Webinar - 16iwyl195vvfgoqu3136p2ly-wpengine.netdna-ssl.com€¦ · 02/07/2020 · Webinar | CEST, Berlin | PDT, Los Angeles | EDT, New York Nathalie Kermelk Marian Willuhn Dr. Thorsten

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| CEST, Berlin| PDT, Los Angeles| EDT, New York

Nathalie Kermelk

Marian Willuhn

Dr. Thorsten Kray

Wind directionality and stowing

position: A new nexus for single-

axis tracker safety

29 July 20205 PM – 6 PM8 AM – 9 AM 11 AM – 12 PM

Ideematec

Philipp Klemm Markus Balz Hans Jürgen Sauter

&

WELCOME TO THE WEBINAR

“Wind directionality and stowing position: A new nexus for single-axis tracker safety“

IDEEMATEC – THE NEW DEFINITION OF DECOUPLED TRACKING

IDEEMATEC is a leading provider of solar trackers with +15 years of experienceand more than 2.5 GW of systems in operation on 6 continents.

IDEEMATEC – COMPANY PROFILE

#maximum economics #bifacial technology #safeguarding advantage

Outstanding technological innovations and over 50 patents deliver valuable benefits – through max. uptime availability

over the entire lifespan of a power plant.

SAFETRACK HORIZON – TECHNOLOGICAL BENEFITS

INSTALLED

TRACKER

+2.5 GW

PRODUCTION

CAPACITY P. WEEK

+60 MW

SIGNED & DELIVERED

YTD

+ 1.5 GW

EXPERIENCE

IN TRACKERS

+ 15 YEARS

COUNTRIES

CONTINENTS

25 / 6

WIND CLAIMS

WORLDWIDE

0

MARKET LEADER

MIDDLE EAST

AUSTRALIA

IDEEMATEC AT A GLANCE

WORLDWIDE PRESENCE – COMPANY PROFILE

AFRICA+130 MW

APAC+500 MW

EUROPE+375 MW

SOUTH AMERICA & MEXICO+100 MW

USA & CANADA+200 MW

MENA+810 MW

FOUNDED in Germany: 2003

REVENUE 2019: >100M US$

EMPLOYEES: 75 (2020)

+2.5 GW installed

safeTrack Horizon trackers H3/H4IDEEMATEC

Headquarter Germany

LOWEST cleaning solution capex 99.82% system availability globally

WIND DIRECTIONALITY AND STOWING POSITIONS: A NEXUS FOR SINGLE-AXIS TRACKERS

INVESTOR FOCUS:“A low-risk investment with steady and predictable cash flows for 20 to 30 years”.

MAIN TRENDS IN BANKABILITY

by Triana Group

by Solarbankability.eu

How the solar industry is responding to the increasing intensity of natural disasters

• Wind tunnel testing

• Compliance with UL standards:• UL 2703 (Grounding/Bonding Standards

for Rack Mounting System)• UL 3703 (Standard for Trackers)

• ASCE7 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 engineering reports by recognized firms such as: Leidos, Black & Veatch, Garrigues, TÜV SÜD, to name a few

49.80%Weather

36.10%Fire

9%Electrical Failure

2.30%Mechanical Breakdown

2.30%Lightning

0.50%Theft

PV CLAIMS IN NORTH AMERICA

Data taken from „Cell, Interrupted “ (2016) by GCube Insurance

Why worry about wind actions?

• It’s because without designing for the wind loads acting on a

single-axis tracker, wind-related damage of the structure may

occur.

• 50% of utility-scale PV failures have happened due to adverse

weather conditions1 where the vast majority of these failures can

be attributed to wind.

1 https://www.solarpowerworldonline.com/2018/01/solar-industry-responding-increasing-intensity-

natural-disasters/

Securing against wind related damage is crucial to the long term

profitability of a utility scale solar installation.

PV CLAIMS IN NORTH AMERICA

STOW STRATEGIES IN THE MARKET

30 degree stow

0 degree (flat) stow

https://www.solarpowerworldonline.com/2018/08/to-improve-solar-trackers-first-look-at-proven-fixed-tilt-strategies/

• Stow policy is associated with a critical wind speed

• Two distinct philosophies: stowing flat vs. stowing at high tilt

angles have high impact on associated wind actions

• A majority of tracker suppliers opt for either 30° stow or, in the

case of Ideematec, 0° stow

• Recent trend towards opting for a stow position of e.g. either -

30° or sometimes -10° (nose down) with the single-axis tracker

designed for worst-case wind actions from one 180° sector only

• To that extent the question arises whether the wind is really so

kind with us to not significantly change its direction during a

storm?

