Global metal flows in the renewable energy transition: Exploring the effects of substitutes, technological mix and development

Highlights: • Metal demand up to 2060 in a renewable energy system is analysed. • Different technological mixes, substitutes and learning effects are analysed. • Current metal reserves were sufficient to enable renewable production and end use. • Increased lithium demand would be the main challenge. - Abstract: This study analysed demand for 12 metals in global climate mitigation scenarios up to 2060 and quantified the impacts on demand of different assumptions on improvements and technological mix. Annual and cumulative demands were compared with reserves and current mining rates. The study results showed that reserves are sufficient to support the total level of solar power, wind power and electric motors. Insufficient reserves may very well constrain certain sub-technologies, but substitutes that take the role of 'back-stop' technologies can be used instead. The exception is batteries, since lithium battery chemistries and reserves were incompatible with the scenarios analysed. Batteries of moderate size, lithium-free chemistry or reserve expansion would make the transition feasible. Choice of sub-technology (e.g. type of solar PV) had a decisive impact on demand for certain metals. Perceptions that many metals are critical and scarce for renewable energy transitions appear exaggerated if a dynamic view on technological development is adopted. Policy-relevant conclusions can be drawn from this, regarding e.g. the benefits of technological diversity, increasing metal intensity, recycling and integrating infrastructure and energy policies (e.g. fast chargers).