Capturing and storing CO₂Considerable space in sandstone

The microscopic image (left) shows just how porous sandstone is. The pore space is coloured blue. This is where the CO₂ can be stored. 500 µm is the equivalent to half a millimetre. To the right is a close-up image of the sandstone that occurs as a saltwater-bearing rock stratum at a depth of one thousand metres. As saline aquifers, these storage areas have enough capacity to store the CO₂ produced from all fossil-fuelled power plants in Germany for more than twenty years.