This article provides an insight into the latest sustainability policies and regulations that have integrated the Life Cycle Design approach. Continue reading
NCC 2022 are proposing some dramatic improvements in residential energy use. This is, in principal a fantastic development and one that eTool very much supports. We do however feel that mandating 7 star NatHERS performance carries some risk and isn’t the most effective deployment of available capital for rapid decarbonisation. The reason is simple, there is much lower hanging fruit available in areas not covered by the NCC proposed changes. It’s also highly likely that the 7 Star requirements will lead to net-negative outcomes for the planet.
See below examples of the life cycle impacts (Global Warming Potential) of three detached residential buildings designs in each capitol city (averaged) selected because of their ubiquity (the homes selected are very standard display home products), plus an overall national population weighted average. Due to their relatively large size (and hence large thermal loads in comparison to other impacts) they represent a somewhat “best case” scenario of what improving thermal performance can achieve. The charts below indicate that moving from 6 to 7 stars doesn’t significantly move the needle on life cycle global warming impacts. Although moving from 6 to 7 stars delivers a 25% (average) saving in heating and cooling energy requirements, it only results in an average 2% reduction in life cycle impacts.
While this change could make sense for particularly hot or particularly cold climates, such as Darwin, Hobart and Canberra, it makes significantly less sense for the more temperate areas of Sydney, Melbourne, Brisbane, Adelaide and Perth. So, the question is, can Australian new home buyers get better bang for buck elsewhere? The “Other Impacts” are broad (see below for a breakdown for the population weighted average example), but the two largest categories are outside of the proposed scope for NCC 2022. So, while eTool are supportive of improved thermal performance of buildings, we also see inherent risk associated with targeting this strategy in isolation. That is because, for homes to “rate” 7 stars in many temperature climates they require a lot of thermal mass (e.g. brick and concrete), so what the 2022 NCC may end up doing is discouraging the use of low carbon materials such as timber in preference of brick and concrete for thermal mass. This will in turn result in higher life cycle material impacts and ultimately higher net impacts, working against the intended goals of the amendments (to reduce greenhouse gas emissions).
Likewise, plug loads are another area – currently outside the NCC – that requires attention. Solar PV most certainly should play a role in reducing the impacts of the building, energy monitoring, and possibly other policy levers the government can pull to improve the energy efficiency of appliances. There’s other easy wins that should be addressed, higher efficiency HVAC, lower GWP refrigerant gases are good examples. Ultimately, life cycle assessment should be the cornerstone of any policy for reducing the environmental impacts of Australian residential and commercial buildings.
The construction industry is going through major changes under the Green flag. The greening of building stock and infrastructure becomes more than just an idea, but a strategical attribute in developing the future of the precincts and entire cities all over the world.
The net zero carbon target is ambitious and requires that all new buildings must be operational zero carbon by 2030, and all new and existing buildings must be net zero carbon by 2050.
Transition from building better to building sustainable.
Impact reduction target is a fundamental aspect of concept design and will assist the transition in sustainable construction. Designers and experts are used to discussing energy efficiency, or kWh/m2, but very rarely there is a carbon target (e.g. 100 kgCO2 per m2 of lettable area per year) set at an early project stage (A rough carbon budget for buildings was presented by eTool in a previous blog article).
We hear more often about passive design principles, energy-efficient equipment and storage, carbon-negative materials and a combination of onsite and offsite production of clean energy. Renewable energy generation is increasing at phenomenal speed and it’s transforming the whole economy, reducing environmental impacts related to building’s operations and manufacturing of construction products.
At a district level, buildings are being thermally and electrically integrated with the community, and energy monitoring platform can track large groups of building performance, scaling up to whole district analysis. Targets climate funding is also helping retrofit existing buildings at municipal level and replicate success cases in other regions.
Different construction sectors define green design through different indicators.
Definition of the green design varies depending on specific needs but aims to accelerate the change towards a future in balance with the planet.
