1. TOP 10 FACTORS
T O C O N S I D E R W H E N A D D I N G
TO A UTILITY SCALE PV PROJECT
Photo: Optimum Tracker, Aspres, 5.5MW
S O L A R T R AC K E R S

2. Contents
Acknowledgements 1
Abstract 1
About the Authors 1
Methodology 3
Disclaimer 3
About this Paper 4
TOP 10 CRITERIA
#1 Bankability 6
#2 Demonstrate Capability via Actual Sites 7
#3 Ease of Tracker Installation and Configurability to Site 7
#4 Maintenance and Warranty on Parts 8
#5 Monitoring and Data Acquisition System 9
#6 Structural Strength 10
#7 Tracker Specifications: 10
#7a Rotational Angle 10
#7b Backtracking 11
#7c Power Supply 11
#7d DC Capacity 12
#8 Supply Chain 13
#9 Local Requirements 13
#10 Performance During Unfavorable Weather 13
(c) The Triana Group, Inc. 2016

3. PAGE 1
Abstract
The paper discusses in detail the factors to be considered when
looking for Horizontal Single Axis (SAT) trackers for a utility scale
project. Note that sizable Distributed Generation solar projects (DG)
2MW+ have similar needs regarding tracking system selection.
Every project comes with its own unique requirements and thinking
one solution fits all is not the best approach. Here we discuss the
top ten criteria to consider before closing on a tracker manufacturer
for your utility scale project. Keeping in mind these criteria while
evaluating your vendors will help you make a sound decision and
ensure that all the important aspects of consideration have been
covered.
The authors would like to thank those who contributed to the
completion of this study, including companies that have
responded to our study and experts who agreed to be
interviewed and took the time to respond to our questions; they
provided decades of cumulative experience relevant to solar
trackers, and their first-hand knowledge helped shape the content
of our research.
A special thank you goes out to Madyan De Welle and Wassim
Bendeddouche (Optimum Tracker), Rune Hansen (SPG
Solar), Heidi Larson (Leidos), Robert Dally (Con Edison
Development), Jay Levin (PSEG Solar Source), Christian Malye
(Generale du Solaire), and Valerie Blecua-Bodin, among others
not mentioned by name, for their valuable contributions.
Acknowledgements
The Triana Group is a New York based company located near Wall
Street, which works with international technology companies to
introduce their products to new markets. This study was sponsored
by Optimum Tracker, a company founded in 2009, with a line of
innovative solar trackers for utility scale solar projects. Optimum
Tracker contributed expertise but the study was completed
independently by The Triana Group.
The study was led by Reed MacMillan, MBA, with a research team
including Khushbu Singh, MBA, Crystelle Desnoyer, MIB, and Jabril
Bensedrine, Ph.D.
About the Authors
(c) The Triana Group, Inc. 2016

4. PAGE 2
(c) The Triana Group, Inc. 2016
Reed MacMillan
Reed MacMillan has been an advisor to the Triana Group since
2013, where she has led market entry and business integration
projects for technology companies. Previously, while working for
Science Applications International Corporation (SAIC), a Fortune
500 company, she led efforts to win large federal contracts in IT,
valued above $200 million. Prior to this, as Training and Operations
Manager, she oversaw enterprise training and operations solutions
for government agencies, overseeing global teams. During this
project, Ms. MacMillan stood up the operations team responsible
for the 24×7 availability of multiple worldwide systems. Throughout
her career, she has achieved successful business outcomes by
connecting people, ideas, and business interests. She holds an
MBA from the MIT.
Khushbu Singh
Khushbu Singh is a business development consultant with The
Triana Group, Inc. With nearly five years of professional
experience in account management, corporate communication,
and business consulting, she has effectively managed projects
from conception through productive completion across industries.
She holds a Masters of Marketing Management degree from Pace
University in New York. Her past experience includes positions in
marketing and communications at the financial services firm
Edelweiss and the global marketing firm Ogilvy & Mather.