Jordan, Quweira 100 MW

ANALYSIS EXTRATROPICAL CYCLONE CIARA

by Triana Group

by Solarbankability.eu

Opting for a negative stow angle associated with a worst-case design for just one 180°

wind sector - does this strategy really work?

The latest major windstorm causing strong wind gusts in

Europe was the extratropical cyclone ‘Ciara’ on February

09/10 2020

The graph shows the variability of the maximum 3-second

gust within subsequent 10min intervals and of the wind

direction at the weather station in Werl, Germany, recorded

at 10m height

The curves show a mean wind direction swath of 60° over

the course of the storm with the gust wind speed above

20 m/s for most of the record

On a shorter timescale, consecutive data points show a

change in wind direction of up to 40°

ANALYSIS HURRICANE JEANNE

The graphs show wind data from Hurricane Jeanne that hit Vero Beach,

Florida on September 25/26 2004, recorded at 10m height

The green curve shows a mean wind direction swath of 135° over a 5

hour period

The yellow curve shows the 15-minute mean wind speed which

increased from 10 m/s to 20m/s over a 12 hour interval

At the same time, the maximum 3-second gust wind speed for each 15-

minute interval increased from 20m/s to 40m/s with the strongest gusts

almost reaching 50m/s during the wind direction swath



VARIABILITY OF WIND SPEED AND DIRECTION DURING STORMS

• We have seen from legacy hurricane data that 3-second gust wind

speeds which were sustained above 20m/s featured a direction swath of

135° over a 5 hour period

• That being said, any tracker not designed for the full compass of wind

directions will sooner or later during a major wind event have to adjust

its stow position

• If a tracker needs to adjust stow position during a storm when conditions

are beyond its go-to-stow wind speed, it may be susceptible to failure

due to either aeroelastic instability or equivalent-static wind loading

exceeding the design wind loading.

• Therefore, at non-zero tilt angles only stow strategies are safe which are

designed for negative and positive tilt at the same time



PRESSURE COEFFICIENTS ON PV MODULES

The design wind load of a PV module is defined according to the equation below:

w = Cp x qz x SW

• Cp [-] is a dimensionless pressure coefficient taken from a boundary layer wind tunnel study

• qz [kN/m²] is the velocity pressure at the reference height; in most wind tunnel studies this reference height corresponds to 10 m above ground;

in major wind loading codes such as EN 1991-1-1:2005 and ASCE 7-10 the velocity pressure is averaged over a duration of 3 seconds which is why

it is also referred to as gust pressure.

• SW is the partial (safety) factor or load factor according to the governing code

MODULE STRESS IN STOW POSITON

• Australian/ New Zealand Standard, AS/NZS 1170.2:2011 (R2016)

• Importance level 2

• Wind zone A4 (which represents most of the country in Australia)

• Terrain category 2

• Regional wind speed at 10 m height above ground V500 = 45 m/s

• Multipliers for terrain/ height, wind direction, shielding, and topography were

set to 1.0

• qz = 1.215 kN/m²

• Ultimate Limit States concept of AS/NZS 1170.0:2002 (SW=1.0)

• Spanish wind loading standard, UNE-EN 1991-1-4:2018

• Wind zone B (which represents most of the country in

Spain)

• Terrain category II

• vb,0=27 m/s (10 minute mean at 10 m height above

ground in terrain category II)

• Flat terrain

• qz = 1.072 kN/m²

• Ultimate Limit States concept of EN 1990 (SW=1.5)


• ASCE 7-16, the code addressing “Minimum design loads and associated

criteria for buildings and other structures”

• Risk Category II

• Basic wind speed of 115 mph or 51 m/s (which represents most of the

desert regions in the USA)

• Exposure C

• Wind directionality factor set to 0.85

• Velocity pressure exposure coefficient, topographic factor and ground

elevation factor were set to 1.0

• qz = 1.357 kN/m²

• Strength design (SW=1.0)

• At a 30° stow position, loads on modules are higher by a factor

of 1.8 compared with a 0° stow position.

