What is it like building a carbon negative home?

It all started with developers from Western Australia who had a vision to create the most sustainable residential community possible.

It took more than 10 years to acquire the land, finalise the design, receive all the required approvals to finally start the construction in March 2021.

The Witchcliffe Ecovillage offers its residents a sustainable lifestyle and the opportunity to be part of a community that is self-sufficient in water, solar energy, fresh food produce, as well as looking after their waste management.

  What is special about this village?


Let’s have a closer look and see what they did differently. A few features of the project that might interest an architect or a builder include:

  • Proof of carbon negativity.

Each house needs to demonstrate that its carbon emissions over 120 years won’t exceed a set specific target of a – 220kgCO2e / occupant / year. Basically, these homes are good for environment. ?

  • Power from the sun.

Houses are carefully designed based on passive solar design principles. Each house needs to install at least 6kW of solar PV panels on the roof. Each cluster is connected to a microgrid and a centralised Tesla Powerpack battery. The connection to the external Western Power grid allows the Ecovillage to sell its excess power and provides power during construction.

  • Water from the rain.

All potable water in the Ecovillage comes from rainwater capture. Each home needs to install a rainwater tank. The water is processed and purified in a closed loop on the site.

  • Food from the garden.

The homeowners of the Ecovillage can use collected rainwater from the communal dam to water their gardens and orchards. It sounds like a dream to have an unlimited supply of fresh vegetables and fruit that everyone can harvest in the Ecovillage.

Image1. U-shaped residential cluster with community garden and open spaces


Why go beyond carbon neutrality?

Carbon neutrality is achieved when a building has zero annual emissions from energy use. This is not a hard task especially with solar passive principles and use of renewables.  Having an extensive solar system helps to neutralize some additional emissions.

The idea to go beyond carbon neutrality came from the need to also neutralise the embodied energy, or emissions caused by materials and their maintenance over the life of the building.

Using low carbon materials can have a positive effect on air quality and health, but also help the building to last longer.  After consulting with sustainability experts to understand which materials to use and which to avoid, it became clear that life cycle assessment (LCA) should be incorporated into the design and review process of each building.

Image2. A beautiful example of a strawbale home in Margaret River

Every parent’s dream is a child coming back home.

Looking at materials is important to make the picture holistic and to make sure the house you are building will last longer and can be passed on to future generations. For those who know LCA, it’s clear that carbon reduction will result in reduction of energy and water bills, cost of future repairs and maintenance, and will have the lowest long-term impact on nature.

It’s a simple equation:

Lower carbon = Lower cost.


How to measure carbon neutrality?

It may surprise many that most new homes could achieve 50-70% CO2 reduction without large investment. In fact, the City of Vincent in Western Australia requires all new houses to achieve at least 50% C02 reduction for design approval. It is a huge mind shift and step forward towards sustainable housing.

Each Ecovillage home needs to demonstrate that its whole of life carbon emissions won’t exceed a set specific target of -220kgCO2e / occupant / year.  It can be also expressed as a percentage of CO2 saving versus a benchmark residence, the target being a 105% carbon saving. Once future homebuyers have completed the concept and materials to use in their new homes, they need to confirm that their home is meeting the set targets in the Witchliffe Ecovillage Sustainable Building Design Guidelines.

To measure carbon, you need a tool that is easy and robust enough to calculate future home emissions. It also should be flexible and non-prescriptive, so that designers can be creative and explore different options of sustainable design and remain within their budget.

To support this effort, the Ecovillage team commissioned software company eTool to develop a new tool, which needed to be intuitive to use and provide the necessary confirmation. eTool is an LCA software provider and passionate environmentalist and has always had a soft spot for residential projects trying to lower their carbon footprint and their energy bills.

The first prototype was called eTool Turbo, then Lifecycle.House, but we ended calling it RapidLCA.


RapidLCA App for Low carbon HOMES and more…

The eTool team was inspired to be involved with such an iconic project as the Witchcliffe.

The process for RapidApp users is simple:

  • Download the app and find your lot or address
  • Spend 20-30 minutes to input data
  • Generate a compliance report showing your home’s carbon footprint and required targets are met
  • Submit for design approval, build permit, or even green loan.







