regional heat pump energy loads - transpower new … · project number: qc5118 date of issue:13th...

Project Number: QC5118 Date of Issue:13th July 2009 of 71 Pages

E528

Regional heat pump energy loads

Author: Ian Page

Manager Economics

Reviewer: Lisa French

Building Energy Scientist

Contact: BRANZ Limited Moonshine Road Judgeford Private Bag 50908 Porirua City New Zealand Tel: +64 4 237 1170 Fax: +64 4 237 1171 www.branz.co.nz

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Report Number: E528 Date of Issue: 13 July 2009 of 71 Pages

Contents

1. CLIENT ............................................................................................................................................... 5

2. INTRODUCTION .............................................................................................................................. 5

3. MAIN RESULTS ............................................................................................................................... 5

4. METHOD .......................................................................................................................................... 10

5. SENSITIVITY RESULTS ............................................................................................................... 12

5.1 Heat pump uptake rates ........................................................................................................................... 13

5.2 Heating and cooling temperatures .................................................................................................... 16

5.3 Area of house conditioned ....................................................................................................................... 17

5.4 Use of summer cooling. ............................................................................................................................. 17

5.5 Heat pump efficiency changes ............................................................................................................. 18

5.6 Electric resistance heating temperatures .................................................................................... 18

5.7 Population growth rate changes ......................................................................................................... 18

6. MONTHLY ENERGY ....................................................................................................................... 18

7. REFERENCES .................................................................................................................................. 22

8. APPENDIX ....................................................................................................................................... 24

8.1 Housing energy use modelling ............................................................................................................24

8.1.1 Population projections ................................................................................................................24

8.1.2 Household formation and new house numbers ........................................................... 25

8.1.3 Fuel mix ................................................................................................................................................. 26

8.1.4 Insulation retrofit ........................................................................................................................... 35

8.1.5 Heat pump efficiencies ............................................................................................................... 35

8.1.6 Heating and cooling schemes ................................................................................................. 37

8.1.7 Use percentage – summer cooling....................................................................................... 37

8.2 Online survey on heat pumps ............................................................................................................... 38

8.3 Simulations ..................................................................................................................................................... 39

8.3.1 Energy efficiency of houses ..................................................................................................... 39

8.3.2 Modelling Assumptions – Heating Times, Temperatures ...................................... 40

8.3.3 Modelling Assumptions – Heated areas ........................................................................... 40

8.3.4 Modelling Assumptions – House Construction ............................................................. 41

8.3.5 Modelling Assumptions – Internal Loads..........................................................................42

8.3.6 Modelling Assumptions – Thermal Performance ....................................................... 43

8.3.7 Weather files ..................................................................................................................................... 43

8.4 Sensitivity analysis .................................................................................................................................... 45

8.4.1 Heating/ cooling regimes ......................................................................................................... 45

8.4.2 Conditioned house areas .......................................................................................................... 52

8.4.3 Use of heat pump for summer cooling ............................................................................... 54

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8.4.4 Heat pump efficiencies ............................................................................................................... 55

8.4.5 Winter electric resistance heating to 21/ 22°C ............................................................. 57

8.4.6 High and low population growth scenarios .................................................................... 58

8.5 Month energy volumes and percentages ..................................................................................... 62

8.6 Hourly energy volumes ............................................................................................................................. 70

TABLES Table 1. Base case energy use – Summer cooling ................................................................. 8 Table 2. Base case energy use – Winter heating.................................................................... 9 Table 3. HP % constant – Summer cooling .......................................................................... 15 Table 4. HP % constant – Winter heating ............................................................................. 16 Table 5. Population forecasts ............................................................................................... 24 Table 6. Insulation retrofit for the existing housing stock ....................................................... 35 Table 7. Heat pump efficiencies ........................................................................................... 36 Table 8.Summer cooling proportions by region .................................................................... 38 Table 9. No Insulation .......................................................................................................... 39 Table 11. New insulation regulations being introduced at present (2007-2008) .................... 39 Table 12. Potential building code insulation levels in 2020 – second option ......................... 40 Table 14. Cooling schedules ................................................................................................ 40 Table 15. Description of existing house models construction ................................................ 41 Table 16. Description of new house models construction ..................................................... 42 Table 17. Existing house internal gains ................................................................................ 42 Table 18. New houses internal gains .................................................................................... 42 Table 19. Summer cooling Evening20 .................................................................................. 46 Table 20. Summer cooling Day19 ........................................................................................ 47 Table 21. Summer cooling Day20 ........................................................................................ 48 Table 22. Winter heating Day22 ........................................................................................... 49 Table 23. Winter heating Evening21 ..................................................................................... 50 Table 24. Winter heating Evening22 ..................................................................................... 51 Table 25. Increased conditioned areas – Summer cooling ................................................... 52 Table 26. Increased conditioned areas – Winter heating ...................................................... 53 Table 27. Summer cooling heat pump use held constant ..................................................... 54 Table 28. Constant heat pump efficiencies – Summer cooling.............................................. 55 Table 29. Constant heat pump efficiencies – Winter heating ................................................ 56 Table 30. Electric resistance heating to 21/22°C .................................................................. 57 Table 31. Summer cooling – High population growth rate scenario ...................................... 58 Table 32. Winter heating High population growth scenario ................................................... 59 Table 33. Summer cooling – Low population growth rate scenario ....................................... 60 Table 34. Winter heating – Low population growth rate scenario .......................................... 61 Table 35. Monthly energy use. Cooling percent by month - 2009 ......................................... 62 Table 36. Monthly energy use. Cooling percent by month – 2026 ........................................ 63 Table 37. Monthly energy use. Heating percent by month – 2009 ........................................ 64 Table 38. Monthly energy use. Heating percent by month – 2026 ........................................ 65 Table 39. Monthly energy use. Cooling volume by month – 2009 ......................................... 66 Table 40. Monthly energy use. Cooling volume by month – 2026 ......................................... 67 Table 41. Monthly energy use. Heating volume by month – 2009 ......................................... 68 Table 42. Monthly energy use. Heating volume by month – 2026 ......................................... 69

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FIGURES

Figure 1. Summer energy use – base case assumptions ....................................................... 6 Figure 2. Winter energy use – base assumptions ................................................................... 7 Figure 3. Energy space conditioning model .......................................................................... 11 Figure 4. Heat pump uptake by region .................................................................................. 12 Figure 5. Compare peak energy with and without heat pump penetration –Summer cooling 13 Figure 6. Compare peak energy with and without heat pump penetration –Winter heating ... 14 Figure 7. Monthly peak energy summer cooling - 2009 ........................................................ 19 Figure 8. Monthly peak energy summer cooling - 2026 ........................................................ 19 Figure 9. Monthly energy use summer cooling - 2009 .......................................................... 20 Figure 10. Monthly energy use summer cooling - 2026 ........................................................ 20 Figure 11. Monthly peak energy winter heating - 2009 ......................................................... 21 Figure 12. Monthly peak energy winter heating - 2026 ......................................................... 21 Figure 13. Monthly energy use winter heating – 2009 .......................................................... 22 Figure 14. Monthly energy use winter heating - 2026 ........................................................... 22 Figure 15. Persons per household, selected regions. ........................................................... 25 Figure 16. New housing numbers ......................................................................................... 25 Figure 17. Housing demolitions ............................................................................................ 26 Figure 18. Fuel type change by region – Existing houses ..................................................... 30 Figure 19. Fuel type change by region – New houses .......................................................... 34 Figure 20. Cooling use of heat pumps percentage use ......................................................... 37 Figure 21: Climate map for HERS ....................................................................................... 44 Figure 22 Hourly energy use. Auckland Cooling Even19. ..................................................... 70 Figure 23 Hourly energy use. Auckland Cooling Day20. ....................................................... 70 Figure 24 Hourly energy use. Auckland Heating Day21. ....................................................... 71 Figure 25 Hourly energy use. Auckland Heating Even22. ..................................................... 71

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REGIONAL HEAT PUMP LOADS

1. CLIENT

Transpower New Zealand Ltd Transpower House 96 The Terrace Wellington 6011

2. INTRODUCTION

Transpower requested BRANZ to forecast by region the energy loads created by domestic space conditioning. This study has been initiated by the increasing uptake of air-to-air heat pumps, which are now in 21% of all households. Both summer cooling and winter heating loads are considered, and the energy demands and peak demands by the 16 regional councils were investigated.

Existing house numbers were obtained from census data and Statistics New Zealand (SNZ) population forecasts were used to estimate new housing. Research was commissioned on the existing use of heat pumps by region and future rates of uptake. Energy modelling was undertaken on a number of typical houses using the SUNREL modelling package, and the results scaled up for the housing stock in each region.

An earlier report, (Page , French 2008) had energy volumes for Auckland, Canterbury and Otago. The values in this report are lower for a number of reasons including a change to smaller average house sizes and higher heat pump efficiencies in this report, compared to the earlier assumptions.

3. MAIN RESULTS

The main results from the base case assumptions are shown graphically below for selected regions. The peak energy use and total energy use for summer cooling is shown in Figure 1. The results for winter heating are in Figure 2.

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Figure 1. Summer energy use – base case assumptions

The cooling peaks per house for Canterbury are higher than for Auckland, but the cooling volumes per house are lower. Hence total peak demand for Auckland and Canterbury are both quite high but the total energy use in Canterbury is lower than in Auckland.

The lines for cooling peaks and total use are fairly flat in most places because the increased heat pump numbers are mostly off-set by insulation retrofit effects and improved heat pump efficiencies. The exception is Auckland where strong population growth over-rides most other factors.

020406080

100120140160180200

2009 2011 2016 2021 2026 2031 2036 2041

Pe

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MW

Year ending March

Auckland

Canterbury

Waikato

Wellington

Otago

BOP

Summer cooling with Heat Pump: Peak DemandConditioning area= const. Conditioning regime= Even19 Pop proj=M Partial HP cooling use

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Ene

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Year ending March

Auckland

Canterbury

Waikato

Wellington

Otago

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Summer cooling with Heat Pump: Energy UseConditioning area= const. Conditioning regime= Even19 Pop proj=M Partial HP cooling use

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Figure 2. Winter energy use – base assumptions

Most of the lines for heating energy use are fairly flat. The reason for this is there is an approximate balance between rising house numbers and a switch from solid to electric fuel, off-set against more heat pumps compared to resistance heaters, improving heat pump efficiency, and more insulation retrofits.

The energy totals and energy peaks are tabulated for all regions in Table 1 and Table 2. Note, winter heating includes electric resistance heaters, where the latter houses are assumed to be at 18°C, not 21°C as used for the heat pump houses.

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2009 2011 2016 2021 2026 2031 2036 2041

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Year ending March

Auckland

Canterbury

Waikato

Wellington

Otago

BOP

Winter heating with Heat pump + Elect Resist Heater: Peak DemandConditioning area= const. Conditioning regime= Day21. Resist. Heater 18DegC. Pop proj=M

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Ene

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Year ending March

Auckland

Canterbury

Waikato

Wellington

Otago

BOP

Winter heating with Heat pump + Elect Resist Heater: Energy UseConditioning area= const. Conditioning regime= Day21. Resist. Heater 18DegC. Pop proj=M

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Table 1. Base case energy use – Summer cooling

Summer Cooling Energy use

2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= even19 Pop proj=M Partia l HP cooling

Northland Energy vol (GWh) 0.5 1.1 2.9 4.0 4.6 5.2 5.6 6.0

Energy peak MW 3.2 6.4 14.3 17.3 18.0 18.9 19.1 19.3

Auckland Vol GWh 5.5 11.1 29.7 42.9 52.1 61.9 70.1 78.4

Peak MW 30.3 56.5 123.6 152.5 162.9 175.9 183.1 190.4

Waikato Vol GWh 2.1 3.8 7.9 10.2 11.5 12.7 13.7 14.6

Peak MW 17.9 28.2 51.0 58.4 59.3 61.3 61.5 61.6

Bay of Plenty Vol GWh 1.2 2.2 6.1 8.6 10.3 12.1 13.5 15.0

Peak MW 6.4 10.9 25.1 31.2 33.4 36.1 37.5 38.9

Gisborne Vol GWh 0.2 0.3 0.6 0.8 0.9 1.0 1.1 1.2

Peak MW 1.6 2.5 3.9 4.4 4.4 4.6 4.7 4.7

Hawkes Bay Vol GWh 0.5 0.9 1.8 2.3 2.6 2.9 3.1 3.4

Peak MW 6.0 8.7 14.5 16.5 16.8 17.4 17.5 17.7

Taranaki Vol GWh 0.2 0.4 0.9 1.1 1.3 1.3 1.4 1.4

Peak MW 2.0 3.7 8.1 9.6 9.7 10.1 10.0 9.9

Man-Wang Vol GWh 0.3 0.7 1.8 2.3 2.6 2.9 3.1 3.3

Peak MW 3.8 7.3 15.6 18.6 19.2 20.2 20.4 20.6

Wellington Vol GWh 1.2 2.1 4.7 6.2 7.2 8.1 8.7 9.4

Peak MW 13.4 21.6 41.0 48.2 50.0 52.5 53.3 54.1

Tasman Vol GWh 0.1 0.3 0.7 0.9 1.1 1.3 1.4 1.6

Peak MW 0.7 1.5 3.3 4.1 4.3 4.7 4.8 5.0

Nelson Vol GWh 0.4 0.6 1.0 1.3 1.5 1.6 1.8 1.9

Peak MW 2.7 3.8 5.5 6.1 6.3 6.5 6.6 6.7

Marlborough Vol GWh 0.4 0.6 0.9 1.2 1.3 1.4 1.6 1.7

Peak MW 2.9 3.8 5.0 5.5 5.6 5.8 5.9 6.0

West Coast Vol GWh 0.0 0.0 0.1 0.1 0.2 0.2 0.2 0.2

Peak MW 0.2 0.6 1.5 1.9 1.9 2.0 2.0 1.9

Canterbury Vol GWh 5.3 7.3 11.6 13.9 15.3 16.8 17.9 19.0

Peak MW 79.3 101.0 142.4 154.4 154.1 158.6 159.4 160.0

Otago Vol GWh 1.0 1.4 2.4 2.9 3.2 3.6 3.8 4.1

Peak MW 12.9 17.4 26.2 29.2 29.7 31.1 31.7 32.3

Southland Vol GWh 0.1 0.1 0.3 0.4 0.4 0.4 0.4 0.4

Peak MW 3.7 5.5 10.2 11.3 11.0 11.1 10.9 10.6

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Table 2. Base case energy use – Winter heating

Winter Hea ting Energy use

2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= Day21. Resist. Hea te r 18DegC. Pop proj=M

Northland Energy vol GWh 25.5 26.9 31.5 31.8 31.2 32.5 33.2 33.5

Energy peak MW 12.4 16.5 25.4 26.8 25.9 26.0 25.3 24.6

Auckland Vol GWh 409.9 407.6 434.9 432.6 429.6 460.1 486.6 502.1

Peak MW 165.6 197.1 275.3 291.4 288.7 299.2 304.5 305.7

Waikato Vol GWh 134.9 140.5 155.2 156.8 158.0 168.8 177.2 182.3

Peak MW 53.9 66.9 93.1 96.6 93.1 93.9 92.7 91.0


Peak MW 24.4 31.8 56.9 61.9 60.1 60.6 59.4 57.6

Gisborne Vol GWh 7.6 7.7 10.9 10.8 9.6 9.8 9.7 9.5

Peak MW 4.0 5.2 7.3 7.3 6.5 6.3 6.0 5.7


Peak MW 20.2 24.3 33.7 33.9 31.2 30.1 28.5 27.1

Taranaki Vol GWh 33.6 33.9 39.8 37.4 33.0 32.9 32.1 31.0

Peak MW 11.2 14.5 22.7 23.0 20.6 20.0 18.9 17.7

Man-Wang Vol GWh 83.6 85.9 95.8 92.1 86.1 89.8 92.4 93.7

Peak MW 26.9 35.1 52.0 52.5 48.0 47.5 46.0 44.4


Peak MW 87.6 103.2 127.9 124.7 114.7 114.8 112.6 109.1

Tasman Vol GWh 3.5 4.3 8.9 10.2 10.1 10.7 10.9 11.2

Peak MW 2.3 3.8 7.3 8.0 7.7 7.7 7.5 7.4

Nelson Vol GWh 10.7 11.0 13.4 13.6 12.9 13.3 13.5 13.7

Peak MW 6.6 8.0 10.1 10.2 9.6 9.4 9.1 8.9


Peak MW 7.5 8.9 10.3 10.1 9.3 9.0 8.6 8.3


Peak MW 2.1 3.3 5.9 6.2 5.6 5.5 5.2 4.8


Peak MW 185.7 208.4 243.9 237.1 218.3 213.0 204.3 195.5

Otago Vol GWh 189.6 195.8 218.5 213.0 201.5 205.6 207.0 206.4

Peak MW 61.5 70.9 87.6 85.2 77.3 74.7 71.0 67.4


Peak MW 18.2 22.9 35.9 35.6 31.2 29.6 27.2 25.1

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4. METHOD

The method used to calculate energy volumes is shown diagrammatically in Figure 3. It is driven by demographics, combined with the thermal modelling results. Household formation forecasts are based on SNZ scenarios, described further in Section 8.1.1. The existing housing stock numbers, by region, are obtained from the five-yearly census of population and dwellings.

