Battery losses during the charging

Hello everybody,

I am modelling a 49 MW stand-alone system with a capacity of 2 hours.

When analysing the results, I have seen that there are high losses when the battery is charging, as it absorbs 25% more energy from the grid than it subsequently discharges. I attach a screenshot of this.



I don't know if this is a common behaviour in battery systems (Can someone explain the typical losses of a BESS?) or if I have misconfigured some parameter (if so, how can i solve it?).
 

I would appreciate your help.

Best regards



 

Hi Antonio,

For the front-of-meter automated dispatch, SAM attempts to charge the battery when the price of electricity is low, and discharge when it is high, taking into account the battery state of charge, and maintaining battery health to minimize battery replacement costs. The following outputs from your file show this behavior:

 

Best regards,
Paul.

Thank you for your reply.

So, is it normal for a 98MWh capacity battery to draw 119.19MWh from the grid to charge 90% of the battery?

Thanks again.

Antonio

Hi Antonio,

The battery voltage model, conversion efficiency and battery loss inputs on the Battery Cell and System page determine how much energy is required to charge the battery.

The voltage model is described in Section 2.1 of DiOrio, N.; Dobos, A.; Janzou, S.; Nelson, A.; Lunstrom, B. (2015). Technoeconomic Modeling of Battery Energy Storage in SAM. 32 pp. NREL/TP-6A20-64641 ( PDF 2.6 MB ).

Best regards,
Paul.