Towards an essential decarbonisation of cement.

The construction industry is accelerating its ecological transition.

The major players in the construction industry are planning to gradually decarbonise their businesses for decades to come. In France, for example, cement manufacturers announced new objectives after their meeting with the Minister for the Ecological Transition last week, Mrs. Barbara Pompili.

24% reduction in greenhouse gas emissions by 2030 and 81% by 2050. In an industry reputed to be very polluting, it was urgent to establish an ambitious roadmap committing the cement industry to decarbonizing the sector.

According to Mr François Pétry, CEO of LafargeHolcim, world leader in the sector, these levels can be achieved in three ways. First of all thanks to the capacity and efficiency of industrial tools; to know how to better and more use green energies. Then by replacing fossil fuels with energy recovery and the use of waste. Finally, it will be a question of developing more eco-responsible products by reducing the proportion of highly polluting ingredients in cements and binders.

While the short-term goals are relatively achievable, the longer-term ones are more difficult and will require heavy investment and support from public authorities.

It would be wrong to think that the construction sector is just beginning its ecological transition. The awareness to reduce the carbon footprint of this activity goes back several years. However, the urgency is there and we must go much faster, as Mr Pétry, CEO of the LafargeHolcim group recently recalled: " What is important to see is that our sector did not have up to now. now initiated in carbon reductions per tonne. But now it is on, and it will accelerate with extremely marked reductions. ”He added: “ In 2050, one tonne of cement produced should only generate 133 kilograms of CO2 against 660 kg in 2015, and 503 expected in 2030 ”.

For this, new techniques are being studied. The future now lies in carbon capture and valorization. The areas for improvement are carbon storage and the development of new, less costly approaches, for example by integrating the CO² from the manufacture of new products. Mr Petry also indicates that fossil energies such as coal will gradually give way to “energy-intensive waste (oils, tires, animal meal, paints, biomass such as end-of-life wood or demolition products): the current substitution rate of 40% will have to rise "to 80% in 2030 and 85% in 2050".

An interesting collaboration is a good illustration of the sector's desire for transformation. Total, Svante Inc (specialist in carbon capture), Oxy Low Carbon (subsidiary of Occidental Petroleum), and LafargeHolcim have come together to conduct a study which should lead to assess the feasibility of CO2 capture in a Holcim cement plant. Portland in Florence (Colorado, United States), whose purpose is to ensure the storage of CO2 in oil wells. Once captured, the carbon dyoxide is then stored in the earth's subsoil for a definitive period, thereby avoiding any release into the atmosphere. In addition to cement factories, this technique is applicable in a large number of industries that emit a large amount of CO², such as oil refineries, steel and petrochemical factories or even coal, fuel or gas-fired thermal power stations, chemical products factories among others.

Recycling is also a very interesting decarbonisation path that is easier to implement. This is the experiment that Eiffage is attempting by using concrete containing up to 100% recycled aggregates. For example, the company plans to recover 100% of the concrete resulting from the demolition of the École Centrale.

Construction is developing strongly and certain regions of the world are experiencing strong expansion. We obviously think of China. And even if alternatives exist and attract more and more; like wood, cement always has a bright future ahead of it. But it will have to quickly become greener and greener.