Australian Residential Building Sector Greenhouse Gas Emissions ...
Australian Residential Building Sector Greenhouse Gas Emissions 1990-2010
executive summary
report
1999
The Australian Greenhouse Office is the lead Commonwealth agency on greenhouse matters
Australian Residential Building Sector Greenhouse Gas Emissions 1990-2010
executive summary
report
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ISBN 1876536 136 © Commonwealth of Australia 1999 This work is copyright. Permission is given for fair dealing with this material as permitted under copyright legislation, including for the purposes of private study and research. Apart from those uses, no part may be reproduced without prior written permission from the Commonwealth. Requests and inquiries concerning reproduction rights should be directed to the: Manager, Communications Australian Greenhouse Office GPO Box 621 Canberra ACT 2601 This study is available online at the Australian Greenhouse Office website at www.greenhouse.gov.au/energyefficiency/building Design Wingrove Wingrove Design Photos Courtesy of the Housing Industry Association
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
FOREWORD Though the full effects of emissions of greenhouse gases on the Earth’s atmosphere are not yet completely understood, the scientific evidence points to a discernible human influence on global climate change. The residential building sector has recognised the need to address greenhouse concerns, and not just from the perspective of climate change, but also to improve the
The Australian Greenhouse Office is pleased to present this study as a valuable sectoral contribution to the broader greenhouse debate.
F O R E WA R D
comfort of the built environment for all Australians.
Importantly, it provides the most up to date and comprehensive baseline data of greenhouse gas emissions for the residential building sector. I hope that members of the building industry will find this study stimulates not only further discussion on the greenhouse problem, but supports the development of initiatives designed to address these concerns. iii Without doubt the building industry has the challenge of becoming more environmentally sensitive while remaining economically efficient. It is a difficult challenge, for the issues are diverse and complex. I would like to commend the authors of the study, Energy Efficient Strategies, as well as acknowledge the contribution of the Steering Committee representing industry and government organisations.
Gwen Andrews Chief Executive Australian Greenhouse Office April 1999
iv
Acknowledgements The study was produced for the Australian Greenhouse Office by Lloyd Harrington and Robert Foster of Energy Efficient Strategies with assistance from Energy Partners George Wilkenfeld & Associates and additional contributions from Graham Treloar, Deakin University Mark Ellis & Associates
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Australian Residential Building Sector Greenhouse Gas Emissions 1990-2010
1
Study Objectives
3
Major Issues
4
Energy forms and end uses
4
Operational versus embodied energy
5
Projection issues
5
Short term versus long term results
6
Voluntary versus mandatory solutions
6
Project Scenarios
8
Key Project Findings
10
Greenhouse gas emissions in 1990
10
Business as usual projections to 2010
10
Quantitative assessment of an equitable committment for the building sector
11
Quantification of the emission gap
11
Project Conclusions
13
Thermal comfort levels
13
Existing housing stock
13
Longevity of building shells
13
Land subdivision
13
Building shell - Performance measures versus prescriptive measures
13
Embodied energy
14
Appliance issues
14
Recommended Further Research
15
CONTENTS
CONTENTS
v
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
AUSTRALIAN RESIDENTIAL BUILDING SECTOR GREENHOUSE GAS EMISSIONS 1990-2010
protect Australian jobs and industry. As a result, the Government is seeking “realistic, cost-effective reductions in key sectors where emissions are high or growing
ABOUT THE REPORT
strongly, while also fairly spreading the burden of action This study estimates energy consumption and greenhouse
across the economy”. The Prime Minister also noted
gas emissions in the residential sector over the period
that “[The Government is] prepared to ask industry to do
1990 to 2010, with the primary aim of providing a basis
more than they may otherwise be prepared to do, that is,
for the determination of an equitable contribution by the
to go beyond a ‘no regrets’, minimum cost approach
building sector to greenhouse gas emission reductions.
where this is sensible in order to achieve effective and
The study looks closely at all end uses (including electrical
meaningful outcomes”.
appliances and equipment, water heating and cooking) but there is particular attention given to space heating and cooling in residential buildings: the interaction of the thermal performance of the building shell, heating and cooling regimes and the type, fuel mix and energy efficiency of space heating and cooling equipment.
Subsequent negotiations resulted in an international agreement to the Kyoto Protocol to the Framework Convention on Climate Change, under which Australia will have an obligation, inter alia, to reduce its greenhouse gas emissions to 108 per cent of the 1990 level by 20082012. This compares with a business-as-usual scenario
Space heating and cooling accounted for 39 per cent of
prior to the Prime Minister’s Statement of 28 per cent
total residential operational energy consumption in 1998.
emissions growth for the economy as a whole, and around
The three main energy sources used in the residential
40 per cent for energy-related emissions, based on
sector are electricity, natural gas and wood. While only a
projections available at that time.
small part of residential electricity consumption is used for space heating and cooling, the vast majority of natural 1
gas and wood consumption in Australia is used for space heating. Because such a large share of the energy is from the less greenhouse gas-intensive energy sources, space heating and cooling account for a lower share of greenhouse gas emissions than of energy use. Even so, heating and cooling account for nearly 15 per cent of residential sector greenhouse gas emissions. Building shell thermal performance has a large impact on the heating and cooling requirements for residential buildings, so improvements in thermal performance are likely to lead to reductions in greenhouse gas emissions. In his statement of 20 November 1997, “Safeguarding the Future: Australia’s Response to Climate Change”, the Prime Minister announced a package of measures to reduce Australia’s greenhouse gas emissions. He noted that this package of measures was designed both to ensure that Australia plays its part in the global effort required to reduce greenhouse gas emissions and to
For the building sector, the Prime Minister’s Statement specified: “The Commonwealth will work with the States, Territories and key industry stakeholders to develop voluntary minimum energy performance standards for new and substantially refurbished commercial buildings on the basis of energy efficiency benchmarks. If after 12 months, the Government assesses that the voluntary approach is not achieving acceptable progress towards higher standards of energy efficiency for housing and commercial buildings, we will work with the States and industry to implement mandatory standards through amendment of the Building Code of Australia.”
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This project has been commissioned by the Australian
It is estimated that water heaters were responsible for
Greenhouse Office (in consultation with the building
28 per cent of residential greenhouse gas emissions in
industry) to determine baseline greenhouse gas emissions
1998. This study has found that 52 per cent of greenhouse
attributable to the residential building sector of the
gas emissions attributable to the residential sector come
economy and to provide a firm, quantitative basis for the
about as a result of electrical appliances selected by
subsequent development of specific greenhouse response
residents or persons outside the building sector, and
measures by industry and government.
therefore cannot be directly affected by changes made
greenhouse gas emissions result from cooking.
greenhouse gas emissions attributable to the residential sector in 1998 come about as a result of householders’
By quantifying the impacts of a range of building
need to heat and cool dwellings. The amount of energy
sector influenced possibilities, this study provides a
used for this purpose over the life of a dwelling depends
basis for establishing the contribution that the residential
largely on its design and materials, and other factors
building industry can make to the national objective of
determined at the time of construction. Therefore the
reducing greenhouse gas emissions, in line with
housing industry has a key role to play in influencing
Australia’s obligations.
ABOUT THE REPORT
within the building industry. The remaining 5 per cent of This study has found that about 15 per cent of the
future demand for residential sector heating and cooling, and on the related greenhouse gas emissions. Its influence also extends to other fixed systems and appliances installed at the time of construction, most notably water heating, and to a lesser extent some fixed space heating appliances and cooking appliances, as well as the fuel choice for these end uses. 2
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
STUDY OBJECTIVES
The business-as-usual projections with measures implemented or announced to date (BAU+) includes
The study objectives are as follows:
those program measures that have been introduced during the period 1990 to November 1997 (the date of
1. Quantify energy related greenhouse gas emissions
the Prime Minister’s statement). This scenario reflects
attributable to the residential buildings sector in 1990;
the actual market situation during the period from 1990
STUDY OBJECTIVES
to 1998 and is used as the primary basis for future 2. Estimate business-as-usual emission growth
projections. The business-as-usual projections without
projections from 1990 - 2010, with and without
measures implemented or announced to date (BAU-) is a
emissions-reduction measures implemented or
hypothetical case which is used to assess the energy
announced to date, taking into account changes in
and greenhouse impact of those program measures
consumer behaviour;
introduced during the period 1990 to November 1997 (program impact = BAU+ less BAU-).
3. Provide a quantitative assessment of an equitable greenhouse emission reduction commitment for the
Energy labelling of appliances commenced in Australia in
building sector, taking into account baseline and
1986. As this program was in place well before 1990, it
projected emissions growth to 2010 and the Kyoto
is included in both the business-as-usual with and without
Protocol commitment for Australia as a whole; and,
scenarios. It is now very difficult to disentangle the impact of energy labelling for appliances from the current trends
4. Quantify any “gap” between the proposed emissions
in energy consumption.
reduction commitment to 2010 for the building sector
3
and the projected emissions growth with measures
This study takes into account changes in user
implemented or announced to date.
behaviour where this affects energy consumption. However, evaluations of historical programs suggests
This study covers Class 1 and Class 2 buildings as defined by the Building Code of Australia - this primarily includes private residential dwellings which are separate (eg stand alone houses) and attached (eg flats, town houses, terrace houses). Residential parts of commercial establishments
that government programs which provide information with the sole objective of influencing daily energy-using behaviour, as distinct from influencing product or dwelling choice, have not had (and are unlikely to have) any significant long term impact on energy use.
are not included. The Prime Minister’s statement of November 1997 The quantification of baselines and the projection of emissions follows, as closely as possible, the relevant Australian Methodologies for the Estimation of Greenhouse Gas Emissions and Sinks, as published by the National Greenhouse Gas Inventory Committee.
included a requirement for electricity suppliers to increase their generation from renewable sources by an average of 2 per cent by 2010. The projected impact of this program has been factored into the greenhouse gas intensity projections for each state. As this program affects all sectors which use electricity (ie is not specific to the residential sector or building shells), it is assumed to form part of all scenarios developed for this study.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Figure 2: Residential Energy Share by End Use 1998
MAJOR ISSUES Energy forms and end uses Electricity is the major energy source for residential buildings, accounting for about 48 per cent of all energy in 1998. Natural gas is the next biggest fuel, accounting for about 35 per cent of energy while wood accounts for about 14 per cent. In terms of greenhouse gas
1% SPACE COOLING 4% COOKING 27% WATER HEATING 30% ELECTRICAL APPLIANCES & EQUIPMENT 38% SPACE HEATING
emissions from residential, electricity dominates accounting
Figure 1: Residential Energy Share by Fuel 1998 Figure 3: Residential Greenhouse Gas Emission Share by End Use 1998
3% LPG 14% WOOD 35% NATURAL GAS 48% ELECTRICITY
MAJOR ISSUES
for 84 per cent of emissions.