The amount of insulation in houses affects their demand for heating and cooling energy, and existing insulation levels are obtained from the BRANZ House Condition Survey (Clark et al, 2005), and the Housing Energy End-use Project (HEEP; Isaacs et al, 2006).

Insulation retrofit of the existing stock will continue into the future and the model allows for these changes. The heating and cooling regimes and the space conditioning modelling of the houses is described later and the results of that work provides the total and peak energy demand for the different locations. Demolitions of the stock are included since their replacements will usually be houses with a higher insulation level and a different space conditioning energy performance. TNS Conversa carried out a survey of over 3,800 households to obtain data on heat pump incidence, likely future uptake rates, and heating and cooling regimes. This was used to select the thermal modelling regimes and estimate future numbers of heat pumps.

The demand model does not have any price information inputs. Electricity price escalation is indirectly included as encouraging a steady increase in the proportion of the housing stock with heat pumps and insulation retrofits. The price of heat pumps is not expected to change significantly in real terms, though there is allowance for efficiency improvements.

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Figure 3. Energy space conditioning model

The main variables set out in the brief relate to:

Population (Low, Medium, High)

Household formation (Medium)

Heat pump Uptake (Static, Medium)

Insulation (no change, retrofit).

Conditioned areas (living only, whole house).

COP/EER (constant, improving).

Heating regime(4 schemes, including Day21 degC)

Cooling regime (4 schemes, including Even19 degC).

Use percentage (full summer, partial and increasing summer).

The assumptions for the base forecasts are shown in bold above, and the shaded boxes in Figure 3 represent where the assumptions can be altered.

The single most important variable is the uptake rate of heat pumps. A summary of the assumptions is shown in Figure 4 for the existing stock. By 2041 the uptake is expected to be up to 60% of all houses in the North Island and 80% in the South Island.

ENERGY DEMAND MODEL

Household Existing

formation housing

by region Demolition stock

replacements

BRANZ & TNS

survey

data Heat pump and

resistant heater

uptake rates Insulation

New housing retrofit

numbers rates

Heating/ cooling

regimes

Heat pump

efficiency trends

New housing Existing stock

energy use Summer cooling energy use

SUNREL modelling percentage use SUNREL modelling

Total energy demand

and peak energy

demand

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Figure 4. Heat pump uptake by region

5. SENSITIVITY RESULTS

A number of the variables listed in Section 4 were changed:

Heat pump uptake rate

Heating and cooling temperatures

Heated areas of the house

Summer cooling use

Heat pump efficiency changes

Electric resistance heating temperatures

Population growth rates.

The effect of changes in these variables were examined as follows. The detailed tables for the sensitivity analyses are in the appendix.

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Heat pumps in existing stock - North Island

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Heat pumps in existing stock - South Island

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5.1 Heat pump uptake rates

The fuel mix assumptions for the base case are shown in Figure 18 and Figure 19 in the appendix. These allow for the heat pump incidence to increase to up to 80% of all houses in some regions. The following sensitivity analysis assumes that the fuel mix is unchanged and remains at the 2009 percentages into the future. The heat pump efficiencies are also keep constant. This is the so-called “demographics only” run and the results are in Figure 5 and Figure 6 for Auckland and Canterbury only.

Figure 5. Compare peak energy with and without heat pump penetration –Summer cooling

Figure 5 indicates the summer cooling peak energy in the Auckland region increases by approximately 80MW by 2016, and 130MW in 2041, comparing increased heat pump penetration with no further gains in the percentage of houses with heat pumps. In Canterbury the peak increases by 60MW in 2016 and 60MW in 2041.

Figure 6 indicates the winter heating peak in the Auckland region increases by approximately 90MW by 2016 allowing for heat pump penetration compared to no change in current market penetration. By 2041 the peaks are similar as electric resistance heater numbers rise in the „No change‟ scenario. In Canterbury the peak

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Auckland Summer cooling - Peak energy

Increased HP %

No change HP%

Conditioning area= const. Conditioning regime= Even19 Pop proj=M Partial HP cooling use

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Canterbury Summer cooling - Peak energy

Increased HP %

No change HP%

Conditioning area= const. Conditioning regime= Even19 Pop proj=M Partial HP cooling use

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heating lines are fairly flat because insulation retrofits offset the increase in new housing.

Figure 6. Compare peak energy with and without heat pump penetration –Winter heating

In Table 3 and Table 4 the energy volumes and peaks decline slightly with time for some regions (Gisborne, Taranaki, West Coast and Southland), and these are locations where the SNZ population projections are for a net loss in population.

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Auckland Winter heating- Peak energy

Increased HP %

No change HP%

Conditioning area= const. Conditioning regime= Day21. Resist. Heater 18DegC. Pop proj=M

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2009 2011 2016 2021 2026 2031 2036 2041

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Canterbury Winter heating - Peak energy

Increased HP %

No change HP%

Conditioning area= const. Conditioning regime= Day21. Resist. Heater 18DegC. Pop proj=M

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Table 3. HP % constant – Summer cooling


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= even19 Pop proj=M Partia l HP cooling use


Energy peak MW 3.2 3.3 3.6 3.8 3.9 4.1 4.3 4.4

Auckland Vol GWh 5.5 6.1 9.5 13.1 16.7 20.2 23.8 27.4

Peak MW 30.3 30.8 34.4 38.2 42.0 45.9 49.9 53.8

Waikato Vol GWh 2.1 2.6 3.6 4.6 5.6 6.6 7.5 8.3

Peak MW 17.9 18.5 20.1 21.5 22.9 24.5 25.9 27.3


Peak MW 6.4 6.6 7.3 8.1 8.8 9.6 10.3 11.0

Gisborne Vol GWh 0.2 0.2 0.3 0.3 0.4 0.4 0.5 0.5

Peak MW 1.6 1.6 1.6 1.6 1.6 1.7 1.7 1.7


Peak MW 6.0 6.1 6.6 6.9 7.3 7.6 8.0 8.4

Taranaki Vol GWh 0.3 0.3 0.4 0.5 0.6 0.7 0.7 0.7

Peak MW 3.0 3.1 3.3 3.4 3.5 3.6 3.7 3.8

Man-Wang Vol GWh 0.3 0.4 0.6 0.8 0.9 1.1 1.2 1.3

Peak MW 3.8 4.0 4.4 4.7 5.0 5.3 5.6 5.9


Peak MW 13.4 13.6 14.4 15.2 16.0 16.8 17.5 18.3

Tasman Vol GWh 0.1 0.1 0.2 0.3 0.4 0.5 0.5 0.6

Peak MW 0.7 0.7 0.9 1.0 1.1 1.2 1.3 1.4

Nelson Vol GWh 0.4 0.4 0.6 0.7 0.8 0.9 1.1 1.2

Peak MW 2.7 2.7 2.9 3.0 3.1 3.3 3.4 3.6


Peak MW 2.9 2.9 3.1 3.2 3.3 3.4 3.5 3.6


Peak MW 0.21 0.22 0.24 0.24 0.25 0.25 0.26 0.26


Peak MW 79.3 79.9 82.5 84.9 87.2 91.4 95.2 98.5

Otago Vol GWh 1.0 1.1 1.3 1.5 1.7 1.9 2.1 2.3

Peak MW 12.9 12.9 13.3 13.6 13.8 14.4 14.9 15.5


Peak MW 3.7 3.7 3.7 3.6 3.5 3.5 3.5 3.5

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Table 4. HP % constant – Winter heating

5.2 Heating and cooling temperatures

The base case summer cooling regime is 19°C in the evening, and for winter heating it is 21°C during the day. These are the base cases as specified by the client. It should be pointed out that HEEP data shows that for winter heating it is evening heating that is more common than the day heating used in the base case.

The tables for different cooling and heating regimes are in the Appendix. The summary results, compared to the base case, are:

Summer cooling Evening 20°C peak MW energy decreases by between 9% and 18%, and the energy GWh total reduces by 30% to 40%, depending on the region (see Table 19).

Summer cooling Day 19°C the peak energy decreases by between 30% and 50%, and energy totals increase by 70% to 120%, depending on the region (see Table 20).


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= day21. Resist. Hea te r 18DegC. Pop proj=M


Energy peak MW 12.4 12.9 14.1 15.2 16.1 17.4 18.5 19.7

Auckland Vol GWh 409.9 401.3 423.6 449.2 476.4 533.3 591.5 650.1

Peak MW 165.6 166.1 185.7 206.5 227.8 255.7 284.0 312.3

Waikato Vol GWh 134.9 139.6 153.4 166.0 178.2 198.2 217.4 235.7

Peak MW 53.9 55.6 60.3 64.7 68.8 74.7 80.2 85.5


Peak MW 24.4 25.0 29.0 32.9 36.9 41.5 46.0 50.4

Gisborne Vol GWh 7.6 7.6 7.8 8.0 8.2 9.0 9.9 10.7

Peak MW 4.0 4.0 4.0 4.0 4.0 4.2 4.4 4.6


Peak MW 20.2 20.2 20.3 20.3 20.1 20.7 21.4 22.1

Taranaki Vol GWh 33.6 33.4 31.8 29.8 27.5 28.4 29.1 29.6

Peak MW 11.2 11.2 10.8 10.4 9.9 10.0 10.2 10.2

Man-Wang Vol GWh 83.6 83.5 83.9 83.6 82.7 89.9 97.1 104.0

Peak MW 26.9 27.0 27.3 27.4 27.3 28.9 30.5 32.0


Peak MW 87.6 87.1 88.5 89.5 90.4 97.2 103.7 109.9

Tasman Vol GWh 3.5 3.9 4.7 5.5 6.3 7.3 8.2 9.3

Peak MW 2.3 2.4 2.7 3.0 3.3 3.6 4.0 4.4

Nelson Vol GWh 10.7 10.6 10.6 10.6 10.6 11.5 12.3 13.1

Peak MW 6.6 6.6 6.6 6.7 6.6 6.9 7.2 7.4


Peak MW 7.5 7.5 7.6 7.6 7.5 7.7 7.9 8.1


Peak MW 2.05 2.24 2.43 2.55 2.61 2.71 2.78 2.82


Peak MW 185.7 184.3 184.3 184.1 183.7 191.6 198.5 204.6

Otago Vol GWh 189.6 190.2 195.9 200.8 205.4 223.1 241.0 258.5

Peak MW 61.5 61.1 60.7 60.2 59.5 61.8 63.9 66.0


Peak MW 18.2 18.3 18.0 17.3 16.5 16.4 16.3 16.3

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Summer cooling Day 20oC the peak decreases by between 40% and 60%, and energy totals increase by 10% to 40%, depending on the region (see Table 21). Winter heating Day 22°C peak and energy total volumes increase by between 6% and 14% depending on the region (see Table 22).

Winter heating Evening 22°C the peak changes reduce by up to 10%, and energy totals increase by up to 10%, depending on the region (see Table 24).

Winter heating Evening 21°C the peak decreases by between 10% and 20%, and energy totals reduce by 5% to 10%, depending on the region (see Table 23). Full details are in the appendix.

These changes can be used to approximate the effect of climate change on space conditioning energy demand. Temperatures are expected to be approximately 1°C warmer, on average by 2041 (see Bengtsson et al 2007). The above indicates that going from 19°C to 20°C evening cooling reduces the energy use by about 30% to 40%. A 1°C temperature rise will increase energy demand and the temperature-energy relationship is approximately linear, for small changes in temperatures. So maintaining 19°C evening temperatures in summer in 2041 will increase energy use by approximately 30% to 40%.

The converse occurs with winter heating, where climate change will reduce energy demand. The base case is 21°C Day and a 22°C Day indoor temperature increases energy volumes by between 6% to 14%. So we can expect winter energy volumes to decrease by about 6% to 14% in 2041 assuming the base case remains at 21°C.

5.3 Area of house conditioned

The areas conditioned in the base case are the living areas and includes the kitchen and dining area connected to the living area in an open plan. Alternative thermal modelling was carried out using an increased house area to cover the bedrooms and hallways. The heating and cooling set points remained the same as the base case. Typically the conditioned area in the alternative modelling was two to three times larger than in the base case.

The energy peaks were typically 270% to 300% above base case summer cooling peaks, and energy use was 180% to 250% higher. For winter heating the peaks were 200% to 260% higher than the base case, and the energy use was 120% to 210% above the base case. Full details are in the appendix.

5.4 Use of summer cooling.

Not all heat pumps are used for summer cooling because it is believed most households purchase them for winter heating as the primary use. The TNS survey indicates about 64% of residential heat pumps nationwide are used for summer cooling, but overseas studies indicates the percentage rises over time. The regional cooling use percentage is shown in the appendix (see Table 8), based on results from the TNS survey. This indicates a regional variation of between 40% and 90% of heat pumps used in the summer at present and the percentage use is assumed to rise by

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30% (to a maximum of 100%) in each region by 2041. This rise in use is included in the base case.

In this sensitivity analysis the summer use percentage was kept constant at the percentage for 2009. The result is that summer energy peak and total use is about 20% to 40% lower, depending on the region, in 2041 compared to the base case. This is because although heat pump numbers are increasing, the percentage used for cooling does not increase, as occurs in the base case.

