Integrated Water Cycle Management Demand Side Management ... · Demand Side Management Decision Support System- Simplified ... management effort. Benefits include reductions in treatment

DEPARTMENT OF ENERGY, UTILITIES AND SUSTAINABILITY NEW SOUTH WALES GOVERNMENT

Integrated Water Cycle Management Demand Side Management Decision Support System- Simplified(Version S1.1) Manual July 2006

CROWN COPYRIGHT 2006 NEW SOUTH WALES The Demand Side Management Decision Support System software (Simplified Version 1.1) has been developed by the NSW Department of Energy, Utilities and Sustainability (DEUS). Crown Copyright New South Wales 2006. All rights reserved This model has been developed by DEUS to enable NSW water utilities to improve the accuracy of their water supply forecasts and obtain a better understanding on how investment in water conservation can bring about significant net savings in capital and operating costs. The model is recommended for use in the preparation of Integrated Water Cycle Management strategies. More advanced models are available from other sources.

Conditions of use The intellectual property of this Decision Support model belongs to DEUS. It is forbidden to modify this model or to insert it into any other software program without written DEUS approval. The model is provided to users on a strict commercial-in-confidence basis, and at no time should the manual or software be distributed to third parties.

Disclaimer DEUS makes no warranty or representation either expressed or implied with respect to the model regarding its quality, performance, or fitness for any purpose. The model is supplied on the basis that, while DEUS believes it will enable a water utility to prepare more accurate demand forecasts and to estimate the financial benefits of conservation, DEUS does not warrant its accuracy or completeness and, to the full extent allowed by law, it excludes liability for any loss or damage sustained by any person from use of the model.

Contact person for this manual Manager, Integrated Water Cycle Management Dept of Energy, Utilities & Sustainability Level 18, 227 Elizabeth St Sydney NSW 2000 GPO Box 3889 Sydney 2001 T: (02) 8281 7777 June 2006

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Table of Contents

GLOSSARY ......................................................................................................... III

1 OVERVIEW....................................................................................................... 1

2 DATA AND ASSUMPTIONS............................................................................ 2

2.1 Data Required to be Entered ............................................................................. 2 2.1.1 Comments in the Setup Sheet ...................................................................... 3 2.1.2 Demographics............................................................................................... 3 2.1.3 Water Use..................................................................................................... 3 2.1.4 Evaporative Cooling Use .............................................................................. 3 2.1.5 Assumed Level of Residential Indoor Use per Person .................................. 4 2.1.6 Infrastructure................................................................................................. 4 2.1.7 Water Pricing ................................................................................................ 5 2.1.8 Calculation of Baseline Water Demand and Financial Data .......................... 5

2.2 Underlying Assumptions ................................................................................... 5 2.2.1 Water Use..................................................................................................... 5 2.2.2 Evaporative Cooling Uses............................................................................. 6 2.2.3 Hot Water Savings........................................................................................ 7 2.2.4 Conservation Measure Assumptions ............................................................ 8

2.3 How the Model Addresses BASIX ................................................................... 11

3 OUTPUT ......................................................................................................... 12

3.1 Building Scenarios........................................................................................... 12

3.2 Impacts of Scenarios ....................................................................................... 12

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Glossary Benefit Cost Ratio is the ratio of total benefits and costs arising from a demand management effort. Benefits include reductions in treatment and transfer costs and windfalls from the delay and downsizing of capital works projects (lower demands means smaller infrastructure). Costs include the cost of implementation incurred by the water utility for planning, administration and education campaigns and additional investment required by the utility and customers for water efficient fixtures and appliances, water loss management and recycled water and rainwater harvesting infrastructure. End use model is the term that describes a model that looks to take account of the impact of different water conservation and source substitution on the volume of water used in different end uses and then aggregates these savings into an estimate of the total potential water to be saved. End use refers to a specific use of water that can be identified within a specific customer category. Toilet use in residential accounts is one example of an end use, cooling system use in commercial would be another. External Use refers to water used externally in irrigation and cooling towers. Internal Use refers to water used internally in buildings and would also encompass any other water consumption that is not influenced by climate. This demand is assumed to remain unchanged by seasonal effects during the year. A Measure is a single water conservation or source substitution initiative. For example, a residential retrofit program would be considered a single measure as would a code requiring water efficient fixtures for all new development. Per Capita Demand is the water demand per capita of the resident population served with water. A Scenario is a group or bundle of individual conservation or source substitution measures. System Loss or Leakage refers to water that escapes from the reticulation system. Total Community Benefit Cost Ratio is the ratio of the combined benefits and costs of the utility and customers. This total community perspective provides and overall assessment of cost-effectiveness given that savings costs and savings accrued by the utility are ultimately passed on to consumers through rates and charges. Unaccounted for Water refers to the difference between metered water consumption and production. Strictly speaking a system with no metering of consumption would have 100% unaccounted for water. Utility Benefit Cost Ratio is the ratio of the benefits and costs from the perspective of the water utility. These benefits and costs do no include the costs to customers of additional investment in water efficient fixtures and appliances and source substitution, nor benefits arising to customers from hot water savings. Water Consumption is assumed to refer to all water passing from reticulation mains into customer’s service lines.

