Demand Management Strategies Resulting In “Zero and Low Cost” Energy Saving Opportunities for Water and Wastewater Treatment Facilities

Abstract

Reducing energy costs is rapidly becoming a major priority for water and wastewater utilities. As a result, many water and wastewater utilities are performing energy management audits and evaluations to identify energy saving opportunities that will provide energy benefits at the lowest possible capital cost. Many water and wastewater facilities can realize "zero or low cost" energy saving opportunities through managing their energy demand in coordination with the energy billing rates. This is especially true for facilities whose electric energy rate structures include demand ratcheting and time of use billing. In order for demand management strategies to be effective, the demand management strategy must not have any negative impacts to the treatment process and must be coordinated with the energy billing rate structure(s). This paper will present multiple demand management strategies that were identified from multiple energy management audits performed for multiple wastewater treatment facilities. The results of multiple demand management case studies will be presented with an emphasis on demand management strategies that provided a payback period of 1 year or less . Specifically this paper will include the following as a minimum:• A description of common electric utility rate schedules (i.e. Time of Use, Demand Ratchets) and how different rate schedules impact the demand management strategies for water and wastewater treatment facilities. • Typical demand management practices commonly used by water and wastewater utilities including flow equalization, peak shaving, and operations management. • The role power monitoring capabilities has on the demand management capabilities.• The results of multiple case studies where demand management opportunities were identified as a part of an energy management project. KEYWORDSEnergy management, demand management, combined heat and power, biogas utilization, electric utility rates 1705 WEFTEC 2013

Prioritize effluent quality, operational costs or global warming? – Using predictive control of wastewater aeration for flexible management of objectives in WRRFs

“…The diffusion of smart grids, favoured by the diffusion of solar and wind electricity sources, have triggered several studies which investigated the possibility of moving WRRF peak consumption in time, thereby decreasing their carbon footprint. Lisk and Long (2013) and Kirchem et al (2018) concluded that both wastewater transport and treatment can provide substantial flexibility in electricity consumption. Further investigations of the WRRF electricity consumption have identified aeration as the most demanding step, accounting for about 50% of total consumption (Longo et al 2016).…”