5.5 Heat pump efficiency changes

Heat pump efficiencies (also known as Coefficients of Performance, or COPs) are given in Table 7 in the appendix and are assumed to rise to between 4.2 and 5.0 by 2041, the efficiency depending on the season and location.

When these efficiencies are keep constant (i.e. there is no improvement in heat pump technology) the energy use in 2041, both peak and volume, rises by about 25% to 60% in winter and 45% to 60% in summer, depending on the region.

5.6 Electric resistance heating temperatures

In houses with electric resistance heaters winter temperatures levels are held at 18°C rather than the 21°C or 22°C level assumed for other fuels. This is the base case assumption for modelling, based on HEEP work that shows houses with electric resistance heaters have lower average winter temperatures than houses using other fuel types.

However, in the sensitivity analysis we allow for electric resistance heated houses to achieve the same temperatures as houses heated with the other fuel types. This gives an energy volume up by about 10% to 35% compared to the base case. The peak demand is up about 30% in the early years but drops to about 10% in later years as the heat pump market penetration rises.

5.7 Population growth rate changes

The demographic projections use a medium population growth scenario for the base case. The sensitivity analysis allows for high and low population growth scenarios. With the high scenario energy use is up about 40% on the base case by 2041 and the peaks are about 15% higher than the base case. With the low population scenario the energy volumes are down about 40% and peaks down about 15% compared to the base case, summer and winter.

6. MONTHLY ENERGY

Figure 7 to Figure 10 show energy use and peaks by month, for summer cooling at 2009 and 2026, for selected regions. The volumes are higher for the later year but the seasonal pattern is similar in 2009 and 2026, i.e. the peak month is February for cooling, though in Auckland and Wellington January is almost as high as February.

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Figure 7. Monthly peak energy summer cooling - 2009

Figure 8. Monthly peak energy summer cooling - 2026

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Figure 9. Monthly energy use summer cooling - 2009

Figure 10. Monthly energy use summer cooling - 2026

Monthly heating for winter is shown in Figure 11 to Figure 14. For peak energy (MW) June is the highest month for Auckland and Canterbury, and July for Wellington. For total energy use (GWh) July is the highest month for the three centres.

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Figure 11. Monthly peak energy winter heating - 2009

Figure 12. Monthly peak energy winter heating - 2026

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Figure 13. Monthly energy use winter heating – 2009

Figure 14. Monthly energy use winter heating - 2026

More details of the monthly volumes and percentages are in Section 8.5.

7. REFERENCES

Bengtsson et al (2007). Assessment of the need to adapt buildings in New Zealand to the impact of climate change. Study Report 179. BRANZ. Wellington.

French L. (2008). Active cooling and heat pump use in New Zealand – Survey results. Study Report 186. BRANZ, Wellington.

Clark S, Jones M, Page I. (2005). New Zealand 2005 House Condition Survey. BRANZ, Wellington

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Page I, French L (2008).Peak load and total energy use forecasting for heat pumps. BRANZ Report QC5112. For Transpower NZ.

Isaacs et al (2006). Energy use in NZ households –Report on the year 10 analysis. BRANZ Study Report 155. BRANZ, Wellington.

Mustard D, Mc Kibbin R. (2009) Research on heat pump usage and incidence rates in New Zealand. TNS Conversa, Auckland.

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8. APPENDIX

This appendix consists of five main sections:

Regional housing energy use modelling

TNS survey results summary

Space conditioning simulations

Sensitivity analysis results

Monthly energy volumes and percentages

Hourly energy volumes

8.1 Housing energy use modelling

The derivation of energy use by region follows the flow chart in Figure 3.

8.1.1 Population projections

The base case used for population growth is the medium scenarios from Statistics New Zealand assuming 10,000 net migration inflows per year on average, and medium levels for mortality and fertility rates, based on recent trends. The usual residential population as at the 2006 is the starting point. These numbers are slightly lower than the numbers used by SNZ for their population projections. SNZ use a 30 June date for their forecasts whereas the table below uses March censuses. The percentage change in five year increments from the SNZ population forecasts for each region were used to obtain the population numbers below. To derive new housing statistics the population forecasts are divided by the persons per household trends, see Table 5 and Figure 15.

Table 5. Population forecasts

Usual resident populationAt March 2006 2011 2016 2021 2026 2031 2036 2041

Northland 148,470 154,207 159,068 163,054 166,166 168,208 169,179 170,194

Auckland 1,303,068 1,409,804 1,518,440 1,626,506 1,733,052 1,836,556 1,936,273 2,030,574

Waikato 382,716 399,086 413,132 425,337 435,895 444,516 450,523 454,072

Bay of Plenty 257,379 271,543 284,349 296,088 306,953 316,461 324,263 330,358

Gisborne 44,499 44,983 45,176 45,273 44,983 44,499 43,780 42,836

Hawke's Bay 147,783 150,504 152,447 153,613 154,099 153,710 153,249 152,789

Taranaki 104,124 104,512 104,609 104,027 102,765 100,728 98,247 95,237

Manawatu-Wang 222,423 225,332 227,756 229,210 229,695 228,725 227,044 224,394

Wellington 448,959 464,845 478,614 490,745 501,143 509,327 515,242 518,827

Tasman 44,625 46,769 48,522 50,081 51,445 52,517 53,239 53,985

Nelson 42,888 44,243 45,405 46,373 47,148 47,729 48,072 48,409

Marlborough 42,558 44,022 45,193 46,072 46,462 46,560 46,653 46,746

West Coast 31,326 31,326 31,131 30,740 30,155 29,277 28,260 27,079

Canterbury 521,832 546,957 568,120 586,964 604,069 619,434 630,847 639,001

Otago 193,800 198,941 203,500 207,477 210,774 213,199 214,939 215,895

Southland 91,494 90,709 89,531 87,764 85,407 82,364 79,399 76,541

NZ 4,027,944 4,229,793 4,417,009 4,591,346 4,752,239 4,895,841 5,021,246 5,128,979

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Figure 15. Persons per household, selected regions.

8.1.2 Household formation and new house numbers

The new housing numbers are obtained by dividing the population by the persons per household and these are shown in Figure 16. Auckland remains the major centre into the future followed by Canterbury and Wellington regions.

Figure 16. New housing numbers

The housing stock is beginning to age and by about 2021 houses from the 1950s and 1960s will require significant renovation to extend their life. It is likely some will be beyond repair/adaptation and will be demolished. These houses will be replaced with new housing and have been added to the numbers derived from population growth demand for houses. The net effect of these demolition replacements is that energy use is reduced because the new replacements have higher insulation levels, on average, than the demolished stock.

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Figure 17. Housing demolitions

8.1.3 Fuel mix

The fuels for winter heating consist of four main types, electric resistance heaters, heat pumps, solid fuel heaters (i.e. wood, pellet and coal burners), and gas heaters (natural gas and LPG). The forecasts for fuel shares by region are shown in the following charts, see Figure 18.

The starting point is the main heating fuel shares at present, by region, as revealed in the TNS survey (TNS Conversa, 2009) (Q4) of approximately 3,800 households. To obtain the shares in 2041 the answers to the question on heating replacement (Q6) were used to allocate the regions to one of three categories, namely a high, medium or low likelihood to purchase a heat pump. An increased share of 50%, 40% and 30% respectively (for high, medium and low likelihoods) was added to the 2009 heat pump regional percentages, to represent the share for 2041. Solid fuel use was assumed to reduce by 50% and gas use by 20% from current levels. The residual was electric resistance, with an assumed minimum of 5% share in all regions.

The decline in solid fuel heating is assumed to be driven by clean air regulations, with most regional councils having air-shed pollution targets to achieve.

The maximum share for heat pumps occurs in Canterbury, Otago and Southland, and the least in Northland, Gisborne, Tasman and the West Coast. A similar set of regional fuel types are shown below for new housing, see Figure 19.

The current incidence by region is based on the BRANZ New Dwellings Survey, and the heat pump percentage in 2041 is assumed to be between 10% and 20% higher than for existing houses at that time. As for existing houses, solid fuel use is assumed to decline by 50%, and gas use by 20%, through to 2041.

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Figure 18. Fuel type change by region – Existing houses

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Figure 19. Fuel type change by region – New houses

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8.1.4 Insulation retrofit

Pre-1978 houses are unlikely to have wall or floor insulation, though most have some ceiling insulation. The BRANZ 2004 House Condition Survey and HEEP provides data on the amount of ceiling and floor insulation in typical houses for a number of regions. These results are shown in Table 6, where nil/little insulation is defined as 50 mm of ceiling insulation or less. The assumptions on retrofit levels are in the table, and indicate that the pre -1978 housing stock (when insulation first became mandatory) will have been retrofitted to a reasonable level by 2026. Many of the post-1978 houses would also have been upgraded by then to current insulation levels (2008). Table 6. Insulation retrofit for the existing housing stock

8.1.5 Heat pump efficiencies

The technology for heat pumps is continually improving and it is assumed there will be efficiencies of COPs between 4.2 and 5.0, depending on location and season, in new heat pumps over the next 30 years. The assumptions are in Table 7 where lower efficiencies are used in cooler climates and for heating compared to cooling. These values are based on some research carried out by Nikki Buckett at BRANZ - see below.

Insulation retrofit - selected regions

Insulation Percent by standard a t

level 2009 2026 2041

Auckland Nil/Little 28 5 0

1978 70 54 40

2008 2 42 60

100 100 100

Waikato Nil/Little 28 5 0

1978 70 54 40

2008 2 42 60

100 100 100

BOP Nil/Little 24 5 0

1978 74 55 40

2008 2 40 60

100 100 100

Wellington Nil/Little 30 0 0

1978 68 48 30

2008 2 53 70

100 100 100

Canterbury Nil/Little 20 0 0

1978 78 48 20

2008 2 52 80

Otago Nil/Little 21 0 0

1978 77 47 20

2008 2 53 80

100 100 100

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Table 7. Heat pump efficiencies

Comments from Nikki Buckett, Building Technologist, BRANZ, on heat pump efficiency trends.

I’ve done a bit of research into the efficiency of heat pumps in order to get a better idea of where their efficiency will be in about 20 years time. There is very little information available, especially regarding COPs of older units. I believe that a typical COP for early NZ models installed in the 90s was around the 2.5 mark – although can’t find any proof of this. Now, going through the EnergyWise database of heat pump units, the average COP over ALL sizes and heat pump types is 3.77 (124 entries). My data from May 07 (3576 entries) has an average COP over ALL sizes and heat pump types of 3.01. The maximum COP a heat pump can reach, or “Ideal COP” as it is known, = Output Temperature (°K)/Temperature differential (°K). So, if the external temperature is 7°C, and the heat pump is heating to 23°C, the equation is: 296.15°K/(296.15°K-280.15°K) = 18.5 (Ideal COP). See the attachment for a good explanation. However, the unit must also operate a fan and a pump for the refrigerant, display, fin direction etc, plus there are external factors such as humidity levels etc. Therefore the actual COP is never anywhere close to the Ideal COP, nor is it likely to be achieved. The maximum efficiency in the new energywise list is 5.22 (Panasonic CS-HE9GKE, under 4kW in output – see http://www.panasonic.co.nz/heatpumps/heatpumps-products/heatpumps-home/cscu-he9gke.html). The maximum efficiency in the May 07 list was the Panasonic RAS-B10SKVP-E (no longer produced by the looks), non ducted single split system under 4kW in output. Also, see http://www.heatpumpcentre.org/About_heat_pumps/HP_performance.asp (last updated April 09) for a handy graph and tables – they reckon maximum efficiency for an electric compressor-type heat pump is around 5. After looking at all of this, and acknowledging the slowing of efficiency improvements over the past few years, I’d say the average COP for NZ air to air heat pumps in 20 years will be hovering around the 5 mark for all types as inverter technology is developed further and adopted for more types of heat pump applications. This does not include losses in efficiency due to ducting in the central heat pump systems. This gives manufacturers some room to improve a little on the current designs, but acknowledges the challenges they have in increasing the COP to closer to Ideal COP levels. Unless there is a radical change in technology, I think this will be about right. The heat pumps with the highest COPs (over 5) are all single split inverters from what I can see, which appeared on the market here about 2-3 years ago. CO2 heat pumps (manufactured in Japan under the name “EcoCute”) are probably the next air to air heat pump technology that will be introduced to our market over the next few years. These have COPs of around 5.

Heat pumps - COPs and EERs

Se lected regions

COP or EER a t

2009 2026 2041

Auckland Summer 3.40 4.20 5.00

Winter 3.20 4.00 4.80

BOP Summer 3.40 4.20 5.00

Winter 3.20 4.00 4.80

Wellington Summer 3.10 3.90 4.70

Winter 2.90 3.70 4.50

Canterbury Summer 2.80 3.60 4.40

Winter 2.60 3.40 4.20

Otago Summer 2.70 3.55 4.40

Winter 2.50 3.35 4.20

http://www.panasonic.co.nz/heatpumps/heatpumps-products/heatpumps-home/cscu-he9gke.html

http://www.panasonic.co.nz/heatpumps/heatpumps-products/heatpumps-home/cscu-he9gke.html

http://www.heatpumpcentre.org/About_heat_pumps/HP_performance.asp

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8.1.6 Heating and cooling schemes

There are four heating schemes for summer cooling and winter heating and these are described later in 8.3.

8.1.7 Use percentage – summer cooling

The TNS survey indicates that users do not all use their heat pump for summer cooling. The assumed track is as below for selected regions, see Figure 20 and Table 8. At present, according to the survey Waikato and Taranaki are the regions most likely to use heat pumps for cooling, followed by Auckland and Canterbury. The percentages are the proportion of houses that use their heat pumps for cooling; the others open windows, use fans or do not actively cool in summer.

Figure 20. Cooling use of heat pumps percentage use

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Table 8.Summer cooling proportions by region

Taranaki and Tasman had very high and very low cooling percentages, respectively, in the survey, and these were somewhat arbitrarily adjusted to align with the percentages in adjacent regions.

8.2 Online survey on heat pumps

The primary goal of this survey was to calculate the incidence of heat pump ownership across New Zealand, with the aim of using this information to forecast the energy usage of heating devices. The survey was done at a regional level. TNS Conversa was contracted by BRANZ Ltd to complete the survey. The TNS Conversa report of this survey is provided as a separate document.

Nationwide ownership of electric heat pumps is at the 21% level. The regions with significantly higher ownership levels are: Hawke‟s Bay, Marlborough, Canterbury and Otago. Heat pump ownership levels are significantly lower for: Northland, Auckland, Taranaki, Manawatu and Wellington.

South Island has a higher penetration of heat pumps; but there are still regions in

the South Island where enclosed woodburners are the norm.

Auckland and Wellington use more forms of „other electric‟ heating devices.

The average number of heat pumps among those who own a heat pump is 1.28

Household income affects heat pump ownership; families that earn more have higher ownership levels.

People with heat pumps are extremely likely to continue using heat pumps; even if they were required to replace their existing form of heating, most would (re)purchase a heat pump.

Heat pumps are primarily post 2000 devices, located in lounges or family rooms.