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Water Supplied is assumed to refer to water passing through bulk meters and treatment facilities into the reticulation system.

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1 Overview The simplified version of the Demand Side Management Decision Support System is designed to facilitate the rapid development of demand forecasts and preliminary evaluation of demand management measures as part of the NSW Government’s Integrated Water Cycle Management planning framework. The simplified version makes use of:

• a simple set-up screen to facilitate data entry; • a number of pre-prepared demand management measures that are

automatically evaluated upon completion of the setup sheet; • pre-determined key assumptions underlying costs and benefits of

conservation measures; and • user-friendly scenario-building and output formats.

The task of developing demand forecasts and evaluating the costs and benefits of demand management measures is a necessarily complex task. This is because to do the job well, an end use model is required. End use modelling, when carried out in a thorough way, requires reasonably detailed calculations to be undertaken underlain by an understanding of water use, the market for water using fixtures and appliances and the interactions between conservation measures targeting the same end uses. The simplified version of the DSM DSS is intended to allow users the benefit of these detailed calculations with a relatively simple and straight-forward data entry process. It provides 30 year forecasts of both water use and estimates of the savings associated with demand management initiatives.

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Current Water Use• Total water use• Number of accounts• System losses• % of water consumed in each

customer category• % of each category connected to

sewerage

Demographics• Current population• Expected growth rate• Household sizes

Scenario BuildingSelection of measures to be included in each scenario

Demand Management Measures• Inclining block tariff• Showerhead retrofit• System leakage management• BASIX• Mandatory Water Efficiency Labelling Scheme (WELS)• Non residential customer water audit• Community education effort• Permanent restrictions on water use• Dual reticulation for new residential development• Rainwater tanks for new residential development• Residential washing machine rebate• Evaporative cooling unit and cooling tower audit

Water and Energy Savings

AssumptionsCosts of Measures

Market uptake

Summary ChartsImpact of scenarios water demand:• per capita• annual average• peak day

Demand Management Decision Support System

Setup Sheet

Output SummarySummary of historical demands and conservation measures and

savings for the baseline case and four scenarios

Figure 1: Configuration of Simplified Version of Demand Management Decision Support System

2 Data and Assumptions 2.1 Data Required to be Entered The data entry for the simplified version is restricted to a relatively straightforward series of questions. These questions cover;

• Demographics; • Current water use; • Climate data; • Details of current infrastructure and planned upgrades; and • Details of current water prices.

All of the information is to be entered in the setup sheet (sheet “SET”). The simplified version of the DSS uses three colour codes for cells:-

Yellow for data to be entered; Green for information calculated by the model; and Tan for information sourced from the setup sheet.

This colour coding is followed throughout the DSS model in the sheets beyond the setup sheet. Where cells beyond the setup sheet in the DSS model accept information from the setup sheet, they are coloured tan.

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2.1.1 Comments in the Setup Sheet Throughout the setup sheet, there are various comments provided to guide the user on the type of data required. Where a comment is made, there is a red flag attached to the top right hand corner of the spreadsheet cell.

2.1.2 Demographics The demographic data to be entered focuses on population, growth rates and household size statistics. Household size considerations are important because as it falls (as has been common in recent years in most Australian urban centres) it drives the rate of dwelling growth above the rate of population.

2.1.3 Water Use The water use information to be entered can generally be derived from a combination of bulk water and customer consumption records. The levels of system losses are best derived using reservoir drop tests or minimum night flow measurements. Note that the proportion of customers connected to the sewer will allow for those customers who are connected to the water supply system but not the sewer. This number is used in the DSS to calculate dry weather sewer flows. In the example below, parks and open space are assumed to be connected to the sewer because, while their use is mostly for irrigation, parks and ovals often have toilet and amenities blocks which do contribute to sewer flow.

