When it comes to modeling carbon neutral projects in eToolLCD, you need to bear in mind that an LCA needs to be conducted first in order to find out what the carbon impact of a product/building is which is then offset outside of the LCA. LCAs give you the information on how much carbon you need to offset in order to achieve carbon neutrality.
With that understanding, it isn’t sound methodology to then go backwards and change the LCA of that product/building to zero after you’ve offset that carbon. Hence why EN 15978 standards do not include carbon offsets in the LCA boundary scope.
LCAs are used to calculate how much carbon a building/product has to know how much needs to be offset outside of the LCA.
Should you wish to demonstrate the benefit of the carbon neutral product in eToolLCD, this will need to be modeled outside of the headline LCA to ensure alignment with EN 15978.
Below is an example of how your ‘Scenarios’ should look like to meet EN 15978 standards while being able to demonstrate to your clients the benefits of using carbon neutral products.
To model your carbon neutral product, please follow the steps below:
- Navigate to the category where your carbon neutral material is in. In this example, the carbon neutral concrete is in the Substructure. Note the current GWP impacts under the ‘Products’ category (highlighted).
- Next, click ‘+Add Substructure‘ to add a new element which in this case, will be the same Concrete | Unreinforced | Portland Cement Blend | 40 MPa material.
- In the material pop-up window, make sure that you enter the negative amount of the quantity you want to offset (pay attention that the units are correct as well) and that the inputs for ‘Lost or Damaged in Transport’ is changed to be the same as the default material. The ‘Disposal or Recovery Method’ & ‘New Product Transport to Site’ inputs (as highlighted below) need to be set to zero to ensure that only A1-A3 material impacts are offset.
- Click ‘Save’ to add the new material to the category.
- Back in the category summary view, you’ll now see that only the GWP for Products and Transport (A1-A4) has been affected while all other impacts have remained the same.
- You can also confirm this by running a custom table in the Analysis Tab. Note that the inputs under A4 are only for the impact of any products lost or damaged in transport.
Alternatively, you can ask the material supplier for an EPD and use that to account for the carbon neutral products. To create the EPD in eToolLCD, please refer to this support post.