Battery Financials

Hi Paul,

I'm a little confused on how best to interpret the battery financial results. Some of the results are presented as present values for electricity costs, capital and O&M. Since those are all the costs I would expect that I could subtract the PV+Battery present value total costs from the No System present value total costs and arrive at the same net present value as given on the summary screen in the normal outputs from SAM. Unfortunately I can't replicate that number given the outputs from the battery financial summary.

Can you assist? I've attached an image to show you what I'm seeing.

Best,

Nathan

Hi Nathan,

The net present value shown on the metrics page is based on the project after-tax cash flow, and as such accounts for both project costs and benefits. It includes not only capital, maintenance, and replacement costs, but also electricity bill savings, debt, taxes, and incentives. The NPV is positive when benefits over the project life are greater than the initial investment, and negative when the reverse is true.

The present values calculated by the Battery Financials macro are of annual costs only: capital, maintenance, replacement, and electricity bill costs. Those present values are always positive. They are meant to give an indication of the relative cost of providing electricity to the building with no system, a PV-only system, and a PV system with battery, ignoring electricity bill savings, incentives, and other benefits.

Best regards,
Paul.

Thanks! That makes sense, I was just confused by the header for that category.