1 irena – m artinique c onference on island energy transitions workshop c : wind resources and...

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IRENA – MARTINIQUE CONFERENCE ON ISLAND ENERGY TRANSITIONS Workshop C : Wind resources and technologies for islands

WIND MEASUREMENTS ON

ISLANDS :

THE BENEFITS OF USING

LIDARS

Martinique, 22th June 2015

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WIND MEASUREMENTS ON ISLANDS : THE BENEFITS OF USING LIDARS

Eoltech short presentation

Wind resource assessment, background and state of the

art

Wind measurements with LiDARs

Specificities of the wind resource on tropical islands

Main conclusions

Summary

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Eoltech at a glance

1st French independent expert in wind resource assessment

Pre and post construction wind potentiel assessments

13 years of expertise, more than 7 GW of projects analyzed

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Wind resource assessment, background and state of the art - 1/3

Main characteristics of the wind resource

High temporal variability

Order of magnitude ± 10 % on wind speed from one

year to another over 15 years

High spatial variability

Depending on the complexity of

the topography and the landscape

High sensitivity wind speed versus production

3 % variation on wind speed could lead to 6 % to

9 % of variation in production

Wind resource assessment subject to high level of

uncertainty without measurement on site

+11 %

- 9%

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On site measurements, the starting point of a standard process

Spatial

extrapolation

State of the art : 1 year of measurement on a representative point of the site at a height the closest to the hub height (2/3 minimum)

Wind

measurement

1 year on site

& Data analysis

5 6 7

0

20

40

60

80

100120

Vitesse de vent (m/s)

Hau

teu

r (m

)

Long term

prediction

Régression secteur : -15/15

VRef (m/s)

VSite (m/s)

5 10 15 20

5

10

15

20

25

+11 %

- 9%

Long term energy output

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On site measurements with met mast

Met mast equipped with sensors (Cup anemometers, Wind vanes…)

Height between 50 m and 80 m

The most recognized process for wind measurements

The fequency of the reflected signal is modified

(Doppler effect)

o Difference of frequency

o Signal return time

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The LiDAR - Operating principle

A laser beam is pulsed by the LiDAR (Light Detection and Ranging),

and reflected by the suspended particles

Wind speed

Height of measurement

Different heights of measurement possible

Usually between 40 m and 200 m

Aerosol speed

LiDAR

Aerosol Speed = Wind speed

f1

f2

Height

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The LiDAR - Who uses it ?

The LiDAR - Accuracy

Well-proven technology on a non complex area

Recognized by industry for wind resource assessment

On going IEC standard for power curve measurement

(started in 2014)

We are talking about the

technology,

not the product itself

Used by developers, manufacturers, consultants and research institutes

More than 400 Lidar Windcube by Leosphere have been deployed

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The LiDAR - Advantages

Easy to install and remove

No building permit required

Satisfactory measurement quality up to 200 m

Low risk of wear due to climatic conditions

(especially corrosion)

But keep in mind….

Precautions of installation are required

(flat terrain, avoid obstacle in the volume of the cone)

The technology is proven, not each device

Conclusions : The LiDAR is an alternative technology to masts for wind

measurements, recognized and easy to implement

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Specificities of wind climate on tropical islands (1/3)

Usually, one year of measurement is strongly recommended to take into account the

seasonality effect of wind resource

Per season Main impact on

Different wind regime Prevailing wind direction

Different landscape (crops or forests summer versus winter)

Vertical wind shear

Atmospheric stability conditions Vertical wind shear

In tropical areas, especially

on islands, the wind climate

is a result of stable trade

winds and temperature

variation

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Specificities of wind climates on tropical islands (2/3)

Seasonality effect on wind resource

Per season Northern France Island on a tropical area

Wind roses

m

2010 - Q1 2010 - Q2

2010 – Q3 2010 – Q4

m

2010 - Q1 2010 - Q2

2010 – Q3 2010 – Q4

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Wind roses x Not stable Stable

Landscape(farmland / forests)

Atmospheric stability conditions(temperature)

Jan.

Feb.

Mar

ch Apr.

May

June Ju

lyAug

.

Sept.

Oct

.Nov

.Dec

.0

5

10

15

20

25

30

Av

era

ge

te

mp

era

ture

(°C

)

Jan.

Feb.

Mar

ch Apr.

May

June Ju

lyAug

.

Sept.

Oct

.Nov

.Dec

.0

5

10

15

20

25

30

Av

era

ge

te

mp

era

ture

(°C

)

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Wind roses x Not stable Stable

Landscape(farmland / forests)

Atmospheric stability conditions

Jul-1

1

Sep-1

1

Nov-1

1

Jan-

12

Mar-1

2

May-1

2

Jul-1

2

Sep-1

2

Nov-1

2

Jan-

130.20

0.25

0.30

0.35

0.40

Wind shear on 6-month rolling periods

Starting date of the 6-month roling period

Win

d s

he

ar

Aug-0

5

Oct-0

5

Dec-0

5

Feb-

06

Apr-0

6

Jun-

06

Aug-0

6

Oct-0

6

Dec-0

6

Feb-

07

Apr-0

7

Jun-

07

Aug-0

70.20

0.25

0.30

0.35

0.40

Wind shear on 6-month rolling periods

Starting date of the 6-month roling period

Win

d s

he

ar

Summer winterwinter

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Wind rose x Not stable Stable

Landscape(farmland / forests) x Not stable Stable

Atmospheric stability conditions x Not stable Stable

Seasonality effect on wind resource is relatively low

on islands in tropical areas

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12 months of measurement is always better than 8 or 10 months for exemple

But . . .

8 or 10 months of measurement on

such area should be enough

To estimate accurately the wind

resource

To allow to get bankable wind

resource assessments

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Conclusions – 1/2

On the one hand….

… A reliable and easy to install (or move)

device for wind measurement

On the other hand…

… A wind climate on tropical islands allowing to

perform an estimate (or a 1st estimate) with less than 12

months of measurements on site

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Conclusions – 2/2

Main applications for using LiDARS on tropical

islands

Standard wind resource assessment studies

Resource mapping

Move one LiDAR on several locations during

few years to carry out a first estimate of wind

resource map

Adjusting meso-cale model on strategic

locations

First estimate of the wind resource on several

islands in the same area

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Thank you for your attention

1 irena – m artinique c onference on island energy transitions workshop c : wind resources and...

Documents

islands wind measurements

wind resources

wind vanesheight

wind resource assessment

site measurements

artwind measurements

year of measurement

lidar windcube