Understanding the role of coal in CO2 geological sequestration

Nowadays, to understand and, ultimately, to control climate changes, considered one of the main international current topics, it is imperative to reduce the CO₂ concentration in the atmosphere, otherwise the environmental, economic, and social consequences will be enormous. The reduction of CO₂ can be carried out using several options, each one having technological, environmental, and economic advantages and/or disadvantages. In this regard, the CO₂ geological sequestration represents itself as an alternative, which is technologically feasible in depleted conventional deposits of oil and natural gas, in abandoned collieries and/or deep unexploited coal seams, and in deep saline aquifers. In the current state of knowledge, the geological sequestration of CO₂ in Portugal, among all available options, will only be possible in existing coal abandoned mines, and deep saline aquifers.

In 2022, a highly interactive work was carried out by secondary school students from Dr. Machado de Matos School Grouping, and researchers from the Fernando Pessoa University – Porto, the main goal being to study and understand the role of coal, in layers in abandoned Portuguese mines, in CO₂ geological sequestration. For this purpose, the students were confronted with different data published in scientific journals and, ultimately, they tried to understand which coals and which Portuguese mines are more suitable to the CO₂ sequestration. Additionally further work will be developed regarding air quality of the place where the school is located.