5. PAGE 3
(c) The Triana Group, Inc. 2016
Disclaimer
The material presented in this white paper is based on publicly
available information. It is provided for informational purposes
only. While every effort has been taken to ensure the accuracy of
this material, legislation, regulation, and market information are
subject to change and may no longer be accurate. The authors
assume no responsibility for errors or omissions, or for damages
resulting from the use of the information contained herein. This
white paper is not intended to provide legal, investment,
technical or commercial advice and is for general informational
purposes only.
Our methodology relied on interviews with industry experts with
experience as solar developers, system integrators, financiers,
tracker manufacturers, and select cus-tomers who have used the
trackers for utility scale solar projects of various sizes. Additional
methods included participation at the leading solar conference, SPI
in Anaheim, CA in 2015; review of articles in industry publications
available in print and on the Internet documented at the end of this
paper; companies’ websites and literature.
Our team reached out to the companies mentioned in this report
to give the oppor-tunity to provide feedback on our research, and
took responses received into consideration.
Methodology

6. PAGE 4
About this Paper
To help narrow down this long list to
only 10 key criteria, we spent weeks
reviewing technical documentation
and interviewing experts totaling
decades of cumulative experience
in the industry.
One of the challenges of evaluating
features and functions among single
axis trackers is that vendors often
highlight features of their product that
are distinctive, which can result in
suggesting something is more
important than another – for example
parasitic power consumption (amount
of energy used to run the trackers.)
Another example of challenge is that
regional quality standards bodies
have different names although they
often are comparable, so evaluators
must become fluent in “UL, ASCE,
ISO” and the like.
The goal of this list of top-10 factors
is to provide a sound basis for single
axis tracker evaluation.
The promise of solar energy globally
has never been greater, due in part to
the reduced costs for solar
modules. When combined with the
10-35% productivity gains possible by
adding solar trackers to multi-
megawatt projects, we think you will be
convinced that “if you’re not tracking,
you’re slacking.”
Different utility-scale PV projects may need different
trackers.
How do you determine which Single Axis Tracker is
best suited for your project?
(c) The Triana Group, Inc. 2016

7. PAGE 5
TOP 10 FACTORS TO CONSIDER
WHEN ADDING SOLAR TRACKERS TO
A UTILITY SCALE PV PROJECT
DC CAPACITY
POWER SUPPLY
BACKTRACKING ROTATIONAL ANGLE
WARRANTY
AND MAINTENACE
EASE OF
INSTALLATION
& CONFIGURABILITY
MONITORING
45o
STRUCTURAL
STRENGTH
DEMONSTRATED
CAPABILITY
$
$
$
$
$
$
$
BANKABILITY
(c) The Triana Group, Inc. 2016

8. For a solar project to be funded, it must be
considered bankable. A project’s equipment and
design are evaluated to determine quality according
to very specific manufacturing standards and
measures.
Those involved in financing, and those who will be
running the plant need to trust that their equipment
manufacturers will be in business long enough to
stand by their warranties.
A bankable tracking system is the one that has
passed the financier’s due diligence process and is
considered a viable long-term investment. Hence,
apart from Lifetime Cost of Energy (LCOE) analysis,
project bankability should also be an important factor
of consideration. This becomes even more important
when multiple vendors are involved in the project.
While assessing bankable solutions and providers,
project managers should start by reviewing
installations and utility scale projects where trackers
have already been deployed. A vendor who has
multiple projects that have made it through the due
diligence process and have been able to establish an
operating history are considered to be a safer bet
and more bankable. However, while examining
operating history, project engineers should not
overrate older products compared to valuable
R&D-intensive innovations.
Listed below are factors which need to be
addressed by technical design specifications to
ensure bankability. Also included on this list are
some of the major certifications of quality which
manufacturers can obtain for their piece of
equipment. Note that some of the testing
standards are comparable, with the names
deriving from the organizational entity testing the
product. Therefore, each bankability report may
include some of these elements but not all.
PAGE 6
1. Bankability
$
$
$
$
$
$
$
BANKABILITY
Wind tunnel testing
Compliance with UL standards:
UL 2703 (Grounding/Bonding Standard for
Rack Mounting System)
UL 3703 (Standard for Trackers)
ASCE7–10 (American Society of Civil Engi-
neers - Minimum Design Loads for Buildings)
Compliance with CE marking
SO Certifications - ISO 9001, ISO 14001, and
ISO 18001
Compliance with Eurocodes and SANS
Number of utility scale projects in operation
Technical due diligence on independent engi-
neering reports by recognized firms such as:
Leidos, Black & Veatch, Garrigues, TUV SUD, to
name a few.
(c) The Triana Group, Inc. 2016
“Bankability is by far the most important criteria. Solar
growth occurs because of massive capital coming in;
capital comes in to finance projects, so people are
knowledgeable and intelligent about the technology
involved. They have picked favorites with qualified
trackers but whichever increases productivity vs costs,
will be the new favorite. That transition stage lasts
about 5 minutes."
Says a founder of a PV leasing company.