2% SPACE COOLING 5% COOKING 12% SPACE HEATING 28% WATER HEATING 53% ELECTRICAL APPLIANCES & EQUIPMENT
Electrical appliances, cooking and water heating account
4
for 61 per cent of residential energy consumption and 85 per cent of residential greenhouse gas emissions. Space heating and cooling account for the balance: about
Figure 4: Residential Heating & Cooling Energy by Fuel 1998
39 per cent of energy consumption and 15 per cent of greenhouse gas emissions. (These estimates cover the use of electricity, natural gas, LPG and wood, but not the minor fuels such as oil and briquettes, which, while small in magnitude, are mostly associated with space heating). In energy terms, space heating is the single largest end use in the residential sector, but the third largest with
3% ELECTRICITY COOLING 3% ELECTRICITY HEATING 3% LPG 35% WOOD 56% NATURAL GAS
respect to greenhouse gas emissions, behind appliances and water heating. The energy consumption required for heating and cooling in residential buildings is a function of both climate and the design and thermal performance of the building shell. It is also heavily influenced by user behaviour (occupancy
Figure 5: Residential Heating & Cooling Greenhouse Emissions by Fuel 1998
levels, proportion of the building that is heated or cooled) and the efficiency of heating and cooling appliances, so quantifying the impact of building shell performance contains significant uncertainties. The energy consumption of electrical appliances, cooking and water heating is largely unaffected by the design and thermal performance of the building shell. Climate has some secondary impact on the operation of refrigerators, freezers and hot water systems and this effect has been incorporated into the end use estimates as far as is
4% LPG 10% WOOD 15% ELECTRICITY COOLING 15% ELECTRICITY HEATING 56% NATURAL GAS
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possible. Climate also has other secondary effects such as
Projection issues
the temperature selected for clothes washing (eg warmer states tend to select cold washing more frequently as the
Energy consumption is projected over the period 1990 to
cold water supply is warmer) and the frequency of clothes
2010. The analysis was carried out in late 1998, almost
dryer use - these impacts have also been incorporated
half way through the projection period, and outputs have
into the model where data is available.
been calibrated to actual energy consumption data at state level (as collected by ABARE) since 1987, so there is a reasonable level of confidence in the projections.
MAJOR ISSUES
Operational versus embodied energy This study concentrates on the “operational” energy used
However, there will inevitably be some uncertainties
to provide a range of energy services such as hot water,
regarding projections, including:
heating and electrical appliance services. There is also a large amount of embodied energy consumed directly or indirectly to manufacture and supply materials and goods used in the construction of a dwelling.
■
population and household forecasts
■
future penetration and ownership of appliances
■
future characteristics of new appliances sold (size, energy efficiency)
Embodied energy can be equal to as much as 20 years of operational energy for a typical new house. Most of
■
this energy is effectively consumed at or before the time
future characteristics of new dwellings (size, insulation and efficiency)
of construction, and most of this is accounted within
■
the industrial and construction sectors of the economy.
changing patterns of user behaviour (frequency and duration of use for appliances in general but particularly
In addition, over a typical building life of up to 100 years,
with respect to space heating & cooling)
a further 20 years of operational energy can be embodied through refurbishments and renovations. Hence embodied
It is also necessary to use average values for variables,
energy can be of the order of 40 per cent of the total
where in reality there will be a frequency distribution around
operational energy consumed over a 100 year period.
the average values for all households. Therefore the values
A detailed quantification of embodied energy is not within
reported in this study will not necessarily be representative
the scope of this study, but the issues related to embodied
of any particular household. Historical shares of end use
energy are explored in some detail and some examples
energy and greenhouse gas emissions by fuel type are
of the interaction between embodied and operational
shown in Figure 6 to Figure 9.
energy for a range of construction materials and approaches are included.
Figure 6: Residential Energy Consumption by Fuel 1986 to 1998
Figure 7: Residential Greenhouse Emissions by Fuel 1986 to 1998 50
160 Electricity
Electricity
45
140
40
100
Greenhouse Gas Emissions MT CO2-e
120
Natural Gas
80 60 Wood
40
35 30 25 20 15 10
20
Natural Gas
5
LPG
Wood
LPG
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
0
0
1986
Energy PJ
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The stock of residential buildings in Australia is generally
Short term versus long term results
have both wall and ceiling insulation and a further 42 per
impact that the building sector could have on energy
cent have only ceiling insulation. In addition, many of the
and greenhouse emissions by 2010. The study shows
houses with only ceiling insulation appear to have this
that greatly improving the thermal performance of new
installed after construction is complete (ie by occupants
residential buildings from 2000 onward can go a significant
rather than builders). Some 38 per cent of dwellings have
way towards meeting greenhouse gas emission reduction
neither wall or ceiling insulation. One area considered in
targets for this sector in the Kyoto commitment period
this study is the retrofit of ceiling insulation into existing
(2008-2012) if space heating and cooling energy were
buildings without ceiling insulation. This could have a
considered separately.
substantial impact on the thermal performance of the existing building stock by 2010 and could help contribute
However, residential buildings, unlike appliances and
to emission reduction targets. Retrofit of wall insulation is
equipment, potentially have a very long life - of the order
generally considered unfeasible, although there are some
of 50 to 100 years, so any measures implemented will continue to have an impact on energy and greenhouse gas emissions for decades to come. This study only quantifies
specialist companies now operating that can retrofit wall
MAJOR ISSUES
poorly insulated. Only 20 per cent of all residential buildings One focus for this study is to estimate the potential
insulation for selected construction types.
these benefits to 2010. A related issue is that the rate of household formation (and hence new construction of
Voluntary versus mandatory solutions
residential buildings) is of the order of 2 per cent per annum (the net demolition rate appears to be very small -
Programs aimed at increasing the thermal performance of
well below 0.5 per cent). So over the projection period
residential buildings could be either voluntary or mandatory
from 2000 to 2010, where program measures for new
in nature, or a mixture of the two. Voluntary measures can
residential buildings are assumed to come into force, only about 20 per cent of the total housing stock can be
high level of consumer interest and involvement.
affected (ie 80 per cent will be outside the scope of any program targeted at new buildings). While this limits the
The relatively large number of parties involved in the
potential contribution by 2010 of programs established
building industry suggests that widespread compliance
before that date (even if they start almost immediately),
with voluntary programs, especially where these may
such programs will have an expanding impact to 2050
involve a significant cost premium during construction,
and beyond.
may be difficult to achieve. The market reality is that there
Figure 8: Residential Energy Consumption by End Use 1986 to 1998
Figure 9: Residential Greenhouse Emissions by End Use 1986 to 1998
140
30
120
80 Water Heating 60 40
Greenhouse Gas Emissions MT CO2-e
Electrical Appliances & Equipment
100
20
Electrical Appliances & Equipment
25
Space Heating & Cooling
20 Water Heating 15
10 Space Heating 5
Cooking
Cooking
0
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1998
1997
1996
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1994
1993
1992
1991
1990
1989
1988
1987
0
1986
Energy PJ
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work well where there is strong industry cohesion and a
MAJOR ISSUES
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is generally little direct incentive for the building industry
mandatory in any state. While there is strong pressure on
to increase the thermal performance of new buildings.
developers to maximise revenue by fitting as many blocks
The purchasers of buildings rarely specify measures that
into a given area as possible with no regard to orientation,
directly impact on the energy efficiency of the building
things are unlikely to change in this respect. (Indeed,
(such as orientation, glazing, insulation levels) and there is
there are transport energy advantages to higher densities,
intense competition within the industry to minimise costs.
although different building forms may be more appropriate
Builders do not pay the ongoing energy bills, so unless
than detached dwellings: however, transport related
the ultimate occupant commissions the design, is involved
impacts are beyond the scope of this study). Local
prior to construction and/or is aware of building shell
government could play a strong role by mandating energy
energy efficiency issues, there is no direct market incentive
efficiency requirements for subdivisions (especially with
to improve thermal performance. Given the relatively poor
respect to orientation of buildings), although this is likely to
average thermal performance of typical new dwellings in
be more effective if implemented at state or national level.
Australia, it would appear that occupants exert little influence over these aspects. There would be some
Traditionally, where there are requirements regarding the
indirect market pressure if energy-efficient dwellings
building shell, the building industry has tended to favour
commanded a higher price; this is one objective of house
prescriptive measures over performance based measures.
energy rating schemes, but their influence on buyer or
Prescriptive measures are relatively easy for builders to
occupant behaviour is still unclear.
assess, cost and install (eg via a standard check list). The main drawback of prescriptive measures is that,
Mandatory programs can achieve results independently of user involvement, but can also impose higher costs on all house builders and buyers. The issue is whether such costs are more than offset by the total value of the energy saved, and whether the savings are distributed widely enough so that the great majority of affected parties are
7
better off (noting that costs are not necessarily borne by beneficiaries). A number of design factors which have a large impact on thermal performance (such as orientation and placement of glazing) can be included during the design process at close to zero cost. However, it is difficult to specify such factors in a prescriptive sense: this is most effectively dealt with through performance based approaches (see below). The inclusion (or otherwise) of key energy efficiency measures at the time of construction is critical: many of these cannot be practically altered after construction is commenced (building orientation,
by necessity, they tend to be overly simplistic and are unable to deal with significant areas of energy efficiency (eg passive solar design = orientation and glazing placement) that often require little incremental cost to implement during construction. Performance measures are often regarded as more difficult as it may mean that the performance has to be assessed by a third party and that a series of iterations may be necessary to meet both the client’s requirements and the thermal performance requirements within the client’s cost constraints. Evidence for this comes from Victoria where builders can comply with building regulations via the inclusion of specified insulation levels or alternatively achieve a minimum star rating1 - to date very few approvals have been done on the basis of the minimum star rating. However, this paradigm within the building industry could change. The mandatory
placement of glazing, wall insulation in most cases).
minimum 4 star requirement in the ACT has forced a
The cost of including other efficiency measures is
change of approach by the local building industry
generally much higher if retrofitted in comparison with
and is now quickly gaining widespread acceptance.
installation during construction. Therefore it is much
Performance based measures have the advantage of
more cost-effective to include an integrated package
providing builders and clients with almost infinite flexibility
of efficiency measures during design and construction
to meet their requirements.
than it is to improve the efficiency of the building shell post construction.
