Transcript Document

OPERATING PUMPS TO MAXIMIZE
EFFICIENCY AND TO MINIMIZE
YOUR CARBON FOOTPRINT
Simon Bunn – Derceto Inc
The Issue
• Al Gore’s “An Inconvenient Truth” brought global
warming to the attention of the general public
• Water Utilities are particularly exposed, they are high
energy users and warmer temperatures lead to less
raw water while simultaneously increasing demand
• “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
Energy Use in US Water Distribution
• The US water industry uses approximately $10B of
electricity to pump water consuming 100 Million MWh
per year of electricity.
• 90% to 95% of this is used for pumping
• Pump scheduling so-far has only targeted time-of-use
tariffs and peak charge avoidance
• Targeting efficiency for each pump and pump station
can lead to considerable kWh reductions
• Each kWh saved also leads to greenhouse gas
reductions
• Targeting the lowest kWh/MG/ft should therefore be a
goal of all water utilities
Typical Energy Use in Water Utilities
Lifecycle costs of a water pump
Improving pump efficiency
A major European Union study of pumps1 recommended:
• Select pumps according to duty requirements
• Measure pump performance regularly
• Replace or refurbish poorly performing pumps
• Polish or coat pump surfaces
• Use automatic pump scheduling / pump selection
software targeting efficiency
1. European Commission, “Study on improving the energy efficiency of pumps”, February 2001,
AEAT-6559/ v 5.1
Polishing/coating pump surfaces
Refurbish or replace?
Pump Installed
Duty
As new Pump efficiency
As new motor efficiency
Present Pump Efficiency
Potential Savings
Present Input Power
Price of Electricity
Present running cost
Potential input power 155.95 kW
Potential running cost $133,610
Saving
$26,435/year
1963
66 gal/s @ 157ft
82%
92%
70%
14.60%
182.7 kW
10 Cents / kW hr
$160,045/year
New pump efficiency
New motor efficiency
New input power
New running cost
Saving
84%
96%
145.9 kW
$127,801
$32,244
Selecting a pump
The moving System Curve
Pump Scheduling Optimization
• Aquadapt software installed in four major US utilities
• It fully automatically schedules production, pumps
and valves including issuing all commands via Scada
• Primary objective is cost minimization but must
supply all customers
• Water Quality requirements are included as rules
• It creates 48 hour ahead schedules for all assets
under its control
• Automatic adaptation to changing conditions is
achieved by re-optimizing every 30 minutes
• Maintenance requirements are easily scheduled and
automatically accommodated
Single Objective : Cost Minimization
• Five key cost reduction methods are employed
◦ Electrical load movement in time, to maximize
utilization of low cost tariff blocks
◦ Electricity peak 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
• Of these, energy efficiency improvements produced
the most unexpected outcome.
Selecting pumps can be counterintuitive
Variable Speed Pump Performance
This affect was seen system wide
Pumps operate more efficiently
Key Energy Management Modules
Operator Panel
OPC
SCADA Interface
PC on
LAN
Current day / real-time
Client SCADA
System
Data Cleaner
Primary Database
Aquadapt
Primary Database
(Live Server)
Optimizer
Simulator/EPANET
Application Manager
PC on LAN
Aquadapt
Back-up
Backup Database
(Historical Server)
Dashboard
PC on
LAN
Real-time pump curve data
In this example a pump is running well on its curve and at
peak efficiency
Flat pump curves can be a problem
Four Case Histories
• We specifically analysed four US utilities running
standard Aquadapt pump scheduling software
Customer System
Pop.
Served
Storage
tanks
Pressure
zones
Pump Pumps Auto
Stations
Valves
Demand
(MLD)
East Bay MUD, CA
660k
28
26
20
66
4
160 to 480
Washington Suburban, MD
1.6m
57
15
18
81
25
640 to 900
WaterOne, Kansas
570k
25
3
26
84
11
190 to 400
Eastern Municipal, CA
630k
68
38
59
149
9
180 to 450
Audited CO2 reductions for our clients
Average
MWH per
Year
Average Efficiency
Gain under
Aquadapt
EPA eGRID 2004
CO2 Emissions
(Tons/MWh)
Extrapolated CO2
Reduction per Year
(Tons)
East Bay MUD, CA
26,000
6.1%
0.502
800
Eastern Municipal, CA
7,000
8.4%
0.515
300
Washington Suburban, MD
99,000
8.3%
0.547
4,500
WaterOne, KS
94,000
6.0%
0.845
4,800
Customer System
Conclusions
• The US water industry uses approximately $10B of
electricity to pump water consuming 100 Million MWh
per year of electricity.
• A reduction of 6% to 9% in this energy consumption
through efficiency improvements would therefore lead
to saving between 6 and 9 Million MWh per year.
• The average CO2 emission for the US is approx.
0.51 tons per Megawatt hour.
• The potential CO2 reduction therefore, is between 3
million tons and 4.5 million tons
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