Tenants are motivated by the reduction of operational costs with energy and water bills, but it can also include aesthetics and being environmentally conscious, stating that “I care” or “I am different”.
Home owners would focus on the durability of materials, life of the entire property and low maintenance cost.
Developers would probably look on environmental aspects in combination to total cost and return on investment – called a “Green per Dollar” perspective.
Finally, the precincts and local governments might go with green construction by various reasons: to encourage innovation, long-term city planning including improvement of citizen’s well-being, quality of life and environment.
Life Cycle Design as a method to look inside the black box.
Green design and performance indicators need to be transparent and standardized to satisfy major motivations of groups and individuals. The best way to fully quantify the environmental impact is by looking at the whole of project life cycle performance and using Life Cycle Design (LCD) methodology to model impacts from construction through to the end of life, including use phase impacts. Most importantly, LCD can help to understand the project functionality, and how well it is delivering the proposed primary function. LCD looks at a building through the prism of many features, holistically and over the life time. This prism includes operational energy and water, durability of materials, maintenance and wide spectrum of environmental impacts. LCD approach is combined with Life Cycle Costing to help designers understand the “Green per Dollar” feasibility of improvement initiatives and how economically sustainable the overall design is throughout its lifespan.
Life cycle thinking to build better buildings today.
There´s a global trend in the construction industry to adopt life cycle thinking and we increasingly hear terms like circular economy, cradle-to-grave or even cradle-to-cradle, closed loop recycling or designing for deconstruction. The use of Life Cycle Assessment is increasing in a number of Green Building Rating Schemes (Green Star, LEED, BREEAM, HQE, LBC), and also is the newly available life cycle inventory data, user-friendly LCA software tools, Environmental Product Declarations.
The growth in regulations within the construction industry is also observed, with planning policies mandating environmental reduction targets and improving the general industry know how. Companies are using science based targets to measure efficiency of their climate action plans and understanding how they are related to the UN´s Sustainable Development Goals (SDGs).
To meet changing requirements related to a sustainable future within the construction industry, systems and tools need to be widely used from concept stage on throughout the design development process. This will allow project teams to set ambitious environmental targets and therefore implement the life cycle approach to deliver the buildings of the future already today.
UN environment – The Global Status Report 2017 – Towards a zero-emission, efficient, and resilient buildings and construction sector
World Resources Institute – What Is the Future of Green Building?
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The use of Life Cycle Assessment (LCA) is gaining greater recognition in sustainability assessment. An LCA credit is embedded as a core credit in the Green Star rating tools Design and As Built v1.2, Interiors v1.2 and Communities v1.1.
Points may now be easier to achieve for some projects provided there’s early engagement of LCA consultants. Points allocation have been adjusted with operational energy reductions capped. Further Additional Reporting initiatives were added with extra points available.
– Design and As Built v1.2 – up to 7 points
– Interiors v1.2 – up to 19 points
– Communities v1.1 – Up to 5 points
This recorded webinar covers the basics of LCA, the eToolLCD software, and how it applies to Green Star – LCA credit.
eToolLCD subscription prices have been recently updated. Please read on for more info.
Why have we updated pricing?
For a few reasons. We have noticed a strong trend where our subscribers are each (on average) conducting more LCAs per year. We wanted to ensure our pricing remained competitive and predictable so have added some plans that reduce the per project fees. For example, the new specialist subscription has no per-project fees and the new enterprise pricing gives a 40% discount on per-project fees. In addition we wanted to simplify our offering and hence dropped our “Freelancer” plan.
How can users benefit upgrading to new plans?
As well as reduced per-project fees the new Enterprise subscription and the updated Specialist subscription include new functionality with improved collaboration, reporting, user admin/management and the soon to be released Revit Plugin. Consultant subscribers will also enjoy additional Life Cycle Cost functionality, and automated BREEAM 2018 reporting that’s coming out soon. All round eToolLCD is getting better for users, and watch this space, more to come!
Why the US Dollar pricing?
