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The Bonneville Power Administration (Bonneville) provides wholesale electric power to over 100 retail distribution utilities in the Pacific Northwest. Bonneville is faced is meeting growing loads from these utilities. It acquires conservation as one means of meeting this load growth. Bonneville has offered a variety of conservation programs since 1980. Efficient showerheads have been a feature in residential conservation program ever since. Bonneville launched the Residential Appliance Efficiency Program to focus on water-heater energy conservation opportunities in 1992. The Residential Appliance Efficiency Program consists of two parts, a water-heater efficiency program, and a hot-water efficiency program. This report evaluates the savings and costs of the first two years of the showerhead portion of the Residential Appliance Efficiency Program (the showerhead program). Although it is not a formal evaluation of the program limited to implementation or a "process" evaluation, observations about program design and implementation are included as appropriate. Results of this evaluation are limited to program participation within the Bonneville service territory.

The showerhead program design was more innovative than most Bonneville programs, because it provided utilities with a menu of program delivery options instead of a single, prescribed program design. This approach was adopted to increase utility acceptance of the program and the associated conservation acquisition goals. In addition, the program included a variety of brands and models of efficient showerheads and faucet aerators. The end result was a program that followed several paths to achieve installation of a variety of conservation measures, each of which performed differently. This variety significantly complicated program evaluation due to variations in measure installation from each delivery path and savings from each showerhead model. The complex nature of the program resulted in a program evaluation approach that continued to evolve during its implementation.

Initially, the evaluation approach was based on an engineering model of showerhead savings that included a number of behavioral variables, such as number of showers per household member and shower length. Bonneville contracted with Pacific Northwest Laboratories (PNL) to conduct a field study to verify the assumptions Bonneville used in its engineering model. The results of the field study called into question both Bonneville's initial assumptions and the usefulness of an engineering model that relied heavily on occupant data, which is highly variable, difficult to obtain, and often unreliable. This launched a series of related studies to explore various facets of hot-water use and energy savings ultimately resulting in a new engineering model for evaluating the program. The final program evaluation algorithm relies on the relationship between monitored energy savings from the program and conditions that vary from site to site, such as water pressure and retrofit showerhead performance. This model provides a more reliable means for estimating program savings because site conditions are easier to measure, more stable, and can be supplemented with laboratory studies to project program savings.

During its first two years the showerhead program achieved the following:
  • Attracted 557,482 participants.
  • Distributed almost 2 million measures, including over 500,000 showerheads.
  • Acquired savings over the next 12 years of 859,020 MWh of electricity.
  • A program cost to Bonneville of 18.4 million dollars (4.8) was for measures and nearly 13 million was for installation costs and incentives to participants and utilities.
  • Energy Savings at a real, levelized cost of about 39 mills/kWh, or 3.9 cents/kWh, which is within Bonneville's cost-effectiveness criteria.
  • Reduced showerhead flow rates an average of .9 gpm and energy use was 337 kWh.
  • First year savings included an estimated 153 kWh savings per house due to a regionwide drought. Thus, net energy savings averaged 184 kWh the first year, in homes where all showerheads were replaced. Only half of the energy savings were obtained when participants were required to install measures themselves.
  • Projected savings at each participant's site totaling an average of 1,541 kWh over 12 years, or average 128 kWh per year once measure persistence is considered.

In addition to these significant energy savings, the showerhead program was also among the most popular Bonneville every offered, in terms of the number of utilities who offered it and consumers who participated. The innovative program design complicated the final evaluation; however, the evaluation approach may significantly reduce the cost and time involved in other program evaluations and permit cost sharing through collaborative effort. This approach relies on small-scale, in-depth field studies to fully explore energy-savings dynamics and the development of models of energy savings that can be adapted to a wide variety of conditions using local data. This contrasts with the most current evaluation approaches that require expensive customization of evaluation methods for each utility or extensive data collection and analysis. These conventional approaches may not be cost-justified in a more competitive utility environment.

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