The construction sector is one of the pillars of our civilizations, however, it is evident that it has ample room for improvement due to the fact that it is one of the main players in the total amount of carbon dioxide emitted into the atmosphere.
This sector accounts for 39% of total carbon emissions, in addition to the large amounts of solid waste it generates (30%) and its high rate of water pollution (20%).
During 2019, record highs were recorded in the Building and Construction sector. According to the 2020 Global Status Report on Buildings and Construction, energy-related emissions increased to 9.95 Gigatonnes of CO2 in 2019, all related to the use of fossil fuels for electricity production.
According to a UNEP Program report during COVID-19, in 2020 carbon emissions from energy production processes for the building sector only continued to increase.
What measures are needed to improve the construction business?
These figures are alarming, however, only prove that there is ample room for improvement and that climate change is of crucial importance. To achieve the goal of limiting the increase of 2°C on our planet, it is of crucial importance to reduce the carbon footprint of the Construction Sector.
This requires a reduction in the carbon footprint of this sector’s emissions by 2050. The International Energy Agency estimates that by 2030 they must be reduced by 50-60% to achieve climate neutrality, which would be equivalent to an annual reduction in emissions of 6% by 2030.
To achieve this, work will have to be done on several aspects:
- Reducing the carbon footprint of raw material production processes and transportation: The cement industry alone is responsible for around 5% of emissions. Annually, 1.6 billion tons of cement are generated, which in turn generates 1 ton of CO2. All this without taking into account all the machinery used in its subsequent transportation, which represents 7% of emissions.
- Increase the energy efficiency of existing buildings: Governments should implement decarbonization policies that channel investments to reduce heat losses that subsequently affect emissions, in addition to increasing the value of the real estate.
- Creation of High Energy Efficiency buildings: Governments should focus their investments on low or zero-emission housing and buildings, such as Passivhaus or Passive Houses.
Invest and implement policies of circular material economies that would reduce carbon emissions after demolitions.
Low Carbon Alternatives in the Construction Sector
Use of Wood
Since concrete is the largest generator of carbon dioxide emissions, a practice that reduces the carbon footprint is the substitution of concrete for another type of product that is more environmentally friendly: Wood.
Wood is an environmentally friendly material, because it retains CO2 throughout its life cycle, besides being fully recyclable and reusable. It represents an excellent alternative because its transformation as a raw material ready for construction requires much less energy than steel and concrete.
In addition, it is a renewable resource, if it is managed with awareness. Among the benefits of using wood are:
- Excellent thermal and acoustic insulation.
- High Resistance
- Higher load capacity
Implementing the 4Rs
Another measure that can be implemented is the use of the 4Rs in the construction sector:
Reduce, Reject, Reuse and Recycle.
- Reduce: A large number of the construction sector’s emissions come from energy costs, so emissions can be reduced by increasing the efficiency of the machinery. If possible, they should be replaced with optimized machinery which will allow for energy reduction.
- Reuse: At the end of each project, there are unused materials left over that can be reused. Avoid classifying them as waste as they may still be of use for future projects.
- Reject: Before choosing materials, the best options to carry out a project should be considered. In this phase, it is important to take into account not only the price but also the quality and durability of the material. To reject with criterion in the long term is beneficial not only in economic issues but also environmentally.
- Recycling: In the steel sector alone, using recycled material can lead to a 3% reduction in carbon emissions. In turn, the process of creating concrete has the alternative of recycling products that were previously classified as waste, which allows for a reduction in solid waste and carbon emissions.
Efficient water use
The construction sector is responsible for at least 20% of water pollution. This is mostly due to surface run-off from construction sites, mostly caused by leaks. The water wasted from construction sites on its way to larger bodies of water is polluted with fuel, oils, solvents, dust and debris that are harmful to marine life and the environment in general. To reduce this contamination it is important to verify the absence of water leaks in pipelines.
Educating and raising awareness of this impact and implementing measures to ensure efficient water use is of crucial importance.
Another way to reduce the amount of water that is polluted is to use low-water consumption equipment or equipment with motion sensors, such as toilets and sinks.
This single measure alone represents a 50% reduction in water use.
Low-carbon cement and EPS
The largest amount of carbon emissions are caused by the production processes of the raw material for buildings, which account for about 9% of total emissions.
Because concrete is the protagonist, its production requires high levels of heat and energy, so one way to reduce the carbon footprint is to use low-carbon cement, which can reduce emissions by up to 6%.
Another type of product that can be incorporated is expanded polystyrene or EPS, a material used in the construction sector that provides thermal, acoustic and humidity insulation qualities, in addition to its reduced price.
The use of EPS has a great impact on the reduction of carbon emissions due to its contribution to thermal insulation. EPS cells are mostly made of air and their production requires less primary energy than other sustainable alternatives.
Its main advantage is that it is fully recyclable and its recycling process requires low energy consumption.
Polypropylene as a Concrete Additive
Another alternative is polypropylene, a type of plastic that is found to a large extent in most of the products we use on a daily basis, such as face masks.
It can be incorporated into the concrete production process. In the United States, at the University of Washington, it was mixed with a graphene oxide solution and found to increase the strength of concrete by up to 47% after 28 days.
Each ton of steel requires the emission of approximately two tons of CO2 into the atmosphere, which translates into 7% of the carbon dioxide produced. Fortunately, there is a more environmentally friendly alternative: Green Steel.
Common steel uses coal and iron and generates high CO2 emissions. Green steel replaces coal with hydrogen using a method called Hydrogen Breakthrough Ironmaking Technology or HYBRIT.
This method is characterized by being highly environmentally friendly because both the hydrogen and the iron particles are obtained in a clean way. In addition, the process releases water vapor instead of carbon dioxide.