THE ENVIRONMENTAL IMPACT OF BUILDINGS
Actualizată în: 30 Apr. 2020
How natural materials can reduce the carbon footprint of a building and pave the way to the EU carbon neutrality 2050 plan
The building sector and the climate change
The building sector has a significant impact on the environment (is responsible of 40% energy consumption and 36% CO2 emissions) which makes it one of the EU's top priorities, which has issued a couple of directives and set ambitious goals for the coming years in order to increase the energy performance and reduce CO2 emissions in this sector. Perhaps the most well-known of these is the Directive 844/2018, which brings the nZEB (nearly Zero Energy Buildings) standard into the spotlight. An nZEB building, is one that requires almost no energy to operate and has a minimum of 10% of energy produces from renewable resources (solar, wind, hydro). This standard is becoming mandatory from 2021 and thus many European countries are doing great efforts to get prepared. Why is this important? The European Union has made a commitment to become carbon neutral by 2050, meaning that it has to reduce to 0 the carbon emissions from all sectors. A very ambitious plan, isn't it?
Our lifestyle and daily activities have do have effects on the environment: we drive to work, we burn fossil fuels to produce electricity to power our home, we consume resources to produce goods and building materials and the list keeps going. All of this requires energy, that we produce largely from conventional sources (burning coal, gas, oil) that emit CO2 into the atmosphere and lead to climate change, which will make our planet uninhabitable (extreme seasons, droughts, floods due to rising ocean levels and melting glaciers etc). Watch this video for more about climate change.
The carbon footprint of buildings
It represents the total amount of greenhouse gases (CO2, CH4, N2O, O3, etc.) produced by a building during its lifetime and includes the carbon emissions associated with:
the energy consumption (embodied energy) necessary to manufacture the building materials (extract of raw material, processing & production, transportation, etc.) and
the energy consumption necessary for the maintenance and operation of the building (electricity, heating, air conditioning, etc.).
As a reference point, a conventional masonry house takes between 50-80 tonnes of CO2 to build (50-80 tonnes of CO2 was emitted in the atmosphere for the production and transportation of materials, along with building the house).
This graphic shows the main building materials and their associated carbon dioxide emissions measured in kgCO2/tonne of material. However, it is important to consider the density of each material (wood has 800 kg/m3 as opposed to concrete 2400 kg/m3 or metal 7850 kg/mc) because a wooden house is 3 times lighter than a concrete house and consequently, the CO2 emissions are 3 times lower for just the same volume. If you are wondering how timber could replace concrete in the construction of the major buildings, well the Norwegians did the impossible and built the world's biggest wood skyscraper.
Environmental friendly materials
Being a natural material, wood has a negative carbon footprint because it absorbs CO2 from the atmosphere through photosynthesis and stores it in its structure to grow, as opposed to brick or concrete that requires significant amounts of energy to be manufactured. Another important component of a building is the thermal insulation, which plays an important role not only in increasing the thermal performance of the building (a topic discussed it this article) but also in the building's carbon footprint.
You can see on this graphic how the natural, organic insulating materials (such as sheep's wool, cellulose, cork, hemp or straw) have a negative carbon footprint because like wood, absorb CO2 from the atmosphere through photosynthesis to grow. This phenomenon is called carbon sequestration and a house build with natural materials can become a carbon sink, meaning that its materials stored more CO2 from the atmosphere than it was emitted to be built.
The straw (either as bale, panels or chopper) is the most environmental friendly insulation material, having the carbon footprint 8 times lower than mineral wool or polystyrene.
According to this study, a conventional masonry house has a carbon footprint 3 times higher than a straw bale house (475 kgCO2/sqm of masonry compared to 150 kgCO2/sqm of straw) and yet meets the same requirements in terms of structural resistance, comfort, and energy efficiency. Straw is a simple but complex material from the construction point of view. In addition to the environmental benefits, straw is also a very good thermal insulation. After many years of research, we have developed TERMOPAIE, an insulation material made from loose chopped blown into the structure at 100 kg/m3. As thermal performance, the thermal transfer coefficient λ varies between 0.038-0.044 W/mK depending on the straw density and has at least the same thermal characteristics as the rest of the conventional materials.
The climate is changing, as well as the requirements of the future buildings, which must provide the comfort needed with a minimum of energy and CO2 emissions. Globally, efforts are being made to develop new technologies, materials and unconventional energy sources to improve the way we build and operate the buildings. We do the same thing, as we continue the research and seek new solutions to improve and optimize each of the Nidus Homes. #nidus #carbon #carbonfootprint #CO2 #termopaie #naturalmaterials #straw