Diego’s commitment to clean energy for both locals and visitors from across the globe.
Additionally, the Zoo site will provide additional charging options for EV drivers.

What are some of the benefits to this project to the Zoo and the community?
The Solar to EV project not only contributes to the Zoo’s ambitious sustainability goals but will
also provide essential charging infrastructure to local electric vehicle owners. Moreover, the
project and similar systems in the region will play an integral role in improving San Diego’s air
quality and establishing us as one of the state’s clean energy leaders.
California has established the most aggressive greenhouse-gas (GHG) reduction goals in the
nation. With almost 40 percent of California’s GHG emissions coming from transportation, the
state’s goal to reduce transportation GHG by more than 13 million tons by 2020 is aggressive.
Integrating clean transportation alternatives will be critical to achieving these goals. The carbon
dioxide saved by the Solar to EV project is equal to:
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Removing 189,216 lbs. of CO2 from the atmosphere
Planting 2,788 trees and allowing them to grow for ten years1.
Removing 21 cars from the road each year1.
What is Smart City San Diego and how is it involved?
Smart City San Diego is a collaboration that combines the resources of San Diego Gas & Electric
(SDG&E®), City of San Diego, GE, UC San Diego and CleanTECH San Diego to drive projects
forward that improve the region’s energy independence, reduce greenhouse gas emissions and
assert San Diego as a clean energy leader. Together, these organizations from government,
business, education and non-profit are maximizing synergies to drive existing energy programs
forward, identify new opportunities, embrace additional collaborators and move the San Diego
region beyond today’s boundaries of sustainability. To learn more, visit the Smart City San Diego
website at www.SmartCitySD.org.
Technical

How many kilowatts is the project’s solar system?
The Solar-to-EV project’s solar system generates 90 kilowatts at peak capacity.

How many houses could the solar system power?
The system generates enough energy at peak capacity to power 59 homes.
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How many electric vehicles will be able to charge there?
Five electric vehicles, including one located in an ADA-accessible parking space, will be able to
charge at the Zoo.

Can all five vehicles parked there charge at the same time?
All five electric vehicles parked at the Zoo will be able to charge at the same time.

How long will it take to charge my electric vehicle at the Zoo site?
Charging time on a Level 2 (240 volt AC input) charging station varies by the electric vehicle
make and model as well as how “full” the battery is when the vehicle begins charging. For a
typical PEV, a Level 2 charger can provide up to about 25 miles of range per hour of charging.
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How does the system store energy?
Using very efficient technology, a 100-kW energy storage system – batteries and power
electronics - can be charged by the solar canopies and used to offset power demands on the grid
to charge the vehicles. When the battery is full, the excess solar energy that is generated will be
put onto the electric grid to improve reliability and benefit the surrounding community.
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How does the system send energy back to the grid?
Energy is sent back to the grid by converting direct current (DC) output from the PV system or
the battery system to alternating current (AC). This function is performed by an inverter.
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What is an inverter?
An inverter is an electrical device that changes direct current (DC) power to alternating current
(AC) power, the form of electricity that we receive in our homes and businesses. The inverter
included in the Solar-to-EV project is “bi-directional” and can take DC power from the PV system
and store it in the battery, convert the DC power to AC to send to the grid, but it can also source
energy from the grid during off peak hours to store in the battery.
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What is DC-to-DC charging?
The output from the solar cell is DC Power. To skip the process of conversion to AC, the Solar to
EV system is designed to store this DC power in the battery and dispense it to a DC charger to be
located at the site. Prior to this project, DC-to-DC charging has not been demonstrated at this
scale anywhere in the world!
Operational

Who owns the system equipment once the project is completed?
SDG&E will own the PV system, battery and inverter. The plug-in electric vehicle (PEV) chargers
will be owned by ECOtality.
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Who will repair it if the system breaks?
Independent Energy Solutions will be responsible for maintenance of the PV system, battery and
inverter. The PEV chargers will be maintained by ECOtality.
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How long will the project be in the Zoo parking lot?
The project is planned to be in the parking lot for 20 years.
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What noise level can be expected from the solar canopies and charging stations once installed
and operational?
The solar canopies will be virtually silent. The charging stations typically emit sound levels
below normal conversation. The inverter used to convert DC power to AC power for the solar
system and the battery system is rated at a sound level of approximately 68 decibels (for
comparison, normal conversation is approximately 60-70 decibels).
Economic

How is the project being paid for? Are SDG&E ratepayers paying for this project?
Yes, SDG&E ratepayers will be paying for the project.
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How much will it cost a driver to charge their car at the Zoo site?
The electric vehicle chargers will be part of the Blink Network, the same network used for other
charging stations in Balboa Park and throughout the region. Information on the network and
charging prices can be found at www.blinknetwork.com.
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Which vendors are involved in this project? How many local vendors is this project bringing in?
The vendors involved in this project are listed below:
o General Contractor and Solar Integrator: Independent Energy Solutions – Vista
o Architect: Ferguson Pape Baldwin Architects – San Diego
o Structural: KPFF – San Diego
o Solar Canopy Contractor: M Bar C Construction – San Marcos
o Civil: Snipes - Dye – La Mesa
o Landscape Architect: Jim Neri Landscape Architects – San Diego
o Solar Panels: Kyocera – San Diego
o System technology: Inverter is from Princeton Power Systems in New Jersey and
battery storage system from Kokam in Korea
o Electrical Contractor: Neal Electric – Poway
o Artist Rendering: Manuel Oncina Architects Inc. – San Diego
o
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Landscaper: Brickman – San Diego
Concrete Contractor: Tony Lopez Construction – Valley Center
In keeping with Smart City San Diego’s economic development goals, the project will use local
vendors for design and construction. The project is bringing in six local vendors total for primary,
structural and civil engineering, architectural and landscape architectural design, contracting,
and solar panel manufacturing.
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How many jobs will this project create?
This project will create 35 jobs during construction.
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Will this project create any kind of revenue stream for the San Diego Zoo, Balboa Park or the City
of San Diego?
The San Diego Zoo will receive an annual license fee.
Footnotes:
1. US Environmental Protection Agency – Greenhouse Gas Equivalencies Calculator
http://www.epa.gov/cleanenergy/energ-resources/calculator.html