21 st -23 rd February 2007 NZSSES Conference, Auckland 2007 1 Sustainable choices for Sustainable choices for residential water supply residential water supply in Auckland in Auckland Nalanie Mithraratne & Robert Vale Centre for Urban Ecosystem Sustainability Centre for Urban Ecosystem Sustainability Landcare Research Landcare Research
27
Embed
21 st -23 rd February 2007 NZSSES Conference, Auckland 2007 1 Sustainable choices for residential water supply in Auckland Sustainable choices for residential.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
21st-23rd February 2007 NZSSES Conference, Auckland 2007 1
Sustainable choices for Sustainable choices for residential water supply in residential water supply in
AucklandAuckland
Nalanie Mithraratne & Robert Vale
Centre for Urban Ecosystem SustainabilityCentre for Urban Ecosystem Sustainability
Landcare ResearchLandcare Research
21st-23rd February 2007 NZSSES Conference, Auckland 2007 2
OutlineOutline
Mains supply vs. rain tanksMains supply vs. rain tanks
Impact of settlement patternsImpact of settlement patterns
Water system in average houseWater system in average house
ConclusionsConclusions
21st-23rd February 2007 NZSSES Conference, Auckland 2007 3
LCA of mains supply LCA of mains supply
System boundarySystem boundary
Initial constructionInitial construction
Maintenance/ replacements - 1% of the Maintenance/ replacements - 1% of the total length of pipes/year total length of pipes/year
replacedreplaced
Operational requirementsOperational requirements
Analysis period – 100 yearsAnalysis period – 100 years
21st-23rd February 2007 NZSSES Conference, Auckland 2007 4
Bulk supply system - constructionBulk supply system - constructionLIFE CYCLE ENERGYLIFE CYCLE ENERGY
Dams 46%
Raw water mains7%
Valve towers, spillways, etc.
2%
Treated water mains45%
21st-23rd February 2007 NZSSES Conference, Auckland 2007 5
Bulk supply systemBulk supply system
Construction
50%
Operation
27%
Maintenance
23%
Maintenance
12%Operation
65%
Construction
23%
LCELCE
LCCOLCCO22
21st-23rd February 2007 NZSSES Conference, Auckland 2007 6
Local supply network - 2005Local supply network - 2005
Unknown 37%
AC19%
CI21%
PE9%
other4%
PVC9%
Steel0% CLS
1%
CLS - cement lined steelCLS - cement lined steel
CI - cast ironCI - cast iron
PE - polyethylenePE - polyethylene
AC - asbestos cementAC - asbestos cement
21st-23rd February 2007 NZSSES Conference, Auckland 2007 7
BIAC - rain tank 1970s - rain tank 1990s rain tank 2000 - rain tank
21st-23rd February 2007 NZSSES Conference, Auckland 2007 21
Building Industry Advisory Building Industry Advisory Council House (BIAC)Council House (BIAC)
PlanPlan[Source: Baird and Chan (1983)]
21st-23rd February 2007 NZSSES Conference, Auckland 2007 22
Section & Front ElevationSection & Front Elevation[Source: Baird and Chan (1983)]
Building Industry Advisory Building Industry Advisory Council House (BIAC)Council House (BIAC)
21st-23rd February 2007 NZSSES Conference, Auckland 2007 23
ASSUMPTIONSASSUMPTIONS
Useful life of NZ houses is 100 years.Useful life of NZ houses is 100 years. Living room faces north.Living room faces north. Space heating: Whole house, temp Space heating: Whole house, temp
1818ooC, 2 schedulesC, 2 schedules Water heating: varies with water Water heating: varies with water
volume.volume.
21st-23rd February 2007 NZSSES Conference, Auckland 2007 24
Life cycle energy by end useLife cycle energy by end use
BIAC 1970s 1990sPost 2000
House construction
15-17% 14-15% 16-17% 16-17%
Space heating
39-44% 43-47% 44-47% 44-48%
Water heating
40-43% 37-40% 36-38% 35-37%
Water supply 1% 1% 1% 1%
21st-23rd February 2007 NZSSES Conference, Auckland 2007 25
Life cycle COLife cycle CO22 by end use by end use
BIAC 1970s 1990sPost 2000
House construction
57-61% 56-60% 39-43% 39-43%
Space heating
18-21% 20-23% 29-33% 29-34%
Water heating
19-20% 18-19% 24-26% 24-26%
Water supply 0.2 -3% 0.3 -4% 0.4 -5% 0.4 -5%
21st-23rd February 2007 NZSSES Conference, Auckland 2007 26
Life cycle cost by end useLife cycle cost by end use
BIAC 1970s 1990sPost 2000
House construction
81-84% 82-84% 82-85% 82-85%
Space heating
5-6% 6-7% 6-7% 6-7%
Water heating
6% 5% 5% 5%
Water supply 5-7% 4-6% 4-6% 4-5%
21st-23rd February 2007 NZSSES Conference, Auckland 2007 27
ConclusionsConclusions Consumption significantly impacts the Consumption significantly impacts the
system choice.system choice.
Use of mains supply in smaller houses Use of mains supply in smaller houses (>150m2) and rain harvesting in larger (>150m2) and rain harvesting in larger houses is better for the environment.houses is better for the environment.
Mains supply is cheaper initially but Mains supply is cheaper initially but costly in life cycle terms.costly in life cycle terms.
Water supply is negligible in terms of Water supply is negligible in terms of total environmental performance of total environmental performance of house.house.