The use of eToolLCD is expanding globally and some of our users provided feedback that the Aussie $ pricing was a unusual. So we’ve now set our pricing in a currency that everybody recognises.
How will this affect existing subscribers?
eTool is “grandfathering” existing eToolLCD subscriptions so you won’t lose any functionality or have to pay any more or less until June 30th 2019 when we’ll ask existing subscribers to migrate to one of the new plans. Please note, if your subscription lapses you’ll need to transition to a new plan.
Who is the new Enterprise Plan for?
Organisations that have a number of consultants using eToolLCD, or developers and builders who want to track the performance of their portfolio is projects. We have a range of features for this plan that will make Life Cycle Design very easy, scaleable and transparent for these businesses. Please get in touch if you’d like more info.
Create an account or access eToolLCD.
Quantificar sustentabilidade ambiental foi o desafio que deu origem à empresa eTool. Desde 2010, os amigos e engenheiros australianos Richard e Alex desenvolvem o software eToolLCD para realizar cálculo de impacto ambiental na construção e promovem uso da metodologia Avaliação de Ciclo de Vida (ACV) para garantir performance ambiental genuína nos projetos em que participam.
Desde então, a equipe da eTool cresceu e expandiu da Austrália para a Europa e agora também para as Américas. A empresa já completou mais de 200 análises de projetos residenciais, comerciais e de infraestrutura, prestando serviço de consultoria ou fornecendo solução de software para a equipe de projeto.
O software eToolLCD é totalmente web-based, atende às normas ISO 14044 e EN15978 (específica para ACV de edificação), possui atualmente mais de 1.500 usuários ao redor do mundo e pode ser utilizado para obter pontos na certificação Green Star, BREEAM, LEED, entre outras.
Eu trabalho com a eTool desde 2012, onde me especializei em Avaliação de Ciclo de Vida e fui líder da equipe responsável por conduzir os estudos técnicos e colaborar com a equipe de desenvolvimento de software. Depois de morar cinco anos na Austrália, voltei para o Brasil para dar continuidade ao trabalho que iniciei em 2014, mas agora em definitivo para desenvolver a eTool Américas. É um grande desafio e também uma realização pessoal e profissional trazer para o Brasil uma metodologia que ainda não é muito utilizada, mas tem um grande potencial para auxiliar equipes de projeto a reduzir o impacto ambiental das construções e também demonstrar viabilidade financeira por meio da Análise de Custo do Ciclo de Vida.
Somos uma empresa apaixonada em projetar melhor e garantir bem estar social e harmonia com o meio ambiente. Estou entusiasmado para trabalharmos juntos.
Life Cycle Design (LCD) has quickly become the go-to method for defining sustainability in buildings in governments, green building councils and organisations around the world. It is considered best practice for good building design by the International Standard Organization (ISO 14044) and is a powerful methodology for ensuring genuinely sustainable and high performance outcomes.
This article and video recording provide an overview of Life Cycle Design and explain five ways to add value to your services using LCD. Be inspired by how LCD has been incorporated in different sectors and projects, and how key stakeholders have taken it on board.
Some of the topics covered include:
What is Life Cycle Design and the methodology
The importance of green buildings and measuring building environmental performance
Green Star projects – general overview
LCA as a required part of ESD tender documentation
ISCA and use of LCD as an integrated desgin approach
LCD for regulatory approvals
Marketing and sales campaign
So if you’re designing an apartment building and you’re stuck with an underground car park things can get pretty nasty with energy consumption. With no natural light and a clear safety requirement to keep the area lit all things point to an energy hungry lighting solution. Even the most efficient lamps will still burn a lot of power running 24 hours a day, 365 days a year.
The most obvious solution to drop run time is lighting controls. Specifically motion sensors. But how should these be set up, and how does the set up (number of lamps per sensor and lamp shutoff delay) actually effect the energy savings the controls will achieve? The short answer is, make sure they turn off really quickly after the car or person is out of the area. The long answer is below:
The interplay between the car park layout, vehicle traffic, pedestrian traffic, simultaneous use of certain areas of the car park, probability of a specific car bay being accessed, the shut-off delay timing and the distribution of sensors means calculating light run time is very complex. Pondering the possibilities got the better of me and I ended up running a simulation to determine effect of some key parameters.
