Dusseldorf The construction industry is booming. Worldwide. House after house is not only being built in metropolises. Infrastructure projects, residential buildings, commercial real estate – the more people live in the world, the more is built. This is not just a question of capacity – but also one of climate protection. Globally, more than 4.6 billion tons of cement are used every year. A total of 2.8 billion tons of CO2 are emitted during its manufacture. That is almost eight percent of global emissions – more than global computing power and global air traffic combined.
Climate-positive building materials could literally change the industry forever: they store more CO2 than their production causes emissions. This method is called “Carbon Capture and Usage” or “Carbon Capture and Utilization” (CCU): The CO2 pollution of the atmosphere is significantly reduced – and a noticeable contribution to climate protection is made.
Companies and start-ups see this as an opportunity to counteract climate change. “This is a very exciting time for innovation in building materials,” said Russell Hill, chief technologist at American start-up Solidia Technologies. “Change requires all hands on deck – public and private.”.
The pressure to reduce emissions is growing, especially in the manufacture of cement or concrete. The latter is one of the worst climate sinners. The problem is the cement clinker, the most important component of the building material.
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CO2 absorbing cement solves many problems at once
This is exactly where Solidia comes in. The start-up from New Jersey wants to produce climate-friendly cement and concrete. Prominent financiers believe in the project: the venture capital firm Kleiner Perkins Caufield & Byers and the chemical giant BASF are involved. “Awareness of the need for more sustainable solutions in manufacturing processes and products has grown rapidly,” says Solidia’s Chief Technologist, Hill.
The high emissions from cement arise primarily during production. So far, the burning process has had to take place at around 1400 degrees. Solidia uses less limestone and more clay, including the substance wollastonite, in its cement formula. This allows the cement to be fired at only around 650 degrees.
This method requires around 30 percent less energy, and CO2 consumption falls accordingly. With this approach, Solidia not only solves the CO2 problem, but also addresses three other climate protection issues at the same time: energy consumption, water consumption and waste recycling.
Because instead of water, Solidia’s cement reacts with CO2 and binds the carbon to create the limestone that holds the concrete together. The otherwise fossil raw materials that heat the rotary kiln are replaced with waste. When you add it all up, Solidia Technologies can reduce the carbon footprint by up to 70 percent compared to commercially available cement and concrete.
The cement manufactured by Solidia requires around 30 percent less energy, and CO2 consumption falls accordingly.
The whole thing can be used in construction companies’ existing furnaces. Water used in the process of forming the finished parts can then be captured and recycled. Solidia’s technology is currently still being used to manufacture CO2-cured precast parts in the USA. The product brand “Solidia SCM”, the company’s first application for ready-mixed concrete and the larger ready-mix market, is in the test phase.
Carbonaut plastic cheaper than petroleum based materials
Not only concrete and cement are climate killers, plastic and aluminum are also in a bad position in terms of climate technology. In 2019, plastic production alone released more than 850 million tons of greenhouse gases.
The demand for the products is very high, access to the necessary CO2 is becoming all the more difficult, reports Solidia technology boss Russell Hill.
The Carbonauts from Giengen in Baden-Württemberg build carbonization plants that convert biomass into biocarbons. To do this, the company mainly uses leftovers from forestry and agriculture, the food and wood industries. The biocarbons permanently bind the CO2 and can serve as a base material for concrete, asphalt and masonry.
Another important point when replacing petroleum-based materials are pipe materials, silicones, construction foam and plastic films, which are used in large quantities in construction. Torsten Becker, founder of the Carbonauts, explains that they are already in contact with several entrepreneurs for the development and production of the fabrics. According to Torsten Becker, insulation materials that were produced in a climate-friendly manner also had a far better functional effect and moisture absorption than conventional materials.
According to the company, each ton of Carbonauten biochar stores up to 3.3 tons of CO2. In the process, there is even green energy left over that can be used for production – also diverted for energy-intensive processes in construction. “The materials produced in this way are also cheaper than petroleum-based building materials,” says Becker. This is an important incentive for construction companies.
In the spring of this year, the first production plant of the GmbH goes into operation in Eberswalde. From then on, 6,000 tons of biocarbon from regional biomass residues are to be produced here per year.
According to Torsten Becker, the founder of Carbonauten, insulating materials produced in a climate-friendly manner often have a much better functional effect and moisture absorption than conventional materials.
Like the Carbonauts, the Berlin-based company Made of Air also uses what is known as pyrolysis technology. For production, they use the thermochemical process in which organic waste such as sawdust, grass, leaves and tree cuttings, but also industrial waste, is broken down with oxygen-free heating at around 400 to 700 degrees. The company uses this to produce plastic elements that can replace petroleum-based products or aluminum and can be used, for example, in large building facades.
Since it was founded, the company has produced more than ten tons of material and delivered it to the car manufacturer Audi and the fashion chain H&M. What has so far prevented the big breakthrough of the climate-positive plastic from Made of Air is the price. Plastic made from fossil oil, gas or coal is significantly cheaper.
Entrepreneur: “The construction industry is arch-conservative”
According to Carbonauten founder Torsten Becker, the turnaround in the industry is also sluggish for other reasons. Companies from the construction industry are interested, but often do not have the financial means. “The knowledge and the will are there, but the industry is arch-conservative,” analyzes Becker.
Because large companies currently also lack the financial incentive. “The orders are running, the construction industry is booming – the building materials are scarce. The economic pressure on the companies is therefore rather low, the ecological pressure is increasing massively,” explains Becker.
In the plastics sector, however, large construction companies are also much more open, says Becker. But the industry still needs time to make the change. If you want to approve building materials in such a central area, the process usually takes up to ten years – and this is justified. “The construction must not collapse.”
But time is of the essence, and companies will have to change over the medium term: “In view of the climate escalation, that means one to two years for me,” says Becker. “The solutions are on the table, the industry is slow to get its butt off.”
In the US, too, the transition of the sector is a challenge – although some problems are eliminated there: “In Europe, the focus is more on regulation, legislation and taxes to promote sustainability,” says Hill, Chief Technology Officer of Solidia.
In the US, the approach tends to be more incentive-based, but the challenge is that regulations for construction and building materials vary widely by state. “As a result, it’s difficult to create a one-size-fits-all solution that works for multiple markets,” Hill said. “We work with manufacturers in Europe, the US and Canada.” The wide variety of approaches to promoting sustainable solutions is a challenge and makes it difficult for manufacturers to respond.
Another problem is surprising: the procurement of harmful CO2 of all things poses a challenge for the industry. The demand for the products is very high, reported Hill from Solidia. “Probably the biggest challenge is carbon access and affordability,” Hill said.
Add to that “issues in the supply chain, making it difficult for manufacturers to pause to adopt new technologies.”
Solidia: Development of a CO2 infrastructure required
The construction industry in Germany is optimistic. “The mood that we are registering is clearly one of upheaval,” says Tim-Oliver Müller, General Manager of the Main Association of the Construction Industry in Germany. Most of the CO2 emissions occurred during the manufacture of the building materials, less so during the construction itself.
Against this background, one must look at the entire life cycle of a building, says Müller. “The big lever for CO2 emissions in the construction and real estate sector lies in the renovation of existing buildings,” says Müller.
Around 75 percent of the emissions in building construction arise from the operation of the building. Renewable energies are therefore the key to operating the buildings. But climate-positive renovation options are expensive. “The client has to want it and commission us accordingly – and then the building materials have to be available in large quantities,” says Müller. “Building renovation must become a holistic product – preferably across districts and sectors.”
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