Environmental Effects related to the operation of a CCS system

 

The operation of a CCS installation involves environmental effects associated with processes designed to make the CO2 stream fit for transport and storage underground. Such processes can, depending on the type of CCS technology, imply combustion, cleansing of gases, CO2 separation, compression and pumping. In the case of oxyfuel CCS, atmospheric nitrogen is removed, so that combustion can take place in an atmosphere of pure oxygen. The extra energy, these processes involve today equals around 40%. I.e. 40% more fuel is demanded for the power plant to deliver the same energy output with CCS as without CCS, which increases the environmental impacts in all stages of the process.

Environmental effects of the operation of CCS plants are predominantly linked to energy consumption and related emissions to the air. Such effects cannot be avoided in the CCS system and should therefore be fully included on the debit side of the environmental account in relation to CCS (discharge of waste, greenhouse gases, etc.).

Further on a significantly increased consumption of water will be a consequence of CCS. "NETL [DOE's National Energy Technology Laboratory] analyses indicate that efforts to capture 90 percent of carbon emissions by using current near-commercial carbon capture and storage (CCS) technologies on PC plants would more than double the amount of water consumed per unit of electricity generated." (STATEMENT OF CARL O. BAUER DIRECTOR NATIONAL ENERGY TECHNOLOGY LABORATORY, March 2009). Energy consumption and associated environmental impacts during the operational phase of CCS depend on the size of the CCS plant.