Publication
Aluminium is one of the most widely used metals in the world, but its production is highly energy intensive and largely dependent on the use of fossil fuels. A typical secondary aluminium production facility consumes 700-1,000 kWh of natural gas and 200-400 kWh of electricity per tonne of rolled aluminium sheets. Thus, in order to meet its global environmental targets, the aluminium industry is shifting towards alternative energy resources. Potential decarbonization routes include the use of biomass to replace fossil fuel via thermal gasification, the integration of carbon abatement and utilization units, the use of power-togas and energy storage systems, direct electrification of aluminium furnaces, installation of waste heat recovery units for power generation, among other alternatives. While most of these technologies have lifetimes of around 20-25 years, decisions on their installation must be made today. Biomass, electricity, and natural gas costs can be subject to unpredictable market variations, whereas carbon prices are related to both environmental regulations and future market situation. In this context, future uncertainty in energy prices should be accounted for in today's decisionmaking. This work presents a systemic approach for assessing the effect of uncertain energy prices on the performance of different decarbonization routes for secondary aluminium production. To this end, a mixed integer linear programming (MILP) approach is used to generate a list of optimal system configurations under different economic conditions. Next, Monte-Carlo simulations are applied to predict representative price trends of commodities and to compute the resilience of each decarbonization scenario based on the likelihood of its occurrence under varying monetary circumstances. Results indicate that decarbonization pathways have a 50% probability to be cheaper than fossil-based CO2 emitting configurations. Moreover, the decarbonization option with the highest probability of being the economic best was the "Elec-bio" cluster which relies on a combination of electricity and biofuels to operate the plant's furnaces. A probability of 22-37% was estimated for realizing a cheaper "Elecbio" solution with respect to the natural gas driven base case over a lifetime of 25 years. Additionally, CO2 tax must not be the only economic incentive for emissions reduction but needs to be coupled with increased fossil fuel prices. Finally, this type of analysis allows decision makers to appreciate the potentials and risks associated with future decarbonization routes.