Overline: New technologies use carbon dioxide emissions
Headline: CO₂: From Waste to Feedstock

Economic activities and consumer behaviour in developed countries are currently based mainly on the use of fossil-based raw materials, whose emissions are largely responsible for anthropogenic climate change. In efforts to reduce human effects on the climate, the avoidance of carbon dioxide (CO2) emissions is and remains the most important measure. But viewing the greenhouse gas CO2 as a source of carbon can also make sense. In recent years scientists have been investigating so-called Carbon Capture and Utilisation (CCU) technologies. The aim of these technologies is to re-cycle the CO2 contained in emissions as a feedstock for industrial processes. This captured CO2 could replace fossil-based carbon as a component of materials and energy carriers, thereby creating a carbon cycle.

Nature knows no waste. And even CO2 is not necessarily a waste product: photosynthesis continually transforms it in a natural cycle. But ever since the Industrial Revolution, humans have been throwing the carbon cycle off balance. Technologies aimed at recycling CO2 now present us with the possibility of imitating this natural cycle. For this to happen, the stable and low-energy CO2 molecule has to be incorporated into a higher-value product. This is made possible by developing new chemical processes, for example, in catalysis research. The challenge here lies in finding energy-efficient processes.

That is why many countries have established research programmes to study the use of CO2. In Germany, the BMBF is currently funding 33 joint projects with a total budget in excess of 100 million euro. There are already initial signs of success: countless pilot and demonstration units exist across the globe. In Germany, for example, polyols as a base material of foams are being produced in Dormagen and synthetic fuels are being manufactured in Werlte and Dresden. The first CO2-based products and fuels have entered the markets. CO2 for industrial use can be sourced at large or small industrial plants or power plants and possible finished products include plastics and liquid or gaseous fuels (see illustration or Fact Sheet).

Ecological and economic effects of using CO2

Unlike Carbon Capture and Storage (CCS) technologies, which aim to store large quantities of CO2 underground in the long term, in the case of CCU technologies, only a small amount of CO2 can be used in industrial processes. According to estimates, around 180 million tons of CO2 could be used annually in materials, while about ten times that amount could be used to produce fuels. That would amount to about five per cent of anthropogenic greenhouse gas emissions. Yet the CO2 used in these products is only bound for the duration of their lifetimes. So it is returned to the atmosphere with a delay or else captured once again from emissions after combustion processes. Thus the ecological advantage of CO2 utilisation lies more in the substitution of fossil-based raw materials than it does in the function of a CO2 sink. And the required process energy can be optimised by developing more efficient CCU technologies, for example in chemical catalysis.

The precise environmental footprint of a new production process can be gauged using the Life Cycle Assessment (LCA). Early research findings suggest that some CO2-based products can lead to a saving of several tons of CO2 per ton of CO2 used by comparison with conventional products. This is due to the substitution of fossil-based raw materials with a high carbon footprint. However, there are still uncertainties regarding the potential harmful environmental effects of CO2 capture. Among other things, the extent to which amine-based capture processes can increase ozone levels in the atmosphere or encourage the formation of carcinogenic substances needs to be investigated.

Moreover, even at times when there is a fall in the price of raw materials and energy, using CO2 can make good economic sense. The extent to which this is the case depends on the efficiency of each individual newly developed technology. Positive effects on the overall economy are also possible, but still need to be evaluated. Thanks to the progress of the Energiewende and greater incentives to reduce CO2 emissions instigated at political level, research on CCU technologies could receive a further boost.

Interdisciplinary research on CO2 utilisation at the IASS

Even if today’s technologies are generally at an early stage of development, it is still necessary to analyse and assess the potentials and risks of CO2 utilisation for the whole of society. This will enable us to address important risks early on and exploit sustainable potentials to the greatest extent possible as these technologies continue to develop. This is why our interdisciplinary research team is focusing on the following questions from the perspectives of the natural sciences, engineering, economics and communications studies.

  • What are the overall societal benefits and risks of utilising CO2?
  • What economic potential do these technologies have and what role does the price of CO2 play?
  • What possible environmental risks and unintended side effects do CCU technologies entail?
  • What role can emerging CCU technologies play in the context of the transformation of energy systems, in particular the German Energiewende?
  • How are CCU technologies currently perceived in the media and the public sphere and how could they be communicated in future?
  • What political instruments should support the further development of CCU technologies?

We take a transdisciplinary approach to our research and are in regular communication with partners from industry, politics and civil society. Within the institute, we collaborate with the Transdisciplinary Panel on Energy Change (TPEC) and the Climate Engineering research group.