System losses

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System losses

Hi Paul,

I have simulated a PV-battery system in SAM. After simulations it generates as a result the following losses: AC inverter efficiency loss (3.1%), AC connected battery loss (1.25%) and Inverter power consumption loss (1.2%) and System energy losses (17400 kWh/year). In addition, the Tab Losses in the results section give some compound losses: soiling (5%) and module (7%).

What is it mean the losses in percentage? From the total system losses 3.1% is lost through the inverter efficiency, 1.25% is due to the battery losses, and so on? Or it represent annual daily mean losses?

Thank you advance.

Giovani Dávi

Paul Gilman

Dear Giovani,

SAM calculates those loss percentages to display in the diagram on the Losses tab. The losses are annual values, and the percentages apply to annual totals. They are meant to make it easier to compare different sources of losses and to identify the largest sources of losses in your system design.

For example, your results suggest that relatively more power is lost from converting DC power from the photovoltaic array to AC through the inverter than converting battery power between AC and DC.

The AC losses (AC battery loss, AC wiring, transformer loss, and AC availability and curtailment) apply to the gross AC energy value.

Please see these posts for related discussions:

Best regards,


Ok Paul. Thank you very much.

Best regards,

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