Slow and steady lowers the electric bill:
Pump station energy efficiency upgrades
Andrew J. Weiss, P.E. | Executive Engineer, OCWA
Nate Medford, P.E. | Project Engineer, GHD
New York’s Water Event – April 15, 2015
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Presentation outline
Water utility energy usage
OCWA system overview
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OCWA energy usage
7G decision-making
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Pump Station Improvements
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Water utility energy usage
Energy usage by water utilities
Breakdown of energy usage
• Pumping (raw water & distribution) ~ 80 percent
• Treatment ~ 20 percent
Increasing energy usage by water utilities driven by several factors.
• New treatment techniques (membrane filtration, desalination, UV, etc.)
• Increasing extent of distribution systems
• Aging infrastructure (increased friction and water loss, decreased efficiency
of mechanical equipment)
• Climate change – droughts force usage of lower quality source water and
expansive distribution
• Unrealized growth resulting in oversized systems and inefficient operations
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OCWA system overview
Total system delivery – 37 MGD
Water sources
• Otisco Lake WTP – 18 MGD
• Metropolitan Water Board
(Lake Ontario) – 18 MGD
• City of Syracuse – 1 MGD
Population served – 340,000
Storage facilities – 55
Pumping facilities – 42
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OCWA energy usage
Energy consumption
OCWA
2010
2012
2013
2014
Total kWh Used
6,750,000
6,580,000
6,600,000
7,170,000
Total Energy Cost
(electric and gas)
$ 901,700
$ 714,300
$ 688,000
$915,000
Total Annual
Water Delivered
by OCWA
13.6 BG
14 BG
13.2 BG
13.5 BG
kWh/MG
496 kWh/MG
470 kWh/MG
500 kWh/MG
530 kWh/MG
No. Customers
92,250
93,512
100,591
100,948
kWh per
customer
73 kWh
70 kWh
65 kWh
71 kWh
Elec. Cost/MG
$ 66/MG
$ 51/MG
$ 52/MG
$68/MG
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Energy consumption breakdown
Use
Total Electric
Total Gas
Total Cost
%
WTP
$
52,000
$
16,000
$
68,000
7%
Storage Tanks
$
43,000
$
300
$
43,300
5%
Large Pump Stations
$
515,000
$
5,000
$
520,000
57%
Small Pump Station
$
174,000
$
5,000
$
179,000
20%
Other Metered Sites
$
19,000
$
300
$
19,300
2%
Buildings
$
62,000
$
23,000
$
85,000
9%
TOTALS $
865,000
$
50,000
$
915,000
2% 9%
2014
7% 5%
20%
57%
WTP
Tanks
Large PS
Small PS
Metered
Buildings
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7G decision making
OCWA sustainability efforts
Recycling & Waste Reduction
Transportation
Purchasing & Procurement
Energy Consumption
Information Technology
Distribution & Operations Efficiency
Carbon Footprint
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Operational changes
Embrace consolidation
Increase use of Otisco Lake water
Hydraulic efficiency improvements
Reduce unaccounted for water
Technology Implementation &
Updates
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Reduced energy usage
WTP Improvements
Increased Use Of Otisco Lake Water
LED Lighting Project
Pump Station Improvements
Northern Concourse Building
Improvements
Smaller, Fuel Efficient Vehicles
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Pump station improvements
Project location
Miles
0
1
2
N
Syracuse
Thurber St. PS
Elev. 530
Seneca PS & WS Tank
Elev. 730
Sentinel Heights WS Tanks
Elev. 1,030
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Existing conditions
Thurber St. PS
• Three, split-case, bottomsuction centrifugal pumps
• 4,600 GPM at 152-ft
• Capacity – 13 MGD
• 250 Hp electric motors
• 16-in pump control valve
Seneca PS
• Three, split-case, bottomsuction centrifugal pumps
• 3,500 GPM at 283-ft
• Capacity – 10 MGD
• 300 Hp electric motors
• 16-in pump control valve
