New user - help please  



I am trying to model a grid-connected PV plant and adding storage to it, but I am unsure if I am doing the right thing.

1) The utility company uses diesel/hfo generators. Do I add a genset AND Grid to the AC side, or only use one? If I want to compare the cost ngs between using the storage instead of the genset would I then definitely need both?

2) The plant is existing, 28MWpeak and 20MWAC. I think that using 20000 as the upper bound in the Advanced Optimizer option is correct, but I really don't know. (RE is not my field, but I'm doing storage for my thesis)

3) I have randomized outages in the Grid, and I have chosen optimization for the genset dispatch. But I am not sure if I'm even doing these correctly.

4) Any recommendation on how to model the BESS system for bulk services and/or ancillary services. I don't know MatLab but maybe I can be guided with an add-on feature and try to figure it out from there.

I'm sorry for so many questions 🙁 


Hey Jen,

Glad to see you're putting HOMER to good use. I recently did a similar sort of project on energy storage for outage mitigation so I may be able to help you a bit.

1) It sounds like you would want to have the genset and the grid if you wanted to compare them. There will be no issue on the software side.

2) The amount of storage is difficult to say, it depends on a number of factors I'm not familiar with but the general rule is to set the optimizer high for initial modeling and progressively reign in the upper and lower bound over a handful of simulations to find the most accurate figure.

3) What is the primary purpose of your storage? If outages are the priority it can be difficult to model the benefit of ancillary services. There are options under the Grid component if you utilize real time rates that will allow you to modify battery interaction with the grid. This can be helpful in forcing the battery into what you want it to do.

The best way to see what the battery is doing in any given simulation is to click on the optimization result in the bottom window in the results page and click on plot at the bottom of the popup window. From there you can highlight the powerflows you want to assess. This allows you to see how the different energy sources are being utilized in real time.

Let me know if you have any more questions.

- AF


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