GASP Global

Spatial coverage of the GASP-Global datasets.

Introduction

"GASP Global" is short for "GASP 1.0 - Global of Atlas of Siting Parameters". It is released with windPRO 3.5+ as a global atlas dataset with the following key features:

• Global 250m wind resources, siting parameters & turbine design classification
• Builds on DTU GWA (Global Wind Atlas) datasets and EMD's Load Response technology
• A joint project by EMD and DTU

Dataset Overview

• Spatial coverage:
  • Onshore: Near global (all land areas from N80 to S58)
  • Offshore: Areas are covered up to 200 km from the coastline
• Resolution:
  • Horizontal: 250m in grid resolution
  • Vertical: 50m, 100m and 150m as vertical levels
• Data-type: Atlas
• Reference period: 10 years (2008-2017)
• Coordinate system: Geographical coordinates (EPSG: 4326) in original data
• Version: 1.0

Validation and Usage Notes

• How accurate is your resource prospecting based on GASP data in windPRO or windPROSPECTING?
  We have prepared a small validation note - based on data from 241 high quality meteorological towers - that gives you a first hint on bias and uncertainty - read more - HERE.
• Need turbulence intensity instead of the GASP windspeed standard deviation?
  We have prepared a small pdf that describes how to convert from wind speed standard deviations to turbulence intensities - and how to use the two model parameters (A) and (B) to derive the turbulence intensity at any wind speed - read more - HERE.
• How is the GASP shear calculated?
  The shear values from GASP are estimated using the DTU-LINCOM flow model. According to DTU, this was the best "local" source of shear given the models available during development of the GASP dataset (neutral atmospheric stability assumed, so the reported GASP shear is representative for "higher" wind speeds). Another option would have been to estimate the shear using the WAsP model (with default or custom-specified atmospheric stability parameters). However, if you are interested in "WAsP-shear" values, it is perfectly possible to derive those directly (but manually) from existing GASP annual average wind speeds in 50m, 100m and 150m [parameter: wsp]. The "WAsP-shear" is currently not included in the GAsP dataset version 1.0, but under consideration for a future dataset update.

Availability from EMD's software

Wind Resouces in 100m height at Lillgrunden, Sweden. GASP data accessed through windPRO 3.5.

50yr Extreme Wind Speeds in 100m height at Tasmania, Australia. GASP data accessed through http://www.windPROSPECTING.com platform.

50yr Extreme Wind Speeds in 100m height at Danish Offshore Wind Farms. GASP data accessed through the EMD-API platform, http://api.emd.dk

• windPRO: In 'Data' menu click 'Siting parameters (GASP etc)' to access the download tool. Data is loaded into a result layer with a .siteres file acting as the data-container.
  • The .siteres file can be used in PARK, Site Compliance, Load Response and Optimization calculations.
• windPROSPECTING: GASP data is available through the data-tab named 'Site-prospecting'. Free access to windPROSPECTING - here.
  • windprospecting offers spatial view of omnidirectinal parameters and detailed point-data with directional results and statistics.
• EMD-API: Read more at the dedicated wiki-page for our Global Atlas Data Services - here. If you are accessing the GASP data from within the EMD-API, you will use the parameter group-names in order to request specific data-packages [resource-omni, resource-sector, siting-extremes, siting-fatigue-omni, siting-fatigue-sector, turbine-fatigue, turbine-fatigue-recommend, turbine-extreme, turbine-extreme-recommend].

Parameters and Dimensions

As seen from the tables below, a very wide range of omnidirectional and sectorwise parameters are available from GASP. These parameters are divided into four main categories:

• Wind Resources / Atmospheric Parameters
• Siting Parameters – Fatigue
• Siting Parameters – Extremes
• Turbine Design Classification - with recommended turbine class. 3 separate aeroelastic models are used as representative for the 3 heights
  • 50m: WindPACT 1.5MW
  • 100m: NREL 5MW
  • 150m: DTU 10MW

The tables below provides an overview of all parameters available and at which dimensions that they are available. We have used the following dimensions for the GASP parameters: The first four (longitude, latitude, height and sector) are used for the basic parameters; the last three (ws_class, iec_class and turbine_component) are used for the turbine design classification - and are releated to the IEC61400-1 code and the aeroelastic load model. Please note that not all dimensions are relevant or used for every GASP parameter.

