Carbon footprint calculation for Tuupala wood school

Carbon footprint calculation of buildings and the results from it give valuable information about the greenhouse gas emissions of the building under consideration and how to reduce them. The footprint calculation of Tuupala wood scool showed that the building materials cause significantly smaller footprint than is caused by the energy consumption during the life cycle of the school. 

Implementation of the carbon footprint calculation of building  

The carbon balance calculation can be carried out already in the planning phase of the project or after the construction. To minimize the greenhouse gas emissions caused by the manufacturing of the building materials, the effectiveness of material choices should be taken into account already in the planning phase. For example, in order to do material comparison, the material calculations should be carried out for alternative materials. 

The carbon balance calculation can also be carried out after the construction, like it was done with Tuupala school. In that case it is important, that the documentation of the project is done sufficiently comprehensively and reliable. It should also be noted, that the comparability of materials and possibility to influence the material choices will be weakened, if the material calculation with different material options has not been done in the planning phase. Only the possibility to influence the use phase and after the use, like the optimization of demolition of the building and direct the materials into beneficial use, remains. 

The effect of building materials on wood school’s carbon footprint  

The carbon footprint calculation of Tuupala wood school showed, that the building materials cause significantly smaller carbon footprint than is caused by the energy consumption during the life cycle of the school. The electricity use of the school is the biggest factor that affects the footprint. It causes a little bit over 60 % of school’s lifetime carbon footprint. The heating of the wood school has produced by bioenergy, which contributes to a reduction of the total carbon footprint. 

According to the results of carbon footprint calculation, the material-based greenhouse gas emissions of the wood school are less than 140 kgCO2-ekv/brm2. Greenhouse gas emission of construction products are second largest factor affecting to the carbon footprint with a share of approximately 23 %. 

Energy consumption during construction was higher than average 

The energy consumption during construction of Tuupala wood school was approximately 50 % bigger than the average energy consumption during construction. Factors that affect the energy consumption during consturction are e.g. following the Healthy House crtiteria, construction method (installation of elements in place and use of work machines) as well as the location and construction time (season of construction, which affects e.g. the need for lighting and heating). 

Energy consumption is reflected in greenhouse gas emissions during construction, which share is 6 % of the total carbon footprint of the building. Energy consumption during construction, and thus the carbon footprint, can be affected by presenting claims to the contractor about bioenergy, biofuel and ecoenergy use. 

Primarily, the construction materials and the quality of construction must be taken care of, and decreasing the carbon footprint can not cause any risks in constructing. For example, constructing Tuupala wood school, Healthy House criteria was followed. This may cause a bigger carbon footprint (than in average constructing) in the construction phase, but on its merits, the length of the life cycle can very likely be extended as well as reducing the need of renovation. In other words, it’s not profitable  to reduce the carbon footprint “at any cost”. Functional building ,for the purpose that it was designed to, is more important.