The cost-effectiveness of these or other approaches has not explicitly been analysed in this study, which
1 From 1992-96, the rating was 4 stars (VICHERS); from 1996 this was amended to 3 stars.
If a policy shift towards higher efficiency building shell
concentrates on the energy and greenhouse gas
standards were to be adopted, then building orientation
reductions possible through improved thermal
would be an important factor in achieving this goal.
performance of building shells. It has of course been
Although some states have guidelines for the development
necessary to assume that there are means for achieving
of energy efficient subdivisions that provide for good
such improvements, so the optimum paths to achieving
solar access and facilitate correct orientation, this is not
them can now be explored.
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PROJECTION SCENARIOS
The heating and cooling energy required under each scenario is calculated as follows: ■
to estimate the impact on changes in building shell
from the characteristics of the building stock using the
thermal performance on residential energy consumption.
NatHERS model for the known range of construction
The population, household size and non-heating/cooling
types and climate types.
energy use assumptions (ie BAU+ for appliance characteristics and performance) were common to all
the unconstrained2 heating/cooling demand is calculated
■
PROJECTION SCENARIOS
Four building shell projection scenarios were modelled
it is assumed that the constraint ratios calculated for
four - the differences lie in the assumptions about change
the years 1990 to 1997 persist: ie if the unconstrained
in the thermal performance of the dwelling stock, and
heating demand in a State doubles, the constrained
the consequent impacts on heating and cooling energy.
heating/cooling demand also doubles.
An additional hypothetical scenario (BAU-) has been developed to estimate the impact of those residential programs introduced from 1990 to 1997. As discussed above, BAU+ and BAU- both include energy labelling for appliances. The projection scenarios are:
■
the constrained demand must then be met by a combination of energy forms and system types that is common to all scenarios given projected penetrations for main heating types at the state level.
It would appear from the modelling undertaken for this study that many householders are accepting standards
1. BAU+ (business-as-usual with measures) - this assumes
of thermal comfort that are significantly lower than those
that dwellings continue to be constructed to the standards
used in NatHERS. This may be because the dwellings
prevailing today, including existing or agreed minimum standards where applicable: eg minimum building insulation standards in Victoria and 4 star ACTHERS energy rating in ACT. MEPS for refrigerators, freezers and electric storage water heaters are also included in this scenario; 2. BAU- (business-as-usual without measures) - as for BAU+, but excluding those program measures that were introduced or announced during the period 1990 to November 1997; 3. ME (Medium Efficiency) - as for BAU+ with the addition of a 3.5 star effective minimum building shell requirement (as defined in the NatHERS model) for all new dwellings in all states (similar to the SEDA “Smart Homes” program) from 2000; 4. HE (High Efficiency) - as for BAU+ with the addition of a 5 star effective minimum building shell requirement (as defined in the NatHERS model) for all new dwellings in all states from 2000; 5. HE+ (High Efficiency Plus) - as for HE for new dwellings, but also assumes that the thermal performance of existing dwellings is improved by an aggressive ceiling insulation retrofit program.
are simply too difficult and/or expensive to heat or cool adequately, but it should be recognised that thermal comfort requirements and occupancy levels can vary
8
considerably. As the thermal performance of the building stock improves, householders in more efficient homes may decide to take some of the potential energy savings as increased thermal comfort rather than as reduced energy consumption. This is quite difficult to model and there is little data to confirm or otherwise the extent of this effect in Australia. There is some documentation regarding this effect in Europe and the USA within particular segments (typically for low income households), but this data is unlikely to translate to Australia given the different climatic and cultural aspects. However, given the high level of constraint of both heating and cooling demands in Australia, small changes in user behaviour would have a large impact on heating and cooling energy. Benefits still accrue from improvements in the building shell, but these may not occur in the form directly intended (eg in the form of improved comfort instead of greenhouse gas emission reductions). Conversely, there is some evidence that improvements in building shell thermal performance may result in the occupants avoiding the installation of space conditioning equipment (typically cooling equipment) which they may have otherwise chosen to install in a building with poorer thermal performance. These possibilities need to be considered when assessing the quantitative data in this report.
2 The term “unconstrained” refers to the theoretical energy consumption required to maintain a house at comfortable conditions all year (assuming space heating and cooling equipment is installed). This “unconstrained” energy then has to be “constrained” to more accurately reflect actual energy used by typical households for heating and cooling. These terms are explained in more detail later in the report.
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Figure 10: Trends in Household Characteristics & Numbers 170% 160% Total Energy Demand 150% % of 1990 value
Average Floor Area 130% No. Houses 120% 110% 100% Energy /m 2
90%
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
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1995
1994
1993
1992
1991
80% 1990
PROJECTION SCENARIOS
140%
Interestingly, modelling showed that attached dwellings
Figure 10 shows the recent and projected key
were 36 per cent more efficient on a per square metre
characteristics of households in Australia which affect
basis in comparison with separate dwellings. In 1998,
energy consumption. While the potential (unconstrained)
attached dwellings consisted of 23 per cent of the total
energy consumption per square metre of floor area is
housing stock and this is projected to increase to
estimated to decline by 15 per cent from 1990 to 2010
26 per cent in 2010.
under the BAU+ scenario, this is expected to be more than offset by an increase in household numbers (+38 per cent)
9
and increase in the average floor area (+39 per cent) by 2010. The net impact on total household energy consumption for space heating and cooling (constrained) is a projected increase of +54 per cent under the BAU+ scenario.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Business as usual projections to 2010
KEY PROJECT FINDINGS
Under the business-as-usual scenario with measures,
Greenhouse gas emissions in 1990
the total greenhouse emissions from residential buildings
Total greenhouse gas emissions from residential buildings in
in 2010 are projected to be 56.7 MT CO2-e. This includes emissions from electricity, natural gas, wood and LPG.
1990 are estimated to be 48.6 MT CO2-e.3 This includes estimated by the model developed by EES for this project. In addition, there were emissions from other fuels such as solid fuels (coal, briquettes), various oil products, town gas and so on. The energy values recorded by ABARE for
KEY PROJECT FINDINGS
In addition, ABARE forecast that a small amount of other
emissions from electricity, natural gas, wood and LPG as
fuels such as solid fuels (eg coal, briquettes), various oil products, town gas and so on will be used in 2010. The energy values projected by ABARE for these additional fuels (4.9 PJ) have been used to calculate greenhouse gas emissions in 2010. These account for an extra 0.4 MT
these additional fuels (11.2 PJ) have been used to
CO2-e in 2010, totalling 57.1 MT CO2-e.
calculate greenhouse gas emissions in 1990. These accounted for an extra 0.9 MT CO2-e in 1990, totalling
Under the business-as-usual scenario without measures,
49.5 MT CO2-e.
the total greenhouse emissions from residential buildings in 2010 are projected to be 58.1 MT CO2-e. Emissions
Note: Some of the greenhouse gas emissions figures and their differences do not add up due to rounding. In addition, the energy and greenhouse values quoted are as estimated by the end use model developed by EES for this project and may not equal the values quoted by ABARE or the National Greenhouse Gas Inventory.4 However the data is broadly consistent with these data sources.
from other fuels are assumed to be the same as the business-as-usual scenario with measures scenario above. Therefore the impact of program measures implemented from 1990 to November 1997 is 1.4 MT CO2-e in 2010 (7.9 PJ), or 2.8 per cent of the 1990 residential sector emissions. These projections include expected changes 10
in consumer behaviour, where these are known. Figure 11 illustrates total greenhouse gas emissions under all 5 scenarios, over the period 1990 to 2010.
Figure 11: Total Projected Residential Greenhouse Gas Emissions 1990 to 2010 60
56 54 BAU52
BAU+
50
ME
48
HE
3 The term CO2-e refers to the net carbon dioxide rom combustion of the specified fuel(s) plus the equivalent global warming potential of associated emissions (methane and nitrous oxide). The CO2-equivalent values are slightly higher than the CO2 value because of the global warming impact of the small amounts of CH4 and N2O emitted
HE+
46 44
during combustion.
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
42 1990
Greenhouse Gas Emissions MT CO2-e
58
4 The Cross Sectoral Analysis for Greenhouse Gas Emissions estimated that greenhouse gas emissions from the residential sector in 1990 were 49.7 MT CO2-e, while this study estimates the value to be 49.5 MT CO2-e in 1990. Differences are due to weather and other effects which cannot be incorporated into the end use model.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
by the building sector could be 108 per cent of the 1990
Quantitative assessment of an equitable commitment for the building sector
emission levels for space heating and cooling, or some 6.9 MT CO2-e.
KEY PROJECT FINDINGS
Greenhouse gas emissions from the residential sector which are attributable to the building sector are assumed
We are not suggesting that “equitable” in this context
to relate only to space heating and cooling. Estimated
means fair or reasonable with respect to the building
greenhouse emissions for space heating and cooling in
sector. This is merely the share of the national emission
1990 were estimated to be 6.3 MT CO2-e. This includes
reduction target assuming that a uniform contribution is
emissions from electricity, natural gas, wood and LPG.
made by all sectors. Ultimately, governments will have to
Emissions from other fuels have been ignored (even though
consider a range of factors such as feasibility and cost
many of these are likely to be related to space heating).
effectiveness of measures within each of the major sectors before settling on specific programs.
Australia’s commitment under the Kyoto Protocol to the Framework Convention on Climate Change is to limit its
Figure 12 illustrates greenhouse gas emissions for heating
total greenhouse gas emissions to 108 per cent of the
and cooling energy only, under all 5 scenarios, over the
1990 value by 2010. Therefore an equitable contribution
period 1990 to 2010.
Figure 12: Projected Heating & Cooling Greenhouse Gas Emissions 1990 to 2010 9.5
8.5 8.0 7.5 BAUBAU+
7.0
ME 6.5
HE
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
Quantification of the emission gap
2010
HE+
6.0 1990
11
Greenhouse Gas Emissions MT CO2-e
9.0
A range of scenarios have been quantified as part of this project to obtain an assessment of possible program
As discussed above, for the purposes of this study, if an
measures which could be used to meet an “equitable”
equitable contribution by the building sector is assumed to
commitment by the building industry to meeting the
be 108 per cent of the 1990 emission levels attributable to
emission targets. The emission gap for each of these main scenarios is outlined below.
space heating and cooling, or some 6.9 MT CO2-e in 2010, the business-as-usual with measures scenario
Medium Efficiency (ME) - The projected greenhouse
projects that greenhouse emissions will be somewhat
gas emissions in 2010 attributable to space heating and
higher at 8.9 MT CO2-e in 2010, which is +39.4 per cent of the 1990 levels. The emission gap in 2010 is therefore
cooling from electricity, natural gas, wood and LPG under this scenario is 8.2 MT CO2-e in 2010, which is +29.6 per cent of the 1990 levels. The emission gap in 2010 for this
some 2.1 MT CO2-e in 2010, or 23.6 per cent of BAU+
scenario is therefore some 1.4 MT CO2-e in 2010, or 16.7
projected heating and cooling emissions in that year.
per cent of heating and cooling emissions in that year.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
High Efficiency (HE) - The projected greenhouse gas
cooling from electricity, natural gas, wood and LPG under
emissions in 2010 attributable to space heating and
this scenario is 7.6 MT CO2-e in 2010, which is 19.9 per
cooling from electricity, natural gas, wood and LPG under
cent of the 1990 levels. The emission gap in 2010 for this
this scenario is 8.0 MT CO2-e in 2010, which is +25.5 per
scenario is therefore some 0.8 MT CO2-e in 2010, or 9.9
cent of the 1990 levels. The emission gap in 2010 for this
per cent of heating and cooling emissions in that year.
per cent of heating and cooling emissions in that year.
Greenhouse gas emissions for the five scenarios relative to
High Efficiency Plus (HE+) - The projected greenhouse gas
1990 are also depicted in Figure 13, together with the
emissions in 2010 attributable to space heating and
Kyoto target (+8 per cent relative to 1990 emissions).
Figure 13: Projected Heating & Cooling Greenhouse Gas Emissions Relative to 1990 1.50 1.45
KEY PROJECT FINDINGS
scenario is therefore some 1.1 MT CO2-e in 2010, or 13.9
1.40
1.30 1.25 1.20
BAU-
1.15
BAU+
1.10
ME
1.05
HE
GAP Kyoto
12
The results of a range of building shell simulations are
The ‘zero energy’ option plotted on the horizontal axis is
summarised in Figure 14 which indicates the impact of
a hypothetical case where all new houses from 2000 use
improvements in the thermal performance of building shells on
zero net energy for space heating and cooling. Even this
the greenhouse gas emissions for space heating and cooling
“optimistic” scenario is unable to achieve the Kyoto
in 2010. The “with retrofit” option assumes an aggressive
commitment for Australia, mainly because of the limited
ceiling insulation program within existing houses currently
proportion of the housing stock that is affected in the
without ceiling insulation as per the HE+ scenario.
period from 2000-10.
Figure 14: Impact of Building Shell Energy Efficiency on Greenhouse Gas Emissions in 2010 1.50
CO2-e Relative to 1990
1.40
BAUBAU+ is slightly better than 2 Star (1.39) No Retrofit
ME HE
1.30 With Retrofit 1.20 HE+
1.10 Kyoto 1.00 BAU-
2 Star
2.5 Star
3 Star
3.5 Star
4 Star
Effective Minimum Star Rating for all New Houses
Note: The star rating bands are non linear and the rate of change varies with climate zone.
4.5 Star
5 Star
Zero Energy
2010
2009
2008
2007
2006
2005
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
2004
HE+
1.00
2003
CO2-e Relative to 1990
1.35
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
PROJECT CONCLUSIONS Thermal comfort levels
Land subdivision Should it be decided that new housing stock will be
PROJECT CONCLUSIONS
required to meet more stringent thermal performance It is clear from this study that present user behaviour
standards, then the need for land subdivision design to
drastically reduces the potential maximum energy
address the issue of solar access and building orientation
demands for both heating and especially cooling.
will be a necessary adjunct to such a program. One of the
However, small increases in required user comfort
most cost effective ways of producing more thermally
levels could significantly impact on energy demand in
efficient housing is through improved orientation and
this area. This potential for increase can be mitigated
glazing placement (ie passive solar design principles).
to a large extent through improved building shell thermal performance standards combined with a public energy saving awareness program.
Existing housing stock
Building shell - Performance measures versus prescriptive measures Whilst prescriptive measures are relatively easy to implement, by their nature they tend to be unsophisticated
The fact that 80 per cent of all housing stock in the year
and their use often results in lost opportunities especially
2010 has already been built by 1998 would indicate that:
in respect of the principals of passive solar design. In Victoria, for example, there are numerous houses that,
1. Improving the existing building stock through various
despite meeting the mandatory insulation requirements,
retrofitting strategies such as installation of ceiling insulation
exhibit poor thermal performance due to poor orientation,
would appear to warrant more detailed investigation.
lack of shading and or lack of winter solar access, all
13
design aspects that often represent a zero incremental 2. More stringent measures to new buildings are warranted to assist in mitigating the relatively poor thermal performance standards of our existing stock.
cost in most cases. The higher the overall thermal performance standard desired, the more likely a performance based measure will produce the most cost effective outcome for the consumer.
Longevity of building shells Building shells generally have a very long life and energy efficiency program measures implemented now will have a very long term impact, well beyond the year 2010, which is the limit of this study.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Embodied energy
Appliance issues
Embodied energy clearly represents a significant
Some appliance related issues have the potential to have a
proportion of a dwelling’s life cycle energy and
large long term impact on greenhouse gas emissions from
greenhouse gas emissions. Policy options that effect
residential buildings:
reductions in this area could have a significant net impact, ■
hot water service fuel selection and efficiency - the
consumed prior to or during construction. Any measures
hot water service is often selected by the builder during
designed to abate greenhouse gas emissions could not
construction and can be considered, de facto, to be part
be considered to be comprehensive if they did not
of the building shell related equipment (replacement
address this issue.
systems are almost always the same fuel). The fuel source for hot water is critical; electric systems typically have greenhouse emissions of the order of 4 times higher per unit of energy service in comparison with natural gas for mainland states. For natural gas units, the variation in the task efficiency from best to worst is
PROJECT CONCLUSIONS
especially given that a large proportion of this energy is
almost twofold. ■
uncontrolled combustion for wood heating - while the share of uncontrolled wood combustion heaters (eg open fire places) and their usage patterns are unclear at this stage, greenhouse gas emissions for these types of heaters is significant (relative to controlled combustion, which is close to zero) and they can also be associated with poor air quality in urban areas. The lack of flue control for many of these systems can also result in reduced thermal building shell performance. These issues warrant further investigation and consideration.
14
RECOMMENDED FURTHER RESEARCH
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
RECOMMENDED FURTHER RESEARCH While this study used existing data sources, there were a
this important end use. The influence of non-thermal
number of areas where data was sparse or non-existent.
factors would also provide greater understanding with
This section outlines areas where further data collection
respect to modelling.
will improve the potential modelling for similar projects in future.
One area not specifically investigated in this study but which could have significant greenhouse gas emission
Standby losses for electrical appliances and equipment
impacts is fuel substitution. The end use with the greatest
appear to be a large and growing end use in the residential
potential impact is water heating. For example, preliminary
sector. Very little is currently known about the nature of
calculations suggest that substituting all existing electric
standby losses. It is recommended that collection of data
water heaters with natural gas or LPG could potentially
on the number, magnitude and type of standby losses in the residential sector be undertaken in the near future. This could be done as part of a growing international effort to limit standby losses.
reduce residential greenhouse gas emissions by some 7 MT CO2-e in 2010, or 12 per cent of the total BAU+ case. This alone could bridge the total residential sector gap of 4.2 MT CO2-e in 2010. However, the infrastructure to achieve this is unlikely to be available within the required
A further study of the more significant building elements would be required to quantify the impact of embodied energy and related greenhouse gas emissions in terms of the life cycle analysis of residential buildings. A baseline study for embodied energy of residential buildings (and 15
another for other building types, such as commercial buildings) is recommended. A report on policy options relating to embodied energy of residential buildings (and another for other building types, such as commercial buildings) is also recommended. Strategies need to be developed for informing and educating design teams, changing the market-place and empowering consumers,
time frame. There is also some limited fuel switching potential within the cooking end use (of the order of 1 MT CO2-e of potential in 2010), although infrastructure and user preferences are likely to be problematic. Fuel substitution in the space heating segment is more limited (less 1 MT CO2-e of potential in 2010 - assuming that reverse cycle air conditioners are not substituted). Further studies are warranted in this area, with particular attention being paid to the likely expansion of the natural gas distribution system within each state and the potential for increasing the saturation of natural gas water heating and space heating in households already supplied with natural gas.
enabling the design, construction and operation of residential buildings with optimised life cycle greenhouse
While wood is a significant and growing source of energy
gas emissions.
for space heating in the residential sector, the continued use of uncontrolled combustion in a limited number
Current poor levels of public awareness, especially within
of households has the potential to produce significant
the industry, of the significance of embodied energy in the
greenhouse gas emissions, create pollution problems in
life cycle energy equation of residential buildings is seen
urban areas, and may have a detrimental impact of thermal
as an impediment to gaining public support for initiatives
performance of buildings. These issues require further
in this area. Options for raising the profile of embodied
detailed examination and quantification before specific
energy issues therefore need to be explored.
actions are implemented.
