Climate protection: Cement manufacturers and waste incinerators and their CO2

As of: November 15, 2023 6:35 a.m

CO2 emissions cannot be avoided during cement production and waste incineration. But the greenhouse gas can be captured and stored underground. For this to happen, laws would have to be changed.

On November 15th, the World Weather Organization (WMO) reported on greenhouse gases in the atmosphere: The Greenhouse Gas Bulletin is an annual publication by the organization. Man-made emissions of carbon dioxide have been rising to record levels for years. The capture and storage of CO2 from industrial processes could make an important contribution to climate protection.

Avoiding emissions is the best way

Carbon dioxide acts as a greenhouse gas in the atmosphere and is the main cause of climate change. To protect the climate, power plants that run on fossil fuels can be replaced by systems that use environmentally friendly, renewable energies such as sun and wind. Avoiding emissions is the best way to protect the climate.

However, there are industrial processes in which avoiding CO2 emissions is not possible or only possible to a limited extent. The top priority here is the production of cement, which accounts for a significant share of global carbon dioxide emissions at seven to eight percent. The greenhouse gas here comes only insignificantly from the fuels. The vast majority of it is released when the limestone is burned. A second process in which CO2 emissions cannot be avoided is waste incineration.

CO2 capture for climate protection

However, it is possible to wash the CO2 out of the exhaust gases from these processes and either store it permanently underground or make it available to the chemical industry as a raw material. Experts speak of Carbon Capture Storage (CCS) or Carbon Capture Utilization (CCU). A liquid in the form of small droplets is sprayed into the flue gas, to which the carbon dioxide binds. At a higher temperature, the CO2 can be separated from the liquid, liquefied and transported away.

The technology has been known for decades, but is still rarely used worldwide. In Norway, CO2 has been captured from industrial processes for more than twenty years and stored permanently beneath the seabed at a depth of three to four kilometers. There has already been criticism here. Above all, gas emissions were feared. But the prevailing opinion among experts is that the procedure is safe. Especially since the CO2 is mineralized in the appropriate environment and thus permanently bound.

Storage of CO2 is still prohibited in Germany

In Germany, injecting CO2 into the underground was banned by law in 2012 – apart from small amounts for research purposes. There were massive protests among the population against planned CO2 repositories. That’s why HeidelbergCement – one of the world’s largest cement manufacturers – is currently building a factory in Norway where the captured CO2 can be stored underground directly on site. Capturing and storing CO2 is associated with costs, but rising prices for CO2 emission certificates will pay off the investment in the medium term.

No CO2 capture for wastethermal power plants

The situation is different when it comes to waste incineration. The recovery of CO2 from the filter liquid takes place at high temperatures. This process can use the entire heating capacity of the power plant. This heating energy is then no longer available to the district heating network. Households would have to switch to ecologically less favorable heating options, which calls the entire measure into question, explains Frank Schumann, managing director of the residual waste cogeneration plant association, which is responsible for waste disposal safety for more than a million people in the greater Stuttgart area.

If you then had to transport the carbon dioxide to Norway and store it there for a lot of money, the garbage fees for citizens would be unreasonably high. And so there are no signs of CO2 capture and storage being used by waste incinerators in Germany.

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