Emission Assessment of Electricity: Mix vs. Marginal Power Plant Method

CO
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emissions associated with electricity can be quantified using either the electricity mix or the marginal power plant method. While the electricity mix method represents an attributional approach, the marginal power plant method reflects a consequential perspective focusing on system changes. Due to the mechanisms of the German-Austrian electricity market the two methods largely result in opposing hourly emission factors for electricity. Thus, the choice of method has a strong influence not only on the emission assessment of electricity, but also on the development of emission-optimized load management strategies. While the mix method describes the current energy system and reflects the share of renewables, the marginal method indicates times of renewable surplus electricity and quantifies marginal system effects. For the assessment of a large-scale introduction of efficiency and electrification measures as well as load management strategies a more comprehensive assessment approach based on energy system simulations is required.