Further data collection and analysis of appliance usage patterns will provide an improved data set from which to undertake future analyses of energy consumption patterns and projections and their related greenhouse gas emissions. In particular, more data on the use of heating and cooling equipment and the relationship with building shell design and climate would greatly enhance the understanding which underpins the modelling of
executive summary
report
1999
The Australian Greenhouse Office is the lead Commonwealth agency on greenhouse matters
Australian Residential Building Sector Greenhouse Gas Emissions 1990-2010
executive summary
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ISBN 1876536 136 © Commonwealth of Australia 1999 This work is copyright. Permission is given for fair dealing with this material as permitted under copyright legislation, including for the purposes of private study and research. Apart from those uses, no part may be reproduced without prior written permission from the Commonwealth. Requests and inquiries concerning reproduction rights should be directed to the: Manager, Communications Australian Greenhouse Office GPO Box 621 Canberra ACT 2601 This study is available online at the Australian Greenhouse Office website at www.greenhouse.gov.au/energyefficiency/building Design Wingrove Wingrove Design Photos Courtesy of the Housing Industry Association
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
FOREWORD Though the full effects of emissions of greenhouse gases on the Earth’s atmosphere are not yet completely understood, the scientific evidence points to a discernible human influence on global climate change. The residential building sector has recognised the need to address greenhouse concerns, and not just from the perspective of climate change, but also to improve the
The Australian Greenhouse Office is pleased to present this study as a valuable sectoral contribution to the broader greenhouse debate.
F O R E WA R D
comfort of the built environment for all Australians.
Importantly, it provides the most up to date and comprehensive baseline data of greenhouse gas emissions for the residential building sector. I hope that members of the building industry will find this study stimulates not only further discussion on the greenhouse problem, but supports the development of initiatives designed to address these concerns. iii Without doubt the building industry has the challenge of becoming more environmentally sensitive while remaining economically efficient. It is a difficult challenge, for the issues are diverse and complex. I would like to commend the authors of the study, Energy Efficient Strategies, as well as acknowledge the contribution of the Steering Committee representing industry and government organisations.
Gwen Andrews Chief Executive Australian Greenhouse Office April 1999
iv
Acknowledgements The study was produced for the Australian Greenhouse Office by Lloyd Harrington and Robert Foster of Energy Efficient Strategies with assistance from Energy Partners George Wilkenfeld & Associates and additional contributions from Graham Treloar, Deakin University Mark Ellis & Associates
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Australian Residential Building Sector Greenhouse Gas Emissions 1990-2010
1
Study Objectives
3
Major Issues
4
Energy forms and end uses
4
Operational versus embodied energy
5
Projection issues
5
Short term versus long term results
6
Voluntary versus mandatory solutions
6
Project Scenarios
8
Key Project Findings
10
Greenhouse gas emissions in 1990
10
Business as usual projections to 2010
10
Quantitative assessment of an equitable committment for the building sector
11
Quantification of the emission gap
11
Project Conclusions
13
Thermal comfort levels
13
Existing housing stock
13
Longevity of building shells
13
Land subdivision
13
Building shell - Performance measures versus prescriptive measures
13
Embodied energy
14
Appliance issues
14
Recommended Further Research
15
CONTENTS
CONTENTS
v
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
AUSTRALIAN RESIDENTIAL BUILDING SECTOR GREENHOUSE GAS EMISSIONS 1990-2010
protect Australian jobs and industry. As a result, the Government is seeking “realistic, cost-effective reductions in key sectors where emissions are high or growing
ABOUT THE REPORT
strongly, while also fairly spreading the burden of action This study estimates energy consumption and greenhouse
across the economy”. The Prime Minister also noted
gas emissions in the residential sector over the period
that “[The Government is] prepared to ask industry to do
1990 to 2010, with the primary aim of providing a basis
more than they may otherwise be prepared to do, that is,
for the determination of an equitable contribution by the
to go beyond a ‘no regrets’, minimum cost approach
building sector to greenhouse gas emission reductions.
where this is sensible in order to achieve effective and
The study looks closely at all end uses (including electrical
meaningful outcomes”.
appliances and equipment, water heating and cooking) but there is particular attention given to space heating and cooling in residential buildings: the interaction of the thermal performance of the building shell, heating and cooling regimes and the type, fuel mix and energy efficiency of space heating and cooling equipment.
Subsequent negotiations resulted in an international agreement to the Kyoto Protocol to the Framework Convention on Climate Change, under which Australia will have an obligation, inter alia, to reduce its greenhouse gas emissions to 108 per cent of the 1990 level by 20082012. This compares with a business-as-usual scenario
Space heating and cooling accounted for 39 per cent of
prior to the Prime Minister’s Statement of 28 per cent
total residential operational energy consumption in 1998.
emissions growth for the economy as a whole, and around
The three main energy sources used in the residential
40 per cent for energy-related emissions, based on
sector are electricity, natural gas and wood. While only a
projections available at that time.
small part of residential electricity consumption is used for space heating and cooling, the vast majority of natural 1
gas and wood consumption in Australia is used for space heating. Because such a large share of the energy is from the less greenhouse gas-intensive energy sources, space heating and cooling account for a lower share of greenhouse gas emissions than of energy use. Even so, heating and cooling account for nearly 15 per cent of residential sector greenhouse gas emissions. Building shell thermal performance has a large impact on the heating and cooling requirements for residential buildings, so improvements in thermal performance are likely to lead to reductions in greenhouse gas emissions. In his statement of 20 November 1997, “Safeguarding the Future: Australia’s Response to Climate Change”, the Prime Minister announced a package of measures to reduce Australia’s greenhouse gas emissions. He noted that this package of measures was designed both to ensure that Australia plays its part in the global effort required to reduce greenhouse gas emissions and to
For the building sector, the Prime Minister’s Statement specified: “The Commonwealth will work with the States, Territories and key industry stakeholders to develop voluntary minimum energy performance standards for new and substantially refurbished commercial buildings on the basis of energy efficiency benchmarks. If after 12 months, the Government assesses that the voluntary approach is not achieving acceptable progress towards higher standards of energy efficiency for housing and commercial buildings, we will work with the States and industry to implement mandatory standards through amendment of the Building Code of Australia.”
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
This project has been commissioned by the Australian
It is estimated that water heaters were responsible for
Greenhouse Office (in consultation with the building
28 per cent of residential greenhouse gas emissions in
industry) to determine baseline greenhouse gas emissions
1998. This study has found that 52 per cent of greenhouse
attributable to the residential building sector of the
gas emissions attributable to the residential sector come
economy and to provide a firm, quantitative basis for the
about as a result of electrical appliances selected by
subsequent development of specific greenhouse response
residents or persons outside the building sector, and
measures by industry and government.
therefore cannot be directly affected by changes made
greenhouse gas emissions result from cooking.
greenhouse gas emissions attributable to the residential sector in 1998 come about as a result of householders’
By quantifying the impacts of a range of building
need to heat and cool dwellings. The amount of energy
sector influenced possibilities, this study provides a
used for this purpose over the life of a dwelling depends
basis for establishing the contribution that the residential
largely on its design and materials, and other factors
building industry can make to the national objective of
determined at the time of construction. Therefore the
reducing greenhouse gas emissions, in line with
housing industry has a key role to play in influencing
Australia’s obligations.
ABOUT THE REPORT
within the building industry. The remaining 5 per cent of This study has found that about 15 per cent of the
future demand for residential sector heating and cooling, and on the related greenhouse gas emissions. Its influence also extends to other fixed systems and appliances installed at the time of construction, most notably water heating, and to a lesser extent some fixed space heating appliances and cooking appliances, as well as the fuel choice for these end uses. 2
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
STUDY OBJECTIVES
The business-as-usual projections with measures implemented or announced to date (BAU+) includes
The study objectives are as follows:
those program measures that have been introduced during the period 1990 to November 1997 (the date of
1. Quantify energy related greenhouse gas emissions
the Prime Minister’s statement). This scenario reflects
attributable to the residential buildings sector in 1990;
the actual market situation during the period from 1990
STUDY OBJECTIVES
to 1998 and is used as the primary basis for future 2. Estimate business-as-usual emission growth
projections. The business-as-usual projections without
projections from 1990 - 2010, with and without
measures implemented or announced to date (BAU-) is a
emissions-reduction measures implemented or
hypothetical case which is used to assess the energy
announced to date, taking into account changes in
and greenhouse impact of those program measures
consumer behaviour;
introduced during the period 1990 to November 1997 (program impact = BAU+ less BAU-).
3. Provide a quantitative assessment of an equitable greenhouse emission reduction commitment for the
Energy labelling of appliances commenced in Australia in
building sector, taking into account baseline and
1986. As this program was in place well before 1990, it
projected emissions growth to 2010 and the Kyoto
is included in both the business-as-usual with and without
Protocol commitment for Australia as a whole; and,
scenarios. It is now very difficult to disentangle the impact of energy labelling for appliances from the current trends
4. Quantify any “gap” between the proposed emissions
in energy consumption.
reduction commitment to 2010 for the building sector
3
and the projected emissions growth with measures
This study takes into account changes in user
implemented or announced to date.
behaviour where this affects energy consumption. However, evaluations of historical programs suggests
This study covers Class 1 and Class 2 buildings as defined by the Building Code of Australia - this primarily includes private residential dwellings which are separate (eg stand alone houses) and attached (eg flats, town houses, terrace houses). Residential parts of commercial establishments
that government programs which provide information with the sole objective of influencing daily energy-using behaviour, as distinct from influencing product or dwelling choice, have not had (and are unlikely to have) any significant long term impact on energy use.
are not included. The Prime Minister’s statement of November 1997 The quantification of baselines and the projection of emissions follows, as closely as possible, the relevant Australian Methodologies for the Estimation of Greenhouse Gas Emissions and Sinks, as published by the National Greenhouse Gas Inventory Committee.
included a requirement for electricity suppliers to increase their generation from renewable sources by an average of 2 per cent by 2010. The projected impact of this program has been factored into the greenhouse gas intensity projections for each state. As this program affects all sectors which use electricity (ie is not specific to the residential sector or building shells), it is assumed to form part of all scenarios developed for this study.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Figure 2: Residential Energy Share by End Use 1998
MAJOR ISSUES Energy forms and end uses Electricity is the major energy source for residential buildings, accounting for about 48 per cent of all energy in 1998. Natural gas is the next biggest fuel, accounting for about 35 per cent of energy while wood accounts for about 14 per cent. In terms of greenhouse gas
1% SPACE COOLING 4% COOKING 27% WATER HEATING 30% ELECTRICAL APPLIANCES & EQUIPMENT 38% SPACE HEATING
emissions from residential, electricity dominates accounting
Figure 1: Residential Energy Share by Fuel 1998 Figure 3: Residential Greenhouse Gas Emission Share by End Use 1998
3% LPG 14% WOOD 35% NATURAL GAS 48% ELECTRICITY
MAJOR ISSUES
for 84 per cent of emissions.
