This document discusses opportunities to optimize the energy performance of water supplies through improvements to pumps, aeration systems, and the use of renewable energy. Key opportunities include properly sizing pumps based on current flows, improving aeration system design to increase oxygen transfer efficiency, and utilizing renewable energy sources like hydro, wind, and solar power where feasible. Case studies demonstrate energy savings of 20-58% through pump upgrades, installing variable speed drives, and a wind turbine. The goal is to minimize total lifecycle energy use through detailed energy audits, accurate system sizing, optimizing controls, and procuring equipment based on lifecycle assessments.

1. Optimising Energy
Performance of Water
Supplies
Paul Kenny, B.E. C. Eng.
Chief Executive
Tipperary Energy Agency
WARES
SEAI Energy Show

2. • €60M spend nationally excl. DBO
• Pumps, blowers and aerators
• Opportunities 20% - 30% from 2009 SEAI report
• Renewable generation a key opportunity
• Significant organisational Change
• How to achieve opportunity?
Context

3. • Pumps
• Poorly sized
• Design Vs current operation
• Demand change
• Improved technology
• Aeration Systems
• Poor O2 transfer efficiency
• Improved design
• PE Changes
• Renewable electricity
• Demand and Cost reduction
Key Opportunities

4. Pumps
• Centrifugal pumps are very simple
• Each pump is best of a specific flow and
head
• The wrong pump could be doing a job
perfectly well – except cost being higher
• How do you know?
– Calculate & compare
– Manufacturers pump data
– Review market best practice.
© TEA. www.tea.ie

5. Case Study
Recommended Max Op Pt
@170 m3/h
Recommended Min Op Pt
@140m3/h
Current Op. Pt
25.00
30.00
35.00
40.00
45.00
50.00
0
m3/h
20
m3/h
40
m3/h
60
m3/h
80
m3/h
100
m3/h
120
m3/h
140
m3/h
160
m3/h
180
m3/h
200
m3/h
220
m3/h
240
m3/h
260
m3/h
280
m3/h
m
Oughterard Hi-Lift Pumping System Curve
Step Control Recommended Operating Points
Head Loss Vs Flow Rate
Good Practice Pump
Author: Enda McGovern, TEA

6. Throttling
• Throttling is “creating artificial head”
• Valves partially closed
• Ballcocks at reservoirs – bell-mouths
better.
• Non return valves - faulty, undersized.
• Eliminate with VSD either
© TEA. www.tea.ie

7. Sewage Pumps
• Impellor choice critical
– Balance between Energy Eff & Blocking
– Wear a big issue – keep well maintained
– Good selection critical
• Warning signs:
– Increased amps without blockages, Decreased flow rates
– Excessive vibration, Any electrical trips etc.
– Overheating
• Replace
– New WW pumps improved massively over last 3 years
– 5-10 year lifespan
– Ragging excessively.
– Energy savings often pay for new pump in months.
© TEA. www.tea.ie

8. • Goal: Minimise total system life cycle energy
efficiency
• Understand system constraints (pipe size,
chlorine retention etc).
• Size pump accurately – should not be done by
the market.
• Identify other optimisation
• Procure on life cycle
Sizing & Procurement

9. Implementation
• Detailed Energy Audit:
– Monitoring and design of actual duty Pressure/ Flow
– Ancillary system design/ requirements
– Understanding full system efficiency not pump only.
– PSAT / ASME-EA2 (Draft ISO) Optimisation.
• Opportunity/ Business case
– Best practice requirements
– Controls and optimisation
• Implementation
– Procurement on life cycle assessment
– EPC accountability
– Engineering time invested pays
© TEA. www.tea.ie

10. Results
© TEA. www.tea.ie

11. Results
© TEA. www.tea.ie

12. Energy Performance Indicator
WSNTG
0
0.1
0.2
0.3
0.4
0.5
0.6
10612
40612
70612
100612
130612
160612
190612
220612
250612
280612
10712
40712
70712
100712
130712
160712
190712
220712
250712
280712
310712
30812
60812
90812
120812
150812
180812
210812
240812
270812
300812
20912
50912
80912
110912
140912
170912
200912
230912
260912
290912
kWh/m3
Date

13. Aeration
• Efficiency by maximising oxygen transfer
efficiency and use
• Minimise excess O2 through controls –
load to demand.
• Maximise transfer efficiency
– Fine bubble diffusers: Smaller bubbles,
slowest assent
– Maximise mixing
– Area of output
© TEA. www.tea.ie

14. Killarney WWTP
Replacement of the horizontal oxygenation rotors
with Fine Bubble Diffused Air System.
• Project Cost €122,000
• Estimated Saving in 2009 - €45,000
• Ditch capacity increased by over 30%
• High maintenance rotors removed.
• 1.93 kWh/kg BOD before
• 0.82 kWh/kg BOD after
58% Less

15. Renewable Energy
• Hydro Wind Solar PV
• Hydro needs high input pressure
• Wind needs high site
• Solar needs a big roof/ area
• Export rates low currently and need either
base load or large scale.
© TEA. www.tea.ie

16. Case Study
• Carna Cill Chiaran
– Pump Efficiency 25% Plant Reduction
– Constant Pump VSD Vs start stop
– 20kW base load wind turbine.
– 32% capacity factor to date
• Combine~40%
© TEA. www.tea.ie

17. • Non profit, public good enterprise
• Partnership approach
• Energy management
• Renewable energy and energy
efficiency
• Procurement, project mgmt.
• Cost effective, value driven
• Paul Kenny
• Chief Executive
• T: 052 7443090
• F: 052 7443012
• E: pkenny@tea.ie
• W: www.tea.ie
Tipperary Energy Agency