Hi Phil and Steve,

Thank you very much for your responses. I really appreciate you spending time sharing your insights.

Steve, your experiment seems very interesting. I would have to think more about the impact of these measurements on the portfolio FSU.

Phil, your explanation is very clear and helpful. To clarify, yes, my intent is to know the expected FSU for a portfolio of 100 sites. However, with your explanation above, I think I understand and now what to do for my analysis. So thank you very much.

Though there is one more issue I would like to raise. Ideally, my team is hoping to eventually move toward using hourly data. However, since uncertainty for hourly method is a tricky subject, we are planning to use daily method FSU to gauge uncertainty. My question is from your experience, do you expect FSU to decrease as we move from billing to daily method for the same site? That has been my assumption since the beginning as we have more granular data when using daily method, thus I would expect non-fractional uncertainty to decrease. However, when I conducted testing on 1 site using hourly, daily and billing method, metered savings results seem to be within acceptable range but FSU results seem to contradict my assumptions. I have significantly larger non-fractional and fractional savings uncertainty when using daily method. Do you have any suggestion or thought on this matter?

Thank you very for your help!

-Nhi