2% SPACE COOLING 5% COOKING 12% SPACE HEATING 28% WATER HEATING 53% ELECTRICAL APPLIANCES & EQUIPMENT
Electrical appliances, cooking and water heating account
4
for 61 per cent of residential energy consumption and 85 per cent of residential greenhouse gas emissions. Space heating and cooling account for the balance: about
Figure 4: Residential Heating & Cooling Energy by Fuel 1998
39 per cent of energy consumption and 15 per cent of greenhouse gas emissions. (These estimates cover the use of electricity, natural gas, LPG and wood, but not the minor fuels such as oil and briquettes, which, while small in magnitude, are mostly associated with space heating). In energy terms, space heating is the single largest end use in the residential sector, but the third largest with
3% ELECTRICITY COOLING 3% ELECTRICITY HEATING 3% LPG 35% WOOD 56% NATURAL GAS
respect to greenhouse gas emissions, behind appliances and water heating. The energy consumption required for heating and cooling in residential buildings is a function of both climate and the design and thermal performance of the building shell. It is also heavily influenced by user behaviour (occupancy
Figure 5: Residential Heating & Cooling Greenhouse Emissions by Fuel 1998
levels, proportion of the building that is heated or cooled) and the efficiency of heating and cooling appliances, so quantifying the impact of building shell performance contains significant uncertainties. The energy consumption of electrical appliances, cooking and water heating is largely unaffected by the design and thermal performance of the building shell. Climate has some secondary impact on the operation of refrigerators, freezers and hot water systems and this effect has been incorporated into the end use estimates as far as is
4% LPG 10% WOOD 15% ELECTRICITY COOLING 15% ELECTRICITY HEATING 56% NATURAL GAS
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
possible. Climate also has other secondary effects such as
Projection issues
the temperature selected for clothes washing (eg warmer states tend to select cold washing more frequently as the
Energy consumption is projected over the period 1990 to
cold water supply is warmer) and the frequency of clothes
2010. The analysis was carried out in late 1998, almost
dryer use - these impacts have also been incorporated
half way through the projection period, and outputs have
into the model where data is available.
been calibrated to actual energy consumption data at state level (as collected by ABARE) since 1987, so there is a reasonable level of confidence in the projections.
MAJOR ISSUES
Operational versus embodied energy This study concentrates on the “operational” energy used
However, there will inevitably be some uncertainties
to provide a range of energy services such as hot water,
regarding projections, including:
heating and electrical appliance services. There is also a large amount of embodied energy consumed directly or indirectly to manufacture and supply materials and goods used in the construction of a dwelling.
■
population and household forecasts
■
future penetration and ownership of appliances
■
future characteristics of new appliances sold (size, energy efficiency)
Embodied energy can be equal to as much as 20 years of operational energy for a typical new house. Most of
■
this energy is effectively consumed at or before the time
future characteristics of new dwellings (size, insulation and efficiency)
of construction, and most of this is accounted within
■
the industrial and construction sectors of the economy.
changing patterns of user behaviour (frequency and duration of use for appliances in general but particularly
In addition, over a typical building life of up to 100 years,
with respect to space heating & cooling)
a further 20 years of operational energy can be embodied through refurbishments and renovations. Hence embodied
It is also necessary to use average values for variables,
energy can be of the order of 40 per cent of the total
where in reality there will be a frequency distribution around
operational energy consumed over a 100 year period.
the average values for all households. Therefore the values
A detailed quantification of embodied energy is not within
reported in this study will not necessarily be representative
the scope of this study, but the issues related to embodied
of any particular household. Historical shares of end use
energy are explored in some detail and some examples
energy and greenhouse gas emissions by fuel type are
of the interaction between embodied and operational
shown in Figure 6 to Figure 9.
energy for a range of construction materials and approaches are included.
Figure 6: Residential Energy Consumption by Fuel 1986 to 1998
Figure 7: Residential Greenhouse Emissions by Fuel 1986 to 1998 50
160 Electricity
Electricity
45
140
40
100
Greenhouse Gas Emissions MT CO2-e
120
Natural Gas
80 60 Wood
40
35 30 25 20 15 10
20
Natural Gas
5
LPG
Wood
LPG
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
0
0
1986
Energy PJ
5
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
The stock of residential buildings in Australia is generally
Short term versus long term results
have both wall and ceiling insulation and a further 42 per
impact that the building sector could have on energy
cent have only ceiling insulation. In addition, many of the
and greenhouse emissions by 2010. The study shows
houses with only ceiling insulation appear to have this
that greatly improving the thermal performance of new
installed after construction is complete (ie by occupants
residential buildings from 2000 onward can go a significant
rather than builders). Some 38 per cent of dwellings have
way towards meeting greenhouse gas emission reduction
neither wall or ceiling insulation. One area considered in
targets for this sector in the Kyoto commitment period
this study is the retrofit of ceiling insulation into existing
(2008-2012) if space heating and cooling energy were
buildings without ceiling insulation. This could have a
considered separately.
substantial impact on the thermal performance of the existing building stock by 2010 and could help contribute
However, residential buildings, unlike appliances and
to emission reduction targets. Retrofit of wall insulation is
equipment, potentially have a very long life - of the order
generally considered unfeasible, although there are some
of 50 to 100 years, so any measures implemented will continue to have an impact on energy and greenhouse gas emissions for decades to come. This study only quantifies
specialist companies now operating that can retrofit wall
MAJOR ISSUES
poorly insulated. Only 20 per cent of all residential buildings One focus for this study is to estimate the potential
insulation for selected construction types.
these benefits to 2010. A related issue is that the rate of household formation (and hence new construction of
Voluntary versus mandatory solutions
residential buildings) is of the order of 2 per cent per annum (the net demolition rate appears to be very small -
Programs aimed at increasing the thermal performance of
well below 0.5 per cent). So over the projection period
residential buildings could be either voluntary or mandatory
from 2000 to 2010, where program measures for new
in nature, or a mixture of the two. Voluntary measures can
residential buildings are assumed to come into force, only about 20 per cent of the total housing stock can be
high level of consumer interest and involvement.
affected (ie 80 per cent will be outside the scope of any program targeted at new buildings). While this limits the
The relatively large number of parties involved in the
potential contribution by 2010 of programs established
building industry suggests that widespread compliance
before that date (even if they start almost immediately),
with voluntary programs, especially where these may
such programs will have an expanding impact to 2050
involve a significant cost premium during construction,
and beyond.
may be difficult to achieve. The market reality is that there
Figure 8: Residential Energy Consumption by End Use 1986 to 1998
Figure 9: Residential Greenhouse Emissions by End Use 1986 to 1998
140
30
120
80 Water Heating 60 40
Greenhouse Gas Emissions MT CO2-e
Electrical Appliances & Equipment
100
20
Electrical Appliances & Equipment
25
Space Heating & Cooling
20 Water Heating 15
10 Space Heating 5
Cooking
Cooking
0
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
0
1986
Energy PJ
6
work well where there is strong industry cohesion and a
MAJOR ISSUES
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
is generally little direct incentive for the building industry
mandatory in any state. While there is strong pressure on
to increase the thermal performance of new buildings.
developers to maximise revenue by fitting as many blocks
The purchasers of buildings rarely specify measures that
into a given area as possible with no regard to orientation,
directly impact on the energy efficiency of the building
things are unlikely to change in this respect. (Indeed,
(such as orientation, glazing, insulation levels) and there is
there are transport energy advantages to higher densities,
intense competition within the industry to minimise costs.
although different building forms may be more appropriate
Builders do not pay the ongoing energy bills, so unless
than detached dwellings: however, transport related
the ultimate occupant commissions the design, is involved
impacts are beyond the scope of this study). Local
prior to construction and/or is aware of building shell
government could play a strong role by mandating energy
energy efficiency issues, there is no direct market incentive
efficiency requirements for subdivisions (especially with
to improve thermal performance. Given the relatively poor
respect to orientation of buildings), although this is likely to
average thermal performance of typical new dwellings in
be more effective if implemented at state or national level.
Australia, it would appear that occupants exert little influence over these aspects. There would be some
Traditionally, where there are requirements regarding the
indirect market pressure if energy-efficient dwellings
building shell, the building industry has tended to favour
commanded a higher price; this is one objective of house
prescriptive measures over performance based measures.
energy rating schemes, but their influence on buyer or
Prescriptive measures are relatively easy for builders to
occupant behaviour is still unclear.
assess, cost and install (eg via a standard check list). The main drawback of prescriptive measures is that,
Mandatory programs can achieve results independently of user involvement, but can also impose higher costs on all house builders and buyers. The issue is whether such costs are more than offset by the total value of the energy saved, and whether the savings are distributed widely enough so that the great majority of affected parties are
7
better off (noting that costs are not necessarily borne by beneficiaries). A number of design factors which have a large impact on thermal performance (such as orientation and placement of glazing) can be included during the design process at close to zero cost. However, it is difficult to specify such factors in a prescriptive sense: this is most effectively dealt with through performance based approaches (see below). The inclusion (or otherwise) of key energy efficiency measures at the time of construction is critical: many of these cannot be practically altered after construction is commenced (building orientation,
by necessity, they tend to be overly simplistic and are unable to deal with significant areas of energy efficiency (eg passive solar design = orientation and glazing placement) that often require little incremental cost to implement during construction. Performance measures are often regarded as more difficult as it may mean that the performance has to be assessed by a third party and that a series of iterations may be necessary to meet both the client’s requirements and the thermal performance requirements within the client’s cost constraints. Evidence for this comes from Victoria where builders can comply with building regulations via the inclusion of specified insulation levels or alternatively achieve a minimum star rating1 - to date very few approvals have been done on the basis of the minimum star rating. However, this paradigm within the building industry could change. The mandatory
placement of glazing, wall insulation in most cases).
minimum 4 star requirement in the ACT has forced a
The cost of including other efficiency measures is
change of approach by the local building industry
generally much higher if retrofitted in comparison with
and is now quickly gaining widespread acceptance.
installation during construction. Therefore it is much
Performance based measures have the advantage of
more cost-effective to include an integrated package
providing builders and clients with almost infinite flexibility
of efficiency measures during design and construction
to meet their requirements.
than it is to improve the efficiency of the building shell post construction.
