New Green Star Buildings rating system

Green Star has launched a new rating system – Green Star Buildings. The Positive category acknowledges the value in understanding the full lifecycle impacts of the buildings which in turn can lead to better low carbon designs.

This article explains how the Positive credits can be achieved using eToolLCD and demonstrates how it will contribute to increase the performance of your projects.

Positive category and the use of eToolLCD software

A total of 14 points can be achieved in the Positive category with the use eToolLCD (plus offsets) contained under three credits:

  • Upfront Carbon Emissions
    • Credit Achievement 3 points  (optional to use LCA Pathway)
    • Exceptional Performance 3 points (required to use LCA Pathway)
    • Leadership Challenge 1 point when Climate Positive Pathway is achieved
  • Other Carbon Emissions
    • Credit Achievement 2 points (optional to use LCA Pathway)
    • Exceptional Performance 2 points (required to use LCA Pathway)
    • Leadership Challenge 1 point when Climate Positive Pathway is achieved
  • Life Cycle Impacts 2 points (required to use LCA Pathway)

Upfront Carbon Emissions

Credit Achievement (3 points)

The building’s upfront carbon emissions are at least 20% less than those of a reference building. Model the proposed and reference buildings following the methodology of the Life Cycle Impacts credit for modules A1 to A5. Module D is excluded.  Results shall be entered into the GBCA Life Cycle Impacts calculator to show the percentage reduction.

Demolition work is offset. eToolLCD demolition templates can make this process easier and quicker when limited data is available. 

Carbon emissions associated with demolition work are not part of the scope when calculating the reduction target, but it needs to be calculated in order to be offset as its offset is a credit requirement. Carbon offsets purchased cannot be used to show compliance against the 20% reduction target. Where an existing building has been fully or partially demolished for construction, an embodied carbon calculation must be done for the demolished portion and these emissions offset, see credit description for more information.

eToolLCD Scenarios feature combined with the Bulk Swap feature will assist the design team to model different improvement strategies and understand the relevance of each one in order to achieve the reduction target. Automated reporting will streamline the communication process to help make informed decisions quicker.

Exceptional Performance (3 points)

Only available when using the LCA pathway. Using eToolLCD will “unlock” these 3 points, but carbon offset needs to be purchased.

The building’s upfront carbon emissions are at least 40% less than those of a reference building. Model the proposed and reference buildings following the methodology of the Life Cycle Impacts credit for modules A1 to A5. Module D is excluded. 

Only available for projects using the Life Cycle Impacts credit pathway. The Upfront Carbon Emissions calculator is not compliant for this credit criteria.

The reduction targets do not include demolition works. Carbon offsets purchased cannot be used to show compliance against the 40% reduction target. 

Leadership Challenge 1 point

The upfront Carbon Emissions credit is part of the Climate Positive Pathway. The Credit achievement criteria is required to be met in order to achieve this extra point. A Leadership Challenge point is awarded when the pathway is achieved. Please refer to the submission guidelines regarding the Climate Positive Pathway requirements.

GBCA Upfront Carbon Emissions Calculator 

This option is only for projects seeking to meet the minimum expectation (10% reduction, no points) or credit achievement (20% reduction, 3 points). Projects seeking the Exceptional Performance (3 points) need to complete the Life Cycle Impacts credit pathway. 

This method requires manual input of data into the calculator and doesn’t allow integration with BIM models or CSV import functionality for example.

The Upfront Carbon Emissions Calculator is limited to modules A1 – A3, excluding significant  impacts associated with transport (A4) and construction (A5) that are not included in the EPiC database used in the calculator. The limited number of material options available can potentially reduce the overall impact calculation therefore reducing the opportunities for performance improvement. Results produced using the EPiC database can reduce consistency when compared with results produced with standard compliant inventory data (EN15804). 

Demolition works to be offset are estimated using the “Existing Building” section of the Upfront Carbon Emissions calculator.

Other carbon emissions

The building´s emissions from refrigerants, upfront carbon, and remaining carbon sources are eliminated or offset.

eToolLCD presents an advantage with an integrated design approach by calculating refrigerant impacts together with HVAC energy efficiency and operational carbon to understand life cycle impacts trade offs. The LCA method not only accounts for the initial charge but it takes into account leakage losses during operations and end of life recovery rates.

A single whole of life model produced with eToolLCD will assist with this credit as well. The extended scope covered by eToolLCD’s whole project approach can be reduced to meet the specific credit requirements. 

Credit Achievement (2 points)

Eliminating or Offsetting refrigerants from building systems or domestic appliances provided by the building.

Carbon emissions are calculated by multiplying the initial refrigerant charge by its GWP (Global Warming Potential). 

Exceptional Performance (2 points)

All other emissions not captured in the Positive category are eliminated or offset, including:

  • Emissions from the building’s energy use including electricity
  • Upfront carbon emissions as determined in the Upfront Carbon Emissions credit
  • Emissions from module A5 construction equipment use (Unless the LCA Pathway was used for the Upfront Carbon Emissions credit)
  • Life-cycle emissions from modules B and C as calculated as calculated in Life Cycle Impacts 
  • Construction waste emissions
  • Any other significant emission (over 1% of the total carbon profile for the building)

These emissions are already being calculated when using eToolLCD for the Life Cycle Impacts credit, which makes it easier to be offset and achieve this exceptional performance criteria. 

Leadership Challenge 1 point

The Other carbon emissions credit is part of the Climate Positive Pathway. The Credit achievement criteria is required to be met in order to achieve this extra point. A Leadership Challenge point is awarded when the pathway is achieved. Please refer to the submission guidelines regarding the Climate Positive Pathway requirements.

Life Cycle Impacts

Conducting a whole project LCA analysis (embodied + operational carbon) will enable the project team to understand the overall project hot spots areas, compare the relevance of each improvement strategy in a single model and reduce capital risk by making sure the investment is going in areas that will most improve the performance.

Credit Achievement (2 points)

The project demonstrates a 30% reduction in life cycle impacts when compared to standard practice.

Life Cycle Impact reduction must be demonstrated through a whole of building life cycle assessment as per EN15978 including modules A to D.

Results must be reported in the functional unit of per square metre of Gross Floor Area (GFA), and entered into the GBCA LCA calculator which will apply normalisation and weighting to the results. Service life of 60 years is to be applied. 

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