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Greenbyte Documentation

Contractual Availability

Production-based Contractual Availability indicates the extent (in %) to which the wind turbine is performing based on the energy produced.

Contractual availability is based on the categories defined in the wind turbine’s availability contract. The contract determines whether the categories should be excluded from the calculation or allocated to either available time or unavailable time.

There are three different types of contracts - service, global, and custom. The respective signals are called Production-based Contractual Availability, Production-based Contractual Availability (Global), and Production-based Contractual Availability (Custom).

This section contains the following information:

Time-based Contractual Availability

The time-based contractual availability gives an indication about the amount of time that a turbine is available to produce energy. This corresponds to the fraction of time that the turbine is fully operational and can generate power. The conditions that should be met to be considered available are defined in an availability contract. There are three different types of contracts - service, global, and custom. The respective signals are called Time-based Contractual Availability, Time-based Contractual Availability (Global), and Time-based Contractual Availability (Custom). These contracts can be used to fulfill different availability conditions. For more information on assigning a contract to a wind farm, see .

Technology

Wind

Remarks

Allocation of available time and unavailable time is based on contract categories. Each category specifies whether the time of a status event should be allocated to available time or unavailable time (or excluded altogether). Contractual categories have a priority, which is used to determine how to allocate the time period when statuses from multiple categories are active at the same time.

Time-based_Contractual_Availability_-_Remarks.png
Equation

The following description exists for each one of the availability signals, according to the contract of that type.

For each time period, the turbine will be seen as Available, unless any one of the following is true:

  • There is an active status, which means that the contract category of the status decides if the period will be seen as Available, Unavailable, or Excluded.

  • There is an uncategorized Stop status and P <= 0, which means that the period will be seen as Unavailable.

  • The status is uncategorized, and neither P nor w has a value, which means that the period will be seen as Excluded.

  • There is no categorized status and w < Cut-inPC, which means that the setting “Windspeed below cut-in“ in the contract defines if the period will be seen as Available, Unavailable, or Excluded.

  • There is no categorized status and w > Cut-outPC, which means that the setting “Windspeed above cut-out“ in the contract defines if the period will be seen as Available, Unavailable, or Excluded.

  • There is no categorized status and P <=0, which means that the setting “No status event and no power output“ in the contract defines if the period will be seen as Available, Unavailable, or Excluded.

Where:

P

is the Power.

w

is the Wind speed.

cut-inPC

is the Power Curve Cut-in.

cut-outPC

is the Power Curve Cut-out.

priority

is the Priority set in the contract for the status category.

Time-based_Contractual_Availability_-_Remarks_2.png

The Time-based contractual availability for the contract type is calculated as the sum of time periods, according to the resolution:

Time-based_Contractual_Availability_-_Equation_2.png

Where:

AT,contract

is the Time-based contractual availability. There is one signal per contract type: AT,contract,service, AT,contract,global, and AT,contract,custom.

Ta

is the amount of time where data is Available.

Tu

is the amount of time where data is Unavailable.

Inputs
Time-based_Contractual_Availability_-_Inputs.png
Usage Example
Time-based_Contractual_Availability_-_Usage_Example.png
Production-based Contractual Availability

The production-based contractual availability uses the same logic as the production-based system availability. The difference lies in the classification of the status codes. This means that not all stops will be considered unavailable. Whether or not a specific status code is deemed to be available or unavailable is dictated by the availability contract you have uploaded to Greenbyte. In most cases, grid stops and predetermined maintenance activities are excluded from this calculation. Let's imagine that this time the turbine was stopped for 30 min due to predetermined maintenance to change the cooling liquid in the power converter at the bottom of the tower. The wind speed during the stop was constantly 7 m/s and then decreased to 5 m/s for the rest of the hour (30min). In this case, even if we are losing energy due to stopping during a time with a wind speed higher than the cut-in wind speed, predetermined maintenance activities are considered available. Therefore, in this case, we will have a production-based contractual availability of 100%.

There are three different types of contracts - service, global, and custom. The respective signals are called Production-based Contractual Availability, Production-based Contractual Availability (Global), and Production-based Contractual Availability (Custom). For more information on assigning a contract to a wind farm, see .

Technology

Wind

Remarks

The calculation for Production-based Contractual Availability can be set to include lost production during available stops in the equation by the corresponding setting on a contract (see equation below for details).

Equation

The following description exists for each one of the availability signals, according to the contract of that type.

Production-based contractual availability is calculated differently depending on the contract setting.

When the contract setting stipulates to Exclude time periods with available stops from the calculation, this formula is used:

Production-based_Contractual_Availability_-_Equation_1.png

Otherwise, all stops and curtailments are counted, and this formula is used:

Production-based_Contractual_Availability_-_Equation_2.png

Total lost production is calculated as:

Production-based_Contractual_Availability_-_Equation_3.png

Where:

AP,contract

is the Production-based Contractual Availability. There is one signal per contract type: AP,contract,service, AP,contract,global, and AP,contract,custom.

Ee

is the Energy Export.

ELP,contract

is the Lost production (contractual), where Et is calculated for unavailable stops Lost Production Contractual (turbine). The Availability signal for each contract type uses the Lost production Contractual for that type, that is, either ELP,contract,service, ELP,contract,global, or ELP,contract,custom.

ELPtot

is the total lost production (both non-contractual and contractual), where Et is calculated for all stops (both available and unavailable).

Epotential

is the potential production, based on the Cascading Potential Power Contractual Cascading Potential Power - Wind. The Availability signal for each contract type uses the Cascading potential power Contractual for that type, that is, either PCP,contract,service, PCP,contract,global, or PCP,contract,custom.

Eactual

is the Energy with fallback Energy or Power with fallback.

A more detailed description:

Production-based_Contractual_Availability_-_Equation_4.png

Where:

AP,contract

is the Production-based Contractual Availability. There is one signal per contract type: AP,contract,service, AP,contract,global, and AP,contract,custom.

Etot+

is the total production, according to the Exclude time periods with available stops contract setting, clamped to the positive part.

ELPD,nc

is the Lost Production Unavailable Non-Contractual

ELP,contract

is the Lost Production - Unavailable - Contractual Lost Production Contractual (turbine). The Availability signal for each contract type uses the Lost production Contractual for that type, that is, either ELP,contract,service, ELP,contract,global, and ELP,contract,custom.

ELPD+

is the Total downtime - Unavailable - loss, clamped to the positive part.

Ats

is the Time-based System Availability.

Epotential+

is the potential production, clamped to the positive part.

Eactual+

is the Energy with fallback Energy or Power with fallback, clamped to the positive part.

Ee+

is the Energy Export, clamped to the positive part.

Pcp,contract

is the Cascading Potential Power Contractual Cascading Potential Power - Wind. The Availability signal for each contract type uses the Cascading potential power Contractual for that type, that is, either PCP,contract,service, PCP,contract,global, or PCP,contract,custom.

T

is the device resolution in hours.

Inputs
Production-based_Contractual_Availability_-_Inputs.png
Usage Example

An example of a contract, where the Exclude periods with available stops setting is turned on:

Production-based_Contractual_Availability_-_Usage_Example.png