Coal will remain an important source of energy for many decades before we can truly base the world’s energy supplies on renewable energy. Until then, we have enough coal, but the problem is that burning coal results in CO2 emissions into the atmosphere. That makes it necessary for us to develop and implement effective CCS technology (carbon capture and storage).
The idea behind CCS is to capture CO2 from power-plant exhaust gases and store it deep underground – where it originally came from as oil or coal. In other words, we are looking to introduce a technology to tackle the climate issue similar to the solution we developed for acidification and deforestation. Back then, sulphur was removed from the emissions.
Several CO2 cleaning technologies
Over the last decade, research has focused on various ways of avoiding CO2 emissions.
Technically, it is possible to capture CO2, but it is still a very energy-intensive process. Today, power plants use 5% of the energy they produce to clean for sulphur and
NOx. Cleaning for CO2 as well using the existing technologies would require 15%-25% of the energy produced.
That is why research currently centres on developing processes that are a lot less energy-intensive.
Lots of capacity for storing CO2
Denmark offers underground storage capacity for several hundred years of CO2 generation. In other words, we have the storage capacity and we are sure that it will stay down there.
For example, CO2 can be stored in depleted oil fields. This has the extra benefit that we can actually enhance oil recovery from these fields. Oil fields are ideal for storing CO2, because oil and natural gas is held in natural traps that it cannot escape from. Similarly, the CO2 stored there will not be able to escape.
CO2 can also be stored in deep layers of sand upwardly sealed by impervious stratums of lime or clay. There are several ideal structures in Denmark’s geology meeting these requirements. Today, they are already being used to store natural gas.
When we create a storage site at DONG Energy, we will, of course, allow other energy producers to make use of it as well. We want our efforts to be good for the world, not just for DONG Energy.
Carbon dioxide storage is not dangerous
Storing CO2 is basically not any different from storing natural gas. On a global scale, there is good experience from storing natural gas, and there have been no accidents or similar events threatening people, animals or the environment.