Carbon Capture: Sense or Nonsense?

The atmospheric carbon dioxide concentration and the global land-water temperature increased steadily during the last decades. There is little doubt that the temperature rise is mainly caused by the growing carbon dioxide emissions. Dramatic consequences for life on earth are foreseen, if the temperature rise continues at the same rate for the next 50 years. Therefore hundreds of millions of dollars have been invested during the last 10 years for the development of technologies to capture carbon dioxide from air and from electrical power plants exhaust gas. Chemical solvents like amines and dissolved amino acids or high-flux, medium selective polymeric or mixed matrix membranes are candidates for carbon dioxide separation.

Using basic thermodynamics this lecture will show that many claims made about carbon capture are highly questionable. In spite of many promises carbon capture from air will not help to slow down the alarming increase of atmospheric carbon dioxide concentration. Post combustion carbon capture from coal-fired power plants consumes a significant fraction of the power plants energy. The energy penalty might approach 40% and Carbon Capture and Storage (CCS) is often used just as an alibi to continue the operation of coal-fired power plants. Recent membrane-based carbon capture activities like the European M4CO2 project will be commented. Many see CCS as boondoggle, an activity that is pointless, but gives the appearance of having value. Meaningful alternatives to CCS are energy conservation, investment in renewables and "green engineering" (replacement of traditional separation and reaction designs by energy saving schemes).