December 12th of 2015 was a historical day for global environmental policy and for the sustainable future of the planet. In this day, 195 countries gathered in Paris, for the Climate Conference of the United Nations (COP21), agreed in reducing the Greenhouse Gas Emissions (GHG) to settle the global warming at 1.5 degrees above the planet’s temperature prior de industrial era.

Being the carbon dioxide (CO2), one of the gases that have contributed for the present scenario, it is necessary to invest and implement solutions that can mitigate the expansion and the presence of this gas in the atmosphere.

The CO2 Capture and Storage (called CCS from now on) presents itself as the most feasible solution to solve this situation. Its process consists in transferring the CO2emitted by electric power plants or industries to geological formations perfectly isolated. These geological formations can be oil or gas depleted fields or salty aquifers situated deep under the sea level, inland or offshore. The transport which is part of the process, when necessary, can be made through pipelines or by artificial reservoirs (like tanks) that carry the compressed CO2until the large storage reservoirs. Depending on the final destination, the CO2 can be stored forever as carbon dioxide or it can be turned in other products such as carbonates, being this last solution better than the first one in case of leakage.

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Figure 1 – CAC Process. Source: World Coal Institute

CO2 emissions result mainly from the burn of fossil fuels, used to generate electricity, or as fuel for transports, in housing needs or in industries. It also can be associated to natural resources extraction industries and from deforestation. Furthermore, according to the annual report from the European Commission, 64% of the 46 billion of tones of GHG emitted in 2010 are carbon dioxide arising from industrial processes and energy production.

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Figure 2 – GEE emissions proportion by source, in 2010. / European Comission

Geographically, there are countries like China and United States that, due to their size and industrial capacity, have the same CO2 emissions’ amount that all European Union. Along with India, these 4 entities are responsible of 61% of the world overall CO2emissions.

CCS technologies have an efficiency set between 90-95% due to their high maturity level in terms of technology, most because the standard-methods applied are already being used in oil and gas industries, as well as in other raw material extraction, so CCS can be replicated in large scale with a high level of success guaranteed.

Nowadays there are 15 large-scale projects operating around the world (see map) with the capacity to extract 28 millions of tons per year of CO2 from the Atmosphere. According to the Global CCS Institute, it’s expected that in 2017, other 7 projects start running, contributing for an additional extraction capacity of 12 million tons per year, which makes a total of 40 million tons that will be extracted from the Atmosphere every year. Those projects are proliferating globally, mainly in North America, Europe, Middle East, Australia and South Africa.

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Figure 3 – CAC Projects running or almost finished (2016). Source: Global CCS Institute

With all the information gathered until now and all the R&D around this area, it is possible to affirm that CCS technologies will see their operation costs reducing up to 30% in 2030. This will result in a lower energy consumption that is necessary for the extraction process from the power plants or industrial plants.

In Europe there are two operational CCS plants, both located at the Norwegian Coast and both with the purpose of avoiding emissions during the Natural Gas pre-combustion process. The oldest, the Spleiner,started operating in 1996 and is capable of extract yearly, almost 1 million tons of CO2. The other one, theSnøhvit, begun working in 2008 and captures around 0.7 million tons of CO2 per year. Aside of those, there are 5 more projects under development.

The techniques used in CCS plants are post-combustion, pre-combustion and oxifuel combustion. Among those known methods, the post-combustion is the most applied and is also the most feasible. The capture of CO2 during the pre-combustion of gas is largely used in the fertilizer industry and in hydrogen production. This method is also the one with the best efficiency.

The major constraints of CCS technologies lie on:

1.The consumption of extra primary energy that is necessary for capturing and transporting when associated to a power plant or an industrial plant. This increase of consumption, around 10 – 40%, according to the type of reservoir used and the distance between it and the plant, results in an increase of carbon dioxide emission and because of that, the CCS will never be able to capture the totality of the emissions produced. However, this technology can reduce the local CO2 emissions by 80 to 90%.

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Figure 5 – CAC efficiency | WMO and UNEP Carbon Dioxide and Storage

2. The choice of the storage reservoir. According to recent studies, the storage capacity is larger than the quantity of emissions to be captured; however, choosing the most suitable places involves a lot of tests and investigations, which results in extra costs, in order to dismiss any risk of leakage. This guarantee is extremely important to avoid environmental catastrophes that can occur from a sudden leakage of a high amount of concentrated CO2.

Given the current global situation, it would be important to integrate this tool in developing countries (non OCDE) that have their economy growing in order to avoid the major impacts that can arise from their industrial sector and need for consuming more energy.

Not being the perfect solution, CCS is an important (I even dare say crucial) step to achieve the goals set in Paris, so the legislation about this area must be revised and restructured in order to allow a fast and significant entry of this technology everywhere, even more, in countries with high levels of GHG emissions.

Jorge Seabra | Energy Consultant

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