water distribution optimization: taking scada one step forward: a case study
Post on 13-Jan-2016
43 Views
Preview:
DESCRIPTION
TRANSCRIPT
Water Distribution Optimization: Taking SCADA One Step Forward: A Case Study
Chuck Weber - WaterOneSimon 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
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.
What to optimize?
Electricity Use by WaterOne
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 speedometerkWh is the distance measured by the odometer
Electricity Supply tariffs
Kansas City Power & Light (KCPL) Flat kWh tariff applies 24 hours day, 365 days year Flat demand charge, 24 hours a day, 365 days year
Kansas City Board of Public Utilities (KCBPU) 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
Operator Panel
Optimizer
Operations Simulator
PC onLAN
Application Manager
PC on LAN
Key Energy Management Modules
Primary Database
Backup Database
Aquadapt Primary Database
(Live Server)
AquadaptBack-up Database (Historical Server)
DashboardPC onLAN
Data Cleaner
SCADA InterfaceOPC
Current day / real-time
WaterOne UCOS SCADA System
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
Peak Demand ReductionsMax Peak-Time kW (May 2006)
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
1-M
ay
2-M
ay
3-M
ay
4-M
ay
5-M
ay
6-M
ay
7-M
ay
8-M
ay
9-M
ay
10-M
ay
11-M
ay
12-M
ay
13-M
ay
14-M
ay
15-M
ay
16-M
ay
17-M
ay
18-M
ay
19-M
ay
20-M
ay
21-M
ay
22-M
ay
23-M
ay
24-M
ay
25-M
ay
26-M
ay
27-M
ay
28-M
ay
29-M
ay
30-M
ay
31-M
ay
Day
Su
m o
f kW
at
WT
P a
nd
Inta
kes
Observed With Derceto Expected Without Derceto
5 MW Reduction
Max Peak-Time kW (June 2006)
0
5000
10000
15000
20000
25000
1-Ju
n
2-Ju
n
3-Ju
n
4-Ju
n
5-Ju
n
6-Ju
n
7-Ju
n
8-Ju
n
9-Ju
n
10-J
un
11-J
un
12-J
un
13-J
un
14-J
un
15-J
un
16-J
un
17-J
un
18-J
un
19-J
un
20-J
un
21-J
un
22-J
un
23-J
un
24-J
un
25-J
un
26-J
un
27-J
un
28-J
un
29-J
un
30-J
un
Day
Su
m o
f kW
at
WT
P a
nd
Inta
kes
Observed With Derceto Expected Without Derceto
Woodson Inflow Valve out of Service
Out of Derceto Control
Even after a major Pipe-break
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?
top related