This study, funded by the California Public Utilities Commission, presents the evaluation, measurement, and verification (EM&V) activities for the Commercial Retro-Commissioning (RCx) High Impact Measure (HIM) for the 06–08 IOU/CPUC Program Cycle.
The evaluation comprised 225 projects from more than two dozen programs offered by the four IOUs. Project-level sampling was used for both the net and gross impact evaluations, while projects with a large retrofit component were excluded. Samples were developed with the goal of achieving 90/10 precision at the IOU level, using a stratified random sample based on the ex ante estimates of gross MMBTU savings for each completed project, on the assumption that the ex ante estimates would serve as a good predictor of the associated ex post savings. Results were calculated at the IOU level, across all programs that included RCx projects.
- A gross impact analysis calculated gross realization rates for individual projects and used the results to calculate a mean realization rate for each utility, by savings parameter (kW, kWh, therms). The impact approach was focused on project-level analysis, with site-specific M&V plans for each project, using a combination of engineering analysis and building simulation methods.
- A net analysis utilized the self-report approach developed and applied to all Large Nonresidential measures and programs to calculate a net-to gross ratio (NTGR) to estimate the degree of program influence in the decision to RCx the facility and the extent of free ridership.
- An investigation of effective useful life (EUL) examined selected measures from prior RCx programs, to determine if each measure was still in place, operational, and yielding savings to estimate EULs for common classes of RCx measures.
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