case studies: pacific gas & electric

Measuring Savings from Whole-Building Retrofits

Many utilities and other organizations are trying to find the most reliable and least expensive way to measure energy savings from wholebuilding retrofits. These retrofits encompass investments in many building systems, equipment, and operating practices. Pacific Gas and Electric ran a pilot program to explore how these measurements might be accomplished and to understand the pros and cons for various methods. They hired SBW to provide a comprehensive assessment of this pilot effort.

The demonstration comprised 12 medium-sized commercial buildings: five grocery stores, six office buildings, and a library. The participants implemented a variety of efficiency measures including retrofitting lighting and HVAC equipment and improving controls settings.

The pilot relied on International Performance Measurement and Verification Protocol IPMVP – whole building approaches, to estimate savings, namely Options C and D. The Option C approach is a regression analysis of building energy meter data against independent variables, such as weather. The Option D approach applies calibrated physics-based simulation of building energy use. Proprietary and public domain tools for Option C were compared to each other and to an Option D model implemented in eQuest for each building.

Our investigation concluded that to achieve transparency the Option C method should be implemented with open-source tools and that the Option D method was too expensive. Follow this Link for more details on our methods and findings.