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Greenbyte Documentation

Resource Index (Cascading)

This section includes information about the following:

Resource Index (Turbine)

Resource Index for a wind turbine provides a measure of the windiness for some time. Wind speed is transformed into power using the turbine default power curve(s) and current values are compared to a historical or budgeted value.

The primary source of wind data is from meteorological historical data (usually ERA-5) if there is such a virtual met mast installed on site. As a fallback, the potential power based on the wind budget Long Term Wind is compared to the actual potential power for the turbine Potential Power Default PC (Manufacturer PC).

Technology

Wind

Remarks
Equation
Resource_Index__Turbine__-_Equation.png

Where:

RI

is the Resource Index (Turbine)

RIhistorical

is the Resource Index (historical wind)

RILTW

is the Resource Index (long term wind)

Avgp(x)

is the average of x for the period P

Avgpp(w)

is the average PC(w) for the wind speed w and the period P

Avgpp20y(w)

is the average PC(w) for the wind speed w and period P for 20 years historical data in the same date span as P, including period P

wmetmast

is the met mast wind speed

wLTW

is the Long Term Wind wind speed

Pp,MPC

is the Potential Power Manufacturer Power Curve (Default PC)

Inputs
Resource_Index__Turbine__-_Inputs.png
Usage Example

Best visualized in Daily or Monthly resolution, as the comparison with a 20-year historical average makes more sense the bigger the averaged period. In case the fall back to the wind budget is used, that is entered every month, so it will be difficult to draw any conclusions from daily values.

Resource_Index__Turbine__-_Usage_Example.png
Resource Index (Long-Term Wind)

Resource Index (long-term wind) measures the windiness relative to the budget, or “Long Term Wind”. Wind speed for the current period is measured by the wind turbine. The signal shows wind speed for the current period, converted to power using the manufacturer power curve, compared to potential power based on long-term wind for the same period.

Resource Index (Long Term Wind) = Current potential power / Potential power based on long term wind

Technology

Wind

Remarks
  • Resolution signal. Aggregating data

  • There is no minimum resolution, but since long-term wind is entered month by month, that is a logical minimum.

  • This is a helper signal.

Equation
Resolution_Index__Long-Term_Wind__-_Equation.png

Where:

RILTW

is the Resource index (long term wind)

Pp,MPC

is the Potential Power Default PC (Manufacturer PC)

Pp,LTW

is the Potential Power (long term wind), using the Manufacturer Power Curve

Avgp

is the average Potential power in period P

PC(w)

is the look-up function on the manufacturer power curve

wLTW

is the Long Term Wind wind speed Long Term Wind

wPC

is the powercurve wind speed

Inputs
Resolution_Index__Long-Term_Wind__-_Inputs.png
Usage Example

This section will be updated later.

Resource Index (Historical Wind)

Resource Index (historical wind) measures the performance of the weather conditions. Weather conditions (wind speed) are monitored by the met mast on-site, preferably a virtual (ERA5) met mast with historical meteorological data. The signal shows wind speed for the current period, converted to power using the manufacturer power curve, compared to the historical wind speed for the same period.

The potential power used provides how much power a wind turbine should theoretically be able to output based on the manufacturer's power curve. There it uses the met mast wind speed with the earliest start time.

Resource Index (Historical Wind) = Current potential power / Average potential power 20 years back

Technology

Wind

Remarks
  • Resolution signal. Aggregating data

  • The minimum resolution is Days.

  • Since wind speed may take many values not specified in the manufacturer power curve, the two best fitting power values around the wind speed are used for linear interpolation. As such, for a power curve with wind speed increments of 0.5, a look-up on 7.1 will be interpolated using the provided values for 7.0 and 7.5.

Equation
Resource_Index__Historical_Wind__-_Equation.png

Where:

RIhistorical

is the Resource index (historical wind)

Pp,historical

is the Potential Power (historical wind), using the Manufacturer Power Curve

Avgp

is the average Potential power in the period P

Avgp20y

is the average Potential Power in 20 years of historical data in the same date span as P, including period P

PC(w)

is the look-up function on the manufacturer power curve

wmetmast

is the met mast wind speed

wPC

is the power curve wind speed

Inputs
Resource_Index__Historical_Wind__-_Inputs.png
Usage Example

Best visualized in Daily or Monthly resolution, as the Potential Power Historical Wind is only fetched for daily values for performance reasons.

Resource_Index__Historical_Wind__-_Usage_Example_1.png

And for several months, in Monthly resolution.

Resource_Index__Historical_Wind__-_Usage_Example_2.png

It’s worth noting that comparing the monthly average for the last 20 years can give more meaningful insights than a specific day, as the wind speed can vary greatly over such a short period.