Resource Impacts of Fully Renewable Energy Systems: The Case of Metals

The deployment of a global renewable energy system has far-reaching implications, most importantly in terms of decarbonization of the energy system. Yet, shifting away from fossil fuels raises new resource questions, in particular the depletion of metals for the manufacturing and maintenance of renewable energy technologies. In this chapter, the resource depletion impacts of five fully, or close to fully, renewable energy scenarios to 2050 are evaluated through life cycle impact assessment. Technological scenarios are simulated for renewable energy sources, including battery energy storage for intermittent renewables, namely solar and wind. As the demand for renewable energy technologies is essentially additional, recycling is expected to play a marginal role. The resource depletion impacts vary significantly across scenarios and much less across assessment methods, which shows the robustness of the results. The renewable energy technology mixes play a central role in these resource impacts, as those scenarios with high shares of biomass fare better than those with high shares of electricity generation technologies. The impact of battery energy storage also shows up high and changes the ranking of the scenarios. However, the large-scale deployment of renewable energy technologies will not deplete metal resources but might make a significant dent in the supply of cadmium, cobalt, lithium and nickel. Moreover, the anthropogenic stocks of those metals and others may not be sufficient for circular economy strategies such as reuse, remanufacture and recycle.