Impact Evaluation and Savings Audit of Avista Demand Side Management Programs
Ecotope developed a comprehensive verification and evaluation of Avista’s primary demand-side portfolio programs, including the non-residential and residential sectors.
What We Did and How
In the Avista non-residential (commercial and industrial) programs the measures used were largely customized to the needs and goals of the participants. Measure savings were developed with simulations or other engineering analysis based on a field review of the individual customers. Ecotope developed a stratified sample of this program. The sample was designed to represent the diverse customers in the program. An Ecotope engineer visited each case and reviewed Avista’s original engineering analysis. Savings were adjusted based on the veracity of the engineering calculations and the observed conditions when Ecotope’s verification survey was done. For the verification sample, Ecotope regenerated most of the engineering calculations including the eQuest® runs developed by Avista engineers for the customers. Savings were adjusted as a result of the review based on engineering simulation, field assessments and/or detailed engineering of the measures installed.
The Avista program also included a multifamily retrofit program. The engineering basis for the program was reviewed and the saving adjusted using a SEEM analysis compatible with the assumptions of the RTF. This analysis was followed by an infield review of a large sample of participants. The multifamily program was a weatherization program administered by a third party. We reviewed the measures installed and compared the results to the filings from the contractor. Adjustments were made both universally based on the engineering assumptions included in the contract specifications and the field verification of the measures at the specific sites.
The single-family program focused on the savings from a customer driven gas weatherization program and a similar program for electric heating customers. In addition, Ecotope conducted a comprehensive review of the low-income weatherization program. The single-family evaluation included several steps:
- Ecotope reviewed the savings estimation procedures used in developing the savings estimates for the regulators. This review employed the RTF analysis for single-family weatherization programs based on the SEEM simulations completed for the 6th Power Plan. This resulted in changes in savings assumptions and calculation procedures (Avista subsequently used these findings to modify their savings calculation for all their single-family programs.
- A small sample was drawn at random for each participant group and Ecotope conducted a field verification of the measure installation and the customer characteristics. This step was important particularly for the gas heated homes as only the installation contractor invoice was used to verify the installations.
- Ecotope then conducted a billing analysis of the entire population of each program. In this evaluation a variable base degree day (VBDD) analysis was developed for each case and a control group was developed for each program. The results of the billing analysis were then compiled using a conditional demand analysis (CDA) based on the characteristics collected on customers during the program.
- Ecotope developed a realization rate for each program and presented to the utility and their regulators. In the case of the multifamily and non-residential sectors, these realization rates were essentially verification rates on the Avista claims for those programs. For the single-family programs, a complete verification rate was calculated from the VBDD billing analysis.