Future of the RapidLCA App

As of early 2021, about 100 homes have undergone an LCA using the RapidLCA app and no-one was struggling to meet the metric of 105% CO2 reduction. In fact, many were exceeding the target, which proved that LCA is not hard and can be done by anyone, even without an architectural or engineering degree.

eTool is now working on enabling the one-off assessments for single use and extra features for interested developers.









Get in contact with US if you would like to know more.


LCA and UKGBC Net-Zero Framework

Given the recent movements in the climate justice campaign, the release of UKGBC Net-Zero Carbon Framework in April this year has been very timely. Although we have seen various “net zero” definitions in the UK in the past (such as the scrapped zero-carbon homes targets under building regs over 10 years ago) it feels this time the general idea has more industry backing with 100s of architects, structural engineers and councils formally declaring a climate emergency.

The UKGBC definition is an interim step on the pathway to assessing full life cycle impacts. It introduces embodied carbon in materials (A1-A3), their impacts for transport (A4) and constriction (A5) alongside operational energy (both regulated and unregulated emissions).

ukgbc net zero

Figure1: UKGBC Net Zero Carbon definition (April 2019)


Unfortunately, it does not go as far as full LCA yet with the idea that it simplifies the work and encourages uptake. However, module B1-B5 presents a large chunk of CO2e that will be missing from the calculations. Typically B1-B5 can be responsible 500-1000 kgCO2e/m2 over 60 years and ignoring these impacts will lead to good potential design opportunities being missed. Onsite renewables such as PV will be replaced over the life cycle and whilst the energy that they offset will be included in B6 the embodied impacts of their replacements are not. There are plans to increase the scope in future updates and it is encouraging to at least see some level of joined-up thinking between operational energy and construction embodied carbon. This will no doubt drive some improved design outcomes as design teams can assess the relative merits of strategies that impact on both energy and construction impacts such as thermal mass or triple glazing.

Modelling in eToolLCD
There are two choices of dataset groups in eTool currently. Either BRE IMPACT data or eToolLCD default data (regionalised data available for UK, EU, Aus, NZ and USA regions). Both can be used to model net-zero under the current definitions however if future expansions include modules C and D then eTool default data would be preferred.


ModuleUKGBC Net Zero ConstructionUKGBC Net Zero OperationalUKGBC Net Zero Whole of Life (Yet to be Finalised)BREEAM 2018 (IMPACT)eTooLLCD
ConstructionA1-3 Product Stage 118698-32  118698-32 118698-32 118698-32
A4 Transport of Equipment and Materials 118698-32  118698-32 118698-32 118698-32
A5 Construction 118698-32  118698-32 118698-32 118698-32
Use StageB1 Products in Use 118698-32 (1) 118698-32 118698-32
B2 Maintenance  118698-32 (1) 118698-32
B3 Repair  118698-32 (1) 118698-32
B4 Replacement  118698-32 (1) 118698-32
B5 Refurbishment  118698-32 (1) 118698-32 (1) 118698-32
B6 Integrated Energy Use 118698-32  118698-32 118698-32 (1) 118698-32
B6+ Non-Integrated Energy Use (Plug Loads) 118698-32
B7 Water Use & Treatment  118698-32 (1) 118698-32 (1) 118698-32
End of LifeC1 Deconstruction & Demolition  118698-32 (1) 118698-32
C2 Transport of Waste Offsite  118698-32 (1) 118698-32
C3 Waste Processing  118698-32 (1) 118698-32
C4 Disposal  118698-32 (1) 118698-32 118698-32
Benefits and Load Beyond the System BoundaryD1 Operational Energy Exports  118698-32 (1) 118698-32 (1) 118698-32
D2 Closed Loop Recycling  118698-32 (1) 118698-32
D3 Open Loop Recycling  118698-32 (1) 118698-32
D4 Materials Energy Recovery  118698-32 (1) 118698-32
D5 Direct Re-use  118698-32 (1) 118698-32

Figure 2: Scope of Carbon Assessments

Below are the impacts in kgCO2e/m2 for a typical medium density office building. (Note B6 energy impacts assume today’s grid (0.25kgCO2e/kWh) applied over the 60 year life cycle. Note the RICS Whole Life Carbon for the Built Environment Professional Statement is provided as a reporting reference, this level of reporting is simple to pull from eToolLCD using our All Impacts Report


Figure 3: Typical medium density low rise office building 


Impacts associated with construction represent a third of the total.  This is significantly higher now than in previous years when the UK grid was 0.6kgCO2e/kWh and usually made up 80-90% of life cycle impacts had that the grid has a lower.  However, there is still a large chunk impacts missing from the guidance in the form of replacement and maintenance (B2-B5) which can be 500-1000 kgCO2e/m2.

