Assess NMEC Approaches for Energy Savings

In response to AB 802, the objective of this study is to develop a viable meter-based program offering for large commercial customers. The legislation and subsequent proceedings and decisions from the CPUC enable Program Administrators to design and implement energy efficiency programs that provide incentives from energy savings that are based on analysis of metered energy use data before and after energy efficiency measures are installed in customer buildings. As a strictly ex-post measurement methodology, through NMEC SCE aims to a) ease the customer burden associated with current Custom program offerings and ex-ante review process b) offer incentives for below-code and traditionally difficult-to-measure savings opportunities and c) embed the evaluation of the program within the design itself, enabling high and pre-determined net-to-gross ratios. SCE will be working with a grocery store to test this alternative pathway for Custom Calculated projects and develop processes to inform the development of this program.

This project involved an application of site-level NMEC in a supermarket. The concept quantified the total EE savings from measures installed in a building based on adjusting the baseline and post-installation energy use to a set of normal conditions. This was accomplished by using empirical models (for example, regressions) developed from energy use and key influencing parameter data (typically weather data). Short-time interval energy use data, combined with more advanced and accurate analytic methods, rendered these savings more discernable at the whole-building level. The assessment objectives were to engage EE PAs and technical reviewers while following the NMEC process and requirements during implementation in an actual building. This would familiarize them with NMEC projects and enable them to address issues, in preparation of more widespread deployment. The project team recruited a supermarket chain to perform an NMEC project at one of their locations in Highland, California. This location was selected because of its high energy use, previously-identified measures affecting multiple systems, and high expected savings. SCE data was available at 15-minute intervals from multiple prior years. In addition, the project team’s corporate office was interested in the meter-based methodology as a comparison with its engineering estimates of total measure savings. Normalized savings for each 12-month performance year milestone (10/15/2018 – 10/14/2021) were computed. It shows the normalized savings achieved during the three 12-month reporting periods compared to the savings expected per the engineering calculations determined prior to measure installation. This approach showed an average of 21.7% more savings than estimated using the engineering calculations. This converts to about $5,576 more in monetary savings per year for the Highland supermarket.