Greenbyte Documentation

Time-Based System Availability Inverter

Availability is the extent (in %) to which an inverter is performing its intended services within its design specification. System availability is the overall availability of the device, not taking into account any contracts.

Time-Based System Availability Inverter is calculated for every timestep and is considered available when the inverter’s reference irradiance is above the cut-in threshold and it has AC power greater than 0.

Please note:

  • The cut-in threshold is different if time-based system availability is used to calculate performance. Normally, it is the Availability irradiance cut-in metadata, but for performance, the Performance irradiance cut-in metadata is used.

  • Without irradiance data or power AC (or energy) data, availability cannot be calculated. However, a stop status for the period gives the power value 0.

Technology

Solar: Inverter

Equation
time_based_system_availability_inv_eq1.jpg
time_based_system_availability_inv_eq2.jpg

where:

ATS

is Time-based System Availability

I

is Solar Irradiance Reference

PAC

is Power AC

E

is Energy Export

T

is the device resolution in hours

Cut-inP

is a cut-in to filter out very low power values that actually mean unavailable, a constant set to 0.0001

Cut-in IA

is the Availability Irradiance Cut-In (W/m2) inverter metadata

Cut-inIP

is the Performance Irradiance Cut-In (W/m2) inverter metadata

Inputs
time_based_system_availability_inv_in.jpg
Example

On its own, this calculation can be used to find out how available your inverter is and if it has any periods of unavailability, for instance through Data studio.

time_based_sys_av_usage.png

This calculation is also further used in other calculations, e.g. various lost productions.