A Conceptual Car Park
The conceptual car park looked like the below pick. Effectively 150 bays with one pedestrian access and a main vehicle exit point at one end.
I used some basic lighting design to work out how many lights would be needed (single globe T5s) to achieve an adequate light levels (50lx). The calcs indicated a requirement of about 80 lamps. I just placed these in the road ways and walk ways in my conceptual design. These are the numbers with the x in front of them. In reality they’d be probably be spaced more evenly but this satisfies the requirements of the model which is just to see how many lights would be triggered when each bay was accessed.
Which Car Bay Triggers which Lamp?
That was a manual process of thinking about how a person will walk from the lift to the car, and then how they will drive out (or vice versa). The below diagram shows that if car bay 125 is accessed the blue line will be traversed by the car driver and passengers, whilst the red line will be travelled by the car. All the lamps highlighted in red will subsequently need to fire.
I got some stats on how many trips and average household does from here and here. The Sydney data also gave these neat graphs on when the trips occur as well. This enabled me to put a probability on a given car being accessed at a certain time of the day. The sensors are obviously going to give the most benefit during lower trip frequency times. But depending on the set up, you can even get a reduced run time during the peak times in this car park (not every day, but some days there’ll be savings due to the random nature of when people take a car trip).
After some sense checking I ran the simulation for different combinations of motion sensor parameters. The focus was on:
- The delay before the lamp is shut down after the motion sensor is activated (or re-activated)
- The number of lamps per sensor (if you whole car park is wired to one sensor, you’re not going to get as much benefit)
The below chart shows the results. It looks pretty clear that the most important attribute is the delay before the lights are shut down again. Amazingly, with 10 lamps per sensor a 90% run time reduction could be achieved if the lamps only fired for a minute. 10 lamps per sensor is probably as sparsely as you’d want to space the sensors to make sure they fired when there was movement
The simulation is obviously not a real live thing so I want to note some possible pit falls.
- I got lazy and didn’t model weekend days separately. So the actual savings are probably greater than what I’ve reported above.
- If you car park is full or big rodents that trigger motion sensors 24 hours a day, the savings won’t be achieved.
- My “Shut off delay time (mins)” is actually the lamp run time from when the motion sensor is first fired during a particular event, not from when it was last fired during that event. So for you to achieve the 1 minute shut-off delay, you’ll probably want the light to go down 5 or 10 seconds after there was no motion in an area. Perhaps this would cancel out the additional savings you’d get from lower weekend trips.
Other Car Park Lighting Ideas
Although motion sensors in car parks are an absolute no-brainer, there are also other things that can be done to make car park lighting smarter, a few of which I’ll include below.
Lux sensors may also be utilised with dimmable lamps to ensure light levels over the requirements are not delivered and hence energy savings may be achieved due to lower average lamp power. The benefit of lux sensors in underground car parks is limited however due to a lack of natural light.
A better coefficient of utilisation can be achieved with light coloured rooms (more reflectance, so better light utilisation from your lamps which means you’ll need less lamps).
The lamp itself should be considered carefully and in conjunction with the lighting controls. The most efficient globe in the world may be the wrong choice if you need more of them than necessary. Similarly, if it won’t handle being turned on and off all the time, that’s going to be a problem.
The light housing can also help if it’s got a nice reflective backing to disperse the light where it’s needed (down and sideways) instead of where it’s not (up).
Below is a summary of our approach to the International residential benchmark. A full EN15978 report on the benchmark model can be found here. International Residential Benchmark Weighted x10 dwellings v28
In light of eTool’s recent exploration into global markets, we thought it prudent to create a “global” benchmark for housing developments. eTool will be using this benchmark for all future housing projects. The reasons an international statistically mixed use benchmark is the most robust model to compare designs against are as follows:
- The planet does not care what kind of house you build only how close it is to zero carbon. A mixed use benchmark provides a fair comparison of performance across different house types be it apartments, detached, maisonettes etc.
