Aug 03, 2021 at 18:03


Is it possible to capture and store CO2 from the atmosphere to keep it locked up underground? This is the objective of a project that wants to demonstrate the viability of this system in Spain, which would save the emission of 69 million tons of CO2 per year. Rather than capturing CO2 from the atmosphere, the aim is to sequester it in the same industrial facilities before it is emitted and store it in a safe place from which it cannot escape.

A multidisciplinary study with the participation of the Higher Council for Scientific Research (CSIC) and the University of Barcelona (UB) proposes to reinvigorate the development in Spain of carbon dioxide (CO2) capture and storage processes through a strategy called in English of hubs & clusters. A hub would be made up of a group of nearby CO2 emitters, while a cluster It would be made up of that group of sources, plus an appropriate underground store for their emissions.

The authors of the work, which has been published in the journal Applied Energy, estimate that with the adoption of this strategy Up to 69 million tons of CO2 per year could be stopped being emitted into the atmosphere, which is equivalent to 21% of Spain’s annual emissions.

“Spain faces the challenge of eliminating the more than 300 million tons of CO2 that it produces each year in order to mitigate the effects of climate change. In order to achieve the decarbonisation objectives subscribed to in the Paris Agreements, it is necessary, among other measures, to return CO2 to the subsoil through capture and storage operations ”, explains CSIC researcher Juan Alcalde, from Geosciences Barcelona (GEO3BCN-CSIC), author principal of the study.

This work, which analyzes the current state of development of CO2 capture and storage in Spain, has identified 15 concentrations of CO2 emitters with a production greater than two tons per year, as well as the possible geological storage structures that each of these emission cores could use.

«The objective of the study is twofold: on the one hand, to determine which are the best options to develop the capture and storage of CO2 in Spain; and, on the other, study its fit within the decarbonisation strategy in the short and medium term, ”says Alcalde.

The researchers’ strategy has consisted in identifying areas with high CO2 emissions produced by concentrations of massive emission sources (power plants, cement plants, steel mills, etc.) close to each other and that may form a hub or emissions core. Next, the most appropriate geological stores are located to which these nuclei can be connected, forming a network or cluster capture and storage, and ensuring that CO2 storage can be carried out efficiently, economically and safely.

The north of the Peninsula, the right place

The work considers that lhe northern area of ​​the Peninsula could be a priority region for the development of capture and storage processes of CO2, since it is where a large part of the emission nuclei identified are concentrated and where, in addition, possible geological structures have been found that offer the most ideal conditions for their permanent storage.

«This strategy allows linking different industrial agents so that they can share the effort of developing a complete CO2 capture and storage program, from the construction of the transport or storage network, to the processing of licenses and the negotiation of permits of exploitation. This way, Cluster users can reduce the costs and risks associated with these types of projects, in comparison with other individual initiatives ”, indicates Enrique Gómez Rivas, from the Faculty of Earth Sciences of the University of Barcelona.

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The study recalls that, although many countries have assigned carbon dioxide capture and storage technology an indispensable role in their national climate change mitigation plans, currently there are few commercial projects of this type, and most are located in countries with significant oil resources, such as the United States, Canada and Australia.

In other countries, such as the United Kingdom and Norway, where the development of CO2 capture and storage had been slowed in the past, it is being seen that, thanks to the core and network strategy, new projects are being developed and extending the use of this fundamental technology for the decarbonization of different industrial sectors that are difficult to transform.

Storing CO2 underground would reduce emissions in Spain by 21%

“The strategy we propose can also serve to awaken interest in CO2 capture and storage in countries with few oil resources, but with significant decarbonization needs, as is the case in Spain. In this sense, the implementation of a strategy of hubs & clusters Capture and Storage can provide the incentive to help unlock this key technology for a zero-emissions future, ”concludes Mayor.

Researchers from the Barcelona Institute of Geosciences, the University of Barcelona, ​​the Institute for Environmental Diagnosis and Water Studies (IDAEA-CSIC), the Mediterranean Institute for Advanced Studies (IMEDEA-CSIC-UIB), the Instituto Carbon Science and Technology (INCAR-CSIC), the Geological and Mining Institute of Spain (IGME-CSIC), Repsol and the University of Salamanca and Valladolid. It has also had the collaboration of researchers from the universities of Aalborg (Sweden), Edinburgh and Strathclyde (United Kingdom).

What is CO2 capture and storage?

The carbon capture and storage (CAC or CCS, by their name in English carbon capture and storage) is a technique to remove carbon dioxide from the atmosphere or, more properly, prevent it from reaching it. CCS consists of separating the CO2 emitted by industry and energy generation in combustion processes, and transported to a geological storage site to isolate it from the atmosphere in the long term.

The chemical process of capturing CO2 it is energy expensive and, according to experts, CO is also produced2 during it. This process, according to some critical voices, only delays the release of CO2, which cannot be stored indefinitely. However, this CO2 it could be used in multiple ways.

Although the CO2 has been injected into geological formations for various purposes, long-term storage of CO emissions2 it is a relatively new concept. The first commercial example is Weyburn in 2000. It is a pilot power production plant with integrated CCS, which has been operating since September 2008 at the Schwarze Pumpe thermal power plant in Vattenfall, in eastern Germany, with the aim of giving response to technological feasibility and economic efficiency.

CCS applied to a conventional modern power plant could reduce CO emissions2. The intergovernmental panel of scientists IPCC estimates that the potential savings of CCS could be between 10% to 55% of total carbon mitigation until 2100.

CO storage2 it is usually seen in deep geological formations, in deep water masses, or in the form of carbonate minerals. In the case of deep ocean storage, there is a risk of greatly increasing the problem of ocean acidification, a problem that also stems from excess carbon dioxide already present in the atmosphere and oceans.

Geological formations are currently considered the most plausible carbon sequestration sites.

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