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Best Practice Guide |
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Local Governments |
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Water UseWaste Water
Municipal water supply and wastewater treatment systems account for about 35 percent of energy used by municipalities. Water and wastewater treatment and distribution in the United States is estimated to consume 50,000 gigawatt-hours - costing over $4 billion annually. Source: American Council for an Energy-Efficient Economy Water and wastewater agencies rely on electricity to pump, treat and distribute water. Pumping alone accounts for 5 percent of the state's peak load and 7 percent of California's total electricity usage - high-level use that comes with a cost. As California's most significant energy users, water distribution or wastewater treatment facilities can each spend more than $500 million annually on energy, a figure that represents 50 to 75 percent of an agency's total costs. To avoid the adverse effects of both rate hikes and rolling blackouts - which can have severe environmental and health impacts for the surrounding community - many water and wastewater districts have enacted conservation and efficiency measures. Measures include adjusting operation schedules, increasing water storage, utilizing generators, optimizing cogeneration and installing efficient water system equipment, variable frequency drives, and advanced equipment controls. While treatment and pumping consumes the most energy, some agencies greatly benefit by auditing and upgrading building shells, heating, ventilation, air-conditioning and lighting systems. Some of these projects require a large investment in time, personnel and money, but the energy savings realized by the districts more than pays for the improvement. Flex Your Power has worked with roughly 250 water and wastewater agencies to conserve 15 percent within their own facilities. Aided by federal, state and utility agency incentives, many water distribution and wastewater treatment facilities have improved the efficiency of the facilities and water systems. There are several steps to consider when cutting energy costs associated with wastewater treatment. Step 1: Gather DataConduct a water system audit, energy audit and/or technical engineering analysis of facilities to identify the areas of greatest need as well as the most cost-effective energy saving opportunities. Monitor energy use and consistently look for ways to improve energy efficiency. Perform comprehensive energy audits and hire consultants to help staff operators and engineers review IEUA's energy centers. The review might consist of power readings and investigating conservation and self-generation options. Each plant and process (primary, secondary, and tertiary) can be evaluated on a case-by-case basis. Consultants, operators and engineers can assess the energy consumption of each plant and identify those that could potentially be run at off-peak hours. With the help of consultants and the engineering department, operators can learn to improve plant operation, collect more relevant data and design new projects. Consider hiring outside contractors to help conduct an on-site, pre-project inspection of your facilities. The contractors can gather power and monthly kW and amp readings from monitors and chillers, audit the HVAC systems - including performing a chemical analysis of the HVAC water systems and gathering data from the HVAC water pumps. Research cost-effective, energy-efficient treatments to determine the least costly technology for capital and annual Operations and Maintenance at your facility. Prior to beginning an energy conservation project, you may want to internally analyze your past energy use and costs. Identify existing energy conservation practices; identify critical systems and components receiving electrical power; determine duration of required operations time during loss of power; and contact industry peers, power specialists, suppliers, engineers, regulators, etc to poll what others are doing. Collect data through audits, surveys, and face-to face discussions. You may consider hiring an advertising firm to coordinate focus group research to test public outreach messages to encourage water and energy savings. For a "How to" guide on hiring an energy consultant/auditor, energy services company or a construction manager, see the California Energy Commission's handbook on
How to Hire an Energy Auditor to Identify Energy Efficiency Projects For assistance in planning and designing energy projects, including an initial free feasibility study, see the California Energy Commission (CEC)’s Energy Partnership Program. Step 2: Devise a PlanBuild an “Energy Team” comprised of department managers and engineers to guide and promote energy efficiency/conservation within and outside your organization. Appoint a coordinator to lead the team in designing, communicating and implementing projects. Based on a careful review and analysis of the research gathered in Step 1, define the targets, objectives and quantifiable goals. Identify short-term goals for energy efficiency and discuss the assumed need, the most cost-effective practices, the staffing requirements and the community response. After a review of your facilities, perform white paper assessments of operational needs. Help prevent rolling blackouts and ensure water supply in spite of external power interruptions. Include engineering, operations, maintenance, HVAC, and public information staff in designing and implementing your programs. You may also want to consider a Green Infrastructure