Which year is SAM expecting the consumption data to be input for

When I enter consumption interval data into SAM is it expecting that this represents data for Sunday, 1 January 2012?

The time convention for simulations depends on the time convention of the weather file. For the NSRDB (TMY3, TMY2) files, the convention is for Hour 1 to be the hour ending at 1 am on Monday, January 1.

This is important so SAM can match the price of electricity for a week day with consumption data for a weekday.

Yes, if you are modeling time-of-delivery pricing in SAM, the weather data and load (consumption) data should use the same time convention.

However, the number of hours (8760) indicates that SAM is expecting a non leap year, but 2012 is a leap year, which suggests that maybe it is not expecting the first day to be 1 Jan 2012, but 1 jan on another year. This woudl materially impact our financial analysis.

SAM assumes that the weather file follows the NSRDB convention, and does not include leap years.

Best regards,
Paul.

So if my load data is for 2015 where 1 Jan is a Thursday, how do I tell SAM this so the weekday and weekend Time of Use tariffs line up properly?

4dmoore, Please see my reply to your question in this thread: 
sam.nrel.gov/node/70056
Best regards,

Paul.