Ordering Information:
ORDER NUMBER:  91201
DATE AVAILABLE: Winter 2007/2008

Printed Report		PDF
Subscribers	Order Report	1.4 mb
Non-Subscriber	N/A

Foundation subscribers may order the printed report or download the PDF. Non-subscribers may download the PDF.

PRINCIPAL INVESTIGATORS:
Steven Carlson and Adam Walburger

OBJECTIVES:
This project sought to develop metrics that allow comparison of energy use among wastewater treatment plants and among water utilities. These comparisons normalized away multiple factors such as specific plant configurations or loading that historically made such comparisons challenging.

BACKGROUND:
Sixty thousand water systems and 15,000 wastewater systems account for 3 percent of the national electricity use. Ten percent or more of a utility’s total operating cost is for energy. Managing energy use requires a means to assess how well energy is being used. Tracking energy use over time can be a valuable tool, especially when load and operational influences can be linked to energy use. Furthermore, comparing energy use to peers can be a valuable exercise for motivating improvement, given that peers can be properly identified with load and operational factors.

HIGHLIGHTS:
The project produced scoring methods that allows comparison of energy use among utilities by normalizing away factors that have made such comparisons challenging in the past. The metric implementation provided a context for understanding how much better energy use would need to be to reach a specific target score. This context gave the range in energy use for peers with similar characteristics. Additionally, the surveys provided a rich dataset that captured utility characteristics along with electricity and fossil fuel energy use.

APPROACH:

The project used the following methodology:

• Reviewed literature for existing energy use data and methods of characterizing a utility
• Developed a statistically representative sample of utility energy use and characteristics
• Related characteristics to energy use
• Applied and evaluated a multi-parameter benchmark score method similar to the U.S. Environmental Protection Agency’s Energy Star rating system for buildings
• Reviewed the resulting metric application at sample utilities

RESULTS/FINDINGS:
The project developed a multi-parameter metric including flow, pumping, and distribution characteristics that provide a means to score energy use of water utilities. Sub-metrics that included additional treatment and distribution details can segregate scores for production, treatment, and distribution, when energy use is available at that level.

The project also developed a multi-parameter metric including flow, loading, and treatment processes providing a means to score energy at wastewater treatment plants. A similar metric scores the collection system.

In spite of the vast amount of utility data tracked by regulatory agencies and industry organizations, little industry-wide information about utility energy use beyond total energy financial expenditures existed before this project. Having metrics is a first step in support of active energy management.

IMPACT:
The metrics developed in this project can provide the means to motivate energy management. Low scoring utilities can pursue investigations as to why they score low, which might lead to implementing improvements. High scoring utilities might be identified as a source to investigate for examples of best practices.

MULTIMEDIA:
The report package includes a CD-ROM with the energy benchmark metric score sheets and the raw survey data.

RESEARCH PARTNERS:

• California Energy Commission
• New York State Energy Research and Development Authority

PARTICIPANTS:

• Sheboygan Water Utility and Wastewater Treatment Plant
• Commissioners of Leonardtown
• Yorktown Wastewater Treatment Plant
• Over 580 water and wastewater utilities responded to the survey