The cost-effectiveness of these or other approaches has not explicitly been analysed in this study, which
1 From 1992-96, the rating was 4 stars (VICHERS); from 1996 this was amended to 3 stars.
If a policy shift towards higher efficiency building shell
concentrates on the energy and greenhouse gas
standards were to be adopted, then building orientation
reductions possible through improved thermal
would be an important factor in achieving this goal.
performance of building shells. It has of course been
Although some states have guidelines for the development
necessary to assume that there are means for achieving
of energy efficient subdivisions that provide for good
such improvements, so the optimum paths to achieving
solar access and facilitate correct orientation, this is not
them can now be explored.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
PROJECTION SCENARIOS
The heating and cooling energy required under each scenario is calculated as follows: ■
to estimate the impact on changes in building shell
from the characteristics of the building stock using the
thermal performance on residential energy consumption.
NatHERS model for the known range of construction
The population, household size and non-heating/cooling
types and climate types.
energy use assumptions (ie BAU+ for appliance characteristics and performance) were common to all
the unconstrained2 heating/cooling demand is calculated
■
PROJECTION SCENARIOS
Four building shell projection scenarios were modelled
it is assumed that the constraint ratios calculated for
four - the differences lie in the assumptions about change
the years 1990 to 1997 persist: ie if the unconstrained
in the thermal performance of the dwelling stock, and
heating demand in a State doubles, the constrained
the consequent impacts on heating and cooling energy.
heating/cooling demand also doubles.
An additional hypothetical scenario (BAU-) has been developed to estimate the impact of those residential programs introduced from 1990 to 1997. As discussed above, BAU+ and BAU- both include energy labelling for appliances. The projection scenarios are:
■
the constrained demand must then be met by a combination of energy forms and system types that is common to all scenarios given projected penetrations for main heating types at the state level.
It would appear from the modelling undertaken for this study that many householders are accepting standards
1. BAU+ (business-as-usual with measures) - this assumes
of thermal comfort that are significantly lower than those
that dwellings continue to be constructed to the standards
used in NatHERS. This may be because the dwellings
prevailing today, including existing or agreed minimum standards where applicable: eg minimum building insulation standards in Victoria and 4 star ACTHERS energy rating in ACT. MEPS for refrigerators, freezers and electric storage water heaters are also included in this scenario; 2. BAU- (business-as-usual without measures) - as for BAU+, but excluding those program measures that were introduced or announced during the period 1990 to November 1997; 3. ME (Medium Efficiency) - as for BAU+ with the addition of a 3.5 star effective minimum building shell requirement (as defined in the NatHERS model) for all new dwellings in all states (similar to the SEDA “Smart Homes” program) from 2000; 4. HE (High Efficiency) - as for BAU+ with the addition of a 5 star effective minimum building shell requirement (as defined in the NatHERS model) for all new dwellings in all states from 2000; 5. HE+ (High Efficiency Plus) - as for HE for new dwellings, but also assumes that the thermal performance of existing dwellings is improved by an aggressive ceiling insulation retrofit program.
are simply too difficult and/or expensive to heat or cool adequately, but it should be recognised that thermal comfort requirements and occupancy levels can vary
8
considerably. As the thermal performance of the building stock improves, householders in more efficient homes may decide to take some of the potential energy savings as increased thermal comfort rather than as reduced energy consumption. This is quite difficult to model and there is little data to confirm or otherwise the extent of this effect in Australia. There is some documentation regarding this effect in Europe and the USA within particular segments (typically for low income households), but this data is unlikely to translate to Australia given the different climatic and cultural aspects. However, given the high level of constraint of both heating and cooling demands in Australia, small changes in user behaviour would have a large impact on heating and cooling energy. Benefits still accrue from improvements in the building shell, but these may not occur in the form directly intended (eg in the form of improved comfort instead of greenhouse gas emission reductions). Conversely, there is some evidence that improvements in building shell thermal performance may result in the occupants avoiding the installation of space conditioning equipment (typically cooling equipment) which they may have otherwise chosen to install in a building with poorer thermal performance. These possibilities need to be considered when assessing the quantitative data in this report.
2 The term “unconstrained” refers to the theoretical energy consumption required to maintain a house at comfortable conditions all year (assuming space heating and cooling equipment is installed). This “unconstrained” energy then has to be “constrained” to more accurately reflect actual energy used by typical households for heating and cooling. These terms are explained in more detail later in the report.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Figure 10: Trends in Household Characteristics & Numbers 170% 160% Total Energy Demand 150% % of 1990 value
Average Floor Area 130% No. Houses 120% 110% 100% Energy /m 2
90%
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
80% 1990
PROJECTION SCENARIOS
140%
Interestingly, modelling showed that attached dwellings
Figure 10 shows the recent and projected key
were 36 per cent more efficient on a per square metre
characteristics of households in Australia which affect
basis in comparison with separate dwellings. In 1998,
energy consumption. While the potential (unconstrained)
attached dwellings consisted of 23 per cent of the total
energy consumption per square metre of floor area is
housing stock and this is projected to increase to
estimated to decline by 15 per cent from 1990 to 2010
26 per cent in 2010.
under the BAU+ scenario, this is expected to be more than offset by an increase in household numbers (+38 per cent)
9
and increase in the average floor area (+39 per cent) by 2010. The net impact on total household energy consumption for space heating and cooling (constrained) is a projected increase of +54 per cent under the BAU+ scenario.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Business as usual projections to 2010
KEY PROJECT FINDINGS
Under the business-as-usual scenario with measures,
Greenhouse gas emissions in 1990
the total greenhouse emissions from residential buildings
Total greenhouse gas emissions from residential buildings in
in 2010 are projected to be 56.7 MT CO2-e. This includes emissions from electricity, natural gas, wood and LPG.
1990 are estimated to be 48.6 MT CO2-e.3 This includes estimated by the model developed by EES for this project. In addition, there were emissions from other fuels such as solid fuels (coal, briquettes), various oil products, town gas and so on. The energy values recorded by ABARE for
KEY PROJECT FINDINGS
In addition, ABARE forecast that a small amount of other
emissions from electricity, natural gas, wood and LPG as
fuels such as solid fuels (eg coal, briquettes), various oil products, town gas and so on will be used in 2010. The energy values projected by ABARE for these additional fuels (4.9 PJ) have been used to calculate greenhouse gas emissions in 2010. These account for an extra 0.4 MT
these additional fuels (11.2 PJ) have been used to
CO2-e in 2010, totalling 57.1 MT CO2-e.
calculate greenhouse gas emissions in 1990. These accounted for an extra 0.9 MT CO2-e in 1990, totalling
Under the business-as-usual scenario without measures,
49.5 MT CO2-e.
the total greenhouse emissions from residential buildings in 2010 are projected to be 58.1 MT CO2-e. Emissions
Note: Some of the greenhouse gas emissions figures and their differences do not add up due to rounding. In addition, the energy and greenhouse values quoted are as estimated by the end use model developed by EES for this project and may not equal the values quoted by ABARE or the National Greenhouse Gas Inventory.4 However the data is broadly consistent with these data sources.
from other fuels are assumed to be the same as the business-as-usual scenario with measures scenario above. Therefore the impact of program measures implemented from 1990 to November 1997 is 1.4 MT CO2-e in 2010 (7.9 PJ), or 2.8 per cent of the 1990 residential sector emissions. These projections include expected changes 10
in consumer behaviour, where these are known. Figure 11 illustrates total greenhouse gas emissions under all 5 scenarios, over the period 1990 to 2010.
Figure 11: Total Projected Residential Greenhouse Gas Emissions 1990 to 2010 60
56 54 BAU52
BAU+
50
ME
48
HE
3 The term CO2-e refers to the net carbon dioxide rom combustion of the specified fuel(s) plus the equivalent global warming potential of associated emissions (methane and nitrous oxide). The CO2-equivalent values are slightly higher than the CO2 value because of the global warming impact of the small amounts of CH4 and N2O emitted
HE+
46 44
during combustion.
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
42 1990
Greenhouse Gas Emissions MT CO2-e
58
4 The Cross Sectoral Analysis for Greenhouse Gas Emissions estimated that greenhouse gas emissions from the residential sector in 1990 were 49.7 MT CO2-e, while this study estimates the value to be 49.5 MT CO2-e in 1990. Differences are due to weather and other effects which cannot be incorporated into the end use model.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
by the building sector could be 108 per cent of the 1990
Quantitative assessment of an equitable commitment for the building sector
emission levels for space heating and cooling, or some 6.9 MT CO2-e.
KEY PROJECT FINDINGS
Greenhouse gas emissions from the residential sector which are attributable to the building sector are assumed
We are not suggesting that “equitable” in this context
to relate only to space heating and cooling. Estimated
means fair or reasonable with respect to the building
greenhouse emissions for space heating and cooling in
sector. This is merely the share of the national emission
1990 were estimated to be 6.3 MT CO2-e. This includes
reduction target assuming that a uniform contribution is
emissions from electricity, natural gas, wood and LPG.
made by all sectors. Ultimately, governments will have to
Emissions from other fuels have been ignored (even though
consider a range of factors such as feasibility and cost
many of these are likely to be related to space heating).
effectiveness of measures within each of the major sectors before settling on specific programs.
Australia’s commitment under the Kyoto Protocol to the Framework Convention on Climate Change is to limit its
Figure 12 illustrates greenhouse gas emissions for heating
total greenhouse gas emissions to 108 per cent of the
and cooling energy only, under all 5 scenarios, over the
1990 value by 2010. Therefore an equitable contribution
period 1990 to 2010.