Once quantified the design team can start to consider strategies, some examples are shown below.  Without strategies, 1.755 tonnes/m2 of CO2e would need to be offset in a typical office. For net zero the cost of implementing these strategies will need to also be weighed up against the cost of purchasing offsets.


Offsets come with varying degrees of quality, cast and “additionality” arguments. The offset schemes referenced by UKGBC (Gold standard and Clean Development mechanism) carry a cost of between £0.6/tonne and £14/tonne. In an average office this could result in up to an extra £24/m2 or 1-2% of construction costs. However, the Greater London Authority recommends a price of £60/tonne. It will be interesting to see whether this gives the industry further incentive to implement low carbon strategies (in particular timber) early on in the design process. Furthermore, the onus will be on us LCA practitioners to improve the accuracy of our LCAs with the total kgCO2e figures resulting in a significant increase to net-zero development costs.


eToolLCD’s Unique Template System

One of the defining features of eToolLCD is our unique template system.  Our ever growing library contains 1000’s of construction templates applicable to all kinds of building and infrastructure projects being built across the globe. The template approach ensures:

  • Repeatable results and consistancy
  • More consistent, accurate and comparable assessments
  • Geographically more relevant
  • Continual improvement in accuracy
  • A deeper understanding of construction make-ups and hotspots

Templates can contain high levels of detail, inputs and assumptions, work that is not only fully referenced and transparent but shared across the entire eTool community to utilise, adapt and improve on

You will almost always find a template that matches or is close to matching your specifications however, the templates are fully adaptible, users can clone and adjust templates to make the required updates.  These can then get added to the library for the rest of the eTool community to use so, every project gets completed in eToolLCD makes LCA quicker and easier for the next project!

Each template will include any number of materials, people and equipment entries with each individual entry having pre-selected LCA variables.

These are combined into complex whole make-ups such as the below, curtain walling insulated spandral panel:

Caurtain Walling

The user inputs the area of the panel in their project and the tempalte system autoamtically calculates the capping, mullions, transoms, fixing brackets, framing, glazing and insulation based on the proportions used to build the original tempalte.

So, users simply need to match their construction specification to the corresponding template and populate the approriate areas/quantities. This means that complex LCA models containing 100s of material entries can be built quickly from only a small number of basic inputs (floor area, wall area, roof area etc).

Hear what some of our users say about our template system.

“eToolLCDs prebuilt templates made it relatively easy to build up the baseline LCA model and then quickly compare different design options”

Ben Carr, AECOM

“The software works well, and the predefined templates that are selected to describe each building element align well to the architectural specifications.”

Anthony, ADW Developments

“The template approach to etooLCD software means that the initial process of formulating a baseline model is relatively quick, so time can be focussed on assessing options and recommendations.”

Peter, CHB Sustainability

For a detailed demonstration of our template system check out this video from our support pages.



Related Posts:
Creating Templates
Automated Reporting

eToolLCD Automated Report Branding

eTools automated reporting allows users to quickly produce high-quality reports from their models without the need to adjust and edit in word.  Having produced many early LCA reports manually in the early days we understand the frustrations that arise from copying into spreadsheets, word reports, formatting, finding errors and re-working.  We highlighted this is a big drain on resources that would be much better spent improving the actual quality of the modelling, recommendations and engaging design feedback. You can read more and see examples of our growing suite of automated reports here.

We also understand that users have their own branding and like to put their stamp on reports issued to clients.  Our reports can be downloaded in either word, pdf or excel formats allowing users to make edits and format as they wish.