Table: List of dimensions in GASP data.

Dimension	Abbreviation	Unit	Range
longitude	lon	deg	180 to -180
latitude	lat	deg	90 to -90
height	h	m	50,100,150
sector	s	deg	0,30,...,330
ws_class	wcl		I,II,III,T
iec_class	iecc		IA+, IA,...IIIC
turbine_component	tc		0,1,2,3

Parameters: Wind Resource

The two tables below show the GASP parameters for wind resource data divided in omnidirectional data [resource-omni] and sectorwise data [resource-sector].

Table: Resource / Atmospheric Omni-directional Parameters [resource-omni]

Variable	Description	Unit	Dimensions
weib_A	Wind distribution: A (Scale) parameter in Weibull distribution	m/s	lon, lat, h
weib_k	Wind distribution: k (shape) parameter in Weibull distribution		lon, lat, h
wsp	Wind speed - annual average	m/s	lon, lat, h
wpd	Wind power density – annual average	W/m2	lon, lat, h
air_dens	Air density (annual mean/average)	kg/m3	lon, lat, h

Table: Resource / Atmospheric Sector-wise Parameters [resource-sector]

Variable	Description	Unit	Dimensions
weib_A	Wind distribution: A (Scale) parameter in Weibull distribution	m/s	lon, lat, h, s
weib_k	Wind distribution: k (shape) parameter in Weibull distribution		lon, lat, h, s
sector_freq	Wind distribution: Sector frequency		lon, lat, h, s
wsp	Wind speed - annual average	m/s	lon, lat, h, s
wpd	Wind power density – annual average	W/m2	lon, lat, h, s
air_dens	Air density (annual mean/average)	kg/m3	lon, lat, h
elevation	Terrain Elevation	m	lon, lat

Parameters: Siting Classification - Wind Extremes

The table below shows the GASP parameters for the extreme event data [siting-extremes]. Please note that this extreme data is only available as omnidirectional parameters.

Table: Siting Parameters – Extremes [siting-extremes]

Variable	Description	Unit	Dimensions
air_dens_p98	Air density at 98th percentile of wind speed	kg/m3	lon, lat, h
wsp_50yr	50yr extreme wind speed: Average	m/s	lon, lat, h
gumbel_alpha	50yr extreme wind speed: Gumbel distribution – alpha parameter	m/s	lon, lat, h
gumbel_beta	50yr extreme wind speed: Gumbel distribution – beta parameter	m/s	lon, lat, h

Parameters: Siting Classification - Wind Fatigue Parameters

The two tables below show the GASP parameters for the siting-fatigue parameters - given either omnidirectional or sectorwise data-requests [siting-fatigue-omni, siting-fatigue-sector].

Table: Siting Parameters Omnidirectional – Fatigue [siting-fatigue-omni]

Variable	Description	Unit	Dimensions
shear_exp	Wind shear exponent (calculated using LINCOM model) - Mean		lon, lat, h
flow_inc	Flow inclination (calculated using LINCOM model)	deg	lon, lat, h
terrain_ic	Terrain complexity as defined in IEC 61400-1 standard (ed 4)		lon, lat, h
sigma_P90A	Turbulence slope parameter from IEC 61400-1 (ed4) – P90		lon, lat, h
sigma_P90B	Turbulence offset parameter from IEC 61400-1 (ed4) – P90	m/s	lon, lat, h
sigma_P90U15	Turbulence P90 at a fixed windspeed of 15 m/s	m/s	lon, lat, h
air_dens	Air density (annual mean/average)	kg/m3	lon, lat, h

Table: Siting Parameters – Fatigue [siting-fatigue-sector]

