Understanding Battery Dispatch Outputs

Hi Paul and team,
I am modeling a BTM battery system with the following key parameters:

• Dispatch: Retail Rate Dispatch, and no ($0) Cycle Degredation Penalty
• Electric Rates:  a TOU plan with a period of significantly higher prices each day
• Demand charges:  minimal demand charges

I would expect that these inputs would result in the battery cycling nearly every day (to avoid the high electricity price periods) but this is not what the simulation results show.   Could you take a look to verify the outcome and shed some light on what is driving the (lack of) battery cycling in this scenario? 

Many thanks! 

Hi Mason,

Thank you for sending the file, and for your patience while we investigate this.

There are a couple of things we need to change about the retail rate dispatch option for it to work as you expect. You can track our work on that on GitHub here: github.com/NREL/ssc/issues/1272

We originally implemented this for PV+Storage, and there are some considerations for standalone batteries that we need to address.

Also, in your file, you chose the Buy All / Sell All metering option (on the Electricity Rates page), which effectively assumes that there are two separate meters: One to measure power from the grid to the battery and load, and another to measure power from the battery to the grid. This means that the battery increases the electricity bill (compared to the "without sytem" bill) because power to charge the battery must be purchased at the appropriate buy rate as defined in the energy rates table. Is this what you are trying to model?

Best regards,
Paul.

 

Thank you Paul and team,
To your question on metering and billing, I was simply trying to model a system that did not compensate for any excess energy returned to the grid.  Given your comment, I think net billing with $0 sell price would the the more appropriate option.  To confirm, I still experience the same relative lack of battery cycling as described originally, and greatly appreciate you all checking it out!  

Best,
Mason