9. PAGE 7
2. Demonstrate Capability via actual
sites
3. Ease of tracker installation and
configurability to site
Installation plays an important role while
considering solar trackers for a large-scale utility
project. It is critical to know if the trackers
provider delivers and installs them efficiently
and effectively, so that the site can be
commissioned without issue.
The following players may take part in the
installation of a utility-scale project.
Tracker manufacturers – Vendors of solar trackers may manufac-
ture or source their trackers from different suppliers. Their forte is
designing and manufacturing solar trackers for large-scale utility scale
projects.
Installation companies – Separate from tracker manufacturers,
these companies are third parties that work closely with or
independently from tracker manufacturers and are responsible for
installing the trackers. These companies perform leveling work, install
foundations, and install the trackers and panels at the project site.
EPC Contractors – They are primarily responsible for the
Engineering, Procurement and Construction of the plant. This usually
includes selecting the suppliers of solar modules, inverters and other
key items of equipment; and finalizing and underwriting the final design
and output projections for the plant.
As a construction project manager, you
must interact with a number of different
vendors and parties. Before selecting a tracker,
make sure you understand all the vendors. It is
not a norm for tracker manufacturers to
execute projects but some of them provide
these services. Working with such providers can
be a good option as it considerably
reduces the chances of error.
DEMONSTRATED
CAPABILITY
When evaluating single-axis tracker vendors, a good
place to start is with a review of their prior projects
and their sites' operating history. Those are good
indicators of their ability to carry out similar projects.
Locations of sites also play an important role in
determining the capabilities of a particular vendor.
Every site comes with its challenges, such as
slopes, vegetation, altitude, shape, size, orientation,
as well as wind direction and strength; as
Valerie Blecua-Bodin points out, "even the nature
of the soil could be important", as foundations
characteristics are an important factor.
A vendor may have fewer projects than others yet
could be more relevant to your specific project.
Also keep in mind that vendors with more installed
projects may not be the most innovative.
A vendor’s demonstrated capability with sites
similar to yours will contribute to your project's
bankability and accelerate your understanding of
future performance, costs and O&M issues.
EASE OF INSTALLATION
& CONFIGURABILITY
(c) The Triana Group, Inc. 2016
"Each tracker technology will differ while being
implemented on site (mainly due to the product design).
The number of piles needed per tracking row, the flexibility
and choice of foundation will impact the overall installation
duration and the manpower needed."
Valerie Blecua-Bodin