Where possible, all current consumption data should be corrected for the influence of climate.

2.1.4 Evaporative Cooling Use The level of ownership of evaporative cooling systems is used to estimate the level of external use in cooling (see Section 2.2.2).

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2.1.5 Assumed Level of Residential Indoor Use per Person The assumed level of indoor use per resident is used to estimate the total % of indoor use in residential consumption. These values are anticipated to vary from 170 L/d to 190 L/d depending on location. By entering an assumed level of consumption in the appropriate cell and clicking on the update button on the right, users can test the sensitivity of the level on indoor use to the assumed level of consumption per account. The proportion of indoor use varies throughout that state and would be expected to vary from approximately 65% to 75% in the northern coastal areas to 45% to 55% in dryer inland areas. This volume of use may vary depending on the type of housing, the water pricing structure and demand management efforts in the supply area.

2.1.6 Infrastructure Information on water and wastewater infrastructure capacities and projects, plus current water and wastewater treatment and transfer costs, are entered in the infrastructure tables. As a minimum, details should be provided for:

• Headworks, bulk water and water treatment infrastructure; and • Wastewater treatment infrastructure.

Other relevant projects can be entered as required. A total of 10 water and 10 wastewater projects can be entered.

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2.1.7 Water Pricing The simplified version of the DSS makes the assumption that there is a two part tariff in place for water charges and asks for information on both the current and previous year’s charge. This information is not used to extrapolate pricing trends, but is simply used to estimate the potential impact of any pricing change from the previous year.

2.1.8 Calculation of Baseline Water Demand and Financial Data Once the above data has been entered, clicking on the button shown below will calculate the baseline water demands and the information used in estimating costs and benefits.

2.2 Underlying Assumptions

2.2.1 Water Use The simplified version of the DSS makes a number of assumptions regarding water use. These are set out in Table 1 below.

Table 1: Outline of Information Used in the Development of the End Use Model

Type of Data Derivation Figure/s Used Internal residential consumption

Totals used broadly based on the Perth Domestic Water Use Study (Water Corp., 2003). Adapted for increased levels of leakage and a lower market penetration of some fixtures and appliances.

Can be set by the user in the Setup Sheet. Typically from 170 to 190 L/d. 180 L/d is the recommended number for regional NSW.

Breakdown in Internal residential consumption

Breakdown used from the Perth study (Water Corp., 2003). Combined bath and shower use in the Perth study was assumed split 95% for showers, 5% for baths. Adjusted for change in the level of leakage outlined above.

Toilets 19.0%Baths 1.9%Showers 36.1%Taps/Sinks 11.4%Dishwashers 1.9%Washing Machine 24.7%Leakage 5.0%

Breakdown in internal use in commercial and public sectors

Breakdown used from the North American Commercial and Institutional End Uses Study (AWWARF, 2000b) for office buildings.

Toilets 26.5%Urinals 6.6%Showers 4.0%Taps/Sinks 20.1%Dishwashers 3.8%Washing Machine 34.0%Int. Leakage 5.0%

Outdoor use – Non-Residential Customer Categories

There is little data on levels of non-residential use in different climatic zones. In the absence of this information, assumptions are required that are reasonable. In this case,

Outdoor use for non-residential customer categories is assumed to be: • 50% of the proportion of

residential use for commercial and public

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approach has been to use some standard assumptions for some types of users and for others to provide a link to the level of residential use.

users. • 90% for parks and open

space uses • 25% of the proportion of

residential use for industrial users

2.2.2 Evaporative Cooling Uses There is limited information available upon which to derive a model of evaporative cooling use. The level of use is dependent on two parameters:

1. The level of ownership of evaporative coolers; and 2. The level of use.

A review of the available information has resulted in a model of ownership based on evaporation levels and a model of use based on temperature levels. Ownership data was collected from a number of sources. While the data set was not large, it indicated that within NSW, there was a low level of ownership in the coastal and ranges areas, with higher levels in the south-west and north-west. The relationship between the level of ownership and annual evaporation is shown in Figure 2. It shows that the relationship between annual evaporation and ownership of evaporative coolers is not a simple one.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 500 1000 1500 2000 2500 3000 3500

Annual Evaporation (mm)

Ow

ners

hip

of E

vapo

rativ

e C

oole

rs (M

ains

C

onne

cted

)

Yarra Valley Water

Alice Springs

Figure 2: Information on the Ownership of Evaporative Cooling Units (Sources: ABS, NT Power and Water, and Yarra Valley Water)

A review of detailed monitoring of evaporative cooling uses for Melbourne shows that cooling units are only used when temperatures are above 22 degrees Celsius (approximately 32% of days). When they are in use, water use is at a rate of approximately half the total rate of external use (assuming 2.5 persons per household using 180L/d per person internal use and 240kL/annum total use per household). Thus in Melbourne, the rate of evaporative cooling use is approximately

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16% the annual external use in those households with evaporative cooling units. For the simplified version of the DSS, it has been assumed that this figure is 20% of the annual level of external use. This increase has been made for the arid and semi arid areas of NSW where it is anticipated that evaporative cooling use will be higher as a proportion of total external use than it is in Melbourne.