Figure 12: Projected Heating & Cooling Greenhouse Gas Emissions 1990 to 2010 9.5
8.5 8.0 7.5 BAUBAU+
7.0
ME 6.5
HE
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
Quantification of the emission gap
2010
HE+
6.0 1990
11
Greenhouse Gas Emissions MT CO2-e
9.0
A range of scenarios have been quantified as part of this project to obtain an assessment of possible program
As discussed above, for the purposes of this study, if an
measures which could be used to meet an “equitable”
equitable contribution by the building sector is assumed to
commitment by the building industry to meeting the
be 108 per cent of the 1990 emission levels attributable to
emission targets. The emission gap for each of these main scenarios is outlined below.
space heating and cooling, or some 6.9 MT CO2-e in 2010, the business-as-usual with measures scenario
Medium Efficiency (ME) - The projected greenhouse
projects that greenhouse emissions will be somewhat
gas emissions in 2010 attributable to space heating and
higher at 8.9 MT CO2-e in 2010, which is +39.4 per cent of the 1990 levels. The emission gap in 2010 is therefore
cooling from electricity, natural gas, wood and LPG under this scenario is 8.2 MT CO2-e in 2010, which is +29.6 per cent of the 1990 levels. The emission gap in 2010 for this
some 2.1 MT CO2-e in 2010, or 23.6 per cent of BAU+
scenario is therefore some 1.4 MT CO2-e in 2010, or 16.7
projected heating and cooling emissions in that year.
per cent of heating and cooling emissions in that year.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
High Efficiency (HE) - The projected greenhouse gas
cooling from electricity, natural gas, wood and LPG under
emissions in 2010 attributable to space heating and
this scenario is 7.6 MT CO2-e in 2010, which is 19.9 per
cooling from electricity, natural gas, wood and LPG under
cent of the 1990 levels. The emission gap in 2010 for this
this scenario is 8.0 MT CO2-e in 2010, which is +25.5 per
scenario is therefore some 0.8 MT CO2-e in 2010, or 9.9
cent of the 1990 levels. The emission gap in 2010 for this
per cent of heating and cooling emissions in that year.
per cent of heating and cooling emissions in that year.
Greenhouse gas emissions for the five scenarios relative to
High Efficiency Plus (HE+) - The projected greenhouse gas
1990 are also depicted in Figure 13, together with the
emissions in 2010 attributable to space heating and
Kyoto target (+8 per cent relative to 1990 emissions).
Figure 13: Projected Heating & Cooling Greenhouse Gas Emissions Relative to 1990 1.50 1.45
KEY PROJECT FINDINGS
scenario is therefore some 1.1 MT CO2-e in 2010, or 13.9
1.40
1.30 1.25 1.20
BAU-
1.15
BAU+
1.10
ME
1.05
HE
GAP Kyoto
12
The results of a range of building shell simulations are
The ‘zero energy’ option plotted on the horizontal axis is
summarised in Figure 14 which indicates the impact of
a hypothetical case where all new houses from 2000 use
improvements in the thermal performance of building shells on
zero net energy for space heating and cooling. Even this
the greenhouse gas emissions for space heating and cooling
“optimistic” scenario is unable to achieve the Kyoto
in 2010. The “with retrofit” option assumes an aggressive
commitment for Australia, mainly because of the limited
ceiling insulation program within existing houses currently
proportion of the housing stock that is affected in the
without ceiling insulation as per the HE+ scenario.
period from 2000-10.
Figure 14: Impact of Building Shell Energy Efficiency on Greenhouse Gas Emissions in 2010 1.50
CO2-e Relative to 1990
1.40
BAUBAU+ is slightly better than 2 Star (1.39) No Retrofit
ME HE
1.30 With Retrofit 1.20 HE+
1.10 Kyoto 1.00 BAU-
2 Star
2.5 Star
3 Star
3.5 Star
4 Star
Effective Minimum Star Rating for all New Houses
Note: The star rating bands are non linear and the rate of change varies with climate zone.
4.5 Star
5 Star
Zero Energy
2010
2009
2008
2007
2006
2005
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
2004
HE+
1.00
2003
CO2-e Relative to 1990
1.35
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
PROJECT CONCLUSIONS Thermal comfort levels
Land subdivision Should it be decided that new housing stock will be
PROJECT CONCLUSIONS
required to meet more stringent thermal performance It is clear from this study that present user behaviour
standards, then the need for land subdivision design to
drastically reduces the potential maximum energy
address the issue of solar access and building orientation
demands for both heating and especially cooling.
will be a necessary adjunct to such a program. One of the
However, small increases in required user comfort
most cost effective ways of producing more thermally
levels could significantly impact on energy demand in
efficient housing is through improved orientation and
this area. This potential for increase can be mitigated
glazing placement (ie passive solar design principles).
to a large extent through improved building shell thermal performance standards combined with a public energy saving awareness program.
Existing housing stock
Building shell - Performance measures versus prescriptive measures Whilst prescriptive measures are relatively easy to implement, by their nature they tend to be unsophisticated
The fact that 80 per cent of all housing stock in the year
and their use often results in lost opportunities especially
2010 has already been built by 1998 would indicate that:
in respect of the principals of passive solar design. In Victoria, for example, there are numerous houses that,
1. Improving the existing building stock through various
despite meeting the mandatory insulation requirements,
retrofitting strategies such as installation of ceiling insulation
exhibit poor thermal performance due to poor orientation,
would appear to warrant more detailed investigation.
lack of shading and or lack of winter solar access, all
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design aspects that often represent a zero incremental 2. More stringent measures to new buildings are warranted to assist in mitigating the relatively poor thermal performance standards of our existing stock.
cost in most cases. The higher the overall thermal performance standard desired, the more likely a performance based measure will produce the most cost effective outcome for the consumer.
Longevity of building shells Building shells generally have a very long life and energy efficiency program measures implemented now will have a very long term impact, well beyond the year 2010, which is the limit of this study.
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
Embodied energy
Appliance issues
Embodied energy clearly represents a significant
Some appliance related issues have the potential to have a
proportion of a dwelling’s life cycle energy and
large long term impact on greenhouse gas emissions from
greenhouse gas emissions. Policy options that effect
residential buildings:
reductions in this area could have a significant net impact, ■
hot water service fuel selection and efficiency - the
consumed prior to or during construction. Any measures
hot water service is often selected by the builder during
designed to abate greenhouse gas emissions could not
construction and can be considered, de facto, to be part
be considered to be comprehensive if they did not
of the building shell related equipment (replacement
address this issue.
systems are almost always the same fuel). The fuel source for hot water is critical; electric systems typically have greenhouse emissions of the order of 4 times higher per unit of energy service in comparison with natural gas for mainland states. For natural gas units, the variation in the task efficiency from best to worst is
PROJECT CONCLUSIONS
especially given that a large proportion of this energy is
almost twofold. ■
uncontrolled combustion for wood heating - while the share of uncontrolled wood combustion heaters (eg open fire places) and their usage patterns are unclear at this stage, greenhouse gas emissions for these types of heaters is significant (relative to controlled combustion, which is close to zero) and they can also be associated with poor air quality in urban areas. The lack of flue control for many of these systems can also result in reduced thermal building shell performance. These issues warrant further investigation and consideration.
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RECOMMENDED FURTHER RESEARCH
A u s t r a l i a n R e s i d e n t i a l B u i l d i n g S e c t o r G re e n h o u s e G a s E m i s s i o n s 1 9 9 0 - 2 0 1 0 E x e c u t i v e S u m m a r y R e p o r t 1 9 9 9
RECOMMENDED FURTHER RESEARCH While this study used existing data sources, there were a
this important end use. The influence of non-thermal
number of areas where data was sparse or non-existent.
factors would also provide greater understanding with
This section outlines areas where further data collection
respect to modelling.
will improve the potential modelling for similar projects in future.
One area not specifically investigated in this study but which could have significant greenhouse gas emission
Standby losses for electrical appliances and equipment
impacts is fuel substitution. The end use with the greatest
appear to be a large and growing end use in the residential
potential impact is water heating. For example, preliminary
sector. Very little is currently known about the nature of
calculations suggest that substituting all existing electric
standby losses. It is recommended that collection of data
water heaters with natural gas or LPG could potentially
on the number, magnitude and type of standby losses in the residential sector be undertaken in the near future. This could be done as part of a growing international effort to limit standby losses.
reduce residential greenhouse gas emissions by some 7 MT CO2-e in 2010, or 12 per cent of the total BAU+ case. This alone could bridge the total residential sector gap of 4.2 MT CO2-e in 2010. However, the infrastructure to achieve this is unlikely to be available within the required
A further study of the more significant building elements would be required to quantify the impact of embodied energy and related greenhouse gas emissions in terms of the life cycle analysis of residential buildings. A baseline study for embodied energy of residential buildings (and 15
another for other building types, such as commercial buildings) is recommended. A report on policy options relating to embodied energy of residential buildings (and another for other building types, such as commercial buildings) is also recommended. Strategies need to be developed for informing and educating design teams, changing the market-place and empowering consumers,
time frame. There is also some limited fuel switching potential within the cooking end use (of the order of 1 MT CO2-e of potential in 2010), although infrastructure and user preferences are likely to be problematic. Fuel substitution in the space heating segment is more limited (less 1 MT CO2-e of potential in 2010 - assuming that reverse cycle air conditioners are not substituted). Further studies are warranted in this area, with particular attention being paid to the likely expansion of the natural gas distribution system within each state and the potential for increasing the saturation of natural gas water heating and space heating in households already supplied with natural gas.
enabling the design, construction and operation of residential buildings with optimised life cycle greenhouse
While wood is a significant and growing source of energy
gas emissions.
for space heating in the residential sector, the continued use of uncontrolled combustion in a limited number
Current poor levels of public awareness, especially within
of households has the potential to produce significant
the industry, of the significance of embodied energy in the
greenhouse gas emissions, create pollution problems in
life cycle energy equation of residential buildings is seen
urban areas, and may have a detrimental impact of thermal
as an impediment to gaining public support for initiatives
performance of buildings. These issues require further
in this area. Options for raising the profile of embodied
detailed examination and quantification before specific
energy issues therefore need to be explored.
actions are implemented.
Further data collection and analysis of appliance usage patterns will provide an improved data set from which to undertake future analyses of energy consumption patterns and projections and their related greenhouse gas emissions. In particular, more data on the use of heating and cooling equipment and the relationship with building shell design and climate would greatly enhance the understanding which underpins the modelling of
