Evaluation of a new technology for carbon dioxide submarine storage in glass capsules

The paper describes the energy and environmental evaluation of a new patented process for the storage of liquid carbon dioxide (CO2) in glass capsules on the deep seabed. This technology is proposed as a safe option to store CO2 captured from flue gas of industrial processes and power plants, as well as directly from the atmosphere, in order to overcome the obstacles that still today limit the commercial deployment of other CO2 storage techniques, such as the injection in saline aquifers. By keeping the liquid CO2 separated from the seawater, the technology might be an alternative that presents reduced risk associated with the storage in the marine environment when compared to other alternatives proposed in the past. A Life Cycle Assessment carried out with different combinations of the geographical and technological parameters showed an average impact of 0.10 tCO2eq per ton of stored CO2. The process with the highest impact was the capsule production, due mainly to the consumption of natural gas and electricity, as well as to calcination taking place during the production of glass. The availability of space in the seabed for submarine CO2 storage in capsules resulted a minor issue for the development of the technology. Close to most coastal areas where CO2 emission sources are located, large surfaces of the seabed at a suitable depth (between 1500 and 3000 m) and distance from the coast (<200 km) suitable for this technology are available, and particularly in the Mediterranean and Black seas. A preliminary cost analysis resulted in an average CO2 levelized cost of US$17 per ton of CO2 delivered by the external source.