0

100

200

300

400

500

600

0 5 10 15 20 25 30 35 40 45

Maximum Temperature (Deg. C)

Use

per

Eva

pora

tive

Coo

ling

Uni

t (Li

tres

)

Figure 3: Relationship between Evaporative Cooler Use and Maximum Daily Temperature (Source: Yarra Valley Water)

2.2.3 Hot Water Savings Hot water savings for customers are based on assumed market penetration of different types of water heating shown in Figure 4. The resulting heating costs are shown in Table 2.

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Electricity60%

Gas36%

Electric Boosted Solar3%

Gas Boosted Solar1%

Figure 4: Assumed Water Heating Energy Sources (Adapted from the Environmental Issues: People’s View and Practices – Australian Bureau of Statistics, Mach 2002)

Table 2: Energy Sources and Costs for Water Heating

Energy type

Units of

Measuremen

t

Cost Per Unit

Units Required to Raise One

Litre of Water in

Temperature by 1 Degree

Water Heating Efficienc

y (%)

Cost Per Degree

Change Per Litre

Electric kWhrs $0.12 1.16E-03 75.0% $1.81E-04 Gas MJ $0.01 4.19E-03 60.0% $9.08E-05 Electric Boosted Solar

kWhrs $0.12 1.16E-03 225.0% $6.03E-05

Gas Boosted Solar

MJ $0.01 4.19E-03 180.0% $3.03E-05

2.2.4 Conservation Measure Assumptions The underlying assumption regarding the costs and impacts of the different demand management measures is shown in Table 3.

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Table 3: Demand Management Options and Assumptions

Description Assumed Market Penetration

Assumed potable water Savings

Assumed implementation costs

Residential Retrofit Program Sheets Upon request, a Council approved plumber would install a retrofit kit in existing single-family residential housing. The kit could contain a low-flow shower head, tap flow restrictors, and a cistern weight for older style toilets. Leaking taps would be repaired.

15% of residential customers over a three year period.

For showerheads: • Based on average

use volumes for each type of shower

• 5% of participants in the program are free-riders.

For taps: • 20% reduction in

Taps/Sink uses per account

For leakage: • 5% reduction lasting

for 5 years

For showerhead: • $100 cost to utility per

showerhead retrofitted. For Taps: • $40 cost to utility per

account retrofitted. For leakage: • $5 cost to utility per

account.

National Mandatory Water Efficiency Labelling Scheme 2005 saw the introduction of a mandatory Water Efficiency Labelling Scheme (WELS) for toilets, washing machines, shower roses, taps, urinals and dishwashers.

Assumed to impact on SFR & MFR customers only; Increase the uptake of efficient washing machines by 5 % and low flow showerheads by 15%. No impact assumed on toilets because the level of participation in the existing voluntary scheme is high.

Based on average use reductions of: • 20% for taps; • 30% for dishwashers; • 30% for washing

machines; and • 30% for efficient

showerheads.

Costs to utility – to enhance and promote scheme: • Setup - $3,000 plus 20

cents for each person in the supply area.

• Annual outlay - $500 plus 5 cents for each person in the supply area.

Rainwater Tanks on all new Residential Development All new development residential development would fit a rainwater tank. Rainwater to be supplied for toilet flushing, cold water to the washing machine and outdoor use.

• 100% of new residential customers from 2006.

• 10 year pump life.

• 60% reduction in targeted water uses under average conditions, zero under peak conditions.

• Cost of installation is $2,500 per account (utility or household).

• $30 per year per customer for operation.

Dual Reticulation for New Subdivisions All new subdivisions to be fitted with dual reticulations systems with recycled water to be used for toilet flushing, and irrigation.

90% of all new residential developments (assume 10% are infill and therefore not suitable for supply with dual reticulation).

100% reduction in targeted end uses.

• $3,000 net per account for additional costs of dual reticulation.

