Losses

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In this document

You will learn how to incorporate your installation’s cabling losses into the design and how to configure auxiliary, degradation, environmental, and unavailability losses for your PV energy system.

Cabling and system losses settings

Cabling and Losses sections let you examine the default losses added to the design and change them if required. They are located within the Energy system section in the main menu.

Cabling losses

Available settings

  • DC cable losses

  • AC losses after inverter

  • AC losses after inverter transformer

Cabling losses can significantly impact the system’s efficiency. Therefore, they must be included in the calculation for higher simulation accuracy. Their values in the energy system designer are represented in percentages.

You can change the default cabling losses in the Cabling section.

  1. Adjust the default values for different cabling sections as required.

  2. The connection diagram helps you visualize the connections between components with numbered cable types for better identification.

Tip: You can examine the impact of cabling loss on overall system performance in the Evaluate Analytic’s PV system losses section.

System losses

In this section, you can examine and edit various system losses, such as degradationauxiliaryunavailability, and environmental losses. They are located in the Losses category.

  1. View and adjust any default values as required. Scroll down to reveal further parameters.

  2. The values you have changed will have a “back” button to revert changes to the default.

Auxiliary losses

Available settings

  • Input method

  • Day constant losses

    • From inverter power threshold

  • Day proportional losses

    • From inverter power threshold

  • Night constant losses

Auxiliary losses refer to the energy consumed by auxiliary systems and components in a solar power system that do not contribute to the primary energy output, impacting overall efficiency and performance.

The auxiliary losses can be set in percent or kW. Select the preferred method based on the required inputs.

Auxiliary loss

Description

Day constant losses

Represents fixed energy losses that occur during the day, regardless of the system's output level.

  • From the inverter power threshold

Refers to energy losses incurred when the inverter operates below the power output threshold, directly related to day constant losses.

Day proportional losses

Indicates energy losses that vary with the system's power output, increasing as the inverter generates more electricity.

  • From the inverter power threshold

Describes losses associated with inverter performance under varying load conditions during the day, directly linked to day proportional losses.

Night constant losses

Accounts for fixed energy consumption during nighttime when the system is not generating power

Degradation losses

Available settings

  • Degradation first year

  • Annual degradation

Degradation losses refer to the gradual reduction in solar panel efficiency over time due to various factors, leading to decreased energy output as the materials in the panels wear down. Default degradation values are added to the system. If you have detailed degradation data from the manufacturer, you can overwrite the default values for higher accuracy.

Degradation loss

Description

Degradation first year

Refers to the initial loss of efficiency that occurs during the first year of a solar panel's operation, primarily due to light-induced degradation (LID).

Annual degradation

Represents the ongoing reduction in solar panel efficiency that occurs each subsequent year after the first, typically at a consistent rate.

Environmental losses

Available settings

  • Snow losses

  • Soiling losses

Environmental losses refer to the reduction in solar energy output caused by external factors such as snow accumulation and soiling from dust, dirt, or debris on the solar panels, which obstruct sunlight and decrease efficiency.

Default soiling and snow loss values are added to every design upon creation. You can adjust these using the respective “Edit” link. The method by which the losses were applied is indicated for each chart (default, manual, Solargis model).

The designer also offers more accurate simulation of soiling and snow losses using our proprietary soiling and snow loss models. The estimation considers the solar resource data specific to your location and the configuration of your energy system, delivering more precise and location-specific results compared to using default values.

Environmental loss

Description

Snow losses

Refers to the reduction in solar energy output caused by accumulated snow covering solar panels, which obstructs sunlight and decreases efficiency.

Soiling losses

This represents the decrease in energy output due to the accumulation of dust, dirt, or debris on solar panels, blocking sunlight from reaching the photovoltaic cells.

Simulating snow and soiling losses

Important: Please be aware that soiling and snow simulations are available only after the initial project data generation (project activation).

As previously mentioned, the energy system designer lets you simulate the snow and soiling losses using the respective models:

  1. Click the “Edit” link of the respective loss you want to estimate and switch to the “Solargis model” tab.

  2. Click “Simulate Soalrgis model” and wait for the result. The respective estimated loss will be calculated and displayed.

  3. Click “Apply” to apply the losses to the system design, or set your cleaning events first, re-simulate, and then apply the changes.

Note: If you want to add soiling or snow losses manually without using the Solargis model simulation, you can do it in the Manual tab. You can use up/down arrows to manually adjust the values.

Adding cleaning events

You can set your cleaning events based on your planned cleaning schedule, or you can plan your cleaning based on the Solargis model simulation (spotting the months where it is needed the most):

  1. While in the respective loss edit mode, select the months you want to schedule cleaning.

  2. Simulate the Solargis model to apply the cleaning events to the model calculation.

  3. Save and apply the changes to the design by clicking the “Apply” button.  

Important:

  • Any change to snow/soiling losses or system configuration requires re-simulation to update results.

  • Changing configuration invalidates existing snow/soiling loss data; the system will notify you during validation.

  • Simulations cannot run with invalidated snow/soiling losses unless you switch these losses to Manual mode.

Unavailability losses

Available settings

  • Internal (yearly)

  • External (yearly)

Unavailability losses refer to the reduction in energy output due to periods when the solar power system is not operational, which can be classified into internal losses caused by equipment failures or maintenance and external losses due to factors like grid outages or environmental conditions.

Unavailability loss

Description

Internal (yearly)

Refers to the energy loss due to system downtime caused by internal factors such as equipment failures, maintenance, or operational issues, impacting overall energy production annually.

External (yearly)

Represents the energy loss due to external factors such as grid outages, environmental conditions, or regulatory constraints that lead to periods of unavailability in the solar power system over the course of a year.