- The planet does not care where you build your building, only how close it gets to zero carbon. Climate change is a global problem, whilst regional benchmarks can be useful for comparing similar buildings in the same area they can produce unfair results. For example, a house built in a low carbon grid area (e.g. Brazil) may have emissions of 2 ton/person/year. This may only be a small improvement against the average Brazil house as they both have the benefit of a low carbon grid. Conversely a building in WA may have higher emissions (say 3 ton/person/year) but despite having higher emissions than the Brazil case could show a larger improvement against the average WA house. A single benchmark is the only way to give correct credit for the true sustainability performance of a building.
Before getting into the nitty gritty, it’s important to understand the purpose of the eTool benchmark, which is:
- To establish a common measuring stick against which all projects are assessed so that any project can be comparable to another.
- To create a starting point, or “average, business as usual case” from which to measure improvements.
Benchmark Form and Structure
The benchmark has been created to represent an average dwelling built in a developed country, the statistics for a range of developed countries have been population weighted and combined into a single theoretical average dwelling.
The statistics used in the benchmark are based on data obtained for each country. The construction type and dwelling size statistics take new build data wherever available, as this data is generally reliable and represents a picture of the way buildings are currently being built across the developed world. For residential buildings there is a mix of houses and apartments. This is the latest breakdown of the new dwellings density mix across the countries considered in 2010:
The occupancy is calculated by dividing teh countries population by the number of dwellings to give an average. This is weighted by population to give a global average of 2.52.
For the single dwelling element (59% of our average dwelling) a building structure has been modelled taking a cross section of commonly used construction techniques. In this instance, the data was obtained for U.S.A. The U.S.A makes up the largest proportion of new housing in the developed world and is considered to represent a fair “average house.” Construction techniques are unlikely to differ significantly enough to impact on the overall modelling, whilst brick houses may be more common in the U.K. and Germany, timber framing is far more prevalent in Japan and Sweden.
A similar approach was taken with windows, internal walls, floors and roofs. The vast majority of those installed in new builds across America and Europe are double glazed and allowances have also been made for the smaller proportions of other window framing options currently in common use.
For the multi-family dwellings, a standard concrete frame structure has been taken with one level of car parking and typical auxiliary and common layouts, such that the apartment living area represents approximately 50% of the total floor area of the building. The total impacts of this building have been weighted on a per m2 basis and 56 m2 has been added to the model to represent the apartment element.
Existing data has been used for operational energy, and arguably new build data would be preferable, but total existing data is generally a lot more robust (and readily available). Whilst new build energy figures were available for some countries, the figures tend to be from modelling completed for regulatory purposes and are therefore theoretical. In many countries there is a perceived “performance gap” between modelling results and actual consumption mainly due to differences in occupant behaviour, but also because of limitations in software and methodologies used for the modelling. The hope is that there will be continued industry effort towards monitoring of new build housing performances. Until further data in this area is available, we have a robust snapshot of how average buildings are currently performing by taking existing housing data.
The data for total residential fuel consumption was divided by the total number of dwellings in each country analysed. This was then weighted according to population to give a final figure for the average energy consumption of a developed country dwelling.
End-use percentage estimates were then used to determine where this energy is being used in the dwellings. Again, U.S. data[ix] has been used to represent the average.
Other impacts such as appliances and cabinetry and finishes have also been included by the estimated proportion of dwellings estimated to include these.
The global average water consumption is considered fairly consistent across most developed countries with America and Australia having higher water consumption due to larger garden sizes. A conservative nominal 169l/person/day has been assumed for water supply and treatment.