10. Another important factor is the foundation
work. Building the right foundations for trackers
requires calculations and accuracy in
execution; most companies provide only the top
structure and leave the foundation work to third
parties, which can also create a potential for
errors. Errors in foundation can lead to
movement problems as well as decreased
energy output. A poorly built foundation may
result in stability issues during high wind
conditions. For this reason, signing up with a
vendor that provides a complete 360 degree
solution is key and is a major consideration when
evaluating tracker manufacturers. "Equipment,
installation and/or design warranties have to be
carefully considered in the evaluation of the
tracker's vendor", says Valerie Blecua-Bodin.
PAGE 8
4. Maintenance and warranty on
parts
WARRANTY
AND MAINTENACE
When developing a PV power plant, it is critical
to accurately consider the O&M costs of tracker
design. Developing an understanding of
maintenance, both preventive and reactive,
(c) The Triana Group, Inc. 2016
"A penny in the tracker or racking costs makes a big
difference. Clients will want to make their due diligence in
trackers' prices but also in their associated metrics: the
installation costs, how easy is the installation process and
how long it takes, the related O&M, failure rates of the
motors, etc."
Technical Services Manager, PV Field Operator
"You’re installing a 25 year asset so developers want
to know how companies back their products."
Says a Business Development expert in solar projects.
that may be required throughout the project's
lifetime is important for accurately calculating
the cost of the additional energy produced. Your
goal here is to maximize system availability,
and minimize downtime.
While independent technical assessments are
critical for getting projects validated and funded, it
is also beneficial to listen to veterans who have
been building these projects to learn how
they balance trade-offs such as equipment
cost, construction costs, productivity, and O&M
costs.
Replacement parts should be budgeted upfront
as part of system cost. Common tracker systems
failures are in motors, gearboxes, and
controller electronics. Architectures impact these
costs and the types of maintenance that can
be expected.
As an example, while it is standard to add a
25% premium to the O&M cost when trackers are
used, the main concern for asset managers is
to understand how to deal with the product after
initial warranties have expired. Since these
installations’ lifespan is between 20-30 years,
while product warranties are up to 10 years
depending on the manufacturer and EPC, there
is a gap in coverage.
One of the most expensive parts for trackers
is their motor. Numerous types of motors are
available, such as: Stepper motors, Permanent
magnet brush dc motors (PMDC) or Brushless
dc (BLDC) motors. Brushless dc motors are
the most efficient today; they are
maintenance-free and have a low cost
of operation. These motors do not have wear-
prone brushes, are highly efficient (typically 85
to 90%) and have a distinct advantage when
a short stowing time is important.

11. PAGE 9
5. Monitoring and Data Acquisition
System
MONITORING
Utility-scale PV plants that require high performance,
low downtime and rapid fault detection need a
data monitoring and supervisory control and
data acquisition (SCADA) system. These systems
provide control and status indication for
equipment included in the substation and across
their solar plant, which also enables them to
“track” the trackers’ performance. This control
system may be combined with a data
acquisition system that gathers remote
equipment status for display or recording.
Solar trackers generally come with their own
sensors, including but not limited to inclinometers.
Some vendors offer systems that enable controlling
solar trackers with an embedded positioning
algorithm, field communications support, and a
variety of specialty inputs for inclinometers and
position feedback sensors. Most of these systems
support MODBUS, DNP3, and other industrial
protocols, and should allow for easy interfacing with
full-scale SCADA packages for grid dispatch and
control.
Monitoring and comparison also help raise warnings
on a daily basis if there is a shortfall. Faults can be
detected and rectified before they have an
appreciable effect on production.
(c) The Triana Group, Inc. 2016
A high level of technical expertise is needed to
detect certain partial faults at the string level.
Otherwise, it could take many months for reduced
yield figures to be identified. Lower yields may
lead to appreciable revenue loss for a utility-scale
PV power plant.
The key to a reliable monitoring and
fault detection methodology is to have
good knowledge of solar irradiance,
environmental conditions and plant
power output simultaneously. This allows
faults to be distinguished from, for example,
passing clouds or low resource days.
Three main methods provide data on
solar irradiance and weather conditions: on-site
weather stations (which is typical once the
site is in operation), meteorological data
gathered from a weather satellite, or from local
weather stations. There are pros and cons for
each method, and some experts focus more
on the Performance Ratio, which is used to
compare PV systems independent of size
and solar resource. By detecting a drop in
the performance curve, they can quickly notice
anomalies in production.