Percentage use of heat pumps for summer cooling

2009 2011 2016 2021 2026 2031 2036 2041

Northland 69 72 77 81 86 90 95 99

Auckland 67 70 74 79 83 88 92 97

Waikato 76 79 82 86 89 93 96 100

Bay of Plenty 52 55 59 64 68 73 77 82

Gisborne 50 53 58 62 67 71 76 80

Hawkes Bay 58 61 66 70 75 79 84 88

Taranaki 60 63 68 72 77 81 86 90

Man-Wang 50 53 58 62 67 71 76 80

Wellington 59 62 66 71 75 80 84 89

Tasman 50 53 58 62 67 71 76 80

Nelson 67 70 74 79 83 88 92 97

Marlborough 53 56 61 65 70 74 79 83

West Coast 50 53 58 62 67 71 76 80

Canterbury 64 67 72 76 81 85 90 94

Otago 40 43 48 52 57 61 66 70

Southland 58 61 66 70 75 79 84 88

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If electricity prices increased, most people would not change their behaviour regarding the use of their heat pump. This is true for both heating and cooling usage.

People tend to heat either the whole house, or just the lounge, with their heat pump.

8.3 Simulations

Five houses have been modelled in SUNREL. Three „existing‟ houses from the HEEP database and two „new‟ houses from group builders. The newer houses tend to have a larger floor area and larger glazing area. All houses are one level except the existing large house, which is two levels with the living space being on the upper level.

A range of assumptions is required to support the simulations; the following section describes the models and the key assumptions.

8.3.1 Energy efficiency of houses

Three levels of insulation are used in the simulations, representing the two major changes in code requirements and before requirements were in place. The R-value of the insulation added to the floor, roof and walls are shown in Table 9 through to Table 12, including the glazing type. The lowest R-value insulation that meets code and is available commercially has been used. Table 9. No Insulation

Component Insulation added (m² °C/W)

Zone 1&2 Zone 3

Roof - -

Wall - -

Floor - -

Glazing Single Single

Table 10. Insulation at 1978 code


Zone 1&2 Zone 3

Roof 1.8 3.2

Wall 1.5 1.8

Floor - -

Glazing Single Single

Table 11. New insulation regulations being introduced at present (2007-2008)


Zone 1&2 Zone 3

Roof 3.2 3.6

Wall 1.8 1.8

Floor - -

Glazing Double Double

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Table 12. Potential building code insulation levels in 2020 – second option


Zone 1&2 Zone 3

Roof 3.6 4.2

Wall 2.6 2.8

Floor 1.9 1.9

Glazing Double, Low-E

Double, Low-E, argon filled

8.3.2 Modelling Assumptions – Heating Times, Temperatures

The following assumptions on heating/cooling times, temperature thermostat set points and heated/cooled areas are taken from survey work. This includes the survey undertaken for this work completed at a regional level in March 2009 (Mustard and McKibbin 2009), the survey undertaken in Auckland and Central Otago in 2008 for Transpower and the BRANZ national survey undertaken in August 2007, (French 2008).

Table 13 sets out the heating times and temperatures and Table 14 cooling in the living spaces of the houses. Table 13. Heating schedules

Schedule name Description

Day 21 Daytime (9am to 5pm) heating to 21°C, all other times 16°C

Day 22 Daytime (9am to 5pm) heating to 22°C, all other times 16°C

Even 21 Evening (5pm to 11pm) heating to 21°C, all other times 16°C

Even 22 Evening (5pm to 11pm) heating to 22°C, all other times 16°C

Occupants were found to be setting the thermostat to a lower temperature for cooling than heating. Table 14. Cooling schedules

Schedule name Description

Day 19 Daytime (9am to 5pm) cooling to 19°C, all other times 16°C

Day 20 Daytime (9am to 5pm) cooling to 20°C, all other times 16°C

Even 19 Evening (5pm to 11pm) cooling to 19°C, all other times 16°C

Even 20 Evening (5pm to 11pm) cooling to 20°C, all other times 16°C

8.3.3 Modelling Assumptions – Heated areas

Two heating areas have been used in the simulations. At present most heating and cooling by heat pumps is in the living room (heated area 1). In new houses and as people retrofit, often larger areas of the house are heated or cooled (heated area 2).

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Heating area 1 covers the living or family room and any spaces open to this room (e.g. often the kitchen and dining room in new houses). Heating area 2 covers the living or family room and spaces open this room, bedrooms, kitchen, dining room and hallways. The areas of the heating living space is given in Table 15.

8.3.4 Modelling Assumptions – House Construction

The key features of the modelled houses are summarised in Table 15 and Table 16. The houses have weatherboard cladding on exterior walls; pitched corrugated steel roof; flat ceilings; and concrete slab on ground floor. The walls are timber-frame (non-solid construction) and are built from 100 mm (nominal) timber. All interior walls are timber-framed with no insulation, and plaster board on each side.

For the purposes of modelling, the concrete floor has been treated as having a perimeter area of one metre. Where the heat loss is modelled to go through the ground, and out to the air (outwards from the slab), and a middle area where the heat loss is straight into the ground. This is the suggested method in the SUNREL manual.

The solar reflectivity for exterior walls is taken as 0.3, which is representative of a medium to light coloured wall. Table 15. Description of existing house models construction

Building Feature Small house Medium house Large house

Floor area 103 m² 167 m² 245 m²

Heating area 1 – Living area including kitchen/dining where it is open plan

21 m² 31 m² 39 m²

Heating area 2 - 90 m² 110 m² 140 m²

Ceiling height 2.4m 2.45m 2.7m

Ground floor Concrete slab Concrete slab Concrete slab

Average eave projection 600mm 600mm 600mm

Construction types Non-solid Non-solid Non-solid

Infiltration rate1 0.5 ac/h 0.5 ac/h 0.5 ac/h

Orientation Family room facing east

Family room facing north

Family room facing north-east

1 Discussions with Mark Bassett, BRANZ ventilation specialist

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Table 16. Description of new house models construction

Building Feature New house one New house two

Floor area 160 m² 211 m²

Heating area 1 – Living area including kitchen/dining when open plan

53 m² 91 m²

Heating area 2 – 127 m² 173 m²

Ceiling height 2.4 m 2.4 m

Ground floor Concrete slab Concrete slab

Average eave projection 450 mm 450 mm

Construction types Non-solid Non-solid

Infiltration rate2 0.3 ac/h 0.3 ac/h

Orientation North North

8.3.5 Modelling Assumptions – Internal Loads

Table 17 and Table 18 document the models occupancy, equipment use and hot water cylinder (DHW) energy losses, in terms of internal gains for use in the thermal simulation models.

Table 17. Existing house internal gains

Sensible heat gains Small house Medium house Large house

7:00-23:00 23:00 7:00-23:00 23:00 7:00-23:00 23:00

Occupants: 3 112.5 W 225 W 150 W 300 W 187.5 W 375 W

Equipment use: 309 W 148.7 W 480 W 240 W 735 W 367.5 W

DHW loss: 100 W 50 W 100 W 50 W 100 W 50 W

Table 18. New houses internal gains

Sensible heat gains New house one New house two

7:00-23:00 23:00 7:00-23:00 23:00

Occupants: 4 187.5 W 375 W 187.5 W 375 W

Equipment use: 572.1 W 222.7 W 727.2 W 341 W

DHW loss: 100 W 50 W 100 W 50 W

2 Discussions with Mark Bassett, BRANZ ventilation specialist 3 75 W/person 4 75 W/person

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8.3.6 Modelling Assumptions – Thermal Performance

In order to correctly model the thermal performance of the timber construction roof, wall and floor it was necessary to determine the cavity to stud ratio. Ian Cox-Smith, BRANZ thermal insulation specialist provided the following proportions:

Walls – studs 18%, cavity 82%

Ceiling – joists 12%, void 88%

Roof – rafters 10%, void 90%

The R-value for an air space was taken as 0.18 m² °K/W – an appropriate value for air in an enclosed space.

All material properties were taken from NZS 4214:2006 “Methods of determining the total thermal resistance of parts of buildings”

8.3.7 Weather files

The weather files used are from EECA they have been converted to the SUNREL format from the HERS Accurate weather files. The HERS files have been used as they are the most up to date and reliable data available for New Zealand at present. The stations for the 16 HERS weather files used and the area they represent can be seen in Figure 21.

The HERS files are TMY format. This means a typical year is developed from analysis of several year‟s worth of data. Internationally this is the suggested format for this type of modelling work.

There is a disclaimer on the HERS weather files as stated below:

“The data is publicly-funded data provided by the National Institute of Water and Atmospheric Research Limited (“NIWA”) and no person or entity may charge for its supply or use. While NIWA has exercised reasonable care and skill in the preparation and collation of the data files, the data is supplied on an “as is” basis, without warranty of any kind. NIWA accepts no liability for any direct, indirect, special or consequential damages, loss, damage or cost arising from and relating to, any use of the data and/or the information associated with it. Full terms and conditions governing the use of the data can be found at: http://edenz.niwa.co.nz/about/terms”.

http://edenz.niwa.co.nz/about/terms

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Figure 21: Climate map for HERS

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8.4 Sensitivity analysis

This section contains the details of the sensitivity analyses described in section 5. It provides the energy use by regions for changes in:

heating/cooling regimes. The base cases are 19°C evening cooling, and 21°C day

heating. The sensitivity cases for summer cooling are 19°C Day, 20°C Day, and 20°C Evening. The sensitivity cases for winter heating are 22°C Day, 21°C Evening, and 22°C Evening.

the area of the house that is heated and cooled. The base case is living room and the adjacent open plan kitchen and dining areas. The sensitivity analysis extends the conditioned areas to hallways and bedrooms.

the change in houses with heat pumps using them for summer cooling. The base case assumes an increase of 30% over 30 years. The sensitivity analysis assumes there is no increase in houses that have heat pumps using then for summer cooling.

changes in heat pump efficiencies. The base case assumes heat pump COPs will improve by 0.5 over the next 30 years. The sensitivity analysis assumes no increase in efficiencies.

Allow electric resistance heating to be 21°C or 22°C instead of the base case 18°C.

Low and high population growth scenarios.

8.4.1 Heating/ cooling regimes

Energy use by region for the alternative regimes are in Table 19 to Table 24.

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Table 19. Summer cooling Evening20


2009 2011 2016 2021 2026 2031 2036 2041



Energy peak MW 2.8 5.6 12.5 15.1 15.8 16.6 16.8 17.0

Auckland Vol GWh 3.9 7.7 20.8 30.1 36.7 43.6 49.3 55.1

Peak MW 26.7 49.8 109.1 134.7 144.0 155.5 161.9 168.3

Waikato Vol GWh 1.4 2.5 5.2 6.7 7.6 8.5 9.1 9.7

Peak MW 15.9 25.1 45.3 51.9 52.6 54.4 54.6 54.7


Peak MW 5.7 9.5 22.0 27.4 29.3 31.7 32.9 34.1

Gisborne Vol GWh 0.1 0.2 0.4 0.6 0.6 0.7 0.8 0.9

Peak MW 1.4 2.3 3.6 4.0 4.0 4.1 4.2 4.3


Peak MW 5.1 7.5 12.5 14.2 14.5 15.0 15.1 15.3

Taranaki Vol GWh 0.1 0.2 0.5 0.7 0.8 0.8 0.8 0.9

Peak MW 1.7 3.2 6.9 8.1 8.3 8.6 8.5 8.5

Man-Wang Vol GWh 0.2 0.4 1.1 1.4 1.6 1.8 1.9 2.0

Peak MW 3.3 6.2 13.2 15.9 16.4 17.3 17.4 17.6


Peak MW 11.4 18.4 34.9 41.2 42.7 44.9 45.6 46.3

Tasman Vol GWh 0.1 0.2 0.4 0.6 0.7 0.8 0.9 1.0

Peak MW 0.6 1.3 2.9 3.6 3.8 4.1 4.2 4.4

Nelson Vol GWh 0.3 0.4 0.7 0.9 1.0 1.1 1.2 1.3

Peak MW 2.3 3.3 4.8 5.4 5.5 5.7 5.8 5.9


Peak MW 2.5 3.3 4.4 4.8 4.9 5.1 5.2 5.3


Peak MW 0.2 0.5 1.3 1.5 1.6 1.6 1.6 1.6


Peak MW 72.4 92.1 129.6 140.4 139.9 144.0 144.8 145.2

Otago Vol GWh 0.7 1.0 1.7 2.0 2.2 2.4 2.6 2.8

Peak MW 11.5 15.5 23.3 26.0 26.3 27.6 28.1 28.7


Peak MW 3.1 4.6 8.5 9.4 9.1 9.2 9.0 8.8

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Table 20. Summer cooling Day19


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= day19 Pop proj=M Partia l HP cooling use


Energy peak MW 2.1 4.2 9.0 10.6 10.7 11.2 11.2 11.3

Auckland Vol GWh 10.9 21.2 54.1 75.3 89.3 105.4 118.7 132.2

Peak MW 21.9 40.5 86.5 104.5 109.4 117.1 120.8 124.7

Waikato Vol GWh 4.2 7.3 14.6 18.2 20.0 22.1 23.7 25.1

Peak MW 10.8 16.8 29.4 32.6 32.1 32.9 32.7 32.5


Peak MW 4.3 7.2 16.3 19.8 20.8 22.3 23.0 23.7

Gisborne Vol GWh 0.4 0.7 1.2 1.4 1.6 1.8 1.9 2.1

Peak MW 1.2 1.8 2.8 3.0 3.0 3.1 3.1 3.2


Peak MW 3.9 5.6 9.2 10.3 10.4 10.7 10.7 10.8

Taranaki Vol GWh 0.4 0.8 1.8 2.2 2.3 2.5 2.6 2.6

Peak MW 1.4 2.5 5.3 6.0 5.9 6.1 6.1 6.0

Man-Wang Vol GWh 0.8 1.6 3.6 4.5 5.0 5.5 5.8 6.1

Peak MW 2.6 4.9 10.1 11.7 11.6 12.2 12.2 12.3


Peak MW 9.1 14.5 26.5 30.1 30.1 31.5 31.9 32.2

Tasman Vol GWh 0.2 0.5 1.2 1.7 2.0 2.3 2.6 2.9

Peak MW 0.4 1.0 2.0 2.4 2.5 2.7 2.8 2.9

Nelson Vol GWh 0.8 1.1 1.9 2.3 2.6 2.9 3.2 3.5

Peak MW 1.7 2.4 3.4 3.7 3.7 3.8 3.9 3.9


Peak MW 1.8 2.4 3.1 3.3 3.3 3.4 3.4 3.5


Peak MW 0.1 0.4 0.9 1.0 1.0 1.0 1.0 1.0


Peak MW 46.5 58.3 79.8 83.9 81.3 83.5 83.8 84.0

Otago Vol GWh 1.4 2.0 3.2 3.9 4.2 4.7 5.1 5.5

Peak MW 7.2 9.5 13.8 14.8 14.4 15.1 15.4 15.7


Peak MW 2.1 3.1 5.4 5.7 5.3 5.3 5.2 5.0

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Table 21. Summer cooling Day20


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= day20 Pop proj=M Partia l HP cooling use


