The Loss Breakdown page provides information to identify causes of energy losses in the plant.


Loss Breakdown Summary

Select a time range to show losses over a particular time range.

  • Actual Production: The production is measured at the inverter output over the selected time range.
  • Recoverable Production: Production can be added to the actual production by taking all cost-effective corrective actions over the selected time range expressed in MWh and the percentage of achievable production.
  • Achievable Production: The sum of actual production and recoverable production over the selected time range.
  • Design Max: The maximum production expected from the system over the selected time range if all corrective actions are taken, regardless of whether they are cost-effective (recoverable). This is representative of “perfect” O&M in the sense of taking all possible actions to mitigate DC health problems, soiling, etc., regardless of the cost of action.


Loss Breakdown Details


The Loss Breakdown graph shows actual and expected percentages for each loss category. The expected values depend on how Solar AI was configured and may be based on estimates calculated by a model of the plant, or on contractual performance obligations. The graph also shows recoverable production, the total production that would be recovered if all cost-effective corrective actions were taken.


A single loss category is defined as the amount of AC energy that would be gained at the inverter output if the limitation caused only by that specific category did not exist. For example, soiling losses are not counted at times, if the inverter is already limited by other factors such as clipping or curtailment.

The snow finder algorithm finds and confirms snow events without using external snow data from weather stations. The algorithm uses site temperature and inverter-level performance indicators to find and confirm snow events, generating a daily true or false snow status for each inverter. The algorithm then allows downtime events to be characterised as being due to snow where applicable.


Recoverable Production Waterfall


The Recoverable Production graph shows the production that can be recovered for each corrective action over the selected period. The far left of the graph shows the actual production, and the far right shows the achievable production. Between those two values is the recoverable production for each cost-effective corrective action. The achievable production is the sum of the actual production and total recoverable production.

The Recoverable Production graph shows actual, recoverable, and achievable production attributable to each cost-effective corrective action category.


Loss Breakdown Definitions


Loss Category  

Description / Cause

Tracker (wind)

Wind stowing of trackers

Tracker (other)

Tracker losses, including stowing outside of wind events

Snow

Snow covering photovoltaic modules in the array         

Soiling

Dust and dirt on the array, calculated based on a zone-level assessment of different parts of the array

Shading

Shadows on the array caused by obstructions, vegetation, and intra-array shade

Module Thermal Loss

Effect of temperature on photovoltaic module performance

Down Strings

Outage of strings of photovoltaic modules

Underperforming Strings

Reduced power of strings of photovoltaic modules

Inverter Efficiency

Actual efficiency compared to manufacturer specifications

Inverter Clipping

When an inverter’s DC input power exceeds the inverter’s nominal power rating, the inverter reduces the input power from the array to avoid damaging the inverter. The inverter clipping loss is the array power lost during this process.

VAr Support

Reactive power for voltage control

Night Loss

Night-time inverter power consumption

Inverter Downtime (other)

Reduction in plant power caused by one or more inverters shutting down. Causes of an inverter shutdown include curtailment, snow, inverter failure, and plant outage. Downtime loss can also be caused when the inverter restarts, either due to an automatic trigger or as initiated by an operator.

Nominal Plant Capacity

The difference between the actual and expected plant capacity under nominal operating conditions.

Partial Capacity Loss 

This category considers both AC and DC underperformance cases. On the AC side, the partial capacity losses are mainly related to failure in the power conversion units or MPPTs, while on the DC side, the partial capacity losses can be related, for example, to string disconnections or combiner box failures.

Curtailment

Plant outages and power level reduction