MAC curves report costs of different abatement measures (per unit of CO2e abated) on the vertical axis and the GHG volumes abated (annual emission savings generated by adoption of the measure) on the horizontal axis, showing a schedule of abatement measures ordered by their specific costs per unit of CO2e abated estimated against what would be expected to happen in a ‘business as usual’ (BAU) baseline (Moran et al., 2011). In this analysis, MAC curves report therefore only the incremental costs with respect to BAU scenario. Moving along the graph from left to right worsen the cost-effectiveness of technology options since each ton of CO2e mitigated becomes more costly. It should be noted that some options may even show negative abatement costs (i.e. the adoption of such measures will increase profits, therefore showing a cost-saving technology opportunity). A ‘bottom-up’ MAC curve for a selected case study is built here according to the following steps: