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ENERCON’s Technologies to tackle Icing Conditions

Katharina Roloff, Project Manager Icing ENERCON Research & Development

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1 ICING RELATED INNOVATIONS Cold Climate Package

Ice Detection

Rotor Blade Heating System

2 ENERGY YIELD OPTIMIZATION FOR WIND FARMS UNDER ICING CONDITIONS IEA Ice Classification

Efficiency of Blade Heating

3 ONGOING RESEARCH ACTIVITIES Innovative Ice Detection Systems

Ice-free Site Assessment

AGENDA

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1 I PREPARING FOR COLD CLIMATE CONDITIONS

ENERCON turbines are able to produce energy down to temperatures of -40°C

Turbines in “Standard Climate” version have a decreased maximum power P for temperatures below -15°C.

With “Cold Climate” adjustments the rated power Pmax can be reached until -30°C.

COLD CLIMATE SITE Site with more than nine days per year with temperatures below -20°C for at least one hour or yearly average temperature below 0°C

0

25

50

75

100

-50 -40 -30 -20 -10 0 10 20

Pow

er [%

Pm

ax]

Temperature [°C]

Standard ClimateCold Climate

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1 I DETECTING ICE USING CHARACTERISTIC CURVES

For detecting ice on ENERCON turbines, deviations from characteristic curves are monitored for temperatures below 2°C. RED GRAPH – POWER CURVE METHOD Deviations from the power curve compared to the current wind speed are detected and registered as ice on the rotor blades. BLUE GRAPH – BLADE ANGLE METHOD Deviations from the blade angle curve compared to the current wind speed are detected and registered as ice.

OPERATING CHARACTERISTIC

WIND SPEED AT HUB HEIGHT (m/s)

POW

ER

BLA

DE

ANG

LE

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1 I USING HOT AIR FOR DE-ICING THE ROTOR BLADES

The Rotor Blade Heating System (RBHS) consists of two main parts, a

heater and a fan which are both located at the blade flange. The heating

elements heat up the air to a maximum of 72°C inside the leading edge

chamber and the fan distributes it down to the blade tip.

• FIRST PROTOTYPE: 1996 on an E-40 turbine

• NUMBER OF SOLD RBHS: more than 1.700

• ACTIVATION MODES: automatically or manually

• OPERATIONAL MODES: heating during turbine in operation

heating during turbine at standstill

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1 I OPTIMIZED POWER CONSUMPTION FOR KEEPING THE BLADES ICE-FREE

The Rotor Blade Heating System melts the ice where the influence on aerodynamics is high. Its power consumption can be adapted to the climatic conditions at site. Whenever blade heating during standstill becomes necessary using the ENERCON Power Consumption Management will decrease the costs for power supply out of the electrical grid.

TURBINE TYPE NOMINAL POWER OF RBHS WEC RATED POWER

E-44, E-48, E-53 46 kW 900, 800, 800 kW

E-70 70 kW 2 / 2.3 MW

E-82 E2 - E4 85 kW 2 / 2.3 / 3 MW

E-92 129 kW 2.3 MW

E-101, E-101 E2 225 kW 3 MW / 3.5 MW

E-115, E-115 E2 225 kW 3 MW / 3.2 MW

E-126 EP4 225 kW (subject to validation) 4 MW

E-141 EP4 225 kW (subject to validation) 4 MW

TURBINE WITHOUT ACTIVE RBHS

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1 ICING RELATED INNOVATIONS Cold Climate Package

Ice Detection

Rotor Blade Heating System

2 ENERGY YIELD OPTIMIZATION FOR WIND FARMS UNDER ICING CONDITIONS IEA Ice Classification

Efficiency of Blade Heating

3 ONGOING RESEARCH ACTIVITIES Innovative Ice Detection Systems

Ice-free Site Assessment

AGENDA

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2 I IEA ICE CLASSIFICATION FOR SITES WITH ICING RISK

IEA ICE CLASS (no.)

METEOROLOGICAL

ICING (% of year)

INSTRUMENTAL

ICING (% of year)

PRODUCTION LOSS

(TURBINE WITHOUT RBHS) (% of AEP)

5 > 10 > 20 > 20

4 5 - 10 10 - 30 10 - 25

3 3 - 5 6 - 15 3 - 12

2 0.5 - 3 1 - 9 0.5 - 5

1 0 - 0.5 < 1.5 0 - 0.5

This ice classification was developed by IEA Wind Task 19 expert group. METEOROLOGICAL ICING: The atmosphere contains super-cooled cloud droplets leading to an active ice growth. INSTRUMENTAL ICING: Ice accretions on structures persist as long as the temperature is below 0°C.