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BASIX – Fixture Efficiency Component The NSW Government’s BASIX program will be implemented.

90% of new residential accounts complying.

20% reduction in use in showers, taps and sinks and outdoor use. The DSS then has two options for meeting the BASIX requirements – dual reticulation on all new development or rainwater tanks on all new development (see above).

Costs to utility: • Setup - $10,000 plus 20


• Annual administration/ enforcement - $3,000 plus 5 cents for each person in the supply area.

Cost to community (excluding rainwater tank and/or dual reticulation costs): • $10 additional for low

flow showerhead. • $10 for tap flow

regulators. • $100 for water efficient

planting/ landscaping. Community Education Council would provide materials, training and technical assistance to implement a comprehensive ongoing community education program.

20% of all customers in each customer category influenced by the community education effort.

Water savings vary dependent on the customer category and end use.



• Annual admin. $3,000 plus 5 cents for each person in the supply area.

Permanent Restrictions on Water use Council would introduce a water waste regulation that would: • prohibit irrigation during the

times of the day with the highest evaporation;

• mandate the use of a trigger nozzle when washing cars; and

• prohibit irrigation that fell on hard surfaces or hosing down of footpaths or driveways.

50% of all customers would adhere to the regulation.

10% reduction in external use in participating customers.




Inclining Block Water Pricing Structure Council would introduce an inclining block tariff for single family residential customers. The increase would result in an effective 50% increase in price for residential external use and no change in price for internal use.

All customers would be affected.

Price elasticity for external use is –0.2.

• Costs to utility; • Setup only - $5,000 plus

20 cents for each person in the supply area.

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Active Leak Detection and Repair Instead of more passive approaches where leaks are fixed when reported, councils would take a more active role by actually search for and repairing leaks in the supply system.

• Leakage assumed to be half of all NRW.

• One third of the system targeted each year for leak detection and repair.

• Reduces leakage by 75% in targeted areas upon completion of work.

• Impact of leakage reduction effort will last 3 years.

• Leak detection and repair assumed to be carried out over 10% of system each year.

• $280/km detection cost. • $230/km repair costs.

Non Residential Water Audits This measure allows for water audits for non-residential customers.

• 10% of non residential customers participating.

• 10% saving in non-leakage consumption per customer.

• 75% reduction in customer leakage – but savings only last 2 years.




• $300 cost to each customer for implementation of audit recommendations.

Evaporative Cooling Unit and Cooling Tower audit This measure allows for water audits for evaporative cooling units and cooling towers for both residential and non-residential customers.

• 4% of customers participating in any one year.

• 20% reduction in cooling uses.

• Measure life of 5 years.




Cost to each customer for implementation of audit recommendations: • $100 for residential. • $300 for non-residential.

2.3 How the Model Addresses BASIX In reducing water use for new dwellings, the NSW BASIX scheme is intended to be applied at the individual dwelling level. The DSS model does not address water savings at the individual dwelling level, but explores the impact of the BASIX scheme on the overall water supply system. The impact is assessed for two possible implementation options:

1. A combination of water efficient fixtures and appliances and recycled water use; and

2. A combination of water efficient fixtures and appliances and rainwater use.

The resulting water savings are provided for the supply system as a whole and the results should not be treated as an assessment of the impact of BASIX on a per tenement basis.

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3 Output 3.1 Building Scenarios The simplified version of the DSM DSS allows for the user to view summary information on each of the standard conservation measures and allows measures to be added to each scenario. The name of the worksheet of the individual measure shown on the left hand side of the table simply needs to be entered under a scenario in the yellow cell on the right. Clicking on the “Update Scenario Calculations” button adjusts all the calculations for the scenarios, recalculates the summary sheet and resets the charts.

3.2 Impacts of Scenarios The outputs from the DSS are found in two places. The first is in the summary sheet (“SUM”) which outlines the historical, baseline and managed demands for the four scenarios of:

• Per capita demands; • Annual average demands; and • Peak day demands.

These three time series are found in Charts “C1”, “C2” and “C3” and shown below.

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0

5,000

10,000

15,000

20,000

25,000

30,000

1985 1990 1995 2000 2005 2010 2015 2020 2025 2030 2035 2040

Year

Tota

l Wat

er D

eman

d (M

L/a)

HistoricalClimate CorrectedBaseline ForecastScenario 1Scenario 2Scenario 3Scenario 4

Integrated Water Cycle Management Demand Side Management ... · Demand Side Management Decision Support System- Simplified ... management effort. Benefits include reductions in treatment

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