Life cycle assessment for CO2 capture from the flue gas of a waste incineration plant
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 state in figures what the ecological costs are compared to the ecological benefits of CO2 capture with storage or with utilisation.
Today, the 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 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 together with hydrogen to produce methanol (CCU) 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 assessment of CCS and CCU through increasingly climate-friendly energy production. In order to assess 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. This is the case as long as the considerable amount of electricity needed to produce hydrogen cannot be obtained from renewable sources. Only when this should be the case in climate-neutral Germany in 2045 will there be a GHG balance similar to no action, i.e. no CO2 capture.
CCU erhöht dagegen heute und auch mittelfristig die THG-Belastung deutlich. Dies ist der Fall, solange die erhebliche Strommenge, die zur Wasserstofferzeugung benötigt wird, nicht aus regenerativen Quellen bezogen werden kann. Erst wenn dies im klimaneutralen Deutschland 2045 der Fall sein sollte, wird sich eine THG-Bilanz ähnlich dem Nicht-Handeln, also dem Verzicht auf die CO2-Abscheidung, einstellen.