plan to alleviate strain on the energy system from intensive water treatment. See the EPA’s webpage on Green Infrastructure for more details. Identify feasible energy conservation measures for the existing facilities and find the most cost effective treatment of wastewater. Apply for financial rebates/grants when possible. Utilize online resources for help in planning and designing energy efficiency, conservation and outreach projects: Use online resources. Utilize online resources for help in planning and designing energy efficiency, conservation and outreach projects: Research funding options and set a budget. Local utilities and state agencies offer a wide range of incentives to underwrite energy-conserving behavior and investments. Negotiate with natural gas providers for the best price possible for long-term natural gas contracts. Reduce on-peak demand at your water recycling plants by running generators more often. To learn more about utility services and rebate and incentive programs, check with your local municipal utility or contact: Pacific Gas & Electric (PG&E) Set a timeline. Target behavioral changes for faster and easier energy savings. Timelines should take into account budget, rebate and grant qualifications and peak demand times. Step 3: Implement Programs/OperationsEfficiency Maintain water/wastewater system equipment. Test, clean and upgrade pumps and pipes as well as disinfection and control system equipment. Increasing maintenance activities will reduce power consumption. Upgrade motors - install energy efficient models. Although sometimes higher in cost, energy-efficient motors are two to eight percent more efficient than standard motors, have longer insulation and bearing lives, lower heat output, less vibration and lower failure rates. Retrofit pump drives or install a more efficient pump with a Variable Frequency Drives (VFD) to act as the lead secondary pump. Unlike single speed drives, VFDs have a soft start and allow for precise control of motors and process, thereby extending the life and enhancing the efficiency of motors, as well as significantly reducing energy demand. Utilize other emerging technologies to make processes more efficient. Use efficient heating, ventilating and air-cooling systems (HVAC). Replace inefficient HVAC equipment with energy efficient models and maintain HVAC systems to increase energy efficiency. Perform chemical treatment analysis on water system boilers and chillers and periodically clean coils. These processes not only extend equipment life, but also optimize heat transfer of equipment and save energy.
Choose efficient lighting. Retrofit T12 lamps (1-1/2 inch diameter) and magnetic ballasts with T8 lamps (1 inch diameter) and electronic ballasts, which provide nearly as much light and use approximately 40 percent less energy. Also replace fluorescent lighting fixtures with high-efficiency lamps and ballasts at the treatment plant and headquarters building and upgrade exit signs with LED (light-emitting diodes).Maintenance of Generators and Batteries Make energy efficiency a top priority in new construction projects. Take advantage of technologies such as the UV disinfection process which utilizes significantly less energy than standard systems and is easier to maintain and use in the long run.
Conservation Conserve with efficient water/wastewater system equipment. Alter the schedules of high-energy-using equipment and processes to reduce usage during peak demand times and/or shift load to off-peak hours. Establish an Electrical Load Management System, utilizing time-of-use and differing rate schedules. Use programmable control systems and energy management systems to regulate schedules and turn off and/or by-pass less efficient system equipment. Install computerized management systems and devices that will automatically regulate or enable users to completely control the use of energy in treatment and pumping equipment.
Choose alternative and/or renewable energy sources. Use alternative means of pumping water that require less energy for distribution such as landfill methane gas generators and on-site photovoltaic systems. Maximize use of cogeneration. Depending on anaerobic digester gas (ADG) production, wastewater facilities can optimize cogeneration engines to increase energy production, provide energy during on-peak or power crunch periods or sell energy to other areas.
Choose alternative water sources. Increase storage or reservoir use– pumping water from distant sources costs significantly more than from local sources. Conjunctive-use programs provide a greater and more reliable water supply.
Create employee awareness and education programs. Disseminate information and tips to employees through such media as e-mail, newsletters, memos and company websites. Encourage employees to participate in conservation efforts through incentive programs, contests, discounts, coupons and public recognition.
Create public awareness programs. Encourage the public to conserve water in an effort to conserve energy. See the Local Governments Best Practices Guide for tips on public awareness campaigns. Step 4: Monitor and Measure ResultsGather information on an ongoing basis to monitor the progress of the program and to make adjustments to maximize results and adapt to changing circumstances. Create a tracking system or use monitoring tools provided by local utilities. Results should be measured against the original budget and goals of the program.Evaluate the success of the program by looking at resources saved, money saved, money spent, the impact on the local economy, city personnel response and the public benefit created. |