Analytics Portfolios are run for older programs or where we have more than a year of post-project data, we call that a Backcast. In Analytics Portfolios we are calculating savings for a program completed or well underway.
This differs from Tracking Portfolios where we have a model of baseline usage and then project model forward in the time after the project.
If, for example, a project started in January and now it’s March, we’ll project for a Tracking Portfolio, the savings from January through March. For Analytics Portfolios, we take a year of data pre project and a year of data post project and then we build a model of both of those. We then calculate a “Normal Year”, which is a compiled set of weather data considered to by “typical”. Data from 1980 to 2010 is used, and they took all the Januarys and picked the most normal looking January, and did the same for each month. We then project the baseline and reporting usage onto that normal year. What the energy usage would have been during that “normal year” for the pre and post periods. That gives us an estimate of what the savings would have been if the weather had been normal.