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An exergy flow analysis of the energy transition

Abstract:

To keep the increase in global mean temperature from global warming to well below 2ºC above pre-industrial levels is a difficult challenge. In order to achieve this, the energy mix is essential and must be modified. The different projections that accomplish this goal agree that most of the sectors must depend on electricity and the electric sector must be based on renewable sources. However, renewable energy technologies are more mineral intensive than current energy sources. In this study the material requirements for the green technologies needed to meet the 2ºC target has been identified and assessed through the concept of exergy replacement costs, which is a novel measure that evaluates mineral resources as a function of their scarcity in the crust and the energy intensity to mine and refine them. Through this concept, one can evaluate and represent in Sankey diagrams, the exergy demand associated to the use of fuel and non-fuel minerals in the different technologies proposed for the new energy transition. As a result, we have obtained that the transition towards a low carbon economy will reduce the exergy consumption of non-renewable resources. However, there will be a shift from fossil fuels to mineral resources consumption because “green technologies” have a greater demand in minerals than conventional technologies.