To limit global warming to two degrees Celsius, some CO2 actually might have to be extracted from the atmosphere. “If one wants to reach the climate targets set by the state of Brandenburg, by Germany, and the European Union, some CO2 even has to be removed from the air in the long run,” says Schellnhuber. “One option for this would be the combination of power plants fired with biomass with CCS. Plants take CO2 from the atmosphere while growing; this gets released again when that biomass gets burnt – and eventually could be put underground.”
Naturally, it is the details that matter: no forests should be cut down to grow bioenergy plants, and for the underground storage of CO2 the geological conditions have to be right, Schellnhuber stresses. “But that is exactly why research on these details is needed.”
There is more at stake than just CCS. “Many people are concerned about the new technologies emerging as the energy system changes direction, and that is understandable,” Schellnhuber says. “However, we should get away from demonizing all these technologies.” This is also true for CCS which should be seen as a part of integrated smart systems.
“Extending the notion of CCS to CCX makes a catchword for the future,” says Schellnhuber. “The X can stand for storage as well as usage of CO2, for instance when windpower is transformed to gas.” Combining CO2 with hydrogen creates a utility gas – which is one option for the much needed storage of the fluctuating power generated by wind and sun.
