wind resource assessment report 4vietnam

RISØ IED Mercapto PNOC-EDC

IE MIME

ASEAN Wind 2005

Feasibility Assessment and Capacity Building for Wind Energy Development

in Cambodia, Philippines and Vietnam

Wind Resource Assessment Vietnam

January 2007

Project reference: EuropeAid/119920/C/SV

Document reference: Task1/Wind/Vietnam Version: 070126/RISO/PN

ASEAN Wind 2005 Wind Resource Assessment - Vietnam

RISO 2 /22 Final 2007-01-26

ASEAN Wind 2005 - Fact Sheet Main project data

Full project title: Feasibility Assessment and Capacity Building for Wind Energy Development in Cambodia, The Philippines and Vietnam

Objective: The main objective of the project is to promote wind energy development and facilitate investments on wind energy projects in The Philippines, Vietnam and Cambodia through feasibility assessment and capacity building.

Start: February 2005 End: December 2006

Total effort: 64.5 man-month

Contracting Authority: EC-ASEAN Energy Facility (www.aseanenergy.org/eaef)

Budget / Support: € 1 000 000 / € 500 000 by European Community

Tasks Task 1: Wind Resource Assessments RISO + IED; PNOC-EDC; IE (10.5 MM)

Task 2: Power System Analyses RISO + PNOC-EDC; IE (7.5 MM)

Task 3: Policy & Market Studies RISO + IED; Mercapto; PNOC-EDC; IE (9.5 MM)

Task 4: Technical Feasibility Studies RISO + PNOC-EDC; IE (10 MM)

Task 5: Economic Feasibility Studies IED + RISO; PNOC-EDC; IE (7 MM)

Task 6: CDM Project Studies Mercapto + All (5.5 MM)

Task 7: Financial Framework IED + All (5.5 MM)

Task 8: Dissemination RISO + All (4.5 MM)

Project partners RISO RISØ National

Laboratory Denmark Niels-Erik

Clausen [email protected]

IED Innovation Energie Développement

France Anjali Shanker [email protected]

Mercapto Mercapto Consult Denmark Bernt Frydenberg [email protected]

PNOC-EDC

PNOC Energy Development Corporation

Philippines Samuel Hernando [email protected]

IoE Institute of Energy Vietnam Pham Khanh Toan [email protected]

MIME Ministry of Industry, Mines & Energy

Cambodia Sovanna Toch [email protected]


RISO 3 /22 Final 2007-01-26

Table of Contents

Preface ....................................................................................................................................... 4

Executive summary .................................................................................................................. 5

1 Wind energy...................................................................................................................... 6 1.1 Characterisation of the wind ...................................................................................... 6

1.1.1 Wind resources................................................................................................... 6 1.1.2 Wind variations .................................................................................................. 7 1.1.3 Wind power forecast .......................................................................................... 7 1.1.4 Extreme winds.................................................................................................... 7

1.2 Case study sites .......................................................................................................... 7

2 Vietnam ............................................................................................................................. 9 2.1 Phuoc Minh site........................................................................................................ 11 2.2 Tuy Phong ................................................................................................................ 15 2.3 Ly Son Island ........................................................................................................... 19


RISO 4 /22 Final 2007-01-26

Preface The present Report forms part of the deliverable and presents parts of the results of Task 1 of the Project: the analyses of the wind resources in Vietnam. Remaining results from Task 1 are presented in the reports: Wind resource assessment report, Philippines Extreme winds in the western North Pacific.

According to the terms for the Project, and confirmed by the Inception Meeting, two cases should be assigned in Vietnam (and two in Philippines) – one with grid connected wind power and one island system – to form the basis for case studies. Wind data should be collected at the two sites for at least one full year as part of the Project. Two sites were originally pointed out by IE for the case studies in Vietnam: Phuoc Minh (in the beginning referred to as Ca Na) and Con Dao Island. Unfortunately, Con Dao had to be given up since a met-mast could not be installed. Another island was then pointed out by IE – the Ly Son Island – and a met-mast was finally installed in January 2006, however rather late in the Project period. The met-mast at Phuoc Minh is operated by PECC3, and at the end of the Project period it turned out that the Project could not have access to the detailed data as originally thought. PECC3 was however prepared to provide results from analysis based on the wind data collected at the site. At the very end of the Project period, IE came up with wind data, collected by IE at another site – the Tuy Phong site – not far from the Phuoc Minh site.

