Parametric analysis of PV and battery configurations

Hi,

I'm attempting to determine the most financial beneficial configuration of net metered PV and battery capacity. This will be a municipally owned system, so various tax incentives won't apply. Also, the project is half-funded through a federal grant and the other half is a low-interest loan, so to account for the grant funding I've used a negative value (-65%)for the project contingency in System Costs to arrive a portion of the project cost that is covered by the loan.

I've uploaded the 15-min electric load information, applied the correct utility rate, and have specified a total PV system size of 200 KW and battery capacity of 200 KWh. I want to determine the optimum solar system size and battery capacity combination. In the parametric analysis I used varying battery capacity (0-200 KWh) and varying solar system size (0-1000 KW) as inputs and NPV as the output. When I run the parametric analysis, the NPV output doesn't seem to be affected by the battery size.

If I specify different PV system sizes and battery capacity, does the parametric analysis automatically adjust system cost and financial parameters? Also, because the goal of the battery capacity is to offset electric utility demand charges, does the parametric analysis incorporate the rate information?

Perhaps there's a better way to approach determining the optimum solar PV system size and battery capacity. Please advise.

Thanks,
Dale

Hi Paul,

I had initially tried to set the Investment Based Incentive to 50%, but then SAM financial projections considered the total project cost. The solution you provided me some time ago ended up working for me: "Based on your description, "half grant funded and half low-interest loan," it sounds like this project has no initial cost to the municipality (who installs, owns, and operates the system). In SAM, the IBI percentage applies to the total installed cost, but the debt percentage (on the Financial Parameters page) applies to the total capital cost, which is the total installed cost minus the IBI and debt-related costs. You can see how the capital cost is calculated on the Cash Flow tab of the Results page. I think the way to model the project's cost is to set the total installed cost on the System Costs page to 50% of the actual cost to account for the grant, and to set the debt percent to 100% to account for the 50% debt size."

I assume this is still the best way to set things up.

Thanks!
Dale

Hi Paul, it's looking like a 100 KWh battery system provides the best financial outcome. Is there a way way to identify what parameter(s) has the most influence on battery system size. I assume it has something to do with the utility rate.
Thanks,
Dale