• In outer zones and at 30° stow, design wind loading exceeds 2.4 kPa for all sample project

sites located in Australia, Spain and in the USA

• Generally speaking, the load bearing capacity of most modules corresponds to 2400 Pa

(for Uplift) if module rails in compliance with the manufacturer’s manual are used.

• However, for any deviation from the default mounting situation, e.g. if short module rails

or no module rails at all are present, the load bearing capacity may reduce to a range of

1400 Pa to 1800 Pa.

• Given these lower allowances for loads on PV modules, at some project sites stowing at

30° tilt may not be possible while stowing at 0° is.


https://www.pv-magazine.com/2018/12/26/filling-in-

the-microcracks/

STOWING STRATEGIES IN THE MARKET

The real benefit of 0° (flat) stow?

Less downtime / lower O&M costs Higher energy yields

www.ideematec.com 17

• Less stress on components

• Less stress on modules

• Less steel needed in installation

• Considerable BOS cost savings

• Higher efficiencies

• Safe positioning

• Less O&M costs

• New requirements:

-> larger modules

-> longer lifetime

Why 0° (flat) stow is the way forward?

0° single axis tracker – Based on a decoupled drive technology.

-> Avoids galloping and offers the most competitive and future-proof

solution for utility scale PV projects.

STOWING STRATEGIES IN THE MARKET

SAFETRACK HORIZON – OVERVIEW

• One Tracker: max. 6 tables

• One table: 30 m

• One tracker: max. 180 m length

• One tracker: one motorgearboxcontrolsensor

• 165 posts per MW

safeTrack Horizon

4 – 5 m span

SAFETRACK HORIZON – OUTSTANDING CONSTRUCTIVE FEATURES

• Decoupled drive system based on patented steel rope

technology

• Table fixation with ropes

• Geometry of rope system reduces forces

• High transmission between table and drive tube

• Patented self-adjusting-spring-system

• Load transfer by tension

• Ropes have a damping effect

• Unique technology such as in crane systems

safeTrack Horizon

SOLUTION - REDUCTION OF FORCES ON THE DRIVE TUBE

Ideematec‘s disconnected drive technology enables

the reduction of the forces on the drive tube:

-> to only 3.6 % of the forces acting on the table.

Winch

Roll pulley

Springs

SAFETRACK HORIZON – UNIQUE ROPE TECHNOLOGY

• Modules mounted

directly on drive tube

• Admission of the full table moment through

drive tube

• High risk of torsional galloping!

Standard „Torque Tube“ Tracker

• High winch ratio leads to less torsional moment

on driving tube!

• Winch transmission ratio is 1:28

• Low risk of torsional galloping!!!

IDEEMATEC safeTrack Horizon


Gear transmission ratioTable : drive tube: = 1:1

IDEEMATEC safeTrack HorizonStandard „Tube“ Tracker

Gear transmission ratioTable : drive tube = 1:28 !!

• 100% of table loads go directly to the drive tube • Only 3,6% of table loads

occur on the drive tube

SOLUTION - HIGH NATURAL FREQUENCY AND DAMPING RATIO

• Ideematec‘s SafeTrack Horizon tracker comes with two

dampers on every post which gives a total of eight dampers

per table

• Since the critical wind speed for onset of aerodynamic

instability is significantly higher than the design wind speed,

wind-related failure cannot occur.

• Measurements were conducted on a REAL SYSTEM

• Stimulating the system to make torsional movement

• “Eigenfrequency” 2.5 Hz / damping ratio 15%

SOLUTION - HIGH NATURAL FREQUENCY AND DAMPING RATIO

HOW TO BEST SECURE YOUR PV PROJECT AGAINST HIGH WIND EVENTS

Ideematec‘s Safetrack Horizon system features

3 KEY DESIGN FACTORS to give it its high dynamic stability

-> 1: Reduction of forces on the drive tube

-> 2: High natural frequency

-> 3: High damping ratio


Benefit of the unique rope design

→ Very low forces on gear box and tubes

→ high damping ratio and natural frequency

→ stiff table without axis flexibility

→ easy rotation impossible

→ flat table over whole 180m without

twists on the tracker ends

→ 0° position as stow position possible

STOW-POSITION at 0°

-> easy to define

-> easy to reach

SAFETRACK HORIZON – COMPARISON

0° STOW-POSITION

• no dependence on wind direction

• 360° safe protection – no safety gap

• lowest static forces on components

• lowest module stress

STOW-POSITION at inclination (30°-45°)

• Safety gap in case of changing wind direction

• If wind comes from the back the stability is worse compared

to 0° stow: VERY DANGEROUS!!!

