Carbon storage

Al-Shaheen Ad oil rig, Qatar (25°30' N – 51°30' E). Gas flaring is used to burn off natural gases in oil deposits because exploiting them is not profitable. Every year, flares waste 150 billion m3 of gas. This is the equivalent of 390 million tons of greenhouse gas or 2 % of the total amount of emitted greenhouse gas. © Yann Arthus-Bertrand

What if we sent carbon back from where/ WHENCE it came, underground? The idea might seem odd but capturing and storing CO2 is a technique that already exists. It could make our emissions decrease by 15 to 55%!

For ten years, the Sleipner offshore platform, off the coast of Norway, has been using this process. It recuperates CO2 from the exploitation of natural gas and puts it back into permeable rocks about 1000 metres below sea level. About 1 million tons of CO2 are « neutralised » like this every year. There are other installations like this that are more or less at the experimental stage in Denmark, Algeria and Canada amongst others.

It is a complex process. To start with, the carbon must be separated from other gases. This step requires heavy equipment and therefore only applies to industrial sites which emit large amounts of CO2, like electric power plants. Then, the gas has to be transferred into a geological reservoir. This can simply be an empty oil or gas deposit.

The gas must not escape. This would of course nullify the efforts that have been made as well as endanger populations. Indeed, even if CO2 is not toxic, it can asphyxiate living things. This happened in Cameroun in 1986. Lake Nyos which stored CO2 naturally released a kilometre cube of it after an eruption. Over a thousand people died instantly. Landfill sites must therefore be chosen carefully and constantly monitored.

All these reasons explain why carbon storage is expensive. It is only profitable if the price of oil exceeds a certain amount or if an international CO2 emissions market develops and the ton of CO2 reaches a certain amount. In any case, this will mean an increase in the price of energy.