[i] Populations by country 2010 http://countrymeters.info/en/United_States_of_America_(USA)
[ii] Characteristics of New Housing U.S.A http://www.census.gov/construction/chars/highlights.html
[iii] Statistics Bureau Japan http://www.stat.go.jp/english/data/nenkan/1431-09.htm
[iv] EU Odysee Data 2008 downloaded on 11.7.2014
[v] Australian Bureau of Statistics Average floor area of new residential dwellings 2012 http://www.abs.gov.au/ausstats/abs@.nsf/featurearticlesbytitle/E9AC8D4A1A3D8D20CA257C61000CE8D7?OpenDocument
[vi] U.S. Energy Information Administration – Annual Energy Outlook 2014 – Energy Consumption by Sector and Source http://www.eia.gov/oiaf/aeo/tablebrowser/#release=AEO2014&subject=0-AEO2014&table=2-AEO2014®ion=1-0&cases=full2013full-d102312a,ref2014-d102413a
[viii] Statistics Bureau Japan Chapter 10 Energy and Water http://www.stat.go.jp/english/data/nenkan/1431-10.htm
[ix] U.S. Energy Information Administration Residential Sector Key Indicators and Consumption http://www.eia.gov/oiaf/aeo/tablebrowser/#release=AEO2014&subject=0-AEO2014&table=4-AEO2014®ion=0-0&cases=full2013full-d102312a,ref2014-d102413a
The standard assumption eTool makes when conducting an LCA is applying the current emission factor of the electricity grid for the specific region over the life of the building. While renewable energy source do not currently make up a large percentage of the energy grid, the cost of renewable technologies has fallen dramatically over recent years. The Australian government also has a legally binding obligation to reduce its emissions by 5% on 1990 levels, under the Kyoto protocol. The Australian government has also committed to an 80% reduction by 2050.
If the decreasing cost of renewable energy trend continues and becomes competitive with coal and gas, the market will naturally shift away from fossil fuels, particularly if fossil fuel subsidies recede. There is also a small but growing consumer demand for more ethical electricity tariffs. This shift of energy sources into the electricity grid opens a potential for a change in the way grid emissions are calculated with life cycle assessment.
Presently in eTool we assume that the grid fuel mix remains at today’s levels for the life of the building. Whilst this is a good conservative position, and drives the right behaviour in terms of energy efficiency, it may divert some focus from other areas of the building, which may be more important if a more realistic future scenario of grid electricity impacts are used.
In response, we have created two other grid emission factors: a 2050 grid and a 2030 grid. The 2050 grid assumes an 80% reduction in the current grid intensity. The 2030 grid takes the average grid intensity over the next 40 years, assuming a linear move towards 80% renewable generation by 2050. The modelled reduction in CO2e intensity is achieved by:
- Eliminating the most carbon intensive fuels from the current Australian electricity mix and replacing these with a combination of renewable sources, and
- Increasing the thermal efficiency gas powered generators from 34% up to 50% (implementation of combined cycle turbines)
The fuel mixes and assumed thermal efficiencies for the different grids modelled is shown in Table 1. There are a few flaws in this method that we need to declare: Firstly, the scenarios assume reductions in CO2e intensity of tailpipe emissions only. It does not account life cycle emissions for electricity, which includes impacts associated with fuel extraction and transport upstream from the power plant as well as downstream impacts associated with transmission and distribution. Secondly, if we accepted that this would be enough to meet the 80% reduction in emissions required, the demand for electricity (or energy in general) could not increase. If there is an increase in demand, we would need to further reduce the intensity of Australian emissions and the target is on absolute GHG pollution, not pollution per dollar of GDP, per capita or per kWh. Nevertheless, we think the approach is suitable for the purposes of illustration and discussion, which is the goal of this technical article.
Table 1: Modelled Grid Fuel Mixes
Life Cycle Impacts of Residential Buildings
The graph below illustrates how the lower grid scenarios impact on a single residential dwellings life cycle emissions. Proportionally, embodied emissions have a much larger impact than operational as the grid de-carbonises.
Reconsidering Design Decisions
Generally speaking, there will be a move toward electric based solutions as the grid de-carbonises and the impacts of electricity become competitive with gas. A few recommendations that we typically apply to residential dwellings are shown for the different grid scenarios below.