For Specialist subscribers users we have introduced branding of reports, from a users profile they can upload their logo.

company logo


The logo then feeds through to the title page and header of the reports run from the users’ models.

report example logo


Freeing up your time to focus on the really interesting parts of your LCA studies!!


Related Posts: Setting Up Your Profile, Automated Reporting

eToolLCD Certification Service


Ever since the early days of eTool we highlighted one of the risks to widespread LCA adoption is the varying levels of quality in building LCA models and subsequent loss in confidence of the results and conclusions drawn.  To mitigate this we have ingrained a formal certification process provided inclusive within your subscription/project access fees.  During the certification process, a senior eTool LCA practitioner is made available to your project for the purposes of:

  • Assisting the LCA team with completing the study in compliance with relevant standards (we have now completed over 400 projects for BREEAM, LEED and Green Star so will ensure the model is completed to the correct requirements and no hold ups occur during the BREEAM/LEED/Gren Star verification).
  • Providing credit for “3rd party verification” under BREEAM 2018.
  • Reducing the risk to your clients and elevating the professionalism of your service by peer-reviewing your LCA study to ISO 14040 and ISO14044 standards.
  • Assisting the LCA team with challenging concepts or modelling requirements.
  • Improving the LCA teams efficiency in completing LCA/LCCs using eToolLCD.
  • Providing the LCA team with potential strategies that may be worth considering to reduce the impact of the design.

The certifier will be “suitably qualified” to undertake peer reviews having as a minimum:

  • Completed at least 3 paid for LCAs within the last 2 years
  • eToolLCD advanced training course
  • Experience or qualifications in interpreting construction documentation

The certification system ensures that consistent, high-quality LCA studies are produced from the eToolLCD software. This lends further credibility to your work when clients see the eTool brand on your reports.

The certification is provided for up to 6 designs within an eToolLCD Building or Infrastructure entity. These designs may be very early stage models, or later stage complete LCA/LCC models or a combination, typically:

  • Concept Design Stage Base Model
  • Concept Design Stage Improved Model(s) (including all options modelled for BREEAM)
  • Concept Design Stage Final Model
  • Technical Design Stage Base Model
  • Technical Design Stage Improved Model(s) (including all options modelled for BREEAM)
  • Technical Design Stage Final Model

eTool understand that good LCA/LCC modelling is an iterative process and will be on-hand from the outset to provide assistance and answer any questions surrounding the modelling and certification.


1. eToolLCD user submits initial model/s for review
2. eTool staff complete QA / QC Checks on eToolLCD model/s and provides feedback
3. eToolLCD user complete / update eToolLCD model/s
4. eToolLCD user submit final model/s for certification
5. eTool staff completes certification (and clones model to BRE account if required)

– An independent review of the eToolLCD designs (6 or less) conducted by a competent LCA practitioner commenting where applicable against each project, structure and model quality checks. As a minimum, the following is reviewed:

– In addition to ISO14040 and ISO 14044 quality checks the certifier will also review the following for both baseline models and optioneering models, in line with BREEAM 2018 requirements

  • Material quantities are within +-10% of those shown in design documentation (both concept and technical design stage models)
  • Where default figures for product service life, transport distance and construction waste have been adapted from generic material default values, there is adequate justificationa dn references.
  • Adhesives are inlcuded if cover more than 20% of materials surface
  • Study period of 60 years

– eToolLCD Certifier Review Statement documenting checks made, comments and user responses using the certification checklist. See example report here.

– Phone/email/weblink support throughout the process

For further information see eTool terms and conditions

Eiffage Kier and eToolLCD PAS2080 Audit

As part of their ongoing quality management process, HS2 joint venture Effiage Kier (EK) contracted Lloyd’s  Register Quality Assurance (LRQA) to undertake a PAS2080 audit on their GHG reporting, processes, systems and tools.  For the past year EK have been using eToolLCD to model, baseline and improve the whole life carbon of their respective HS2 assets. 

PAS 2080 is an environmental protection standard for carbon management in infrastructure and includes requirements for effective governance and leadership, quantification of greenhouse gas emissions, target setting, reporting, information management and continual improvement. 