The three wind data sets are presented in the present Report, but in varying forms due to the above described reasons.

The report is prepared by Per Nørgaard, Risø National Laboratory.


RISO 5 /22 Final 2007-01-26

Executive summary The overall wind resources in Vietnam, estimated in other studies based on available global meteorological databases, indicates that the best resources are found in the mountains and along the sea in the southern part of Vietnam. However, the actual wind resources are very dependant on local conditions and must be verified through dedicated measurements of the local wind resources. Several organisations in Vietnam, including the Institute of Energy (IE) and PECC3, have initiated measurements of the wind at selected site around Vietnam.

Two sites in Vietnam, the Phuoc Minh mainland site and the Ly Son Island, were selected by IE to form the basis for illustrative wind power feasibility case studies performed in the present project. PECC3 is operating a wind measuring station at the Phuoc Minh site, while IE is operating a wind measuring station at Ly Son. The project could not get access to the detailed wind data from the Phuoc Minh met-station. Instead, the detailed wind analysis were demonstrated using detailed wind data provided to the project by IE from a met-mast operated by IE at another site, Tuy Phong, not far from Phuoc Minh.

The main results from the three sites are indicated in the table below: Phuoc Minh Tuy Phong Ly Son

Period 2005 2005 2006

Measured at height 60 m 60 m 60 m

Annual mean wind speed 7.0 m/s 6.7 m/s 6.6 m/s

Annual mean wind power density (@ 1.225 kg/m3 air density)

400 W/m2 320 W/m2 290 W/m2

Max wind speed 20 m/s 29 m/s

The met-masts at the three sites in question are very well situated, the wind has been measured in height levels relevant for wind power and the data are expected to be representative for the sites. For all sites the results are based on one full year of data, but not the same year for all sites. No information was made available for the project if the wind resources observed for each site are representative for the long term wind resources for the sites.

Whether the indicated wind resources are feasible for power generation depends on the actual value of the wind power, which again depends on the alternative power production options and how the wind power can be integrated. These matters are described in the two feasibility reports for the project.


RISO 6 /22 Final 2007-01-26

1 Wind energy

1.1 Characterisation of the wind When dealing with the perspectives and planning of utilisation of the wind energy for power generation, the wind conditions should be characterised by various characteristics important for specific aspects: the wind energy resources indicating the annual energy production; the variations – during the day, during the year and from year to year – important for the

integration and the value of the wind power; the turbulence important for the power performance and the structural loads; and the extreme winds – as basis for the structural design of the wind turbines.

Important for the operation is in addition the ability to forecast the wind power generation hours ahead.

1.1.1 Wind resources The wind resources may be determined on the basis of local, dedicated, high quality wind data (for at least one full year) in combination with long term wind data (several years), representative for the site.

The local wind data should be measured at a site well exposed by the free wind, at a height level representative for the height of the wind turbines, using high quality measurement equipment, automatically recording the (average) wind speed and direction at least each hour (preferable each 10 minutes).

The (average) wind speed should be measured in more height levels in order to determine the vertical wind speed profile. For a given surface roughness length, z0, the vertical wind speed profile is approximately logarithmic in the lower part of the atmospheric boundary layer1:

00 ln)(

zzuzu = (1)

giving the following relation between wind speeds, u1 and u2, at two height levels, z1 and z2:

01

02

0

1

0

2

1

2

lnlnlnln

ln

ln

zzzz

zzzz

uu

−−

=

= (2)

The long term wind data should come from measurements representative for the local wind, meaning that the long term met-station should not be too far away from the site and the wind sensors should be exposed by the free wind. The data period should be several years, and must include the period with wind data from the local station. The wind data should be indicated at least as monthly average.