• additional sensor for wind direction necessary

• higher static forces on components

• higher module stress

• more loss of energy if tracker moves to opposite direction of

the sun

Jordan, Quweira 100 MW

STOW ANALYSIS Conclusion

• The safest tilt angle for stow is 0° if combined with intelligent

load transmission or mechanical locking, high natural

frequency and high damping ratio.

• The 0° stow position leads to enormous material savings in

the structure and provides the best protection of photovoltaic

modules against damages such as micro cracks in cells as well

as back sheet and glass defects through sandblast abrasion.

• The 0° stow position is not vulnerable to changes of wind

direction as opposed to tracking systems which rely on stow

at a high tilt angle without being designed for the full

compass of wind direction.

sbp sonne works on increasing the use of renewable energy sources since 1985.

Solar experience:

25 countries and on 4 continents.Commercial Photovoltaic >10 000 MWCommercial CSP > 2 450 MWCommercial CSP technology prov. > 700 MW

sbp sonne numbers:

Founded / spin off 2009

Annual Turn Over ´17 4.2 Mio€Staff (Dipl. Ing/Masters 13, PhD 5 ) 20

Consulting engineers forrenewable energy

sbps reference / numbers

sbp sonne designs and optimizes solar applications:

Photovoltaic systems• fixed tilt, • one and two axis tracking, • building integrated photovoltaics (BIPV), • we further develop Argi PV and Floating PV systems.

Dish-Stirling systems, Central receiver systems, Parabolic trough and the solar updraft tower technology are the large scale Concentrated solar power applications.

Our highly qualified, motivated and constantly growing team is willing to contribute in research and development of any kind of technologies.


Know How

Technical Expertise

Structural Engineering

Mechanical Engineering • Drives• Thermodynamics

Electrical & Cabling Engineering • Control system • PV solar field

Series Production/Automotive mass manufacturing

Software Development • Energy output optimization• FEM• Optics & solar tracking

Meteorology • Solar Radiation and Wind statistics


Technical Ideematec - check

sbps check of IdeematecH4 and H4 plus

Innovative cable gear on each post ensures:

• SafeTracker enables that the torsional moments are largely derived directly to posts (without having to take the soft load path to the drive via a long torsion tube)

• Result in a high torsional stiffness, preventing most aerodynamic instabilities (divergence)

• The high natural frequency that can be achieved and the good damping properties also reduce the susceptibility to other forms of aerodynamic instability and thus allow a zero-degree stow strategy without excessive rocking.

• With the zero-degree Stow Strategy, Ideematec is on the right path to reduce costs and further technological developments in this direction are on the way - watch this space!

INNOVATION LEADING TECHNOLOGIES

PREVIEW – TO BE ANOUNCED SOON:IDEEMATEC’S STATE OF THE ART TRACKING SYSTEM

• Decoupled drive system

• Permanently locked

• Fixed tilt with tracking function

SAFETRACK HORIZON – AUSTRALIA, LIMONDALE – 349 MW

SOURCE: https://www.group.rwe/en/our-portfolio/innovation-and-technology/project-proposals/construction-projects-renewables/limondale-solar-plant

SAFETRACK HORIZON – JORDAN, BAYNOUNA – 250 MW

SAFETRACK HORIZON – SPAIN, TENDEIROS – 50 MW

SAFETRACK HORIZON – VIETNAM, HADO – 50 MW

&

STAY SAFE & THANK YOU FOR JOINING OUR WEBINAR

Webinar - 16iwyl195vvfgoqu3136p2ly-wpengine.netdna-ssl.com€¦ · 02/07/2020 · Webinar | CEST, Berlin | PDT, Los Angeles | EDT, New York Nathalie Kermelk Marian Willuhn Dr. Thorsten

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