The PAS promotes reduced carbon, reduced cost infrastructure delivery, more collaborative ways of working and a culture of challenge in the infrastructure value chain through which innovation can be fostered. It includes requirements for all value chain members to show the right leadership and to establish effective governance systems for reducing whole life carbon through the use of a detailed carbon management process. “


The overall structure of GHG reporting within PAS2080 largely follows the modular approach defined in EN15978 – the European standard on how to measure the environmental performance of buildings.



The PAS2080 audit demonstrates EKs ability to quantify, compare and improve the life cycle environmental impacts of their infrastructure projects.

Spanning several months, LRQA undertook a rigorous technical review process that goes beyond PAS2080 and also incorporates ISO14064-3 Specification with guidance for validation and verification of greenhouse gas statements.  Both EKs systems for data gathering and aggregation as well as eToolLCD modelling software have been extensively assessed against LRQA requirements, including the following:

  • Gap analysis
  • Design team collaboration
  • Management systems and policies
  • Internal quality assurance
  • Database reliability
  • Calculation methodologies
  • Testing procedures

This can be a daunting process however the transparency of the systems and procedures in place at both EK and eTool has provided effective documentation to satisfy the LRQA audit. The following eTool policies and procedures were interrogated with particular detail.

  • eTool quality management policy
  • eTools data validation processes
  • eToolLCD Regression Testing Methodology and Practices
  • eToolLCD Error Handling
  • Cybersecurity incident response plan
  • Data Breach Response Plan
  • eToolLCD Patterns and Practices
  • eToolLCD Development and Deployment Procedure
  • Software Delivery Methods
  • Disaster recovery plan

Another big part of effective LCA reporting is multidisciplinary collaboration (eTools Enterprise feature is perfectly set up for effective LCA collaboration). A good LCA will involve input from a wide range of expertise including change estimators, planners, designers and operation managers.    Further opportunities have been presented for EK, eTool and our stakeholders to learn and continually improve the quality of our LCA modelling and reporting.

“PAS2080 accreditation is at the forefront of innovative verification schemes. Early in 2018, Eiffage Kier subscribed to eToolLCD software to help facilitate carbon quantification and management in a full Life Cycle Assessment. Having eToolLCD not only achieves significant BREEAM credits but has helped Eiffage Kier achieve PAS2080 verification as a designer working on HS2, Britain’s largest infrastructure project.

Using eToolLCD’s user friendly software, we have produced a variety of carbon assessments – ranging from full, contract-wide baselines to smaller carbon quantification – in asset balanced scorecards for different design methods. This has helped save thousands of tonnes of carbon dioxide, in turn helping EiffageKier move towards a 50% reduction in embodied carbon.

eTool’s proactive approach to responding to LCA queries from the Eiffage Kier team has helped deliver a compliant life cycle assessment report in line with various standards including PAS2080. eTool’s in house assurance on published life cycle assessments has also been important to the success of Eiffage Kier’s verification of PAS2080 and life cycle assessments. The output from our partnership has been instrumental in providing our stakeholders with confidence in both our methods and our data.”

Matthew Pygott – Carbon Assessment Engineer

Eiffage Kier JV, HS2 Team


For further information on PAS2080, the audit or if you are working on infrastructure projects and looking to further understand their CO2e impacts please contact info@etoolglobal.com



Green Star D&AB version 1.2 Opportunities for Improvement

DAB 1.2

The Building Life Cycle Impact Reduction credit in version 1.2 has significant gaps outlined below, detailing why the B6 points cap and focus on other modules doesn’t work.

eTool disagree with the method selected for the version 1.2 of the Green Star Design and As Built as it could lead to poor outcomes for the planet. Some examples are presented below:

Example 1:

Design team works hard to identify low impact materials that reduce the overall impacts of the design by an average of 10% per indicator in the LCA credit. Operational energy efficiency is resulting in a 50% saving. This results in about 3 points in the LCA credit for materials choices and 3 points for energy (B6). They decide to install a PV system that increases the operational energy saving to 90%. They achieve 8 extra points in the GHG calculator. But the PV results in a 10% average increase in impacts in other life cycle modules in the LCA credit. So they gain 8 points, and lose 3. At this point, the low impacts materials could be removed with no effect to the total Green Star points. So the design team decides to not pursue the original low impact material choices because excluding them will make no difference to their Green Star points. Although this could be considered as an “Edge Effect” considering 20% of Australian households now have PV, in the residential space it’s not at all uncommon potential scenario, particularly when dealing with high performance buildings that are aiming for best practice.

