Although utilisation of CO2 is not new -it is used for Enhanced Oil Recovery in the US since the 1970s- it is only until recently that the development of applications took a flight. There are many different forms and ways to utilise CO2, which is explained in this section.
There are different reasons why carbon dioxide utilization processes are of interest. First it helps reducing net emissions of carbon dioxide to the atmosphere and/or other environmental impacts. Furthermore, CO2 utilization offers alternatives for resources such as oil for the production of fuels and polymers. This can also lead to other benefits, such as reducing energy dependency by producing energy locally.
Different forms of CO2 utilization
Utilisation of CO2 comprises many different processes and the concept is poorly defined. In its most simple form, CO2 utilisation can be defined as any process making use of carbon dioxide. One can categorise CO2 utilisation options into two groups: CO2 utilisation without conversion of the carbon dioxide and CO2 utilisation with the conversion of carbon dioxide.
Utilization – without conversion of carbon dioxide
Utilization – with conversion of carbon dioxide
Before utilization, CO2 can be biological or chemical converted and then used in a product. Depending on the type and usage of this product, the CO2 will be stored for a short or long term. In biological conversion, CO2 is used to grow plants and trees. In combination with reforestation, CO2 utilization will lead to a long-term CO2 storage. When the CO2 is used for algae production to produce chemicals or fuels, the utilization of CO2 is considered short term storage. Also for chemical conversion short and long-term storage opportunities are possible: production of methanol, polymers, etc. is considered short term use, while mineralisation for building materials and olivine weathering are seen as long term storage.
Motivation to stimulate CCU in Europe
From the section above can be concluded that there are good reasons to develop CO2 utilisation processes to reduce emissions or other environmental impacts, improve security of energy supply or develop cost-competitive processes. In practice there are numerous of different technologies that utilise in one way or another carbon (dioxide). The impact of the above-mentioned themes for each process is very different and often very difficult to determine to a reasonable level.
CO2 utilisation may offer competitive processes for the European industry, especially in areas where the EU is traditionally strong, like the chemical industry. It may reduce the reliance on fossil fuels and its associated carbon. However, the potential of cost-competitive industrial use of CO2 is limited. In the period that worldwide large amounts of fossil fuels are used including associated production of CO2, storage of carbon dioxide would be unavoidable at least to meet stringent climate targets. CO2 utilisation could be a good stepping stone to accelerate CCS infrastructure as it provides the opportunity to get experience and improve CO2 capture process while revenues may be earned in the utilisation process to cover the costs. In expanding the network and following the learning curve, costs for CCS go down and become competitive with alternative CO2 emission reduction options.