1 European Wind Atlas, Risø National Laboratory, 1990.


RISO 7 /22 Final 2007-01-26

1.1.2 Wind variations The wind fluctuates from second to second, both the wind speed and the wind direction. These fluctuations may be indicated (and is in general well represented) by the turbulence intensity, and the maximum and the minimum values – provided by most modern wind data loggers. The wind turbine must be designed for these fluctuations, and the fluctuations in the wind are to some extend represented in the output from the wind turbine.

The energy in the wind also varies from minute to minute, and the output from a wind turbine may change substantial within this time scale. This is of cause important for the utilisation of the wind power and the integration into the power supply system. Data for each 10 minutes will to some extend represent these fluctuations.

In general, the correlations between fluctuations in the wind speed at different sites decrease with increasing distances between the sites. The high frequency fluctuations in the aggregated power output from more wind turbines in a wind farm will therefore be lower than the fluctuations from the single wind turbine unit. And the aggregated production from more wind farms in a region will further levelling the variations at time scales from minutes to hours.

The wind is generated by the sun’s heating of the surface, and at many sites you may find typical variations of the wind over the day (well represented by hourly values) and typical variations over the year (well represented by monthly values). The value of the wind power depends on the correlation between the wind power generation and the local need for power.

1.1.3 Wind power forecast

In order to optimize the operation of the entire power supply system the forecast and the uncertainty of this forecast are critical parameters. The quality of the forecast is dependent on the input data available and on a reliable model. The uncertainty is in addition dependent on the nature of the wind – steady wind, typical daily pattern etc.

1.1.4 Extreme winds The wind turbine must be designed to withstand the extreme wind conditions at the site. Typically, the wind turbine is designed according to the expected 50-years wind – the maximum wind speed that statistically will occur each 50 years. The 50-year wind is determined on basis of long term wind data series.

In order to make it simple to estimate, the design wind speed in existing international design codes for wind turbines are based on the average wind speed and the turbulence intensity. This simplification is however not representative for regions wind hurricanes, that normally then will define the design wind speed.

1.2 Case study sites Within the present Project four sites have been selected for wind studies – two in Vietnam and two in the Philippines: Phuoc Minh (Ca Na) site (Vietnam) at the mainland Ly Son Island (Vietnam) in the Chinese Sea Sta. Ana (Philippines) – at the north of the Philippines Dinagat Island (Philippines) – an island in the mid-east of the Philippines


RISO 8 /22 Final 2007-01-26

Meteorological masts have been erected at all four sites, instrumented to measure and record wind speed and wind direction at several height levels.

Only from the Sta. Ana and the Dinagat sites, the present study has access to one full year of data. At Ly Son site the met-masts were unfortunately installed late. The met-mast at the Ca Na site is owned and operated by the organisation PECC 3 that is not part of the present Project, and the data have not (yet) been made available for the Project. An overview of the data availble is given in Table 1.

Table 1: An overview of the case study sites within the present Project.

Site Phuoc Minh Ly Son Sta. Ana Dinagat

Country Vietnam Vietnam Philippines Philippines

Location

Wind speed measurement heights

40 / 50 / 60 m

40 / 50 / 60 m 30 m 30 m

Data period (2006) Jan 2006 – Jan 2007 Sep 2005 – Sep 2006 Aug 2005 – Aug 2006


RISO 9 /22 Final 2007-01-26

2 Vietnam Wind resources in Vietnam have been indicated by studies using mesoscale modelling of meteorological data – see Figure 1, Figure 3 and Figure 2. IE and PECC3 have then initiated comprehensive wind measurement programmes with the installation of met-masts at indicative promising sites.

Two sites have been selected in Vietnam as cases for the present Project – the Phuoc Minh site and the Ly Son Island.