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Demand and capacity
Thurber St PS Demand
• Average: 1.1 MGD
• Peak: 1.9 MGD
Seneca PS Demand
• Average: 0.9 MGD
• Peak: 1.3 MGD
Reduced demand from projections estimated during initial station design
• Expected build-up of communities south of Syracuse never realized
• Water conservation efforts
Pump
Station
Thurber
Seneca
Capacity 1 (MGD)
Original
6.6
5.0
New
2.1
1.8
Run time (hr)
--
Original
New
Average
4
12
Peak
7
21
Average
4
12
Peak
6
18
Note:
1. Single
pump
capacity
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System - Average
System - Max
System - Min
Pump - Flow
Pump - Efficiency
Thurber Street PS
350
1
0.9
300
250
0.7
0.6
200
0.5
150
0.4
Efficiency
Total Dynamic Head (ft)
0.8
0.3
100
0.2
50
0.1
0
0
500
1,000
1,500
2,000
0
2,500
Flow (GPM)
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Other energy efficiency improvements
Existing
conditions
Modifications
Final
conditions
High-intensity discharge
(HID) lights
Improve energy
efficiency of lighting
High-efficiency fluorescent
lighting
Roof insulation – 2-in rigid
insulation
Take advantage of
roofing replacement
to improve building
energy efficiency
Roof insulation – 6-in
polyiso (ASTM C1289)
Roof-mounted exhaust fans
• Two, ¾-Hp, 5,000 CFM
Electric unit heaters
• Three, 10-kW, 34,000
BTU/hr
Decrease ventilation
requirements
• Removal of diesel
engine
• Smaller pump
motors
Roof-mounted exhaust fans
• One, ½-Hp, 2,600 CFM
Gas unit heaters
• Three, 105,000 BTU/hr
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Present value comparison: baseline
Thurber St PS – Original pumps (replace in kind)
• 71 percent efficiency
• 3,800 gpm at 168 ft
• 20 year project life
• 5 hours per day
• 3 percent discount rate
Cost item
Base date
cost
Year of
occurrence
Discount
factor
Present
value
Initial
investment
$3,500,000
--
--
$3,500,000
Capital
improvement
$75,000
10
0.744
$60,000
Electricity
($0.10/kWh)
$33,100
Annual
14.88
$490,000
Maintenance
$5,000
Annual
14.88
$74,000
Salvage
($10,000)
25
0.478
($5,000)
Total
$4,100,000
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Present value comparison: alternative
Thurber St PS – New pumps
• 81 percent efficiency
• 1,600 gpm at 160 ft
• 12.5 hours per day
• 20 year project life
• 3 percent discount rate
Cost item
Base date
cost
Year of
occurrence
Discount
factor
Present
value
Initial
investment
$3,250,000
--
--
$3,250,000
Capital
improvement
$50,000
10
0.744
$40,000
Electricity
($0.10/kWh)
$21,700
Annual
14.88
$320,000
Maintenance
$5,000
Annual
14.88
$70,000
Salvage
($5,000)
25
0.478
($2,000)
Total
$3,700,000
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Total usage
Peak demand
50,000
45,000
Total usage (kWh)
240
New pumps
operational
220
200
40,000
180
35,000
160
30,000
140
25,000
120
20,000
100
Original
pumps
demolished
15,000
Peak demand (kW)
Actual energy savings – Thurber
80
60
Nov-14
Sep-14
Jul-14
May-14
Mar-14
Jan-14
Nov-13
Sep-13
Jul-13
May-13
Mar-13
Jan-13
Nov-12
Sep-12
Jul-12
May-12
Mar-12
Jan-12
Nov-11
Sep-11
10,000
Month
Total electrical usage – 25 percent decrease; Peak demand – 40 percent decrease
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During construction
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During construction
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During construction
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Finished project
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Finished project
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Finished project
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Acknowledgements
Mr. Anthony Geiss, P.E. – OCWA
Mr. Geoffrey Miller, P.E. – OCWA
Mr. Anthony Palamara – OCWA
Mr. Sean Hayes – OCWA
Mr. Michael Eckert – OCWA
Mr. Kevin Castro, P.E. – GHD
Mr. Jeremy Boyer – C.O. Falter
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