Hourly data output?

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Hourly data output?

I am interested in using the hourly data output to compare performance of e.g. a fixed PV system vs. a 1-axis tracker. My particular interest is in the shape of the output curve vs. my local utility's demand curve (which tends to peak a bit after fixed systems peak).

Here's my question: What's the reference frame for the hourly output data, which runs from 1 to 8760 (no leap years, I guess)? Specifically: Does the data for hour 1 correspond to system performance between 12am and 1am on 1 January, local time zone (not daylight-savings adjusted)? And 8760 for 11pm to 12am, 31 December?

Paul Gilman

Thanks for the question.

The reference frame for the hourly output data depends on the reference frame of the data in the weather file.

For TMY2 and TMY3 weather files, there is no leap year or daylight savings, and the first hour is the hour ending at 1 am on January 1. You can read about the time reference frame and more about those file formats at:


Best regards,

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