Energy peak MW 1.8 3.5 7.4 8.7 8.8 9.2 9.2 9.3

Auckland Vol GWh 8.0 15.6 39.6 55.2 65.4 77.1 86.8 96.6

Peak MW 18.7 34.5 73.3 88.0 91.7 98.0 101.0 104.1

Waikato Vol GWh 2.9 5.0 10.0 12.5 13.7 15.2 16.3 17.2

Peak MW 9.4 14.6 25.3 27.8 27.2 27.9 27.7 27.6


Peak MW 3.6 6.0 13.5 16.4 17.2 18.5 19.1 19.7

Gisborne Vol GWh 0.3 0.5 0.9 1.1 1.2 1.3 1.4 1.5

Peak MW 1.0 1.6 2.5 2.7 2.6 2.7 2.7 2.7


Peak MW 3.2 4.6 7.4 8.2 8.2 8.4 8.4 8.5

Taranaki Vol GWh 0.2 0.5 1.1 1.4 1.5 1.6 1.6 1.7

Peak MW 1.1 2.0 4.2 4.8 4.6 4.8 4.7 4.7

Man-Wang Vol GWh 0.5 1.0 2.3 2.9 3.2 3.5 3.8 4.0

Peak MW 2.1 4.0 8.1 9.3 9.2 9.6 9.7 9.8


Peak MW 7.5 11.8 21.4 24.1 23.9 25.1 25.4 25.7

Tasman Vol GWh 0.1 0.4 0.9 1.2 1.4 1.6 1.8 2.0

Peak MW 0.4 0.8 1.7 2.0 2.1 2.2 2.3 2.4

Nelson Vol GWh 0.5 0.8 1.3 1.6 1.8 2.1 2.2 2.4

Peak MW 1.4 2.0 2.8 3.0 3.0 3.1 3.2 3.2


Peak MW 1.5 2.0 2.5 2.7 2.7 2.8 2.8 2.9


Peak MW 0.1 0.3 0.8 0.9 0.8 0.9 0.9 0.8


Peak MW 41.0 51.3 69.6 72.6 69.7 71.7 72.1 72.3

Otago Vol GWh 1.0 1.4 2.2 2.6 2.8 3.2 3.4 3.7

Peak MW 6.5 8.6 12.4 13.3 12.9 13.5 13.8 14.1


Peak MW 1.8 2.6 4.6 4.8 4.4 4.5 4.3 4.2

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Table 22. Winter heating Day22


2009 2011 2016 2021 2026 2031 2036 2041



Energy peak MW 13.1 17.7 27.9 29.7 28.7 28.7 28.0 27.2

Auckland Vol GWh 416.6 419.6 462.1 466.7 466.5 501.0 530.0 547.9

Peak MW 171.5 207.6 296.7 316.2 313.6 324.7 329.7 330.7

Waikato Vol GWh 138.4 146.2 165.6 168.7 170.3 181.7 190.3 195.6

Peak MW 56.8 71.3 100.7 105.0 101.3 102.0 100.6 98.6


Peak MW 26.1 34.5 62.7 68.5 66.7 67.3 65.9 63.9

Gisborne Vol GWh 7.9 8.2 11.7 11.7 10.6 10.7 10.6 10.5

Peak MW 4.3 5.7 8.0 8.0 7.2 7.0 6.7 6.3


Peak MW 21.7 26.4 37.0 37.5 34.6 33.4 31.7 30.2

Taranaki Vol GWh 34.3 35.4 42.6 40.5 35.9 35.8 34.9 33.6

Peak MW 11.7 15.5 24.7 25.2 22.7 22.0 20.8 19.5

Man-Wang Vol GWh 85.3 89.2 102.2 99.1 92.9 96.8 99.3 100.6

Peak MW 28.2 37.4 56.4 57.3 52.6 52.0 50.2 48.4


Peak MW 91.3 108.9 137.9 135.6 125.2 125.2 122.6 118.7

Tasman Vol GWh 3.7 4.8 10.0 11.4 11.4 12.1 12.4 12.8

Peak MW 2.5 4.2 8.1 8.9 8.6 8.6 8.4 8.2

Nelson Vol GWh 11.3 11.9 14.7 15.0 14.3 14.8 15.0 15.3

Peak MW 7.2 8.7 11.1 11.3 10.6 10.4 10.1 9.8


Peak MW 8.3 9.8 11.4 11.2 10.4 10.1 9.6 9.3


Peak MW 2.1 3.5 6.4 6.7 6.2 6.0 5.7 5.3


Peak MW 197.6 223.0 263.4 257.2 237.5 231.6 222.0 212.4

Otago Vol GWh 194.3 202.1 227.6 222.8 211.2 215.6 217.0 216.5

Peak MW 65.3 75.7 94.3 92.1 83.8 81.0 76.9 73.0


Peak MW 19.3 24.5 38.7 38.6 34.0 32.1 29.6 27.3

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Table 23. Winter heating Evening21


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= Even21. Resist. Hea te r 18DegC. Pop proj=M


Energy peak MW 9.9 12.9 19.7 20.9 20.2 20.3 19.9 19.4

Auckland Vol GWh 394.7 390.0 410.5 405.4 401.3 430.1 455.5 470.2

Peak MW 131.9 154.8 212.5 223.3 219.7 226.8 229.8 229.9

Waikato Vol GWh 129.5 133.7 145.3 145.8 146.7 157.0 165.1 170.2

Peak MW 44.5 54.8 75.7 78.5 75.7 76.5 75.6 74.2


Peak MW 18.9 25.0 45.2 49.1 47.6 47.9 46.9 45.5

Gisborne Vol GWh 7.5 7.6 10.7 10.6 9.4 9.5 9.5 9.3

Peak MW 3.5 4.5 6.4 6.4 5.7 5.6 5.3 5.0


Peak MW 17.2 20.5 27.9 27.8 25.1 24.2 22.9 21.7

Taranaki Vol GWh 32.1 32.1 36.9 34.4 30.2 30.1 29.4 28.4

Peak MW 9.9 12.8 19.8 19.8 17.6 17.1 16.1 15.2

Man-Wang Vol GWh 80.2 81.6 89.3 85.2 79.4 83.0 85.5 86.9

Peak MW 24.0 31.1 45.4 45.4 41.1 40.8 39.6 38.3


Peak MW 78.4 91.7 111.9 108.0 98.5 98.8 97.2 94.4

Tasman Vol GWh 3.5 4.2 8.8 10.0 9.9 10.5 10.8 11.1

Peak MW 1.8 2.9 5.6 6.2 5.9 5.9 5.8 5.7

Nelson Vol GWh 10.5 10.8 13.1 13.3 12.6 13.1 13.3 13.6

Peak MW 5.2 6.2 7.8 7.8 7.3 7.2 7.0 6.8


Peak MW 5.8 6.8 7.9 7.7 7.1 6.9 6.6 6.4


Peak MW 1.8 2.9 5.2 5.4 4.9 4.8 4.5 4.2


Peak MW 146.7 163.9 190.7 184.7 169.5 165.4 158.6 151.8

Otago Vol GWh 183.3 188.5 208.9 203.0 191.6 195.6 197.0 196.5

Peak MW 57.0 65.4 79.9 77.0 69.2 66.8 63.4 60.2


Peak MW 14.6 18.2 28.7 28.5 25.0 23.7 21.8 20.2

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Table 24. Winter heating Evening22


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= Even22. Resist. Hea te r 18DegC. Pop proj=M


Energy peak MW 10.5 14.1 22.1 23.7 23.0 23.1 22.5 22.0

Auckland Vol GWh 399.6 398.8 430.5 430.7 428.8 460.5 487.8 504.3

Peak MW 137.3 164.5 232.8 247.5 244.5 252.3 255.1 255.2

Waikato Vol GWh 131.9 137.7 152.7 154.4 155.6 166.3 174.6 179.8

Peak MW 47.2 58.8 83.0 86.7 83.9 84.6 83.5 81.9


Peak MW 20.5 27.6 50.7 55.5 54.1 54.6 53.5 51.9

Gisborne Vol GWh 7.8 8.1 11.4 11.4 10.2 10.4 10.3 10.2

Peak MW 3.8 5.0 7.0 7.0 6.4 6.2 6.0 5.7


Peak MW 18.5 22.3 30.9 31.0 28.4 27.4 25.9 24.7

Taranaki Vol GWh 32.7 33.1 38.8 36.6 32.2 32.2 31.4 30.3

Peak MW 10.4 13.7 21.7 21.9 19.7 19.1 18.0 17.0

Man-Wang Vol GWh 81.4 83.9 93.7 90.1 84.3 88.0 90.5 91.9

Peak MW 25.2 33.2 49.6 50.1 45.8 45.4 43.9 42.4


Peak MW 81.8 96.9 121.4 118.7 109.1 109.3 107.3 104.1

Tasman Vol GWh 3.7 4.6 9.7 11.1 11.1 11.8 12.2 12.6

Peak MW 1.9 3.3 6.4 7.1 6.8 6.8 6.7 6.5

Nelson Vol GWh 11.1 11.6 14.3 14.5 13.9 14.4 14.6 15.0

Peak MW 5.7 6.9 8.8 8.9 8.3 8.2 8.0 7.8


Peak MW 6.5 7.7 9.0 8.9 8.2 8.0 7.6 7.4


Peak MW 1.9 3.1 5.7 6.0 5.5 5.3 5.0 4.7


Peak MW 157.8 177.7 209.6 204.5 188.8 184.1 176.4 168.8

Otago Vol GWh 187.0 193.4 215.9 210.5 199.1 203.3 204.7 204.3

Peak MW 60.6 69.9 86.4 83.8 75.7 73.1 69.4 65.9


Peak MW 15.6 19.7 31.3 31.4 27.8 26.3 24.2 22.4

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8.4.2 Conditioned house areas

The sensitivity analysis extends the conditioned areas to hallways and bedrooms, see Table 25 and Table 26.

Table 25. Increased conditioned areas – Summer cooling


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= incr. Conditioning regime= even19 Pop proj=M Partia l HP cooling use


Energy peak MW 12.6 24.7 53.5 63.4 64.6 66.9 66.5 66.2

Auckland Vol GWh 18.3 35.4 87.1 118.3 137.4 158.1 174.4 190.8

Peak MW 112.1 207.4 440.6 528.7 549.7 580.7 591.2 601.9

Waikato Vol GWh 7.2 12.2 23.7 29.0 31.4 34.1 35.7 37.2

Peak MW 71.4 111.0 195.8 219.5 217.6 221.1 217.6 214.1


Peak MW 25.0 41.7 93.6 113.4 118.2 125.2 127.3 129.4

Gisborne Vol GWh 0.7 1.1 1.9 2.4 2.6 2.8 3.0 3.2

Peak MW 6.4 10.1 15.4 16.8 16.5 17.0 17.0 17.0


Peak MW 23.6 33.8 55.4 62.0 62.1 63.5 63.1 62.8

Taranaki Vol GWh 0.6 1.2 2.7 3.3 3.6 3.8 3.8 3.9

Peak MW 7.5 13.9 29.8 35.0 35.2 36.2 35.7 35.2

Man-Wang Vol GWh 1.1 2.3 5.2 6.6 7.3 7.9 8.3 8.6

Peak MW 14.4 27.1 56.6 66.7 68.0 70.6 70.6 70.5


Peak MW 49.9 79.9 148.2 171.5 174.3 180.7 180.9 181.0

Tasman Vol GWh 0.3 0.8 1.9 2.5 2.8 3.2 3.5 3.8

Peak MW 2.6 5.7 11.9 14.3 14.8 15.7 16.0 16.3

Nelson Vol GWh 1.3 1.9 3.0 3.6 3.9 4.3 4.5 4.8

Peak MW 10.1 14.1 20.1 22.0 22.0 22.5 22.5 22.5


Peak MW 10.8 14.3 18.2 19.5 19.6 20.0 20.1 20.2


Peak MW 0.9 2.4 6.1 7.2 7.2 7.4 7.3 7.2


Peak MW 304.5 383.8 530.7 565.1 553.0 561.5 556.5 550.9

Otago Vol GWh 3.2 4.4 7.0 8.2 8.6 9.4 9.9 10.4

Peak MW 49.4 65.9 97.4 106.6 106.0 109.4 110.0 110.4


Peak MW 13.6 19.9 36.6 40.2 38.6 39.0 38.0 37.0

ICP LJF


Table 26. Increased conditioned areas – Winter heating


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= incr. Conditioning regime= Day21. Resist. Hea te r 18DegC. Pop proj=M


Energy peak MW 44.3 58.6 89.8 93.8 88.7 87.2 83.5 79.7

Auckland Vol GWh 1224.5 1201.8 1212.3 1137.7 1061.1 1097.1 1123.1 1128.2

Peak MW 570.7 679.8 932.2 963.5 926.4 934.9 925.6 907.8

Waikato Vol GWh 410.9 414.6 428.1 404.8 382.4 394.2 400.9 401.1

Peak MW 188.3 231.3 316.8 321.3 301.0 296.6 285.8 274.2


Peak MW 87.1 113.1 199.3 213.3 202.7 200.1 191.8 182.6

Gisborne Vol GWh 23.9 23.9 32.1 30.2 25.2 24.8 23.9 23.0

Peak MW 14.7 19.0 26.2 25.7 22.7 21.8 20.4 19.1


Peak MW 72.3 86.9 119.5 119.2 108.0 103.2 96.4 90.4

Taranaki Vol GWh 100.9 100.5 113.1 101.5 84.5 83.1 80.0 76.2

Peak MW 38.4 50.1 78.6 78.8 70.0 67.6 63.3 59.0

Man-Wang Vol GWh 250.8 253.5 267.1 241.0 210.0 214.3 215.4 214.0

Peak MW 91.9 120.3 177.3 176.5 158.3 154.7 147.3 139.9


Peak MW 297.6 351.4 432.5 415.4 373.7 367.6 354.0 337.3

Tasman Vol GWh 10.5 12.4 24.4 26.5 25.0 25.9 26.0 26.3

Peak MW 8.1 13.4 25.5 27.6 25.9 25.7 24.6 23.7

Nelson Vol GWh 31.8 32.2 37.5 36.2 32.6 33.0 32.8 32.8

Peak MW 23.6 28.3 35.5 35.3 32.5 31.6 30.1 28.9


Peak MW 27.1 31.7 36.3 35.1 32.0 30.6 28.9 27.4


Peak MW 7.2 11.4 20.6 21.3 19.2 18.6 17.4 16.2


Peak MW 636.3 710.5 821.2 785.1 708.8 681.1 643.2 606.3

Otago Vol GWh 561.8 566.4 598.2 552.4 494.3 493.9 487.3 477.1

Peak MW 209.7 240.6 293.1 280.4 249.4 237.9 222.9 208.8


Peak MW 62.6 78.2 122.0 120.3 104.6 98.8 90.7 83.4

ICP LJF


8.4.3 Use of heat pump for summer cooling

This sensitivity analysis assumes the percentage of houses with heat pumps using them for summer cooling is held at the current 2009 percentages, see Table 27.