Example 2:

Similar to example one with a different technology. Design team of a residential multi unit dwelling building has focussed on low impact materials, and is achieving a 30% reduction in energy consumption through energy efficiency. They’re currently achieving 4 points in the LCA credit (1 for materials, 3 for B6) and 5 points in the GHG credit. They look into replacing the electric instantaneous solar hot water units with electric heat pumps. They find out it’s only possible with large central unit. The design changes required for the hot water ring main (additional service risers, copper ring main, pumps, insulation etc.) and the heat pump itself (including refrigerants) adds significant impacts to the materials (reduce LCA points by 1) but results in a large positive impact in the operational energy (20% saving increases GHG points by 4). Design team could now remove the low impact materials with no effect to Green Star points.

Example 3:

If the GHG calculator excludes plug loads from the assessment, projects that add technology or design features that reduce plug loads may be penalised for those features in the Green Star credits (regardless of the life cycle benefits). An example would be additional PV (not required for integrated equipment).

Example 1 and 2 are particularly problematic as they may actually drive less effort and innovation in materials etc which is against the principle of fostering optimisation in all life cycle modules.

Lack of Normalisation and Weighting in the Green Star LCA calculations:

Normalisation and weighting should be seriously considered for the points calculation. The method currently advocated in the credit (no normalisation and equal weighting) is somewhat contradictory to accepted LCA methodology. It has also already lead to some potential adverse penalties in the LCA credit.

An example that best illustrates this is the application of a large solar array on a buildings which led to an increase in ODP (more than 10%) in the characterised results. In the particular example (which we can’t publicise) when the results were normalised the reference buildings had GHG emissions equivalent to 500 Australian persons average emissions. The ODP on the other hand was 1.9 persons average emissions. So the solar array was reducing the GHG by 100’s of person’s average GHG emissions, but only increasing the ODP by 0.19 persons average emissions. So use of characterised results was effectively saying “we will reward a building more if it reduces the impacts of ODP by 0.19 person’s average emissions but increases GHG emissions by hundreds of average person’s emissions”. Potentially this would be justified if ODP was a far bigger environmental problem than GHG. Weighting could be applied to test for this (and the established weightings systems globally and in Australia seem to suggest GHG is a bigger problem). ISCA have a normalisation and weighting system which could be drawn upon by the GBCA. Similarly, BPIC established normalisation and weighting figures that could be used as a first pass by the GBCA.

Super Credit (Materials+Energy+Water) for Green rating schemes

eTool believes the “Super Credit” based on the life-cycle methodology should be adopted in the short term as an innovation credit (alternative pathway for material, water and energy) in rating schemes like Green Star and ISCA.

In Green Star, LCA could be used to reward not only “Materials” but also the ‘Greenhouse Gas Emissions’ and ‘Potable Water’ credits when whole of building LCA is considered. Operational energy and water impacts are accounted for in separate credits within the existing rating tool – ‘Greenhouse Gas Emissions’ and ‘Potable Water’, respectively. Given the LCA would also account for these impacts, the proposed approach uses the LCA model as a pathway to integrate all three credits. This option became known as the ‘super credit’.

Project could potentially tap into 39 points under the Green Star – Design & As Built (v 1.2) rating tool using this performance based approach:

Materials (Life Cycle Assessment):  7 Points

Greenhouse Gas Emissions (Modelled performance): 20 Points

Potable Water (Performance pathway): 12 Points

This approach means that the energy and water modelling will still need to be done following the original credit description, however the inclusion of the “operational impact” data (modules B6 and B7) into the same LCA model will enable the most accurate and transparent environmental picture of a building project. Understanding how each part of the building (from material choice, water supply and treatment, up to a HVAC system selected) accounts for the total environmental performance, is a key for better design decisions. In addition, the combination of energy, water and material credits into one LCA model and quantifying points achievable via the ‘Super credit” could help to close some gaps of the Green Star Design and As Build 1.2 rating scheme.