Figure 1: Map indicating the wind resources in Vietnam at 65 m agl, created by TrueWind Solutions for World Bank using MesoMap – a mesoscale atmospheric simulation system. (Source: Wind Energy Resource Atlas of Southeast Asia, World Bank, 2001)

Figure 2: Wind resources in Vietnam indicated by the calculated capacity factor of an Enercon E-66 / 1800kW wind turbine with 70 m rotor diameter and 65 m hub height. (Source:Wind Energy in Vietnam (paper), Khanh Q. Nguyen, 2006)


RISO 10 /22 Final 2007-01-26

Figure 3: Wind resources in Vietnam indicated for the four sesons of the yesr: Dec-Feb; Mar-May; Jun-Aug; Sep-Nov. (Source: see Figure 1)


RISO 11 /22 Final 2007-01-26

2.1 Phuoc Minh site The site is located towards the Chinese Sea in a N-S oriented gab between 500 m high mountains. The site was visited by a project team in June 2005.

Figure 4: The Phuoc Minh site and the Ca Na site indicated on map. (Map source: GoogleEarth)

Figure 5: Digital map indicating the Phuoc Minh site and the Ca Na site. (Map data source: NASA/SRTM)


RISO 12 /22 Final 2007-01-26

Wind data have been collected at two sites: 1998-1999: at Ca Na 2005-2006: by PECC3 at Phuoc Minh

Ca Na site

Wind data have been collected at the Ca Na site for one year during 1998-1999 by a projected involving Elsamprojekt, Denmark. Monthly average wind data – wind speed at 10 m and 30 m heights and wind direction – have been provided to the Project by Elsamprojekt. The

site conditions are indicated in Figure 6

The monthly average wind speed and wind direction are indicated in Figure 7, showing two seasons during the year: from October to April with prevailing wind direction from north and

with the best wind resources, and from south the rest of the period.

Figure 6: Site of the former Ca Na met-mast (towards south), indicated by the remainings from the foundation. (Photo: Risø, 2005)

0

5

10

15

20

Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun

Month

Win

d sp

eed

(m/s

)

0

90

180

270

360

Dire

ctio

n (d

eg)

30 m 10 m Direction Figure 7: Monthly average wind data June 1998 – June 1999 from the Ca Na met-mast. (Data source: Elsamprojekt)


RISO 13 /22 Final 2007-01-26

The reliability of the data have been analysed and the up-wind surface roughness have been estimated by plotting the relations between the wind speed data at the two height levels for the data with wind direction from north and south respectively (Figure 8). The plot indicates good quality of the data.

Phuoc Minh site

PECC3 has installed a 60 m met-mast at the Phuoc Minh site and has collected data since 2005 (Figure 10). The present Project was intended to have access to these detailed data, but did never succeed. However, at the Project workshops PECC3 has presented some results from the data collection, presented in Figure 9.

Wind speed correlation 10 m / 30 m

0

5

10

0 5 10Wind speed 30 m

Win

d sp

eed

10 m

SouthNorthLinear (South)Linear (North)

Figure 8: The correlations of the wind speeds from the Ca Na met-mast at 10 m and 30 m height for wind from south and north respectively indicate difference when the wind is from south (towards the sea) corresponding to low roughness length while the difference for the wind from north (towards the town) corresponds to a roughness length of approximately 10 cm.

Monthly Average Wind Speed at all of high levelsNinh Phuoc Wind Measurement Station

0.0

2.0

4.0

6.0

8.0

10.0

12.0

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

m/s

NP12m

NP40m

NP60mH

NP60mV

Figure 9: Average monthly wind speed data and wind direction rose for 2005 from Phuoc Minh met-mast at three height levels. (Source: Mr Pham Sy Quoc Hung, PECC3, 2006)


RISO 14 /22 Final 2007-01-26

The wind statistics for the site indicated by PECC3 are annual average wind speed of 7.0 m/s and 400 W/m2 (at 65 m height @ 1.225 kg/m3 air density).

Figure 10: PECC3’s 60 m met mast at the Phuoc Minh site. (Photo: Risø, 2005)


RISO 15 /22 Final 2007-01-26

2.2 Tuy Phong


RISO 16 /22 Final 2007-01-26

One full year (Jan 2005 – Jan 2006) of detailed wind data with 10 min average wind speed and wind direction at 60 m height level from the Tuy Phong site 30 km south-west of the Phuoc Minh site have been provided for the project by IE (Figure 11). Data seems to be of high quality with no mission data during the period.

