Case Study: Stored carbon and structure cost
In this analysis our team observed twelve projects that were developed by Acetra during 2021 and 2019. We have analysed the total amount of carbon that was stored in structures. It was taken from processing of timber up to assembly phase of all structural elements.
Detail parameters that were considered are as follows: wood harvesting and processing, transport to the CLT or GL producer, producing CLT with prefabrication of elements, producing GL with prefabrication of elements, timber transport and connecting elements to the site, assembling structural elements with steel connections.
The CO2 embodied in the wood that was used in a complete building was reduced from processing of timber up to assembly phase. The total CO2 embodied in the wood for a complete building was reduced by:
1. CO2 emitted during the production phase of wood
2. CO2 emitted during the production of steel parts
3. CO2 emitted during transport
4. CO2 emitted during assembly
5. CO2 emitted during building designing
1. CO2 embodied in the wood
Carbon content in the wood is typically expressed as the equivalent quantity of carbon dioxide. The exact quantity of CO2 in one cubic meter of CLT varies by different manufacturers of CLT. It depends on wood species used for panels and manufacturer’s composition of a CLT panel.
CO2 AND THE COST OF A STRUCTURE
In developing carbon strategies of timber projects, one of the main topics are the balance between CO2 stored in the structure and the cost of the structure.
The point is to have as much CO2 stored in structural elements as possible, and on the other side, not to raise the cost of the structure.
Our goal is to have over 200 kg/sqm stored of CO2, and on the other side to have a cost-effective structure. One of the ways to do it is by playing with the structure. It all depends on the thickness of the walls, size of the flooring, and even the size of window frames plays a big role. .
The correlation between the cost of the structure and the stored CO2 is very aligned. More timber used means more CO2 stored in the structure, but that also affects the price.
What we consider in order to have as sustainable structure as possible, we recognize two parallel processes:
1. Applying CO2 strategies on projects
2. Structural design organization
We can conclude that for each project it is mandatory to perform C02 strategy in the early phase of a design in order to achieve CO2 goal set up for the structure.