Another rating scheme that is currently adopting the life-cycle philosophy and will benefit from it in a short term is IS – Infrastructure Sustainability.

As a member of the iSupply register with ISCA (Infrastructure Sustainability Council of Australia), eTool suggested the 3-in-1 LCD for materials, energy water ISCA credits. Among all rating schemes in Australia, IS rating is probably most innovative and progressive, adopting the continuous improvement processes and developing a new WWEM tool to combine water, waste, energy and materials calculators into one tool, sort of a “super calculator”.

With an LCA conducted using eToolLCD software even more IS credits could be achieved: Mat-1, or RSO-6, Ene-1, Ene-2, Wat-1, Wat-2, ECN-4, Man-6, Man-7, Lea-3, Innovation credits, resulting in up to 40 points (or almost half of the IS rating 2.0).

Super credit 3 ISCA

Siloed thinking of environmental performance leads to adverse trade offs for the planet. LCA prevents these adverse trade offs, and when coupled with a life cycle design process leads to large environmental performance improvements. There is now a strong trend in uptake of LCA for environmental decision making.

Examples below:

– In standards development: CEN was directed by the EU to produce standards for voluntary rating of sustainable buildings. They developed “EN 15978: Sustainability of Construction Works, Assessment of Environmental Performance of Buildings, Calculation Method” which is entirely LCA-centric.

– In regulation: Laws such as the 2011 Grenelle regulations in France require mandatory LCA-based environmental product labelling.

– In Green Building Rating Schemes: DGNB. LCA forms the bulk of the environmental assessment, LCC for economic and there are some tick boxes for social credit.

– A new EU rating scheme Level(s) that encourages the use of the LCA. Still early phases but it could end up being rolled out across the EU.

eTool believes the “super credit” would enable any sustainable rating scheme to progress towards the most holistic assessment methodology.

The advantages of the super credit

Good Environmental Outcomes: There is a much lower risk of negative trade-offs by integrating embodied and operational impact into the same analysis, instead of understanding the impacts of different categories separately.

More tangibility for the design team to understand the contribution of each improvement strategy and prioritise them. For example: recycled carpet vs lighting sensors vs high efficiency HVAC vs high efficiency water fixtures.

– Identifying different hot spots of a building depending on location (energy and water grids type) and building type. For example, an office building located in Victoria today (very high operational energy requirement, highly intensive grid) will likely need to focus largely on energy efficiency to improve environmental performance. Alternatively, residential buildings in Tasmania will likely have to put much more effort into materials, transport, construction, maintenance, replacement, water efficiency etc as the impacts relating to energy will be a much smaller percent of a reference buildings.

Aligned with global trend towards LCA (future-proofs the rating tool) that accounts for whole of project impact analysis.

Simplifies the maintenance of the existing calculator tools. Single LCA model to enter results from materials, energy and water.

Time-efficiency. The LCA outputs can be used to address multiple credits, not only related to the materials, energy, water, but also cost, innovation, waste, recycling content, maintenance and management decisions.

The reasons put forward for not adopting the super credit are not aligned with eTool’s experience in the application of LCA in the design process of hundreds of projects in Australia and abroad. LCA is only a “relatively coarse approach” if the practitioner is not guided on the method of underlying calculations that are applied in the LCA.

In the case of Green Star and ISCA projects there is nothing preventing the use of the same calculation methods for Operational Energy and Water that exist today (and indeed these are the figures used in Green Star and ISCA LCA studies).

Module A1 – A5 are arguably more predictable than water and energy consumption estimates (which rely on occupant behaviour). The significant challenges faced by eTool as a business who supply LCA software and LCA services to the construction sector are not generally technical in nature. For example, we’d consider the psychology of building developers to adopting strategies that the LCA identifies to improve the environmental performance of their projects to be more challenging.

We are not aware of challenges that would prevent the industry from adapting to a rating scheme using LCA as a core calculator for environmental performance (as for example DGNB have done) and offer our assistance in overcoming those challenges facing GBCA, ISCA and other rating systems.

eTool Response to the Green Star Future Focus consultation paper 2019

Green Star Future Focus
Suggested changes to the framework have been presented in the Future Focus consultation paper – Green Star for New Buildings. The industry has been asked to submit comments to the proposed changes, that include the new set of categories and credits, encourages the elimination of carbon emissions from the built environment and sets high and ambitious requirements for 5-star and 6-star projects.