The site surroundings are indicated by the map in Figure 12.

Figure 11: Map indicating the two sites at Phuoc Minh and at Tuy Phong. (Source: GoogleEarth)

Figure 12: The Tuy Phong site just south of the Highway 1A and approximately 2 km from the sea, indicated at a satellite image map. (Source: GoogleEarth)


RISO 17 /22 Final 2007-01-26

The time series plot of the wind data in Figure 13 and the statistical graphs in Figure 14 indicates two prevailing wind directions depending on the season of the year: E-SE from May to September and from NE the rest of the year.

The statistic analysis of the wind data indicate an average wind speed of 6.7 m/s and a wind power density of 320 W/m2 (@ 1.225 kg/m3 air density) and a maximum wind speed of 20.2 m/s – little less than the figures indicated by PECC3 for the Phuoc Minh site.

Figure 13: Time series plot of one full year (Jan 2005 – Jan 2006) of wind speed and wind direction at 60 m height agl from the met-mast at Tuy Phong. The data indicate a shift of the wind direction in the middle of the year – like also indicated in Error! Reference source not found.. (Data source: IE)

Figure 14: Wind direction and wind speed statistics for one year wind data (Jan 2005 – Jan 2006) at 60 m height agl from the met-mast at Tuy Phong. (Data source: IE)


RISO 18 /22 Final 2007-01-26

The Project has no information if the one year wind data are representative for the long term wind resources for the site.


RISO 19 /22 Final 2007-01-26

2.3 Ly Son Island The Ly Son Island is situated in the Chinese Sea, 30 km from the mainland at the central Vietnam. The island was visited for collection of data by a project team in July 2006.

Wind data have been provided from: 2005: The Ly Son Meteorological Station 2006: The IE 60 m met-mast

The shape of the island is indicated in Figure 15 and the positions of the Meteorological Station and IE’s met-mast are indicated at the map in Figure 16.

Figure 15: Map indicating the hills at Ly Son Island. (Map data source: NASA/SRTM)

Figure 16: WAsP map of Ly Son Island indicating the positions of the Met Station (to the east) and IE’s met-mast (in the middle).


RISO 20 /22 Final 2007-01-26

One year of wind data (all 2005) have been provided from the 12 m mast at the Met Station (Figure 17). The monthly average wind speeds are indicated in Figure 18. Unfortunately, the Project only has data for one year and with no time overlap with the data from IE’s met-mast. The available data from the Met Station can therefore not act as a long term reference.

Figure 17: The 12 m met-mast at the Ly Son Met-Station that may provide long term wind reference. (Photo: RISO 2006)

0

2

4

6

8

10

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Win

d sp

eed

(m/s

)

Figure 18: Monthly average wind speed statistics of data at 12 m height level from the Ly Son Met Station for 2005. (Source: IE)


RISO 21 /22 Final 2007-01-26

Wind data have been collected during one full year (Jan 2006 – Jan 2007) at 40 m, 50 m and 60 m height levels by IE from their met-mast (Figure 19). The data seems to be of high quality with no missing data during the period.

Time plots of the data are shown in Figure 21. The typhoon ‘Xansane’, which passed Manila 28 November, later passed the Ly Son around 1 Oct 2006 with maximum wind speed of 29 m/s – shown in detail.

The wind statistics are indicated in Figure 20, indicating the two prevailing wind directions – north and south. The average wind speed for the period at 60 m height level was 5.9 m/s with an average wind power density of 290 W/m2 (@ 1.225 kg/m3 air density).

Figure 19: IE’s 60 m met-mast at Ly Son. (Photo: RISO 2006)

Figure 20: Wind statistics based on one full year of data (060123-060110) from the IE met-mast at Ly Son. (Data source: IE)


RISO 22 /22 Final 2007-01-26

Figure 21: Time plot of the wind speed and wind direction at 60 m height level from the IE met-mast at Ly Son for one full year (upper) and a zoom around 1 Oct 2006 with a typhoon pass. (Data source: IE)

wind resource assessment report 4vietnam

Documents