12. The rotational angle of trackers plays an
important role by positioning them to capture
maximum solar energy. This is especially
important in a utility scale project, and can help
developers achieve greater utilization of their
site and help to generate more revenue.
The optimum angle depends on a number of
factors such as location, distance from the
equator, site topography, plant foundation,
distance between panels, and the earth’s
movement around the sun during different
seasons. In other words, there is no one-size-fits-
all.
The rule of thumb is to install panels in a manner
that make sunrays reach them at a perpendicular
angle, ensuring that the angle of incidence should
be 0 degrees or as close to 0 as possible.
Algorithms are used to calculate the solar azimuth
and zenith angles; these angles are then used to
position solar panels to point towards the sun.
Some algorithms are mathematically based with
astronomical reference points, while the others
use real time light intensity readings and adjust
accordingly. Trackers typically offer rotational
angles ranging from +- 45 to +- 60 degrees.
Higher angles may not necessarily provide
significantly better results: you must configure
your installation in accordance with your specific
site characteristics.
PAGE 10
6. Structural Strength
STRUCTURAL
STRENGTH
Since solar trackers have moving parts versus
fixed tilt solutions, the installation's structural
strength and durability must guarantee that trackers
will function well over the project lifetime.
Warranties are generally shorter for trackers than
for fixed tilt structures. A solar tracker makes one
revolution per day, which totals 7,300 revolutions in
a 20-year period. In an environment with calm and
stable weather this movement is not significant in
terms of wear and tear that compromises the
installation. Today, nearly all environments are
faced with weather challenges, and so it is critical to
have an understanding of the forces that may
impact the structure such as wind speed, snow
load, rain storms, sand and sun, especially in desert
areas, where the durability and structural strength of
the trackers are especially important.
Systems in close proximity to salt water require
more weathering, steel parts need additional
galvanization during welding, and gears and
exposed parts may require protective boots.
Generally, installing trackers is not recommended in
areas prone to hurricanes or heavy snowfall.
However, most vendors can augment the strength
of their designs and provide greater wind speed
tolerance. Without considering anomalous weather
events, studying data from prior years should
provide a fairly accurate picture of wind speeds in a
specific region. In some specific locations, gusts
and wind direction are also important.
7. Tracker Specifications
ROTATIONAL ANGLE
45o
(c) The Triana Group, Inc. 2016
a. Rotational Angle

13. PAGE 11
b. Backtracking
Solar trackers vary significantly in how they
handle their own needs for energy, which is
generally referred to as parasitic power load.
Vendors seek to decrease energy consumption
required to move trackers, since it counts against
the gains generated from adding trackers.
There are active and passive tracking
systems. Passive tracking systems use the
shifting weight of a liquid refrigerant to keep
the array of modules pointed at the sun.
Active tracking systems use a controller
and one or more actuators for targeting. Active
tracking is more accurate — but more expensive
— than passive tracking and also requires a
power source for the controller and various
actuators.
“It is a mistake to get too concerned about
tracker engines' energy consumption” says
Christian Malye, a Chief Technical Officer
overseeing several utility-scale PV
projects. The engine works about 5 seconds
every 3 to 4 minutes, resulting in a loss of
energy that is far less than that of the
transformers. He also mentioned that in
comparison to the energy cost for air
conditioning operations buildings near the site,
the “parasitic load is negligible.”
c. Power Supply
BACKTRACKING
Solar trackers can be made more efficient by the
use of backtracking. Backtracking refers to solar
trackers’ ability to move and adjust according the
sun’s position. All trackers must be able to adjust
simultaneously to avoid any shading on the adjacent
tracking row. Shade on solar panels reduces the
electric output and compromises the overall
efficiency.
A backtracking algorithm takes into account
the sun's position, spacing between tracking
rows, and the size and shape of panels in the
rows. Its goal is to minimize shading
and maximize perpendicularity of sun’s rays
on panels to harvest the maximum amount of
solar energy.
Other factors that impact output are topography,
location, season and weather. Because of these
diverse site-specific factors, customized
backtracking solutions are needed. This might
mean that each array is treated differently, requiring
a tailored algorithm adjusted to ensure the
maximum solar energy can be harvested. Each
tracking system technology has its specific
backtracking solution and associated software.
POWER SUPPLY
(c) The Triana Group, Inc. 2016

