Читать книгу Mineral Resource Economics 1 - Florian Fizaine, Xavier Galiegue - Страница 12

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 of wind power, also significant, remains rather concentrated on major metals (iron, copper, manganese, nickel, chromium). As things stand, other forms of electricity production consume smaller quantities of metals. This study concludes that the shift to a “clean” mix, as described in the International Energy Agency’s World Energy Outlook, should, at a constant amount of electricity produced, increase the electrical system’s consumption of iron by 23%, copper by 242%, silver by 633% and tellurium by a factor of 10. Of course, these results must be put into perspective, particularly because we do not take into account the importance of the production of these metals and the potential for production increases, since the current consumption of the electrical system plays a minor role in the consumption of most metals.

Of course, these studies also bring with them other areas of shadow, on the one hand because they often reason in isolation; that is, they consider only the material necessary for the manufacture of the wind turbine but not necessarily the mining waste brought by the extraction of the neodymium incorporated in the permanent magnets of the latter (except for this last study). On the other hand, the environment is often excluded from the electrical production system. So, what about the material footprint of the connection of offshore wind turbines and back-up, smart-grid or storage solutions necessary for intermittent renewable energies to perfectly replace fossil fuels? In the same vein, these studies often ignore the intra-technological complexity of power generation systems by considering only large groups (onshore wind, offshore wind, photovoltaics, etc.), whereas there is a significant intratechnological variability in the material footprint, especially for certain specific metals. It may be added that while the share of electricity in the energy mix is expected to increase in the future, metals used in the energy sector are not limited to the production of electricity alone, but also concern other sectors of energy production or use, which themselves consume metals (LEDs, batteries, electric vehicles, etc.). Finally, reasoning in partial equilibrium, ignoring other sectors, induces large blind spots, for example by ignoring the conflicts of use between the digital and energy sectors for metals such as cobalt and lithium (electrochemical batteries) and also indium and gallium (flat screens, printed circuit boards and thin-film PVs).

However, more than these studies, the awareness of the media, the public and decision-makers has probably taken place through the epiphenomenon of the rare earth crisis (used in many offshore wind turbines). The soaring price of lanthanides quickly triggered deep concerns among industrialists and the general public. And what if, beyond the geopolitical crisis, our world was to enter a mining impasse, sending the boom in renewable energies halfway into limbo for lack of metals?

Moreover, the many reports and photos of workers in artisanal cobalt mines in the Democratic Republic of Congo and in rare earth mines in China remind us that environmental sustainability in industrialized countries is meaningless if it is not also part of a socially just and economically secure support for all citizens of the world.

Figure I.1. Material footprint of various power generation production systems (source: data from Boubault (2018)). For a color version of this figure, see www.iste.co.uk/fizaine/mineral1.zip

Figure I.2. Metal footprint per kWh by type of power generation system (source: data from Boubault (2018))

Figure I.3. Share of metal footprint of the electricity sector by power generation system (source: data from Boubault (2018)). For a color version of this figure, see www.iste.co.uk/fizaine/mineral1.zip

Although a number of technological impasses have been identified and many points of tension on particular resources must be thwarted with these insights, the realization has nevertheless opened up a lot of thinking on all fronts.