Issues with "Electricity to battery from System" and "Electricity to/from grid "

Hi There,

I had simulated a (Behind the meter) Detailed PV-Battery Model. The dispatch algorithm was set manual for 4 hours from 7pm to 11pm and charging during the rest of the day. The charging and discharging from the grid is disabled. 

As per the manual discharge set, it works perfectly. 

For charging, I do understand that the default algorithm supports the load first and the excess charges the battery based on C RATE and the maximum charging power. But I find that there is a issue with the charging part. 

The results of the simulation shows that the load is supported first and the excess is shown as being "exported to the grid" and also the battery being charged at the same time. But the as per the simulation numbers,  the excess after the load is shown as the grid export The battery charging power is not subtracted from the grid excess power. Hence the numbers dont match.
This also happens when the PV power is lower than the (load + battery charging power) combined.

My question is why the (Electricity to Grid = Psolar - Pload - PBat)    is not as per the equation. 

But instead (Electricity to Grid = Psolar - Pload ) but at the same time the battery is being charged. This reflects a wrong number, being exported to the grid, for that hour. 

I have attached the simulated results. 

Would appreciate if someone can comment and help on this.

Thanks.

Vinoth 

Hi Vinoth,

We made some improvements to the battery model in SAM 2020.11.29 to address some issues with the way time series power values were being reported. Are you seeing these results in the latest version? You can download it at sam.nrel.gov/download .

Also, if you are modeling a DC-connected system, the new "Electricity produced without the battery or curtailment" output variable represents the power generated by the photovoltaic array and inverter.

Best regards,
Paul.

Hi Paul,

Thank you so much for the response. 

I was apparently using the older version. 

Will try using the newer version SAM 2020.11.29 and simulate again and update further. 

"Electricity produced without the battery or curtailment"  - Noted on this ! 

Appreciate your reply.