Carbon Capture and Storage (CCS): Geological Storage

Huge amounts of carbon dioxide are continuously flowing into the atmosphere. The main reason for this is the burning of fossil fuels for energy, transportation, and power generation. We have less and less time to curb global warming and prevent uncontrolled climate change. Carbon Capture and Storage (CCS) could be useful in reducing emissions from the cement, concrete, chemical, and steel industries that are difficult to decarbonize. That only makes sense if these emissions can be stored. One possible way to do this would be to store them geologically. But with all the advantages of this type of CO2 storage, there also come problems.

Photo by Chris LeBoutillier on Unsplash

Repository selection

In principle, all large cavities in the earth’s crust that are impermeable and geologically stable so that they permanently keep the CO2 from escaping into the atmosphere can be used as repositories. Exploited crude oil or natural gas deposits, as well as saline aquifers, are considered possible CO2 repositories. Final storage in the deep sea is also possible.

The problems with this type of CCS

  • It consumes a lot of energy. The efficiency of the power plants deteriorates and the use of primary energy will increase by around 30 percent.
  • It is completely uncertain whether the carbon dioxide will remain trapped over thousands of years.
  • The compression of CO2 in rock layers could lead to cracks and earthquakes, through which it could escape again.
  • When the CO2 is pressed into geological formations, saltwater can be displaced from the rock pores and salts can get into the groundwater.
  • The equipment is expensive and together with the reduction in the efficiency of the power plants, the price of electricity will rise dramatically.

Benefits for the oil extractors

The storage of CO2 in such depleted reservoirs increases the pressure and thus drives the remaining oil upwards. This in turn enables higher production. In addition to CCS, this enables oil and gas companies to bind millions of tons of carbon dioxide.

Operation costs

Basically, the higher the CO2 concentration, the lower the costs of operation. This is also the reason why the separation directly from the air is the most cost-intensive variant. In comparison, the CO2 concentration in the exhaust gases of a coal-fired power plant is much higher.

Furthermore, it is only worthwhile if the CO2 prices are high. The economic attractiveness of CCS is directly linked to CO2 pricing and taxation. As long as it is cheaper to emit a ton of CO2 into the air than to store it, there is no economic incentive to build CCS systems without government subsidies. Increasing pricing and taxation of CO2 will boost CCS technology over the decade.

With CCS, we only treat the symptoms and not the cause of the problem

Many experts doubt that CO2 can be safely geologically deposited in the long term from escaping into the atmosphere. They fear slow outgassing of the deposits, so only a time delay in the increase in the CO2 concentration in the atmosphere is achieved. The high investment costs for CCS slow down or prevent much more sensible investments elsewhere.

Leave a Reply

%d bloggers like this: