and thus withdrew a little more from the rhythm imposed by the biosphere.
This mastery of a new form of energy from a more abundant and concentrated stock than biomass, accompanied by the development of knowledge (physics and chemistry), gave rise to a new surge in the production/consumption of mineral resources. For example, the production of copper rose from 216,500 tons per year in 1800 (about the level of the Roman period) to more than 500 kt per year in 1900 (Hong et al. 1996). This century also marked the discovery of new elements that expanded the seven metals known since Antiquity. Finally, the generalization of industrialization and of the Western way of life spread throughout the world from the contemporary period (since 1945), leading to another leap in the consumption of already existing mineral resources, as well as to a surge in the production of small metals that had hitherto remained confined to the role of curiosities. However, this last period, although recent, brought with it a new and deep mark of humans in their environment. The latter itself became the primary force of change for the geosphere, the biosphere and the climate. Is history moving into a new era – the Anthropocene (Steffen et al. 2015)? While the opening of a new era is still under debate, it is clear that a look back leads us to believe that each time humans free themselves a little more from the constraints and temporalities that their environment places on them, they do so by making more intense use of mineral resources.
Beyond the past, mineral resources also shape the present. If the climate crisis remains, at first glance, regularly associated with an increasing use of fossil resources (coal, gas and oil), a more seasoned analysis, like that of historian V. Smil (2013), shows that a great part of this energy is dedicated to the extraction, production and provision of material resources for the economy. Thus, according to his book, 20% of the world’s primary energy is used for the production of materials, including 13% for mineral resources alone (10% for metals and 3% for construction materials), which is roughly the size of the United States in the world’s primary energy consumption. This major role of mineral resources in energy consumption is closely related to their environmental impact in terms of greenhouse gases (GHGs), insofar as the energy used remains predominantly carbon-based (Mudd 2010; Northey et al. 2013). Our relationship with mineral resources is, therefore, not unrelated to the current climate crisis and other environmental issues. Indeed, the latest UNEP report (2019) indicates that the predominance of metals in the environmental impacts of natural resources. Thus, metals account for 18% of the impacts in terms of greenhouse gases related to resources and 39% of the effects of particles on health and the environment. Other non-metallic mineral materials, although representing the bulk of the mass and experiencing the strongest growth, generate less environmental stress on a global scale (less than 2% of total resources), though there are exceptions here again, particularly when looking at cases of local degradation. Most of the impact of this other important category of mineral resources today comes from their use in cement and fertilizer production.
While the role of mineral resources in today’s issues is not disputable, they also appear repeatedly in the utopias of our time, particularly that of the circular economy. Therefore, they are also a part of the future considered (fantasized?) by the new thinkers of sustainable development, alongside renewable resources (biomass and renewable energies). The words change according to the context: circular economy, symbiotic economy (Delannoy 2017) or blue economy (Pauli 2011). What these concepts have in common, however, is that they draw on the circularity present in natural ecosystems to ensure the sustainability of human economic systems. In this framework, mineral resources, because they are mostly recyclable, clearly fall within these concepts evoking the intrinsic regeneration of future economic systems. For example, stone paper, a mixture of calcium carbonate and high-density polyethylene is often advanced by Pauli as a practical example of the blue economy (Pauli 2011). This new form of paper does not use water and can theoretically be recycled ad infinitum (no pilot factory for the moment). The symbiotic economy is also inspired by industrial ecology, evoking the “Kalundborg Symbiosis”, the industrial eco-park of a Danish port city where the unwanted byproducts of some manufacturers become inputs for others. Here, again, mineral resources will play a key role as some future activities are expected to continue to mobilize capital, often through the use of metals and other non-metallic resources, as is the case with most mobility solutions, whether or not they fit into the economy of sharing or functionality.
Mineral resources have played a major role in many periods of human history and will certainly continue to accompany it in its development. Made use of in the fight against global warming, the energy transition and the switch to renewable energies are, nevertheless, raising new questions in the scientific community. Indeed, increasingly important evidence seems to confirm the existence of a growing relationship between the consumption of mineral resources and the development of renewable energy.
I.1. Should we fear a new mineral jump caused by the decarbonation of energy?
To our knowledge, the first study to have reported on this hypothesis is that of Lund (2007), a material intensity analysis of the different electric production technologies. Later, other general studies confirmed this hypothesis (Kleijn et al. 2011; Phihl et al. 2012; Ashby 2013; Elshkaki and Graedel 2013; Vidal et al. 2013). At the same time, other analyses have also raised the greater sensitivity of green energy to specific categories of mineral resources like rare metals (Yang 2009; Kleijn and Van der Voet 2010; Elshkaki and Graedel 2013; Fizaine 2013; Moss et al. 2013). Generally speaking, these scientists highlight the greater consumption of materials and metals caused by the use of green energy and also more broadly by decarbonated energy (we thus compare fossil fuels without CO2 capture and sequestration and fossil fuels with CO2 capture and sequestration). This means that, with constant electricity production, the shift towards a greener electricity mix should lead us to consume more metals (and mineral resources).
For example, the latest study to date, that of BRGM (Boubault 2018), sheds an interesting light on the material footprint of electricity production systems. Through a lifecycle analysis, and in contrast to previous studies, it shows that fossil fuel-based electricity production systems are more intensive in raw materials per kWh, on the one hand because they consume large amounts of fossil fuels and also because of the mining waste generated to access these fossil resources. Figure I.1 shows the material footprint of electrical systems in decreasing order of CO2 equivalent emissions. If we focus on the material footprint, the energy transition appears to be consistent with a policy of resource conservation. Coal is far ahead at more than 2,715 kg/kWh compared to only 0.036 kg/kWh for hydropower. Renewable energies continue to consume fossil fuels for their construction but in much smaller proportions than fossil fuel-based electrical systems. A more specific analysis of the metal footprint reveals a much less clear general pattern (Figure I.2). Here, geothermal energy, followed by wind and concentrated solar power, now appear to be the highest in metal consumption.
Conversely, other renewable energies, such as photovoltaic energy and biomass, and hydropower even more so, do as well as nuclear or fossil fuels. If we follow the results of this study, the metal footprint of the electrical system would not necessarily increase in case of decarbonation; it would all depend on the precise content of the energy transition and in particular the respective shares of each of the renewable energies. An even finer analysis by metal leads to even more disparate rankings (Figure I.3). Thus, Figure I.3 shows the share of metal consumption of the electrical system absorbed by each type of technology. Three main conclusions can be drawn from observing these results. Firstly, what is obvious is the significance of photovoltaics, which concentrates an important part of the consumption of several minor metals (tantalum, gallium, indium, strontium) and also of some major metals (aluminum, copper, zinc and lead). Secondly, nuclear power monopolizes a much more limited range of metals and also plays a major role (uranium, platinum, lithium, titanium oxide, chromium, nickel). Thirdly, the consumption
