Environmental assessment of amine-based carbon capture Scenario modelling with life cycle assessment (LCA)
This report contains a first attempt at introducing the environmental impacts associated with amines and derivatives in a life cycle assessment (LCA) of gas power production with carbon capture and comparing these with other environmental impacts associated with the production system. The report aims to identify data gaps and methodological challenges connected both to modelling toxicity of amines and derivatives and weighting of environmental impacts.
A scenario based modelling exercise was performed on a theoretical gas power plant with carbon capture, where emission levels of nitrosamines were varied between zero (gas power without CCS) to a worst case level (outside the probable range of actual carbon capture facilities). Because of extensive research and development in the areas of solvents and emissions from carbon capture facilities in the latter years, data used in the exercise may be outdated and results should therefore not be taken at face value.
The results from the exercise showed:
· According to UseTox®, emissions of nitrosamines are less important than emissions of formaldehyde with regard to toxicity related to operation of (i.e. both inputs to and outputs from) a carbon capture facility.
· If characterisation factors for emissions of metals are included, these outweigh all other toxic emissions in the study.
· None of the most recent weighting methods in LCA include characterisation factors for nitrosamines, and these are therefore not part of the environmental ranking.
These results shows that the EDecIDe project has an important role to play in developing LCA methodology useful for assessing the environmental performance of amine based carbon capture in particular and CCS in general.
The EDecIDe project will examine the toxicity models used in LCA in more detail, specifically UseTox. The applicability of the LCA compartment models and site specificity issues for a Norwegian/Arctic situation will be explored. This applies to the environmental compartments and dispersion models inherent in the LCA UseTox model. The characterisation factors (CFs) available in the current version of UseTox have several data gaps concerning relevant amine degradation products. Further work will be performed in order to calculate relevant CFs for missing degradation products. The relatively high importance of formaldehyde will also be scrutinised further.
The EDecIDe project is also studying the important dimensions to be included in a weighting method, in relation to CCS projects and Nordic or Arctic conditions in particular. As a result of this, future work will be adjusted to make sure relevant compounds and models are part of the weighting method.