Energy balances in water savings and reuse programmes

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Energy balances in water savings and reuse
programmes

• Process to save water and energy

Pat McCafferty General Manager Strategy
Communications IWA World Water Congress Vienna, 9
September 2008
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Overview

• Background
• Objective
• Methodology
• Business value
• Summary

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BackgroundThe retail water sector in Melbourne
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BackgroundMelbournes Water Industry
City West Water,
Melbourne Water
Melbourne Water
South East Water,
Yarra
Valley Water
Headworks
Bass
Strait
disposal
Eastern
Treatment
Disinfection
Plant
Plant
Delivery of
Transmission
Sewage
water and
sewerage
Sewer Main
services to
final
(inc.trade waste)
customers
Western
Treatment
Plant
River Diversion
Treatment
Reservoirs
disposal
Local
Plant
Storm Water
Treatment Plant
Port
Storm Water
Phillip
Drainage
Bay
responsibility of local council
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• Worst Drought in our History
• Suddenly got Even Worse

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BackgroundResource Constraints

• Not enough water
• need to reduce demand by 30 by 2015
• Need to increase rivers flows
• Too much Greenhouse Gas
• Committed to being GHG net neutral
• 40 increase in 10 years with growth
• Could increase 300 with desalination
• Discharge too many nutrients
• need to reduce discharge of nitrogen into bay by
  1000 tonnes
• Australian soils are nutrient poor

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Objective

• Develop process
• that provides the business with information to
  show the interconnection of water and energy
• which can be used in major business decision
  making to get the best outcomes

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MethodologyWater System Overview
Delivery Infrastructure
Catchment
Treatment
Water
Sewer
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MethodologyData Used
Spatial Zone Information
Energy Maps
Output
Zone Operation Information
General Asset Data
Empirical Formula
Asset Flow Data
Energy Bills
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Methodology Energy Density Map - Water Supply
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Methodology Energy Density Map Sewage Disposal
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MethodologyEnergy Density Map - Combined
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Business valueShowerhead retrofit program
Map shows payback period from reduced energy use
by Company if it funds a shower retrofit program
at 40 per retrofit.
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Business valueRainwater tank rebate
Map shows payback period from reduced energy use
by Company if it funds a 300 rebate program for
rainwater tanks.
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Customer valueShowerhead retrofit program
Kenway S. (2007) Personal communication
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Energy savings from showerheads offset GHG
emissions..
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Business valueInfrastructure planning
Function Energy use (kWhr/ML)
Water pumping station 40-450
Sewerage pumping station 140
Conventional water supply treatment 50
Recycled water treatment (membranes) 200
Dual membrane filtration plant 400
Wastewater treatment 500-1000
Household pressure pumps (for rainwater tanks) 230-3100
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Business valueCommunity cost benefit
Actual Costs
Imported Water 1 per KL
1,600.00
Nitrogen 800 per kg
GHG 20 per tonne
1,400.00
1,200.00
1,000.00
Total Community Cost Millions
800.00
600.00
400.00
Conventional
200.00
0.00
Environmental improvements dont always cost more
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SummaryProcess to save energy and water

• We live in a world with resource constraints
• Better decisions will be made having a process
  that shows interconnections
• Energy density maps deliver that benefits
• Experience has shown that it can help with the
  following
• Deliver customer value with showerhead retrofits
• Business value with reduced environmental impacts
  and operational costs
• Community value with better infrastructure
  selection