Life cycle assessment of CO2 capturing from the flue gas of a waste incineration plant
bifa analyses CCS and CCU based on the greenhouse gas balance for the Augsburg waste incineration plant (Abfallverwertung Augsburg, AVA).
The waste incineration plant in Augsburg emits more than 235,000 t of CO2 annually, of which about 50 % is of biogenic origin. Against the background of the probable inclusion of these CO2 emissions in emissions trading, bifa has carried out life cycle assessments of various process variants and future scenarios for the AVA. This means that it is now possible to quantify the ecological costs and the ecological benefits of CO2 capturing either with storage or with utilisation.
Today, AVA generates electricity and heat through waste incineration. These are fed into the supply networks and thus replace electricity and heat generation from other sources, most of which are still based on fossil fuels today. The current mode of operation was compared with CO2 absorption, transport of the CO2 to a depleted natural gas field and permanent storage there (CCS). In addition, the use of captured CO2 to produce methanol (CCU) together with hydrogen was also considered. The efforts required to achieve the climate targets will, on the one hand, promote the spread of CCS and CCU. On the other hand, they will significantly improve the impact assessment of CCS and CCU through increasingly climate-friendly energy production. In order to quantify these influences, the greenhouse gas balance (GHG balance) was also considered for two future scenarios.
Results of the study
The results show that in the case of waste incineration without CCS or CCU, the GHG balance of the AVA will deteriorate in the future, at least as long as significant fossil GHG-relevant fractions are still found in the waste. The reasons for this are the declining GHG credits from feeding the generated electricity and heat into the grid.
CCS, on the other hand, offers the potential to significantly improve the climate balance for AVA and even contribute to climate relief in the future. The storage of CO2 from the biogenic carbon in the waste is responsible for this particular opportunity to relieve the climate.
CCU, on the other hand, significantly increases GHG pollution today and also in the medium term. As long as the significant amount of electricity needed to produce hydrogen cannot yet be obtained from renewable sources. Only when the latter case is valid in climate-neutral Germany in 2045 the GHG balance is expected to be similar to a no-action scenario, i.e. without any CO2 capturing.