ESBJERG, Denmark (AFP) — In the North Sea where Denmark once drilled for oil, imported European carbon dioxide (CO2) will soon be buried under the seabed in a carbon capture and storage (CCS) project nearing completion.

CCS technology is one of the tools approved by the United Nations’ Intergovernmental Panel on Climate Change and the International Energy Agency to curb global warming, especially for reducing the CO2 footprint of industries like cement and steel that are difficult to decarbonize. But the technology is complex and costly.

Led by British chemicals giant Ineos, the Greensand project 170 kilometers off the Danish coast consists of a deep, empty reservoir beneath a small, wind-swept oil platform in the North Sea.

In its first phase due to begin in the next few months, Greensand is slated to store 400,000 tons of CO2 per year.

It’s “a very good opportunity to reverse the process: instead of extracting oil, we can now inject CO2 into the ground,” Mads Gade, Ineos’ head of European operations, told AFP.

Liquefied CO2 sourced mainly from biomass power plants will be shipped from Europe via the Esbjerg terminal in southwestern Denmark to the Nini platform above an empty oil reservoir, into which it will be injected.