Table 27. Summer cooling heat pump use held constant


2009 2011 2016 2021 2026 2031 2036 2041



Energy peak MW 3.2 6.4 13.3 15.1 14.8 14.7 14.0 13.5

Auckland Vol GWh 5.5 11.1 27.7 37.4 42.7 47.8 51.1 54.1

Peak MW 30.3 56.5 115.2 133.1 133.5 135.8 133.4 131.3

Waikato Vol GWh 2.1 3.8 7.5 9.2 9.9 10.5 10.8 11.0

Peak MW 17.9 28.2 48.4 52.8 51.1 50.5 48.5 46.5


Peak MW 6.4 10.9 23.0 26.3 26.0 26.1 25.3 24.6

Gisborne Vol GWh 0.2 0.3 0.6 0.7 0.7 0.7 0.8 0.8

Peak MW 1.6 2.5 3.6 3.7 3.4 3.3 3.1 3.0


Peak MW 6.0 8.7 13.4 14.1 13.4 13.0 12.3 11.7

Taranaki Vol GWh 0.2 0.4 0.8 1.0 1.0 1.0 1.0 0.9

Peak MW 2.0 3.7 7.5 8.2 7.8 7.6 7.1 6.6

Man-Wang Vol GWh 0.3 0.7 1.6 1.9 2.0 2.1 2.1 2.0

Peak MW 3.8 7.3 14.2 15.6 14.9 14.5 13.6 12.9


Peak MW 13.4 21.6 37.9 41.4 40.0 39.4 37.5 35.8

Tasman Vol GWh 0.1 0.3 0.6 0.8 0.9 0.9 0.9 1.0

Peak MW 0.7 1.5 3.0 3.4 3.3 3.3 3.2 3.1

Nelson Vol GWh 0.4 0.6 1.0 1.1 1.2 1.3 1.3 1.3

Peak MW 2.7 3.8 5.1 5.4 5.2 5.0 4.8 4.6


Peak MW 2.9 3.8 4.6 4.6 4.4 4.2 4.0 3.9


Peak MW 0.2 0.6 1.4 1.6 1.5 1.4 1.3 1.2


Peak MW 79.3 101.0 132.4 134.1 125.5 121.4 115.0 109.0

Otago Vol GWh 1.0 1.4 2.1 2.3 2.4 2.4 2.4 2.4

Peak MW 12.9 17.4 23.5 23.7 21.9 21.0 19.7 18.5


Peak MW 3.7 5.5 9.4 9.7 8.8 8.3 7.6 7.0

ICP LJF


8.4.4 Heat pump efficiencies

The efficiencies of heat pumps, both summer cooling and winter heating are held constant at 2009 levels, see Table 28 and Table 29.

Table 28. Constant heat pump efficiencies – Summer cooling


2009 2011 2016 2021 2026 2031 2036 2041



Energy peak MW 3.2 6.4 15.4 20.0 22.2 24.8 26.6 28.4

Auckland Vol GWh 5.5 11.1 32.0 49.6 64.3 81.3 97.6 115.3

Peak MW 30.3 56.5 133.3 176.4 201.2 231.1 254.9 279.9

Waikato Vol GWh 2.1 3.8 8.5 11.8 14.1 16.7 19.0 21.4

Peak MW 17.9 28.2 55.0 67.6 73.2 80.6 85.6 90.6


Peak MW 6.4 10.9 27.1 36.1 41.2 47.4 52.2 57.1

Gisborne Vol GWh 0.2 0.3 0.7 0.9 1.1 1.4 1.6 1.8

Peak MW 1.6 2.5 4.2 5.1 5.4 6.0 6.5 7.0


Peak MW 6.0 8.7 15.6 19.0 20.7 22.8 24.4 26.1

Taranaki Vol GWh 0.2 0.4 1.0 1.3 1.5 1.8 1.9 2.1

Peak MW 2.0 3.7 8.7 11.1 12.0 13.2 13.9 14.6

Man-Wang Vol GWh 0.3 0.7 1.9 2.7 3.3 3.9 4.4 5.0

Peak MW 3.8 7.3 16.9 21.8 24.2 27.1 29.2 31.2


Peak MW 13.4 21.6 44.5 56.5 62.8 70.6 76.3 82.0

Tasman Vol GWh 0.1 0.3 0.7 1.1 1.4 1.7 2.0 2.4

Peak MW 0.7 1.5 3.6 4.7 5.4 6.3 6.9 7.6

Nelson Vol GWh 0.4 0.6 1.1 1.5 1.9 2.2 2.5 2.9

Peak MW 2.7 3.8 6.0 7.2 7.9 8.8 9.5 10.2


Peak MW 2.9 3.8 5.4 6.4 7.0 7.8 8.4 9.1


Peak MW 0.2 0.6 1.7 2.2 2.4 2.7 2.8 3.0


Peak MW 79.3 101.0 155.9 183.8 198.1 219.1 235.4 251.4

Otago Vol GWh 1.0 1.4 2.6 3.5 4.2 5.0 5.9 6.7

Peak MW 12.9 17.4 28.9 35.4 39.0 44.1 48.4 52.6


Peak MW 3.7 5.5 11.2 13.6 14.3 15.5 16.3 17.0

ICP LJF


Table 29. Constant heat pump efficiencies – Winter heating


2009 2011 2016 2021 2026 2031 2036 2041



Energy peak MW 12.4 16.5 27.0 30.6 31.2 32.9 33.5 34.0

Auckland Vol GWh 409.9 407.6 449.1 465.9 480.7 533.7 582.4 621.5

Peak MW 165.6 197.1 290.5 325.3 338.0 365.7 385.8 401.4

Waikato Vol GWh 134.9 140.5 163.3 174.3 183.6 203.9 221.2 235.1

Peak MW 53.9 66.9 99.6 110.3 112.4 119.2 122.8 125.4


Peak MW 24.4 31.8 61.1 71.3 73.8 78.8 81.3 83.1

Gisborne Vol GWh 7.6 7.7 11.6 12.2 11.6 12.4 12.9 13.4

Peak MW 4.0 5.2 7.9 8.4 8.0 8.3 8.3 8.3


Peak MW 20.2 24.3 36.3 39.2 38.4 39.4 39.5 39.6

Taranaki Vol GWh 33.6 33.9 42.1 42.2 39.3 41.2 42.1 42.4

Peak MW 11.2 14.5 24.4 26.5 25.3 26.1 25.9 25.7

Man-Wang Vol GWh 83.6 85.9 101.5 104.0 102.5 112.1 119.9 126.4

Peak MW 26.9 35.1 56.1 61.0 59.5 62.5 63.7 64.4


Peak MW 87.6 103.2 137.2 143.9 141.0 149.3 153.8 156.4

Tasman Vol GWh 3.5 4.3 9.6 11.7 12.4 13.9 15.0 16.2

Peak MW 2.3 3.8 7.9 9.4 9.7 10.3 10.7 11.0

Nelson Vol GWh 10.7 11.0 14.2 15.3 15.4 16.7 17.7 18.9

Peak MW 6.6 8.0 10.9 11.8 11.8 12.4 12.6 12.9


Peak MW 7.5 8.9 11.2 11.9 11.8 12.1 12.3 12.5


Peak MW 2.1 3.3 6.4 7.1 7.0 7.2 7.2 7.1


Peak MW 185.7 208.4 266.9 282.7 281.1 294.1 300.5 305.4

Otago Vol GWh 189.6 195.8 238.1 253.7 259.8 285.1 306.5 326.0

Peak MW 61.5 70.9 96.8 103.5 102.2 106.6 108.7 110.3


Peak MW 18.2 22.9 39.4 42.7 40.6 41.3 40.7 40.0

ICP LJF


8.4.5 Winter electric resistance heating to 21/ 22°C

Electric resistance heating is allowed to rise to 21/22°C instead of the base case 18°C, see Table 30.

Table 30. Electric resistance heating to 21°C


2009 2011 2016 2021 2026 2031 2036 2041



Energy peak MW 16.1 19.6 27.5 28.5 27.4 27.4 26.8 26.0

Auckland Vol GWh 580.8 565.6 576.7 568.1 571.0 614.1 655.2 678.0

Peak MW 222.2 248.6 315.9 326.7 322.0 331.3 335.7 335.1

Waikato Vol GWh 163.7 166.2 174.9 175.2 178.7 192.5 204.2 211.5

Peak MW 62.5 74.0 97.3 99.4 95.5 96.2 95.0 93.0


Peak MW 28.5 35.0 59.1 63.6 61.7 62.1 60.9 58.9

Gisborne Vol GWh 8.5 8.1 11.6 11.6 10.4 10.5 10.4 10.2

Peak MW 4.3 5.4 7.5 7.5 6.7 6.5 6.2 5.9


Peak MW 22.2 25.7 34.8 34.9 32.0 30.9 29.3 27.9

Taranaki Vol GWh 41.4 40.0 43.9 40.7 36.1 36.0 35.3 34.0

Peak MW 13.0 16.0 23.7 23.7 21.3 20.7 19.5 18.3

Man-Wang Vol GWh 103.3 102.2 107.1 101.9 96.4 101.1 104.8 107.0

Peak MW 31.6 38.9 54.3 54.1 49.5 49.0 47.4 45.6


Peak MW 104.6 118.4 137.0 131.1 120.4 120.2 117.8 113.7

Tasman Vol GWh 4.3 4.6 9.7 11.2 11.2 11.8 12.1 12.5

Peak MW 2.5 3.8 7.5 8.3 8.0 8.0 7.8 7.6

Nelson Vol GWh 13.2 12.9 15.5 15.7 15.1 15.5 15.8 16.1

Peak MW 7.4 8.5 10.7 10.8 10.2 10.0 9.7 9.4


Peak MW 7.9 9.0 10.5 10.4 9.6 9.3 8.9 8.5


Peak MW 2.6 3.7 6.2 6.4 5.8 5.7 5.4 5.0


Peak MW 199.8 220.3 250.6 241.4 222.1 216.5 207.7 198.5

Otago Vol GWh 206.1 208.9 227.0 219.5 207.5 211.5 213.0 212.2

Peak MW 65.2 73.9 89.5 86.6 78.6 75.9 72.1 68.5


Peak MW 19.4 23.7 36.6 36.2 31.8 30.1 27.8 25.7

ICP LJF


8.4.6 High and low population growth scenarios

Table 31. Summer cooling – High population growth rate scenario


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= even19 Pop proj=H Partia l HP cooling use


Energy peak MW 3.2 6.4 14.5 17.8 18.9 20.2 20.7 21.0

Auckland Vol GWh 5.5 11.1 31.2 46.4 57.6 69.6 79.8 90.1

Peak MW 30.3 56.5 125.5 156.9 169.8 185.7 195.4 205.1

Waikato Vol GWh 2.1 3.8 8.4 11.2 13.1 15.0 16.5 18.0

Peak MW 17.9 28.2 52.0 60.6 62.6 65.9 67.3 68.5


Peak MW 6.4 10.9 25.6 32.3 35.1 38.6 40.8 42.9

Gisborne Vol GWh 0.2 0.3 0.7 0.9 1.1 1.3 1.5 1.7

Peak MW 1.6 2.5 4.0 4.6 4.7 5.1 5.3 5.5


Peak MW 6.0 8.7 14.8 17.1 17.7 18.7 18.9 19.1

Taranaki Vol GWh 0.2 0.4 0.9 1.2 1.4 1.6 1.7 1.8

Peak MW 2.0 3.7 8.2 9.9 10.2 10.7 10.8 10.9

Man-Wang Vol GWh 0.3 0.7 1.9 2.6 3.0 3.5 3.8 4.2

Peak MW 3.8 7.3 15.9 19.3 20.3 21.6 22.3 22.9


Peak MW 13.4 21.6 41.6 49.7 52.2 55.7 57.3 58.9

Tasman Vol GWh 0.1 0.3 0.7 1.0 1.3 1.5 1.7 1.9

Peak MW 0.7 1.5 3.4 4.2 4.6 5.1 5.3 5.6

Nelson Vol GWh 0.4 0.6 1.1 1.5 1.7 2.0 2.2 2.4

Peak MW 2.7 3.8 5.6 6.4 6.7 7.1 7.3 7.4


Peak MW 2.9 3.8 5.1 5.7 6.0 6.3 6.4 6.6


Peak MW 0.2 0.6 1.6 1.9 2.0 2.1 2.2 2.2


Peak MW 79.3 101.0 144.4 158.5 160.4 167.1 169.9 172.5

Otago Vol GWh 1.0 1.4 2.5 3.2 3.7 4.2 4.7 5.2

Peak MW 12.9 17.4 26.7 30.3 31.4 33.5 34.7 36.0


Peak MW 3.7 5.5 10.4 11.8 11.7 12.1 11.8 11.5

ICP LJF


Table 32. Winter heating High population growth scenario


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= Day21. Resist. Hea te r 18DegC. Pop proj=H


Energy peak MW 12.4 16.5 26.0 28.1 27.7 28.4 28.4 27.6

Auckland Vol GWh 409.9 407.6 447.9 456.9 465.3 508.0 545.4 569.1

Peak MW 165.6 197.1 281.1 302.3 304.8 320.7 330.9 335.9

Waikato Vol GWh 134.9 140.5 163.8 173.4 182.9 202.2 218.7 231.1

Peak MW 53.9 66.9 95.7 101.6 100.6 104.1 105.4 105.9


Peak MW 24.4 31.8 58.2 64.4 63.8 65.4 65.3 64.3

Gisborne Vol GWh 7.6 7.7 11.4 11.9 11.2 11.9 12.3 12.6

Peak MW 4.0 5.2 7.5 7.6 7.0 7.0 6.8 6.7


Peak MW 20.2 24.3 34.3 35.2 33.0 32.4 30.8 29.3

Taranaki Vol GWh 33.6 33.9 41.2 40.5 37.7 39.1 39.7 39.9

Peak MW 11.2 14.5 23.1 23.7 21.8 21.6 20.8 19.9

Man-Wang Vol GWh 83.6 85.9 101.3 102.9 102.2 111.4 118.9 125.1

Peak MW 26.9 35.1 53.3 55.1 51.9 52.8 52.5 52.0


Peak MW 87.6 103.2 130.5 129.7 121.9 124.4 124.4 122.7

Tasman Vol GWh 3.5 4.3 9.4 11.0 11.4 12.4 13.1 13.3

Peak MW 2.3 3.8 7.5 8.4 8.2 8.4 8.3 8.2

Nelson Vol GWh 10.7 11.0 13.9 14.6 14.5 15.4 16.0 16.2

Peak MW 6.6 8.0 10.3 10.6 10.2 10.2 10.1 9.8


Peak MW 7.5 8.9 10.5 10.5 9.9 9.8 9.4 9.0


Peak MW 2.1 3.3 6.1 6.5 6.2 6.2 6.1 5.9


Peak MW 185.7 208.4 247.7 244.3 228.8 226.5 220.5 214.0

Otago Vol GWh 189.6 195.8 229.6 234.3 232.0 244.9 253.8 259.8

Peak MW 61.5 70.9 89.4 88.6 82.2 81.0 78.5 76.0


Peak MW 18.2 22.9 36.9 37.6 34.1 33.3 30.7 28.3

ICP LJF


Table 33. Summer cooling – Low population growth rate scenario


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= even19 Pop proj=L Partia l HP cooling use


Energy peak MW 3.2 6.4 14.0 16.7 17.1 17.6 17.5 17.7

Auckland Vol GWh 5.5 11.1 28.2 39.4 46.7 54.4 60.7 67.1

Peak MW 30.3 56.5 121.7 148.1 156.1 166.5 171.2 176.1

Waikato Vol GWh 2.1 3.8 7.4 9.1 9.8 10.5 10.9 11.3

Peak MW 17.9 28.2 50.0 56.3 56.0 56.9 55.9 54.9


Peak MW 6.4 10.9 24.6 30.1 31.6 33.6 34.3 34.9

Gisborne Vol GWh 0.2 0.3 0.6 0.7 0.7 0.8 0.8 0.8

Peak MW 1.6 2.5 3.8 4.2 4.1 4.1 4.1 4.0


Peak MW 6.0 8.7 14.2 15.9 15.9 16.1 16.3 16.4

Taranaki Vol GWh 0.2 0.4 0.8 1.0 1.1 1.1 1.1 1.0

Peak MW 2.0 3.7 7.9 9.3 9.3 9.5 9.2 9.0

Man-Wang Vol GWh 0.3 0.7 1.6 2.1 2.2 2.4 2.4 2.4

Peak MW 3.8 7.3 15.2 17.9 18.2 18.8 18.6 18.4


Peak MW 13.4 21.6 40.3 46.8 47.8 49.5 49.5 49.5

Tasman Vol GWh 0.1 0.3 0.6 0.8 0.9 1.0 1.1 1.2

Peak MW 0.7 1.5 3.2 3.9 4.0 4.3 4.3 4.5

Nelson Vol GWh 0.4 0.6 1.0 1.1 1.2 1.3 1.3 1.5

Peak MW 2.7 3.8 5.4 5.9 5.9 6.0 5.9 6.0


Peak MW 2.9 3.8 4.9 5.2 5.2 5.3 5.4 5.5


Peak MW 0.2 0.6 1.5 1.8 1.8 1.8 1.8 1.7


Peak MW 79.3 101.0 140.4 150.4 148.1 150.5 149.3 148.0

Otago Vol GWh 1.0 1.4 2.2 2.6 2.7 2.9 3.0 3.1

Peak MW 12.9 17.4 25.7 28.2 28.0 28.8 28.8 28.7


Peak MW 3.7 5.5 10.0 10.9 10.4 10.2 10.0 9.8

ICP LJF


Table 34. Winter heating – Low population growth rate scenario


2009 2011 2016 2021 2026 2031 2036 2041

Conditioning a rea= const. Conditioning regime= Day21. Resist. Hea te r 18DegC. Pop proj=L


Energy peak MW 12.4 16.5 24.7 25.6 24.1 23.6 22.4 21.8

Auckland Vol GWh 409.9 407.6 422.1 408.7 394.6 413.6 429.6 437.0

Peak MW 165.6 197.1 269.5 280.6 273.0 278.2 278.8 276.4

Waikato Vol GWh 134.9 140.5 146.8 140.5 133.9 136.5 137.4 135.8

Peak MW 53.9 66.9 90.5 91.6 85.7 84.0 80.6 76.9


Peak MW 24.4 31.8 55.6 59.4 56.5 55.8 53.6 51.0

Gisborne Vol GWh 7.6 7.7 10.3 9.8 8.1 7.7 7.2 6.6

Peak MW 4.0 5.2 7.1 6.9 6.0 5.7 5.2 4.8


Peak MW 20.2 24.3 33.1 32.8 29.4 27.8 26.3 25.0

Taranaki Vol GWh 33.6 33.9 38.2 34.3 28.5 26.9 24.9 22.7

Peak MW 11.2 14.5 22.3 22.2 19.5 18.5 17.1 15.7

Man-Wang Vol GWh 83.6 85.9 90.4 81.4 70.4 69.0 66.8 63.8

Peak MW 26.9 35.1 50.7 49.9 44.1 42.4 39.7 37.1


Peak MW 87.6 103.2 125.3 119.8 107.7 105.5 101.3 96.1

Tasman Vol GWh 3.5 4.3 8.5 9.3 8.8 9.0 8.9 9.3

Peak MW 2.3 3.8 7.1 7.7 7.2 7.1 6.8 6.6

Nelson Vol GWh 10.7 11.0 12.9 12.5 11.3 11.2 10.9 11.2

Peak MW 6.6 8.0 9.9 9.8 9.0 8.6 8.1 7.9


Peak MW 7.5 8.9 10.1 9.7 8.8 8.3 7.9 7.6


Peak MW 2.1 3.3 5.7 5.8 5.1 4.8 4.4 3.9


Peak MW 185.7 208.4 240.2 229.9 208.2 199.9 188.8 177.8

Otago Vol GWh 189.6 195.8 207.3 191.9 171.6 167.5 161.8 155.1

Peak MW 61.5 70.9 85.8 81.8 72.5 68.6 63.7 59.2


Peak MW 18.2 22.9 34.8 33.6 28.4 25.9 23.9 22.1

ICP LJF


8.5 Month energy volumes and percentages

The following tables show the monthly energy percentages, and volumes, for the two base cases for cooling and heating. The top panel shows the monthly percentage of annual energy use and totals 100% for the year. The lower panel shows what each month‟s peak is as a percentage of the highest month. Generally the cooling peak occurs in January but it is in February for some locations. For heating the peak is either June or July, depending on the location. Two years, 2009 and 2026 are shown and both have similar monthly patterns.

Table 35. Monthly energy use. Cooling percent by month - 2009



Percentage of tota l (GWh) year use

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Total

Northland 30 26 22 4 0 0 0 0 1 1 4 12 100

Auckland 24 28 20 5 1 0 0 0 0 1 3 17 100

Waikato 27 30 19 3 0 0 0 0 0 1 4 15 100

Bay of Plenty 26 27 18 7 1 0 0 0 0 1 4 17 100

Gisborne 28 22 16 6 0 0 0 0 0 2 5 20 100

Hawkes Bay 26 39 13 5 0 0 0 0 0 0 2 13 100

Taranaki 33 35 12 2 0 0 0 0 0 1 2 15 100

Man-Wang 33 35 12 2 0 0 0 0 0 1 2 15 100

Wellington 33 35 12 2 0 0 0 0 0 1 2 15 100

Tasman 29 26 22 5 0 0 0 0 0 1 4 12 100

Nelson 29 26 22 5 0 0 0 0 0 1 4 12 100

Marlborough 29 26 22 5 0 0 0 0 0 1 4 12 100

West Coast 50 25 16 1 0 0 0 0 0 1 2 5 100

Canterbury 26 26 13 2 0 0 0 0 1 1 7 23 100

Otago 37 23 9 1 0 0 0 0 0 2 9 19 100

Southland 39 28 11 1 0 0 0 0 0 0 7 14 100

Percentage of highest peak (MW) month

Northland 100 87 89 40 9 7 1 7 15 23 38 61

Auckland 97 100 81 47 18 2 1 3 17 25 33 89

Waikato 88 100 69 34 16 4 3 2 4 13 38 59

Bay of Plenty 100 93 95 60 20 5 0 8 13 14 41 97

Gisborne 100 77 81 54 14 1 3 4 12 34 62 93

Hawkes Bay 64 100 61 47 8 0 0 1 3 4 29 48

Taranaki 100 95 82 25 6 0 0 3 1 10 14 55

Man-Wang 100 96 82 27 7 0 0 3 1 12 15 56

Wellington 100 96 82 27 7 0 0 3 2 12 16 57

Tasman 100 88 85 42 8 0 0 7 9 24 40 64

Nelson 100 88 85 42 8 0 0 7 9 24 40 64

Marlborough 100 88 85 42 8 0 0 7 9 24 40 64

West Coast 100 65 69 9 1 0 0 0 1 7 20 25

Canterbury 73 100 61 24 5 2 0 5 15 16 69 79

Otago 100 75 57 9 0 0 0 0 16 22 65 70

Southland 100 55 26 13 0 0 0 0 1 0 27 37

ICP LJF


Table 36. Monthly energy use. Cooling percent by month – 2026


Conditioning area = const Conditioning regime = Even19 Pop proj= M Year = 2026



Northland 27 25 22 5 1 0 0 0 1 2 4 13 100

Auckland 22 27 21 7 1 0 0 0 1 1 3 16 100

Waikato 24 29 21 4 1 0 0 0 0 1 5 15 100

Bay of Plenty 23 26 19 8 1 0 0 0 0 1 5 16 100

Gisborne 25 23 18 7 1 0 0 0 0 2 5 19 100

Hawkes Bay 24 36 16 6 1 0 0 0 0 1 3 13 100

Taranaki 30 33 14 3 1 0 0 0 0 1 2 15 100

Man-Wang 30 33 14 4 1 0 0 0 0 1 2 15 100

Wellington 30 33 14 4 1 0 0 0 0 1 2 15 100

Tasman 26 26 23 6 1 0 0 0 0 1 4 13 100

Nelson 26 25 23 6 1 0 0 0 0 1 4 13 100

Marlborough 26 25 23 6 1 0 0 0 0 1 4 13 100

West Coast 43 26 17 3 0 0 0 0 0 1 3 6 100

Canterbury 25 26 15 3 0 0 0 0 1 1 7 22 100

Otago 35 24 10 1 0 0 0 0 1 2 8 19 100

Southland 34 28 13 1 0 0 0 0 0 0 8 16 100


Northland 100 90 90 46 15 11 3 9 18 25 41 64

Auckland 96 100 84 53 27 5 3 6 19 27 36 87

Waikato 88 100 73 38 20 7 5 4 6 17 38 59

Bay of Plenty 100 96 97 67 27 7 1 11 16 17 44 98

Gisborne 100 83 86 61 20 3 7 8 13 36 60 96

Hawkes Bay 70 100 65 54 15 2 2 3 6 8 33 51

Taranaki 100 93 82 32 12 1 0 7 4 14 18 58

Man-Wang 100 94 83 34 13 1 0 8 5 16 20 59

Wellington 100 94 83 35 13 1 0 8 5 16 20 59

Tasman 100 91 89 49 16 4 0 10 12 25 41 66

Nelson 100 90 88 48 15 3 0 10 12 26 41 66

Marlborough 100 90 88 48 15 3 0 10 12 26 41 66

West Coast 100 70 75 14 4 0 1 2 3 10 23 29

Canterbury 75 100 65 26 8 4 0 6 14 14 69 80

Otago 100 77 61 12 0 0 0 0 17 21 62 72

Southland 100 59 29 19 3 0 0 0 4 3 27 40

ICP LJF


Table 37. Monthly energy use. Heating percent by month – 2009





Northland 0 0 0 3 8 16 23 21 16 8 5 1 100

Auckland 0 0 0 2 9 18 23 22 13 10 2 1 100

Waikato 2 1 2 5 10 18 21 19 11 7 4 1 100

Bay of Plenty 1 0 1 3 8 17 26 21 13 7 3 1 100

Gisborne 1 0 1 5 11 18 18 19 12 7 5 1 100

Hawkes Bay 1 1 3 6 10 16 17 19 11 10 7 2 100

Taranaki 1 1 2 7 9 15 20 17 13 9 5 2 100

Man-Wang 1 1 2 7 9 15 20 17 13 9 5 2 100

Wellington 1 1 2 7 9 15 20 17 13 8 5 2 100

Tasman 0 0 1 4 9 16 21 20 14 8 5 1 100

Nelson 0 0 1 4 9 16 21 20 14 8 5 1 100

Marlborough 0 0 1 4 9 16 21 19 14 8 5 1 100

West Coast 1 1 2 7 9 16 18 16 12 9 6 3 100

Canterbury 1 1 2 6 11 17 19 15 11 9 5 2 100

Otago 2 2 4 7 12 17 17 16 10 7 4 2 100

Southland 3 3 4 7 10 14 15 14 11 9 6 4 100


Northland 26 11 24 52 64 83 100 87 79 58 57 23

Auckland 25 14 11 44 73 100 94 88 77 69 40 30

Waikato 45 28 43 58 70 97 100 87 84 59 49 31

Bay of Plenty 34 9 39 60 71 91 100 92 78 62 57 36

Gisborne 45 31 42 67 89 91 100 94 83 67 58 45

Hawkes Bay 41 38 51 71 80 100 85 89 70 66 68 40

Taranaki 37 41 46 67 69 83 100 82 73 63 57 46

Man-Wang 37 41 46 67 69 83 100 82 73 62 57 46

Wellington 37 41 46 67 69 83 100 82 73 62 57 46

Tasman 39 29 33 59 73 94 100 93 81 67 63 33

Nelson 38 28 33 59 73 94 100 93 81 67 62 33

Marlborough 42 31 36 61 74 94 100 93 82 68 64 35

West Coast 40 37 54 81 74 100 95 98 80 81 62 52

Canterbury 46 45 50 60 76 100 95 87 71 70 53 41

Otago 45 51 56 72 88 100 100 93 81 69 56 50

Southland 48 53 57 75 79 87 100 90 75 62 60 54

ICP LJF


Table 38. Monthly energy use. Heating percent by month – 2026





Northland 0 0 0 2 8 16 23 21 16 8 5 1 100

Auckland 0 0 0 2 8 17 23 23 14 10 3 1 100

Waikato 1 0 1 4 9 19 22 20 12 7 4 1 100

Bay of Plenty 1 0 1 3 8 16 25 21 14 7 3 1 100

Gisborne 1 0 1 4 11 18 19 21 13 7 4 1 100

Hawkes Bay 1 0 2 5 9 16 17 19 12 10 7 2 100

Taranaki 1 1 2 6 9 15 20 17 13 9 5 2 100

Man-Wang 1 1 2 6 9 15 20 17 13 9 5 2 100

Wellington 1 1 2 6 9 15 21 17 13 9 5 2 100

Tasman 0 0 0 3 9 16 22 21 15 8 5 1 100

Nelson 0 0 0 3 8 16 22 21 15 8 5 1 100

Marlborough 0 0 1 3 9 16 21 20 15 8 5 1 100

West Coast 1 1 2 6 9 15 18 17 12 9 6 3 100

Canterbury 1 1 2 6 11 17 20 16 11 9 4 2 100

Otago 2 2 3 7 12 17 18 16 10 8 4 2 100

Southland 3 3 4 7 10 14 15 14 11 9 6 4 100


Northland 34 15 28 56 73 88 100 91 84 65 65 27

Auckland 24 9 14 51 74 100 94 91 75 69 42 34

Waikato 41 27 46 59 73 97 100 87 85 62 48 33

Bay of Plenty 35 8 38 64 74 93 100 91 78 68 57 39

Gisborne 48 27 36 69 90 91 100 95 85 70 61 47

Hawkes Bay 45 37 56 73 82 100 88 91 77 71 72 43

Taranaki 34 47 53 74 76 87 100 86 76 71 63 52

Man-Wang 34 46 52 74 76 87 100 86 75 71 62 51

Wellington 34 45 52 74 75 87 100 86 75 70 62 50

Tasman 42 27 33 62 77 94 100 94 85 71 67 35

Nelson 41 27 33 61 76 94 100 94 84 70 66 34

Marlborough 43 28 35 62 77 95 100 94 85 71 67 35

West Coast 49 47 63 82 80 100 98 100 82 86 66 59

Canterbury 48 47 54 64 77 100 95 89 73 72 54 45

Otago 48 54 58 73 88 99 100 93 83 70 59 52

Southland 54 56 60 76 81 89 100 91 79 67 60 59

ICP LJF


Table 39. Monthly energy use. Cooling volume by month – 2009


JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DECYear total or

Conditioning area = const Conditioning regime = Even19 Pop proj= M Year = 2009 max peak

Northland Energy vol (GWh) 0.2 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.5

Energy peak MW 3.2 2.8 2.9 1.3 0.3 0.2 0.0 0.2 0.5 0.7 1.2 2.0 3.2

Auckland Vol GWh 1.4 1.6 1.1 0.3 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.9 5.5

