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Water Distribution Optimization: Taking SCADA One Step Forward: A Case Study Chuck Weber - WaterOne Simon Bunn – Derceto Inc 1950’s – 1970’s Control room PLC and RTU provide local control 1970’s : Mixed auto/manual systems 1980’s : SCADA systems appear 1990’s :Historical Databases arrive 1990-2000 Smart Instruments arrive WaterOne is a quasi-municipal agency that provides water to more than 400,000 individuals WaterOne serves residential and commercial accounts in 16 cities in the Johnson County area. WaterOne serves approximately 135,000 customers. WaterOne has nearly 3,000 miles of transmission and distribution mains, equal to the distance from Kansas City to Seattle. WaterOne's service area covers more than 270 square miles. WaterOne’s current treatment capacity is 180 millions gallons per day. Modern UCOS Scada System Single control room for treatment and distribution Installed in 1991, upgraded 2006 What next after Scada? Decision Support Systems What to optimize? Energy cost minimization is a good target, as it is one of the highest costs in producing the “next gallon of water.” "The more than 60,000 water systems and 15,000 wastewater systems in the United States are among the country’s largest energy consumers, using about 75 billion kWh/yr nationally – 3 percent of annual U.S. electricity consumption." Electric Power Research Institute, Energy Audit Manual for Water/Wastewater Facilities, (Palo Alto: 1999), Executive Summary. Electricity Use by WaterOne Water Treatment (Backwash/Transfer Pumps) 10% Transmission Pumps 46% Intake/Pretreatment Pumps 26% Distribution Pumps 14% Offices 4% Energy and Demand Charges Pricing is based on two components, energy use in kWh and demand in kW Car Analogy for kWh and kW kW is like the speed that is measured by a speedometer kWh is the distance measured by the odometer Electricity Supply tariffs Kansas City Power & Light (KCPL) Kansas City Board of Public Utilities (KCBPU) Flat kWh tariff applies 24 hours day, 365 days year Flat demand charge, 24 hours a day, 365 days year Flat kWh tariff applies 24 hours day, 365 days year Demand charge only applies 10 hours/weekday with monthly peak and 70% of highest summer peak setting winter charge (effectively a 12 month ratchet clause) Almost no incentive at all for shifting electrical load No options for time-of-use or real-time pricing Last KCPL tariff structure changes were made10 years ago Market is unlikely to change or deregulate in the mid term Solving the energy equations Numerically impossible to solve, but the following techniques have been attempted Localized optimization at each pump station using profiling or time triggers Expert Systems using cascading rules Advanced techniques using Genetic Algorithms Multi-Objective Polynomial Systems (MOPS) Dynamic Programming with Stochastic analysis All still make considerable assumptions and do not achieve optimality A 2001 AWWA report said “the market is waiting for an off-the-shelf solution” A New Customized-Off-The-Shelf tool Over the last 4 years, Derceto Aquadapt has implemented energy cost optimization systems with leading US water utilities Five key cost reduction techniques were employed Electrical load shifting in time, to maximize utilisation of low cost kWh tariff blocks (time-of-use tariffs) Peak electricity kW demand reduction Energy efficiency improvements from pumps and pumping plants. Utilization of lowest production and chemical cost sources of water. Utilization of shortest path between source and destination WaterOne benefited primarily from peak demand reduction and lowest cost source selection Key Energy Management Modules Operator Panel OPC SCADA Interface PC on LAN Current day / real-time WaterOne UCOS SCADA System Data Cleaner Primary Database Aquadapt Primary Database (Live Server) Operations Simulator Application Manager PC on LAN Optimizer Aquadapt Back-up Backup Database (Historical Server) Dashboard PC on LAN Project Timeline Feasibility Study - June 2004 to August 2004 Detailed Design - September 2004 to April 2005 Configuration and Testing - July 2005 to Mar 2006 Delivery, Implementation and Site Testing - April/May 2006 Had to be ready in time for peak summer demand otherwise majority of savings would be lost for 2006/07 WaterOne created and maintained an audit tool to measure savings on a monthly basis. This is a sophisticated analysis tool Uses formulation of kW versus MGD from four previous years Created non-linear functions to calculate kW at each major point Allowed for changes in tariff in future years to be incorporated Maintenance, Enhancement and Support contract started in June 2006 with latest Aquadapt version 5.5 rolled out in 2008 0 Observed With Derceto Day Expected Without Derceto 31-May 30-May 29-May 28-May 27-May 26-May 25-May 24-May Max Peak-Time kW (May 2006) 23-May 22-May 21-May 20-May 19-May 18-May 17-May 16-May 15-May 14-May 13-May 12-May 11-May 10-May 9-May 8-May 7-May 6-May 5-May 4-May 3-May 2-May 1-May Sum of kW at WTP and Intakes Peak Demand Reductions 5 MW Reduction 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 Observed With Derceto Day Expected Without Derceto 30-Jun 29-Jun 28-Jun 27-Jun 26-Jun 25-Jun 24-Jun 23-Jun 22-Jun 21-Jun 20-Jun 19-Jun 18-Jun 17-Jun 16-Jun 15-Jun 14-Jun 13-Jun 12-Jun 11-Jun 10-Jun 9-Jun 8-Jun 7-Jun 6-Jun 5-Jun 4-Jun 3-Jun 2-Jun 1-Jun Sum of kW at WTP and Intakes Even after a major Pipe-break Max Peak-Time kW (June 2006) 25000 Woodson Inflow Valve out of Service 20000 Out of Derceto Control 15000 10000 5000 Results to date – Electricity $ savings First month of operation May 2006, saved $90,000 First year of operation May 06 to April 07 saved $565,000 First six months of 2007/08 saved $553,000 Total of $1,118,000 saved in 18 months of operation Reduced greenhouse gas emissions by 4800 tons/year Other impacts Has required changes in operation, but no additional hardware or instrumentation was required Operators were involved all the way through the process and had valid concerns which needed to be addressed Ongoing program of training and product enhancement is helping culture change and acceptance Aquadapt is now being used to identify areas where further savings can be made Conclusions The considerable investment in a Scada system is often hard to justify financially, but it is an essential tool Utilization of the data and interfaces presented by a Scada system in areas such as planning and operations optimization can provide additional financial benefits Even in an energy market that looked unfriendly to energy optimization, significant benefits were achieved Buying advanced software “off-the-shelf” reduces risk Use robust systems to measure the benefits to avoid doubt Operators need to be involved from start to finish, they know the treatment and distribution systems best This is just one step in the path to operations optimization, keep an eye on costs and benefits in all areas to best serve your customers Questions?