EXERGY ANALYSIS OF THE PRODUCTION OF SELECTED CHEMICALS IN THE ENERGY TRANSITION SCENARIO

Chemical reactants, mainly acids and bases – e.g. sulfuric acid, hydrochloric acid, sodium carbonate, and others – are a key part of mining and industrial processes. This means that their production – from a life-cycle perspective – plays a crucial role in the environmental impacts and exergy costs of the production of metals and other materials. In fact, up to 3 % of all global anthropogenic greenhouse gas emissions can be traced back to the chemical industry. The production of chemicals consumes a large amount of energy, which is trying to be decarbonized. However, changing the energy from fossil fuels to electricity means that the chemical industry will be indirectly more dependent on metals, as renewable energy is more materials-intensive. The production of these metals, as explained before, is, in turn, dependent on chemicals. This situation poses a dynamic feedback loop whose effects propagate as the energy and electricity mix become greener and fossil fuels diminish their importance. In this work, we use a dynamic life-cycle assessment approach to study how different scenarios of the energy transition will affect the renewable and non-renewable exergy costs and environmental impacts of the two most used inorganic chemicals – sulphuric acid and sodium hydroxide – and how these exergy costs affect the exergy costs of metals production. Furthermore, we discuss opportunities to achieve higher energy and exergy efficiencies. This work is part of the great model of the exergy analysis of the economy developed by our research group.