All CO2 molecules are equal, but some CO2 molecules are more equal than others

Sammanfattning: This thesis deals with some challenges related to the mitigation of climate change and the overall aim is to present and assess different possibilities for the mitigation of climate change by: • Suggesting some measures with a potential to abate net greenhouse gas (GHG) emissions, • Discussing ideas for how decision-makers could tackle some of the encountered obstacles linked to these measures, and • Pointing at some problems with the current Kyoto framework and suggesting modifications of it. The quantification of the net CO2 effect from a specific project, frequently referred to as emissions accounting, is an important tool to evaluate projects and strategies for mitigating climate change. This thesis discusses different emissions accounting methods. It is concluded that no single method ought to be used for generalisation purposes, as many factors may affect the real outcome for different projects. The estimated outcome is extremely dependent on the method chosen and, thus, the suggested approach is to apply a broader perspective than the use of a particular method for strategic decisions. The risk of losing the integrity of the Kyoto Protocol when over-simplified emissions accounting methods are applied for the quantification of emission credits that can be obtained by a country with binding emissions targets for projects executed in a country without binding emission targets is also discussed. Driving forces and obstacles with regard to energy-related co-operations between industries and district heating companies have been studied since they may potentially reduce net GHG emissions. The main conclusion is that favourable techno-economic circumstances are not sufficient for the implementation of a co-operation; other factors like people with the true ambition to co-operate are also necessary. How oxy-fuel combustion for CO2 capture and storage (CCS) purposes may be much more efficiently utilised together with some industrial processes than with power production processes is also discussed. As cost efficiency is relevant for the Kyoto framework, this thesis suggests that CCS performed on CO2 from biomass should be allowed to play on a level playing field with CCS from fossil sources, as the outcome for the atmosphere is independent of the origin of the CO2.