Screening Tool for Energy Evaluation of Projects

A Reference Guide for Assessing Water Supply and Wastewater Treatment Systems

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• Publisher: Asian Development Bank
• Year: 2021
• Print ISBN: 9789292627348
• eBook ISBN: 9789292627355
• Topic: Technology & Engineering
• Subtopic: Environmental Management
• Index: Technology & Engineering

The Screening Tool for Energy Evaluation of Projects (STEEP) is designed to help improve energy use efficiency in water and wastewater treatment systems. This publication provides a detailed overview of STEEP and guides users on how to apply it during energy use assessments of proposed or existing water supply and wastewater systems. Since 2017, STEEP has been under continuous development based on pilot assessments carried out in various projects financed by the Asian Development Bank. STEEP is available online and can be downloaded for free.

1 INTRODUCTION

1.1 Screening Tool for Energy Evaluation of Projects Explained

Water supply and wastewater treatment services are basic but critical utilities that have major roles in supporting social and domestic needs of people, sustaining local economic activities, and ensuring healthy urban environments. By 2050, about 65% of the population in Asia and the Pacific are expected to live in cities. This dictates the need to increase access to water supply and wastewater management services. The increase in service coverage would also translate to additional investments by water utility operators, which will lead to increased energy demand in their operations. This means energy management should be incorporated into the designs of urban water supply and wastewater utility investments to ensure optimal operations.

The Asian Development Bank (ADB) has an extensive portfolio of water supply and wastewater investment projects in its developing member countries (DMCs) in Asia and the Pacific, and the number of these projects has steadily increased annually since 2010. Out of ADB’s average annual investments of about $2 billion under the water and other urban infrastructure services projects, 40%–60% are on water supply and wastewater investment projects. These investments focused primarily on the quantity (supply, nonrevenue water, etc.), duration (continuous service), and quality (water quality, health, etc.) of service to improve livability conditions of communities in cities and towns in the region. However, due to rapid urbanization, statistics showed that countries in Asia and the Pacific generate approximately 40% of the world’s greenhouse gas (GHG) emissions.¹ It should be noted that this incidence is determined without yet any consideration on the energy use or possible GHG emissions from water supply and wastewater system facilities.

A number of computer-based tools have been developed to support energy assessments, such as Sigma software and AWARE-P. These are also designed to support the International Water Association’s Performance Indicators for Water Supply Services.

Given its decades of experience in designing and implementing water supply and wastewater management projects, ADB has also embarked on developing a computer-based tool for energy evaluation of urban water supply and wastewater management projects called the Screening Tool for Energy Evaluation of Projects (STEEP).

STEEP is a free Excel-based reference guide that can be used to make system assessments and identify potential areas for energy use savings in existing or planned water supply and wastewater facility projects. Since 2017, STEEP has been continuously developed based on lessons and experiences from pilot assessments carried out in various water and wastewater investment projects financed by ADB.²

Based on the results of pilot assessments and accepted principles of energy management, the potential energy savings can range from 20% to 80%, depending on the type and stage of project implementation. Table 1 presents the range of savings and possible sources in water supply production and wastewater treatment system facilities based on the pilot assessment conducted.

Table 1: Possible Sources and Range of Savings in a Water Supply and Wastewater Treatment System

System Source for Potential Savings	Range of Savings
Operations	5%–30%
Mechanical systems	5%–20%
Process	5%–30%
Electrical systems	5%–20%
Use of advanced technology	10%–30%
Use of smart management systems	10%–25%
Reduction of physical losses	5%–50%

Source: Asian Development Bank.

Importance of Energy Screening

Energy Utilization in Water Utility Operations

Energy use, or simply consumption, occurs at many points within the domestic water cycle (Figure 1). Accepted benchmarks indicate that the average energy intensity (specific energy use) for water extraction, treatment and distribution, and wastewater collection and treatment typically range from 0.5 to 0.6 kilowatt-hour per cubic meter (kWh/m³). It is worth noting, however, that the energy intensity for specific systems varies depending on different factors. For water supply systems, these may include water source type, physical terrain of the facilities’ location, and water quality parameters. For wastewater management systems, the factors affecting energy intensity include environmental discharge requirements, type of treatment, bioresources management, and physical terrain of the facilities’ location.

Figure 1: Water and Wastewater System Energy Utilization

kWh = kilowatt-hour, m³ = cubic meter.

Source: K. Bijl, ed. 2015. Innovative Energy Recovery Strategies in the Urban Water Cycle. Final Report Innovative Energy Recoveries Strategy (INNERS) Project. Zwolle.

Lessons and Experiences from STEEP’s Pilot Activities

Under the guidance and leadership of ADB’s Urban and Water Sector Groups, STEEP is continuously being improved since the initial pilot assessment in 2017. ADB’s Pacific Department was the first to run a pilot test of the tool’s applications and assess potential system energy savings in their water supply and wastewater treatment projects. The results showed potential energy savings (or energy production plus energy savings) ranging from 20% to over 50%, compared to the energy use or production of the existing system facilities. Follow-on system assessment exercises were also done for selected projects in ADB’s Central and West Asia Department and East Asia Department.

The energy production associated with water and wastewater system facilities in ADB’s DMCs were assessed in these pilots. Results showed that the total energy use of existing water and wastewater systems exceed 90 billion kilowatt-hours (kWh), and more than 64 million tons of carbon dioxide (CO₂) are produced annually. The recorded CO₂ is approximately 1% of all global emissions. This amount of annual emissions is expected to go up significantly as the water and wastewater coverage in the countries improve and will then increase to more than 2% of the total emissions generated. Section...

Table of contents

• Front Cover
• Title Page
• Copyright Page
• Contents
• Tables, Figures, and Box
• Acknowledgments
• Abbreviations
• 1. Introduction
• 2. The STEEP Evaluation System
• 3. Opportunities for Energy Savings in Water Supply and Wastewater Treatment Utilities
• 4. Results from the Assessment of Pilot Cases on Using STEEP
• Appendixes: STEEP Sample Worksheets
• References
• Footnotes
• Back Cover