Variable	Description	Unit	Dimensions
shear_exp	Wind shear exponent (calculated using LINCOM model) - Mean		lon, lat, h, s
flow_inc	Flow inclination (calculated using LINCOM model)	deg	lon, lat, h, s
sigma_meanA	Turbulence slope parameter from IEC 61400-1 (ed4) – Mean	m/s	lon, lat, h, s
sigma_meanB	Turbulence offset parameter from IEC 61400-1 (ed4) – Mean	m/s	lon, lat, h, s
sigma_P90A	Turbulence slope parameter from IEC 61400-1 (ed4) – P90		lon, lat, h, s
sigma_P90B	Turbulence offset parameter from IEC 61400-1 (ed4) – P90	m/s	lon, lat, h, s

Parameters: Turbine Design – Loads

The four tables below show the GASP parameters for the turbine design classification. The two main groups are fatigue and extreme load cases, divided into four data-groups so requests is possible for turbine load indexes and iec class recommendations: [turbine-fatigue, turbine-fatigue-recommend, turbine-extreme, turbine-extreme-recommend].

Table: Turbine Design – Fatigue [turbine-fatigue]

Variable	Description	Unit	Dimensions
flsidx	Load index for the fatigue limit state	%	lon, lat, h, iecc, tc
flsidx_w	Load load index for the fatigue limit state with wakes	%	lon, lat, h, iecc, tc
tc_woehler	Turbine component (tc): Wöhler exponent used		lon, lat, h, iecc, tc
tc_name	Turbine component (tc): Name		lon, lat, h, iecc, tc
tc_sensor	Turbine component (tc): Sensor name		lon, lat, h, iecc, tc

Table: Turbine Design – Fatigue Recommendations [turbine-fatigue-recommend]

Variable	Description	Unit	Dimensions
iecr_fls_id	IEC Class Recommendation – fatigue limit state (FLS) - id		lon, lat, h
iecr_fls_txt	IEC Class Recommendation – fatigue limit state (FLS) - text		lon, lat, h
iecr_flsw_id	IEC Recommendation (with wakes) – fatigue limit state (FLS) - id		lon, lat, h
iecr_flsw_txt	IEC Recommendation (with wakes) – fatigue limit state (FLS) - text		lon, lat, h

Table: Turbine Design – Extreme Loading [turbine-extreme]

Variable	Description	Unit	Dimensions
ulsidx	Design load index for ultimate limit state (ULS)	%	lon, lat, h, wcl

Turbine Design – Extreme Recommendations [turbine-extreme-recommend]

Variable	Description	Unit	Dimensions
iecr_uls_id	Design load index for ultimate limit state (ULS)		lon, lat, h
iecr_uls_txt	IEC Class Recommendation – ultimate limit state (ULS) – text		lon, lat, h

License and Attribution

The data is available through a Creative commons 4.0 by attribution license (CC BY 4.0).
Please accept the license conditions and use a proper attribution when using this dataset, such as:

GASP 1.0: Global Atlas of Siting Parameters 1.0 by EMD and DTU, is a free dataset accessible via 
EMD (windprospecting.com, windPRO & EMD-API) and DTU (globalwindatlas.info, science.globalwindatlas.info & data.dtu.dk). 
License: CC-BY-4.0

Acknowledgement

• GASP is the result of a BIG collective effort by many people at: EMD International A/S & DTU Wind Energy, with overall project manager Xiaoli Larsén (DTU)
• Develoment and integration of this dataset into EMD services was done through the GASP project which is co-funded by the EUDP and the Danish Energy Agency

External Links & References

• GASP Project Home-Page at DTU - here
• An open-access, peer-reviewed paper is available from the Wind Energy Journal:
  The Global Atlas for Siting Parameters project: Extreme wind, turbulence, and turbine classes by Xiaoli Guo Larsén, Neil Davis, Ásta Hannesdóttir, Mark Kelly, Lasse Svenningsen, René Slot, Marc Imberger, Bjarke Tobias Olsen and. Rogier Floors.
• GASP data is available from the Global Wind Atlas App (from version 3.3) - here
• GASP data from DTU data portal - here