It is a POSITIVE change to see the proposed integration of the categories Energy, Water and Materials into one new category called “Positive”.

Previous and new credits

For LCA devotee like eTool, it gives hope that the new rating (Green Star for new buildings) will bring the circular economy thinking within Green Star to a whole new level. It is a great chance to close gaps in the previous rating “Green Star Design and As Built version 1.2” as pointed out by eTool feedback on the Material Life Cycle Impact Reduction credit.

How each decision, like a PV system, a new material with an available EPD or water saving technology, would influence the proposed design of a green building? These options need to be modelled to provide a transparent picture of the environmental footprint of the whole project, ideally before drawings are finished and contracts are signed.

eTool believes that the previous separation of energy, water and materials is no longer necessary with the advancements in standards, LCI data sources, LCA tools available and the knowledge within the industry.

Higher requirements for 5 and 6 Star projects.

Another positive change presented in the Discussion Paper is the redefinition of the 5-Star and 6-Star requirements. It is not new to anyone, that the construction industry moved to a new level with an increasing number of Green Star certified projects. Original 4-Star and some of 5-Star projects in Australia became business as usual, which means the “Reference” needed to be redefined – and the rating required a shift to a higher level.

GBCA is aiming to have the new 5 Stars as “Net zero ready”, and 6 Stars as “Net zero carbon”.

net carbon ready and zero

In short, the “Net zero Carbon” (= future 6 Stars) must be 100% powered by renewables and reduce their embodied carbon by 20%. This cannot be done just by simply buying offsets, but through the building design improvement.

The “Net zero READY” projects will still need to reduce embodied carbon (by 10%) but won’t have to be 100% powered by renewable energy.

This is a very positive change, however a clear definition how this needs to be measured is still missing. The European standard EN15978 sets the calculation method and potential options for specific performance targets include an absolute figure (i.e. 85kgCO2e/m2/year) or a percentage reduction against equivalent code compliant design.

New Badges for Champions.

The idea of badges is great and it is a good way to encourage innovations. Supporting the GBCA badges, eTool suggested the following ideas:

  • “Super positive champion” badge for those projects that used LCA model to achieve a “Super Credit” within the new rating, integrating energy, water and materials into the same analysis.
  • “Life cycle costing champion” badge for those projects using LCC to achieve the best environmental performance at the lowest cost, and use that as a metric to prioritise improvement strategies.
  • “Full Operational Net Zero Carbon champion” badge (including building-related and non-integrated building energy use as per EN15978). More details in our Position Statement on Green Star Net Zero Label from 2016.

How can we make sure that “Net zero carbon projects” (ready or not) consider ALL GHG emissions?

Is it enough to use 100% renewables in the Scope 2 and reduce water consumption for the building operation? Is it enough to reduce the embodied carbon (in the building materials) by 10-20% and offset the remaining carbon by purchasing the NCOS certificates?

Zero carbon is a very ambitious goal and to get there the projects will need to use life cycle design from concept phase to understand the key impact areas, prioritise strategies and make sure they are economically viable. The goal is to capture as much impact as possible in the LCA scope and use the design methodology to provide full transparency on the results and support the industry to make the right decisions towards a future in balance with the planet.

Materials Efficiency Metrics

Thanks to our work with HS2 we have recently added a number of new indicators to help measure materials efficiency.

  • Mass of non-renewable primary material (t eq) – virgin materials not including timber
  • Mass of non-renewable secondary materials (t eq) –  all recycled materials currently largely metals
  • Mass of renewable primary material (t eq) – timber and organic products that can be continually renewed
  • Mass of reused non-renewable materials (t eq) – quantifies directly re-used materials, in the LCA these would only have transport impacts
  • Mass of reused renewable materials (t eq) – such as re-used timber
  • Materials Efficiency Metric – HS2 KPI combining the above

These new indicators will help users understand where the hotspots are and greatest improvement opportunities for material consumption, waste, recycling and circular economy.  Please see here for further detail on how circular economy can link with LCA.