Weibull wind climates
Weibull wind climates are a new alterative to specifying the wind distributions at a location or at the turbines. These have been introduced to support calculations without on-site measurements typically called the non-association method using weibull distributions from a WaSP wind resource grid (WRG) or other sources.
Compared with using a measured wind climate, the weibull climate approach requires a list of Weibull parameters
for each direction sector, that direction sector probabilities adds up to 1
, and
only a single value of turbulence intensity can be specified.
Note
Its a requirement that the
number of direction steps defined in the energyEfficienciesSettings
is divisible by the number
of direction sectors in the weibull climate and that all weibull climates have the same number of sectors.
"weibullWindClimates": [
{
"id": "M3 100m",
"location": {
"easting_m": 199186.0,
"northing_m": 2242285.0,
"terrainHeightAboveSeaLevel_m": 25.555407094778687
},
"heightAboveGround_m": 100.0,
"numberOfDirectionSectors": 12,
"directionForFirstBinCentre_degrees": 0.0,
"turbulenceIntensity": 0.1,
"sectorWeibullParameters": [
{
"probability": 0.076,
"a": 8.1,
"k": 2.43,
},
{ ... },
{ ... },
...
]
},
{ ... }
]
Typically wind climates contain measured data at a given location and are then associated with
the turbines using associatedWindClimateId
property on the latter, this is used together with the
flow model speed-ups to determine how the wind speed changes from reference to the turbine location. The
Weibull wind climates can be used in the same way and be drop-in replacement for this method.
Another method is to use the Weibull wind climates when there are no measurements at the site
but there is a Weibull prediction for each turbine location, usually from a WRG or RSF file. To use this method
a weibull wind climate must exist for each turbine and use associatedWindClimateId
property on the turbine
to link the two. For this scenario the speed-ups for each turbine in the flow model should be
set to 1.0
.
Note
Weibull climates and wind climates cannot coexist, so only one set can be specified in a call. Since a Weibull is a continuous distribution it's necessary to specify the maximum wind speed for the calculation, currently the calculation is using a 1 m/s bin width when doing the AEP calculation when using Weibull climates.
Example with 2 turbines associated to weibull wind climate M3 100m using a flow model with speed-ups.
Some of the other properties: turbineModels
,
referenceAirDensity
, energyEfficiencySettings
have been ommited for simplicity but are necessary for an API call.
{
"windFarms": [
{
"name": "My Turbines",
"turbines": [
{
"name": "T 1",
"associatedWindClimateId": "M3 100m",
"turbineModelId": "Hawaii 2.0 MW",
"isInstalled": false,
"location": {
"easting_m": 199977.0,
"northing_m": 2242510.0,
"terrainHeightAboveSeaLevel_m": 46.2
},
},
{
"name": "T 2",
"associatedWindClimateId": "M3 100m",
"turbineModelId": "Hawaii 2.0 MW",
"isInstalled": false,
"location": {
"easting_m": 200556.0,
"northing_m": 2242405.0,
"terrainHeightAboveSeaLevel_m": 66.2
}
}
],
"isNeighbor": false,
"includeInBlockageCalculation": true
}
],
"turbineModels": [
{
...
}
],
"weibullWindClimates": [
{
"id": "M3 100m",
"location": {
"easting_m": 199186.0,
"northing_m": 2242285.0,
"terrainHeightAboveSeaLevel_m": 25.555407094778687
},
"heightAboveGround_m": 100.0,
"numberOfDirectionSectors": 12,
"directionForFirstBinCentre_degrees": 0.0,
"turbulenceIntensity": 0.1,
"sectorWeibullParameters": [
{
"probability": 0.076,
"a": 8.1,
"k": 2.43,
},
{
"probability": 0.056,
"a": 7.7,
"k": 2.47,
},
{
"probability": 0.064,
"a": 8.0,
"k": 1.98,
},
{
"probability": 0.060,
"a": 6.8,
"k": 2.33,
},
{
"probability": 0.044,
"a": 6.1,
"k": 2.46,
},
{
"probability": 0.038,
"a": 6.4,
"k": 2.35,
},
{
"probability": 0.048,
"a": 7.1,
"k": 2.72,
},
{
"probability": 0.060,
"a": 8.5,
"k": 2.70,
},
{
"probability": 0.086,
"a": 9.3,
"k": 3.13,
},
{
"probability": 0.235,
"a": 9.6,
"k": 2.49,
},
{
"probability": 0.122,
"a": 9.1,
"k": 2.24,
},
{
"probability": 0.113,
"a": 8.6,
"k": 2.42,
}
]
}
],
"referenceAirDensity": {
...
},
"flowModel": {
"referenceDirections_degrees": [
0.0,
30.0,
60.0,
90.0,
120.0,
150.0,
180.0,
210.0,
240.0,
270.0,
300.0,
330.0
],
"speedsUps": [
{
"locationDescription": "My Turbines T 1",
"easting_m": 199977.0,
"northing_m": 2242510.0,
"heightAboveGround_m": 100.0,
"speedUps": [
1.0028143377131944,
0.9843104548424364,
1.0053479331193076,
1.0394420347586153,
1.0651719619780702,
1.0522770909890518,
1.0135434300400987,
0.9903602988842,
0.99366477336923686,
1.0372414322436432,
1.0633412609252502,
1.052277356798347
]
},
{
"locationDescription": "My Turbines T 2",
"easting_m": 200556.0,
"northing_m": 2242405.0,
"heightAboveGround_m": 100.0,
"speedUps": [
1.0264343439257435,
0.99901760491617708,
1.0096788835406509,
1.0394590287278338,
1.0702136531696893,
1.0699283709532854,
1.0355733800830866,
1.0069336029418576,
1.0005897889837203,
1.0368132112347412,
1.0700066500067467,
1.0699283835514024
]
},
{
"locationDescription": "M3 100m",
"easting_m": 199186.0,
"northing_m": 2242285.0,
"heightAboveGround_m": 100.0,
"speedUps": [
1.0,
1.0,
1.0,
1.0,
1.0,
1.0,
1.0,
1.0,
1.0,
1.0,
1.0,
1.0
]
}
]
},
"energyEfficienciesSettings": {
...
"numberOfDirectionSectorsForWakeCalculation": 180,
"maximumWindSpeedForEvaluation_m_per_s": 50.0,
...
}
}