Discrepancy, What Discrepancy? Reasons for the Difference between Claimed and Evaluated Savings

摘要

Program cycle-to-program cycle, evaluators find a discrepancy between claimed savingsrnfrom energy efficiency programs and their verified savings. These differences are caused by arnnumber of factors, but which are most important? Which reasons for discrepancy affect thernclaimed energy savings to a large degree, to a smaller degree, and in which direction? Thernrecent 2010 to 2012 California IOU (investor owned utility) custom impact evaluation involvedrnthe analysis of over 400 energy efficiency projects, including gross impact evaluation of savingsrnclaims, representing the IOU-wide custom portfolio. This paper quantifies the energy impact ofrnthe main reasons for discrepancy that were found from the evaluation’s commercial buildingrnenergy efficiency measures, disaggregated by measure type for greater insights into trends byrnenergy efficiency project. In evaluating the gross energy savings claims, we found that therndiscrepancy for each project could be due to a number of factors, including, for example,rneligibility requirements, changes in operating hours, or the applicable baseline. By investigatingrnand quantifying the reasons for the discrepancy, the evaluation community will assist the IOUsrnand their implementers in better assessing projects as they are being developed with respect tornthe highest risk factors. The expectation that the evaluated savings will better match the claimedrnsavings, at least for factors the IOUs can control, will improve the effectiveness of customrnprograms in any jurisdiction where they are in use.