The hype of clean and renewable energy projects generally makes bold claims about the benefits of these resources for a green, low-carbon economy. Correct, renewables such as solar, wind, waves, and geothermal are freely available. Still, the metals used to produce technologies such as wind turbines, solar panels, and electric cars are often overlooked. The truth? These materials are limited. For instance, essential for manufacturing are base and precious metals like copper, nickel, silver, neodymium, and other rare earth elements. A short supply of these metals may slow down the green transition. The caveats of today: most people probably assume they’re infinite in the low carbon economy. This article invites readers for a short tour of problems and opportunities.
Figure 1. Copper coils – Sourced from Unsplash
Base metals like copper, aluminum, and zinc are the backbone of future power generations [1], [2], especially important to curb carbon emissions. International Energy Agency (IEA) reported in 2021, not only the metal demands will be needed, but the amount will have to quadruple or even soar six times to today’s consumption in 2050 [3]. Indeed, the extraction implicates a large amount of energy, water, and toxic waste behind the operation.
Recycling can be a solution, given that metals have inherent recyclability in nature [4]. Reproducing metals from scrap waste already helps decrease resource burdens. Secondary copper from scrap goes directly to the refinery with no mining or smelter, making it possible to get new copper with smaller energy expenditures than the standard route. But this may not be enough for some reasons: Firstly, many metals have a long lifespan, particularly in building sectors. There are lag periods before we can repurpose metals from long-lasting buildings, at least not until demolition. Secondly, certain metals like nickel suffer a low level of recycling of around 50%—further deterring economic appetite when no decent policy supports are in place [5].
Another issue is the global trades of minerals from politically unstable regions and ecologically sensitive areas. Metal supply may experience abrupt shock if production stops and is linked with poor governance in fragile countries. Next to that problem is the competition with local resource vulnerability. For example, 65% of copper reserves should be mined in locations with high water risk [6].
Finding a reliable and sustainable way to satisfy growing metal demand is then a 21st-century challenge. Some propose the ideas of material mining from abandoned sites employing novel circular solutions: some examples include extraction, bioprocessing, to valorization. The others suggest the use of alternative methods to remediate mine waste using nature-based adsorber. The appearances of emerging alternatives show different perspectives and might offer less dependence on conventional metal mining [7].
As for takeaways, energy transitions will bring about environmental benefits and linked problems. Therefore, the supporters must take extra care when promoting new technologies as clean, flawless solutions. Though problems may arise, at the same time, this also provides a window of opportunity for redefining strategies.
The rapid energy shift towards net-zero 2050, with increasing reliance on metals, will come. Looking for a silver bullet to immediately realize this vision with a single solution is nearly impossible. But there is a promising outlook from interdisciplinary scientific bodies. We will be fortunate to see them, hopefully soon.
References
[1] R. Kleijn, E. van der Voet, G. J. Kramer, L. van Oers, and C. van der Giesen, “Metal requirements of low-carbon power generation,” Energy, vol. 36, no. 9, pp. 5640–5648, Sep. 2011.
[2] J. Lee et al., “Reviewing the material and metal security of low-carbon energy transitions,” Renewable and Sustainable Energy Reviews, vol. 124. Elsevier Ltd, p. 109789, 01-May-2020.
[3] IEA, “The Role of Critical Minerals in Clean Energy Transitions,” Paris, 2021.
[4] T. E. Graedel et al., “What do we know about metal recycling rates?,” J. Ind. Ecol., vol. 15, no. 3, pp. 355–366, Jun. 2011.
[5] B. K. Reck and T. E. Graedel, “Challenges in Metal Recycling,” Science (80-. )., vol. 337, no. 6095, pp. 690 LP – 695, Aug. 2012.
[6] R. K. Valenta, D. Kemp, J. R. Owen, G. D. Corder, and É. Lèbre, “Re-thinking complex orebodies: Consequences for the future world supply of copper,” J. Clean. Prod., vol. 220, pp. 816–826, 2019.
[7] EEA, “Emerging waste streams: Opportunities and challenges of the clean-energy transition from a circular economy perspective,” 2021. [Online]. Available: https://www.eea.europa.eu/publications/emerging-waste-streams-opportunities-and/emerging-waste-streams-opportunities-and. [Accessed: 14-Oct-2021].