In this instance, the annual CO2e savings associated with PV have more than halved in the 2050 scenario. Savings from embodied impacts in materials become much more important as the grid decarbonises and materials make up a larger proportion of a buildings CO2e. Moving to fly-ash concrete or replacing carpets gives greater savings than installing a gas hot water unit, which under todays grid scenario would ordinarily provide significantly more.
It’s important to note is that while the transition to a low carbon grid will likely occur incrementally over the coming years, the embodied impacts of the materials are locked in from the day of manufacture. Providing that the grid does decarbonise, material choice can be considered to be equally as important as operational energy, especially when dealing with buildings with a long design life.
What about the gas grid?
We have yet to add a CO2e intensity for future gas grids but watch this space. There is potential for a reduction in the gas grid emission factor with more input into the gas grid from landfill collection and anaerobic digestion. Then again, potential impacts of shale gas fracking will also need to be considered.
The technologies that make up a dwellings services (cookers, boilers, heat pumps etc.) typically have a lifespan of no more than 20 years. Our approach at eTool remains to recommend the lowest carbon solution based on today’s grids with the assumption/hope that they will be replaced with whatever the lowest carbon solution happens to be in 20 years time.
The future may also bring an appropriate price on carbon and studies show that $150+/tonne reflects the true cost of climate change (social and economic cost), which will drive behavior. For example, a gas hot water system is significantly lower in carbon emissions today but in 20 years time when it is replaced, the electricity grid may have decarbonised such that a heat pump is now the low carbon option. Perhaps the occupant will be further incentivised by the price of a renewable electricity grid versus finite gas with a high carbon price.
What about Materials Future Impacts?
The manufacturing of some materials will decarbonise over the coming years, such as the use of biomass in the heating processes in cement production. However, for a building constructed today, the key structural elements of a building such as the impacts associated with the concrete or steel are locked in on the day of construction. The recurring impacts of replacing high carbon materials like plasterboard and carpet may also decrease as the economy de-carbonises. For some elements, this may be due simply to using renewable electricity in the manufacturing plant. For others it may require something more innovative such as developing sheep food that does not make them burp and fart.
There is a high level of uncertainty associated with future impact intensities for the system processes and materials making up a buildings use phase. For example, as Australia’s economy de-carbonises, the impacts associated with energy inputs, maintenance, replacement, repair, water use, and transport will likely decrease (particularly with regard to global warming potential). This has not been accounted for in the analysis. One could potentially model the effects of this parameter on GWP alone as we do know Australia’s current commitments to reduced greenhouse gas emissions, however, even this is very speculative as we do not know how the economy will decarbonise (through efficiency, reduced growth, alternative fuels, renewable energy sources or other mechanisms). The building energy inputs, and the fuel mix for manufacturing products used through the building life span has therefore been assumed constant, and set at today’s values throughout the modelled life cycle of the building.
What else might change?
Australia has been seeing first-hand the effects of climate change for a number of years. The meteorology department has confirmed that 2013 was the hottest year on record experiencing a greater number and intensity of heat waves than ever before. Even if global CO2e emissions are kept within the threshold for a 2 degree global rise in temperature, we will still need to adapt to the climatic changes that have resulted from our current emissions. The Garnet Institute makes the following predictions regarding changes to climate in Perth assuming no mitigation:
– 4 degree rise in average temperature in Perth,
– 56% increase in number of days over 35 degrees by 2070
– 15% – 45% reduction in rainfall in Perth by 2070
– 15 – 65% increase in number of days with “Extreme fire risk”
In the best case scenario with emissions stabilising at 450 ppm, there is still a 2 degree rise in average temperature across most of Australia. The reality is that we have already passed 400ppm and 550ppm (3 degree rise) is realistic. To adapt to these changes we will see a greatly increased use of air conditioning across all building types to maintain thermal comfort.
-Researched and written by Pat Hermon
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