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2 I EFFICIENCY OF THE ROTOR BLADE HEATING SYSTEM

5000

5500

6000

6500

7000

unheated heated

AEP

/ M

Wh

NUTTBY (CA)

4 % 0,5 %

3500

4000

4500

5000

5500

unheated heated

AEP

/ M

Wh

MOLAU (DE)

4 % 0,3 %

4000

4500

5000

5500

6000

unheated heated

AEP

/ M

Wh

DRAGALIDEN (SE)

3 % 15 %

3000

3500

4000

4500

5000

unheated heated

AEP

/ M

Wh

10 % 3 %

KRYSTOFOVY HAMRY (CZ)

AEP ICING LOSSES

(incl. RBHS consumption for heated turbines)

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2 I IEA ICE CLASSIFICATION FOR SITES WITH ICING RISK

* Proved by Meteotest, external consultant from Switzerland

IEA ICE CLASS (no.)

METEOROLOGICAL ICING

(% of year)

INSTRUMENTAL ICING

(% of year)

PRODUCTION LOSS (TURBINE WITHOUT

RBHS) (% of AEP)

PRODUCTION LOSS (TURBINE WITH EC RBHS,

CONSUMPTION INCL.) (% of AEP)

VALIDATION (Site)

5 > 10 > 20 > 20 > 4 -

4 5 - 10 10 - 30 10 - 25 1.5 - 5 Krystofovy Hamry (CZ)* Dragaliden (SE)* Gabrielsberget (SE)

3 3 - 5 6 - 15 3 - 12 0.5 - 3 St. Brais (CH) Nuttby (CA)

2 0,5 - 3 1 - 9 0.5 - 5 0 - 1.5 Molau (DE)*

1 0 - 0.5 < 1.5 0 - 0.5 < 0.5 -

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1 ICING RELATED INNOVATIONS Cold Climate Package

Ice Detection

Rotor Blade Heating System

2 ENERGY YIELD OPTIMIZATION FOR WIND FARMS UNDER ICING CONDITIONS IEA Ice Classification

Efficiency of Blade Heating

3 ONGOING RESEARCH ACTIVITIES Innovative Ice Detection Systems

Ice-free Site Assessment

AGENDA

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FOS4X EIGENFREQUENCY

MEASUREMENT

EOLOGIX

IMPEDANCE MEASUREMENT

3 I TESTING INNOVATIVE ICE DETECTION SYSTEMS

WÖLFEL EIGENFREQUENCY

MEASUREMENT

ENERCON is willing to strike new paths after numerous customer requests and requirements from authorities.

ONGOING VERIFICATION

CAMPAIGN!

SYSTEMS ARE NOT AVAILABLE YET.

• Measurement with acceleration sensor in the blade • Transmission via fiber-optic cables • Warnings starting from 10 kg ice on a

blade, Alarms from 20 kg ice on a blade as a default

• Installation of a structural noise sensor in the blade

• Transmission via electric cables • Warnings starting from 10 kg ice

on a blade, Alarms from 20 kg ice on a blade as a default

• Bonding of tags on blade • Impedance measurement with a

planar capacitor • Self support by solar panel • Default installation: 4 sensors per

blade • Safe turbine restart: 12 sensors per

blade

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3 I ENSURING UNDISTURBED MEASUREMENTS AT SITE

QUESTIONS

• How can a customer ensure an ice-free wind measurement

in the preconstruction phase of a wind farm?

• Which sensor should be used for measuring duration and

intensity of icing events?

• How long should a measurement campaign last?

SOLUTIONS

1. Execute measurement campaigns at sites with different

icing severity and validate all available sensors.

2. Develop an ENERCON Standard for meteorological

measurements at icy sites.

METEOROLOGICAL MEASUREMENTS

WIND MEASUREMENTS

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Thank you for your attention!

June 2006: Mawson Base, Antarctica © Arno Hildebrandt, WRD GmbH ENERCON GmbH | Dreekamp 5 | D-26605 Aurich Telefon: +49 4941 927-0 | Fax: +49 4941 927-109