Availability chart | mc Help Center

Last modified: 2026-06-19

Previously, the chart was called: System availability.

Chart

View the chart at System level in the Evaluation tab in the Section: System KPIs.

Basic info

Description	System availability is the percentage of a system that is available over a period of time. It is an indicator of how quickly faults are identified and remedied.
Prerequisites	Actual energy term `E_Z_EVU` is defined. See Terms. Plane of array irradiance/POAI term `G_M0` is defined. See Terms. Or POAI is derived from satellite data.
Further details	Calculation The smallest period of the availability calculation is one day. Within one measurement interval, the entire system is either available (100%) or not available (0%). If the energy is not equal to 0 within an interval, the availability is 100%. Intervals in which energy data is missing are treated as if the system is available. Editable calculation parameters With the VCOM module KPI editor, you can adapt the calculation parameters to your needs. See System availability with the KPI editor. Without the KPI editor, the standard formula is used. Standard formula The following availability formula is used by default: Default system availability formula With the default formula, availability is only calculated during intervals where POA irradiance is greater than 100 W/m².

Description

System availability is the percentage of a system that is available over a period of time. It is an indicator of how quickly faults are identified and remedied.

Prerequisites

Actual energy term E_Z_EVU is defined. See Terms.

Plane of array irradiance/POAI term G_M0 is defined. See Terms.

Or POAI is derived from satellite data.

Further details

Calculation

The smallest period of the availability calculation is one day.
Within one measurement interval, the entire system is either available (100%) or not available (0%). If the energy is not equal to 0 within an interval, the availability is 100%.
Intervals in which energy data is missing are treated as if the system is available.

Editable calculation parameters

With the VCOM module KPI editor, you can adapt the calculation parameters to your needs. See System availability with the KPI editor.
Without the KPI editor, the standard formula is used.

Standard formula

The following availability formula is used by default:

With the default formula, availability is only calculated during intervals where POA irradiance is greater than 100 W/m².

Note

Find further information on the general functions within charts under Evaluations & charts.

Sample calculation

The following sample calculation is based on the standard availability formula:

Interval	POA irradiance (W/m²)	Energy (kWh)	Result
I1	90	10	Not rated
I2	125	20	100%
I3	200	30	100%
I4	80	0	Not rated
I5	250	0	0%
I6	200	NULL*	100%
I7	150	30	100%
I8	130	20	100%
I9	110	0	0%
System availability			5/(5+2) = 71.4%
*NULL means no data available for this interval.