“Save the planet” is the mantra that is heard reciting daily in the global contest by all media and all events. Being an environmentalist or becoming it fast is an obligation imposed on us by reckless use of resources. They are the ones under twenty who pull their ears to the system. It may surprise, but let’s think about it, this is the generation that advances to boast the most considerable rights, considering that their life expectancy is more than double compared to that of a fifty-year-old today. It will be them, their children, their grandchildren, and so on, who will have to take charge of a planet on the brink of collapse. All this imbued by the rhetoric of the climate summits where we solemnly promise that by 2020 .., 30 and ..40 emissions will be reduced by a whole lot.
Then let’s start the electric cars, the self-extinguishing shopping bags, the towels that should not be thrown away after the first use. In all this exciting change of climate, there is a substance or rather a material that, despite being one of the main culprits of global emissions, is not (almost) never brought to the dock. If this substance were a country, it would alone be the third largest in terms of emissions after China and the USA. Since no one speaks of it clearly, I have called it the “silent killer” of the planet, but it has a name and is called cement. A few months ago, a friend stuck in traffic was telling me on the phone that he couldn’t stand to queue up for most of his daily transfers. “All this,” he said, “would inevitably lead to the dissolution of our system. The enormous quantity of emissions that our cars release into the atmosphere is killing us”. I tried to reassure him by saying that cars weren’t the first to be the cause. He replied with a questioning grunt: “What then would this first cause be?” “The cement,” I told him. He cut off the call by sending me to hell and adding that the cement was a “neutral substance.” It is difficult to explain the consequences of a process only known to experts. When you see pouring it from a cement mixer, it is hard to guess it as a killer. Or better saying, it has been, because the moment it leaves the duct, the crime has already been committed.
It is in its manufacturing process that causes and proofs of the crimes that accumulate exponentially in the form of millions of tons produced must be sought. In 2018, global production was 4.1 billion tons (EPA). In this case, one is worth one, which means that for every ton of cement produced, one ton is released into the atmosphere. To be precise, there are two leading causes of emission in the production process. A chemical reaction causes the first one. The calcareous rock extracted from a quarry is progressively crushed and reduced to granules of about 3 cm in diameter. Later, it is added with binding substances and conveyed in industrial rotating kilns about tens of meters long and up to six wide. Here limestone and clay are cooked together at a flame temperature of about 2,000 degrees. At the operating temperature of 1500 °, the limestone dissociates into calcium oxide and carbon dioxide. Thus clinker is formed, an artificial mineral that comes out of the oven and is then air-cooled. Gypsum and ash from thermoelectric power plants are then added to the clinker, and the mixture is further ground and cement is obtained as a final result. The second cause is the energy consumption required to activate the process.
In the background a cement production site. With 2.8 billion tons of CO2 released each year in the atmosphere, the cement industry is one of the most responsible for the global pollutant emissions.
In a cement plant, 60% of CO2 emissions come from the decarbonation of limestone, which is formed by calcium, carbon, and oxygen. Vast amounts of heat must be provided to activate this process. The cement industry is a hell of energy-consuming. To manufacture one ton of clinker, it requires 3,200 to 4,200 MJ (Mega Joules). On average, the Italian cement industry consumes 2.3 million tons of non-renewable fossil fuel each year. If the CO2 emissions due to decarbonation are incompressible, it is instead possible to intervene by reducing the remaining 40%, deriving from the use of fossil fuels in the kiln. The use of alternative fuels such as biomass produced from urban waste could lead to a reduction in emissions.
According to Aitec (the Italian technical and economic association of cement), the use of alternative fuels in Italian cement plants, at current levels of use in our country, makes it possible to avoid the emission of over 300,000 tons of CO2 per year. Nonetheless, this proposal tends to clash with the general idea that any waste used in a combustion process leads to further emissions. As far as bio-masses managed in a controlled process are concerned, this is untrue.
C02 emissions vs CO2 sequestrian
1 ton of timber sequesters 1.6 tons CO2 [1 ton = 2.5m3 di abete]
Meanwhile, attempts to make green cement generate, and bt then the expression becomes almost an oxymoron. There is very little indeed in the current process and in the additives to be able to mitigate the environmental impact. A chemical reaction is ever a non-return reaction. What is extracted from the soil and forced into an industrial process cannot be defined sustainable: it is merely a subtraction of resources leading an irreversible process. It is from here that we need to start again. Consider a tree, and after cutting it, plant at least a new one. The joint actions become a sustainable one. Precisely because it is implemented organically and reversibly: the cut tree is replaced. Simple right? The Mass Timber, or in other words, the engineering of a reversible process, is the only real viable alternative. Cement is a great invention that will always be present but indeed confined to areas where it is essential, and when there are no other chances.
Waugh and Thistleton Architect, when they designed the first multi-story building in London in 2009, showed that an equivalent concrete and steel building would release up to 125,000 kg of carbon in the air. The use of CLT sequesters 185,000 kilograms of CO2, for a combined savings of about 300,000 kilograms of carbon. CO2 savings can only go through the downsizing of carbon-emitting industries and the acceptance of a technology able to learn through nature. And as a great environmental architect stated:
“Mankind cannot compete with photosynthesis.”
Eugenio decided to leave his previous position as aCEOof a European stainless steel company to found InnovHousing and to apply his knowledge to challenge the status quo in the South African construction industry. His vision is to innovate the local market thanks to the latest European technology and by implementing new efficiency standards of well being. Eugenio is the mastermind of theTreeOne project at Nelson Mandela University