14. PAGE 12
A photovoltaic array consists of multiple photovoltaic
modules that convert solar radiation (sunlight) into
usable direct current (DC) electricity. A grid-
connected system, such as a PV plant with solar
trackers, is typically connected to and feeds energy
to the public electricity grid. Feeding electricity into
the grid requires the transformation of DC into AC by
a special, synchronizing grid-tie inverter. Most
modules (60 or 72 crystalline silicon cells) generate
160 W to 325 W at 36 volts. Currently most
utility-scale project are based on 305-315 Wdc
modules (modules in 60 cells are not often used on
trackers.) The DC power supply must have
components that can handle tracker specifications
for the linear actuator and slewing drive.
PV systems may be built in various configurations,
two of which are related to utility-scale projects:
Other configurations (such as off-grid with or without
battery, for DC-only or both AC and DC) exist but are
related to stand alone systems which won't use
trackers.
The number of modules in a system determines the
total DC watts that can be generated by the solar
array. The inverter controls the amount of AC watts
that can be distributed for consumption. For
d. DC Capacity
DC CAPACITY
Appliances Grid-tie without battery
Grid-tie with battery storage (rare in the US)
(c) The Triana Group, Inc. 2016
example, in a large scale project, the standard in
the industry is to use 2,000 kWac inverters pad,
and the usual DC-AC ratio is 1.25-1.45
depending on the location.
When calculating the LCOE for the PV project, it
is important to ensure that the inverters are
sized appropriately to capture the additional
energy generated by your trackers.

15. PAGE 13
(c) The Triana Group, Inc. 2016
8. Supply Chain
Solar project management is complex, and
selecting the right supply chain partner is as
important as executing project construction. Large
solar projects have numerous requirements that
need to be fulfilled by a variety of manufacturers
and suppliers. Selecting the right suppliers is vital for
project success and helps avoid costly overruns
and delays.
Project managers make sure to meet with
suppliers, EPCs and developers to discuss their
project details. Discussions about components'
manufacturing timeline, shipping and delivery
schedule, and on-sight assembly can go a long
way and provide important insights into project
execution capabilities of solar service providers.
This helps you mitigate the risks that come with
large scale projects, and increases chances of
project success at every step of execution.
9. Local Requirements
Each country and state has its own specific
requirements, which may range from standards to
labor regulations. Few tracker manufacturers -if
any- can provide systems and installation that
meet the requirements of every single location
without any compromise in effectiveness or
quality. Local specificity significantly affects which
solar tracker to chose. Once again, there is no
one-size-fits-all.
10. Performance during
unfavorable weather
One of the most critical but not very often
discussed issue is the amount of energy
generation contributed by the trackers during
cloudy days. All 12 months of the year are not the
same and the amount of sunlight that reaches the
earth considerably depends on how clear the sky
is. When solar tracker manufacturers claim that
installing trackers can improve the energy
production by up to 30%, it means this is the
case under perfect weather conditions. There is
little that is discussed about cloudy days when sun
rays don't reach the surface as strongly. It is
important that project managers discuss such
scenarios and take them into consideration
before deciding on which manufacturer to choose.
Some manufacturers, such as Optimum Tracker for
example, have patented technology to collect
significantly more energy than older trackers even
on cloudy days.
"Logistic is also a key factor. It should be encompassed
in the procurement ability of the vendors. The EPC will
dispatch the product on site, but the tracker's vendor will
be responsible to properly and efficiently deliver the
equipment on site."
Valerie Blecua-Bodin

16. PAGE 14
(c) The Triana Group, Inc. 2016
For further information:
solar-technologies@trianagroup.com
www.trianagroup.com
1-646-417-8136