Peak MW 29.1 29.9 24.2 14.1 5.4 0.6 0.2 0.9 5.2 7.5 9.8 26.5 29.9

Waikato Vol GWh 0.6 0.6 0.4 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.3 2.1

Peak MW 15.7 17.9 12.3 6.1 2.9 0.8 0.5 0.4 0.8 2.4 6.8 10.6 17.9

Bay of Plenty Vol GWh 0.3 0.3 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 1.2

Peak MW 6.4 6.0 6.1 3.9 1.3 0.4 0.0 0.5 0.8 0.9 2.6 6.3 6.4

Gisborne Vol GWh 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2

Peak MW 1.6 1.2 1.3 0.9 0.2 0.0 0.1 0.1 0.2 0.5 1.0 1.5 1.6

Hawkes Bay Vol GWh 0.1 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.5

Peak MW 3.8 6.0 3.7 2.8 0.5 0.0 0.0 0.0 0.2 0.2 1.7 2.8 6.0

Taranaki Vol GWh 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3

Peak MW 3.0 2.8 2.4 0.7 0.2 0.0 0.0 0.1 0.0 0.3 0.4 1.6 3.0

Man-Wang Vol GWh 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.3

Peak MW 3.8 3.6 3.1 1.0 0.3 0.0 0.0 0.1 0.1 0.4 0.6 2.1 3.8

Wellington Vol GWh 0.4 0.4 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 1.2

Peak MW 13.2 12.7 10.9 3.6 1.0 0.0 0.0 0.4 0.2 1.6 2.1 7.5 13.2

Tasman Vol GWh 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1

Peak MW 0.7 0.6 0.6 0.3 0.1 0.0 0.0 0.1 0.1 0.2 0.3 0.4 0.7

Nelson Vol GWh 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4

Peak MW 2.7 2.3 2.3 1.1 0.2 0.0 0.0 0.2 0.2 0.6 1.1 1.7 2.7

Marlborough Vol GWh 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.4

Peak MW 2.9 2.5 2.4 1.2 0.2 0.0 0.0 0.2 0.2 0.7 1.1 1.8 2.9

West Coast Vol GWh 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Peak MW 0.2 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2

Canterbury Vol GWh 1.4 1.4 0.7 0.1 0.0 0.0 0.0 0.0 0.1 0.0 0.4 1.2 5.3

Peak MW 57.7 79.3 48.0 18.7 4.0 1.4 0.0 4.2 11.6 12.3 54.8 62.3 79.3

Otago Vol GWh 0.4 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 1.0

Peak MW 12.9 9.6 7.4 1.1 0.0 0.0 0.0 0.0 2.0 2.8 8.3 9.1 12.9

Southland Vol GWh 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1

Peak MW 3.7 2.0 1.0 0.5 0.0 0.0 0.0 0.0 0.0 0.0 1.0 1.3 3.7

ICP LJF


Table 40. Monthly energy use. Cooling volume by month – 2026



Conditioning area = const Conditioning regime = Even19 Pop proj= M Year = 2026 max peak


Energy peak MW 20.5 18.4 18.4 9.4 3.0 2.2 0.7 1.9 3.7 5.0 8.5 13.1 20.5

Auckland Vol GWh 13.4 16.0 12.8 4.1 0.7 0.1 0.0 0.1 0.3 0.8 2.0 9.7 59.9

Peak MW 178.2 185.7 156.0 98.4 49.8 9.2 5.6 11.1 35.5 49.8 66.1 161.3 185.7

Waikato Vol GWh 3.2 3.8 2.7 0.5 0.1 0.0 0.0 0.0 0.1 0.2 0.6 1.9 13.2

Peak MW 59.8 68.2 49.6 26.2 13.5 4.7 3.4 2.5 4.4 11.3 26.2 40.2 68.2


Peak MW 37.8 36.3 36.8 25.3 10.2 2.8 0.5 4.2 6.0 6.4 16.5 37.0 37.8

Gisborne Vol GWh 0.3 0.2 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 1.0

Peak MW 5.0 4.2 4.3 3.1 1.0 0.1 0.3 0.4 0.6 1.8 3.0 4.8 5.0


Peak MW 13.6 19.3 12.6 10.4 2.8 0.3 0.4 0.5 1.2 1.5 6.3 9.9 19.3

Taranaki Vol GWh 0.6 0.6 0.2 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 1.8

Peak MW 14.0 13.0 11.5 4.5 1.7 0.1 0.0 1.0 0.6 2.0 2.5 8.1 14.0

Man-Wang Vol GWh 0.9 1.0 0.4 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.5 3.1

Peak MW 22.1 20.7 18.3 7.6 2.9 0.2 0.1 1.7 1.0 3.5 4.3 13.0 22.1


Peak MW 57.2 54.0 47.8 20.1 7.6 0.5 0.2 4.5 2.7 9.1 11.4 33.8 57.2

Tasman Vol GWh 0.3 0.3 0.3 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 1.3

Peak MW 4.9 4.5 4.4 2.4 0.8 0.2 0.0 0.5 0.6 1.3 2.0 3.2 4.9

Nelson Vol GWh 0.5 0.4 0.4 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 1.7

Peak MW 7.2 6.5 6.4 3.5 1.1 0.2 0.0 0.7 0.9 1.9 3.0 4.7 7.2


Peak MW 6.4 5.8 5.7 3.1 0.9 0.2 0.0 0.7 0.8 1.7 2.7 4.2 6.4


Peak MW 2.2 1.5 1.6 0.3 0.1 0.0 0.0 0.0 0.1 0.2 0.5 0.6 2.2


Peak MW 135.8 181.9 117.9 47.2 14.7 7.0 0.0 11.3 25.5 26.0 125.7 144.9 181.9

Otago Vol GWh 1.3 0.9 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.3 0.8 3.8

Peak MW 35.5 27.3 21.7 4.2 0.0 0.0 0.0 0.0 6.0 7.4 22.0 25.5 35.5


Peak MW 13.1 7.7 3.8 2.5 0.4 0.0 0.0 0.1 0.5 0.4 3.6 5.3 13.1

ICP LJF


Table 41. Monthly energy use. Heating volume by month – 2009



Conditioning area = const Conditioning regime = Day21 Pop proj= M Year = 2009 Partial Resist heating 18degC max peak


Energy peak MW 3.3 1.3 2.9 6.5 7.9 10.3 12.4 10.8 9.8 7.2 7.0 2.8 12.4

Auckland Vol GWh 1.3 0.3 0.4 8.2 35.8 73.6 94.2 90.3 53.4 39.3 10.2 2.9 409.9

Peak MW 41.5 23.5 18.4 73.3 120.1 165.3 155.0 145.5 127.3 113.7 66.2 49.1 165.3

Waikato Vol GWh 2.3 0.8 2.2 6.5 12.8 24.8 28.6 25.8 15.0 9.6 5.0 1.5 134.9

Peak MW 24.4 14.9 23.4 31.1 37.8 52.4 53.9 46.8 45.0 31.7 26.6 16.7 53.9


Peak MW 8.2 2.3 9.5 14.7 17.2 22.3 24.4 22.3 19.0 15.0 13.9 8.7 24.4

Gisborne Vol GWh 0.1 0.0 0.1 0.4 0.8 1.4 1.3 1.5 0.9 0.6 0.4 0.1 7.6

Peak MW 1.8 1.2 1.7 2.7 3.6 3.7 4.0 3.8 3.4 2.7 2.3 1.8 4.0


Peak MW 8.2 7.6 10.3 14.3 16.1 20.2 17.1 17.9 14.2 13.3 13.7 8.0 20.2

Taranaki Vol GWh 0.3 0.3 0.8 2.3 3.1 5.0 6.7 5.7 4.2 2.9 1.7 0.6 33.6

Peak MW 4.1 4.6 5.2 7.5 7.7 9.3 11.2 9.2 8.1 7.0 6.4 5.1 11.2

Man-Wang Vol GWh 0.7 0.7 1.9 5.7 7.7 12.5 16.8 14.2 10.5 7.1 4.3 1.5 83.6

Peak MW 9.9 11.0 12.4 18.1 18.6 22.3 26.9 22.0 19.6 16.8 15.4 12.3 26.9


Peak MW 32.4 35.5 40.0 58.5 60.1 72.4 87.6 71.5 63.7 54.3 49.8 39.9 87.6

Tasman Vol GWh 0.0 0.0 0.0 0.1 0.3 0.6 0.7 0.7 0.5 0.3 0.2 0.0 3.5

Peak MW 0.8 0.6 0.7 1.3 1.6 2.0 2.2 2.0 1.7 1.4 1.3 0.7 2.2

Nelson Vol GWh 0.0 0.0 0.1 0.4 1.0 1.8 2.3 2.1 1.5 0.8 0.5 0.1 10.7

Peak MW 2.4 1.8 2.1 3.7 4.6 6.0 6.3 5.9 5.1 4.2 3.9 2.1 6.3


Peak MW 3.0 2.2 2.6 4.4 5.4 6.8 7.2 6.7 5.9 4.9 4.6 2.5 7.2


Peak MW 0.8 0.8 1.1 1.7 1.5 2.0 2.0 2.0 1.6 1.7 1.3 1.1 2.0


Peak MW 84.7 84.0 92.5 112.3 140.8 185.7 176.4 161.4 131.4 130.7 98.9 75.7 185.7

Otago Vol GWh 2.9 4.0 6.6 13.3 22.7 32.1 32.7 29.5 19.4 14.1 7.9 4.3 189.6

Peak MW 27.6 31.4 34.4 44.0 53.8 61.0 61.0 56.8 49.7 41.9 34.0 30.4 61.0


Peak MW 8.8 9.7 10.4 13.6 14.4 15.9 18.2 16.3 13.7 11.3 10.9 9.9 18.2

ICP LJF


Table 42. Monthly energy use. Heating volume by month – 2026



Conditioning area = const Conditioning regime = Day21 Pop proj= M Year = 2026 Partial Resist heating 18degC max peak


Energy peak MW 9.9 4.4 8.1 16.5 21.2 25.7 29.3 26.5 24.5 19.0 19.0 7.8 29.3

Auckland Vol GWh 1.1 0.1 0.5 7.8 37.0 80.8 107.9 105.2 62.4 45.0 11.6 2.7 462.1

Peak MW 76.9 29.2 43.7 161.5 236.6 319.3 300.1 291.7 239.6 220.8 135.1 108.4 319.3

Waikato Vol GWh 2.3 0.5 1.9 7.3 16.1 32.3 38.1 34.5 20.4 13.0 6.2 1.6 174.3

Peak MW 43.1 28.1 48.5 62.6 77.0 102.7 105.4 91.3 89.8 65.7 51.1 34.9 105.4


Peak MW 23.8 5.7 26.2 43.9 50.8 63.7 68.8 62.4 53.6 46.7 39.2 26.5 68.8

Gisborne Vol GWh 0.1 0.0 0.1 0.4 1.2 2.0 2.1 2.2 1.4 0.8 0.5 0.1 10.9

Peak MW 3.6 2.0 2.7 5.1 6.8 6.8 7.5 7.1 6.4 5.3 4.6 3.5 7.5


Peak MW 16.2 13.2 20.0 26.0 29.2 35.8 31.4 32.5 27.6 25.4 26.0 15.4 35.8

Taranaki Vol GWh 0.3 0.2 0.8 2.4 3.4 5.6 7.5 6.3 4.8 3.2 1.9 0.7 37.0

Peak MW 8.1 11.0 12.6 17.5 17.9 20.5 23.6 20.3 17.9 16.7 14.8 12.2 23.6

Man-Wang Vol GWh 0.8 0.5 1.9 6.0 8.8 14.6 19.7 16.7 12.5 8.4 5.0 1.7 96.5

Peak MW 18.9 25.3 29.0 40.9 41.8 48.1 55.3 47.5 41.7 39.1 34.5 28.2 55.3


Peak MW 44.7 59.1 67.9 96.7 98.9 114.2 131.3 112.6 98.6 92.2 81.2 66.2 131.3

Tasman Vol GWh 0.0 0.0 0.1 0.3 1.0 1.9 2.5 2.4 1.7 1.0 0.6 0.1 11.5

Peak MW 3.7 2.4 2.9 5.3 6.6 8.2 8.7 8.2 7.3 6.1 5.8 3.0 8.7

Nelson Vol GWh 0.0 0.0 0.1 0.4 1.2 2.4 3.2 3.0 2.2 1.2 0.7 0.1 14.5

Peak MW 4.3 2.9 3.5 6.5 8.1 10.0 10.6 10.0 8.9 7.5 7.1 3.6 10.6


Peak MW 4.5 3.0 3.6 6.6 8.1 9.9 10.5 9.9 8.9 7.5 7.1 3.7 10.5


Peak MW 3.1 3.0 4.1 5.3 5.1 6.5 6.3 6.4 5.3 5.5 4.3 3.8 6.5


Peak MW 124.2 122.0 138.4 164.1 199.5 257.7 245.8 228.6 188.5 186.2 139.6 116.8 257.7

Otago Vol GWh 3.7 4.3 7.5 16.2 28.5 40.8 42.0 38.0 25.0 18.1 9.8 4.9 238.9

Peak MW 44.5 50.1 54.1 68.2 82.0 92.2 93.3 86.9 77.2 65.2 54.8 48.7 93.3


Peak MW 20.1 20.7 22.4 28.3 30.0 33.1 37.1 33.8 29.2 24.9 22.3 21.9 37.1

ICP LJF


8.6 Hourly energy volumes

The volume of energy used in the middle of the peak month (January for cooling, and July for heating) is shown in Figure 22 to Figure 25 by hour for Auckland. The kWhs are the average for all five houses used in the analysis. Other regions are expected to have a similar pattern of hourly use. The main determinant is the assumed cooling and heating regime, so the peak generally occurs in the first hour of the start of the regime (i.e. 9 am or 5 pm). The exception is day cooling where demand peaks about midday.

Figure 22 Hourly energy use. Auckland Cooling Even19.

Figure 23 Hourly energy use. Auckland Cooling Day20.

0

0.5

1

1.5

2

2.5

3

3.5

4

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Ene

rgy

use

kW

h p

er

day

Hour

Cooling - Average all houses Auckland Even19 , const area

Cooling to 19degC 5pm to 10pm, no cooling outside

these hours

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Ene

rgy

use

kW

h p

er

day

Hour

Cooling - Average all houses Auckland Day20 , const area

Cooling to 20degC 9am to 4pm, no cooling outside

these hours

ICP LJF


Figure 24 Hourly energy use. Auckland Heating Day21.

Figure 25 Hourly energy use. Auckland Heating Even22.

0

0.5

1

1.5

2

2.5

3

3.5

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Ene

rgy

use

kW

h p

er

day

Hour

Heating - Average of all Auckland houses Day21, const area

Heating to 21degC from 9am to 5pm and min 16 degC heating outside

these hours.

0

0.5

1

1.5

2

2.5

3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Ene

rgy

use

kW

h p

er

day

Hour

Heating - Average of all Auckland houses Even22, const area

Heating to 22degC from 5pm to 9pm and min 16 degC heating outside

these hours.

regional heat pump energy loads - transpower new … · project number: qc5118 date of issue:13th...

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