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| Fig. 1: Kilograms of Minerals Required per Electric Vehicle. (Source: G. Clark, after the IEA [1]) |
To limit global warming to less than 2°C, governments and the commercial sector alike are making aggressive changes across many industries. Within transportation, the electric vehicle (EV) market is booming as consumers ditch plain internal combustion engines in favour of battery-electric and plug-in-hybrid vehicles. This switch is sending serious ripples through mineral resource supply chains. EVs are over six times more mineral intensive (by mass) than conventional passenger vehicles. [1] While traditional cars require copper (Cu) and manganese (Mn) for wiring and metal processing, EV technology demands cobalt (Co), nickel (Ni), graphite, and lithium (Li) in addition to twice as much Cu and Mn than traditional vehicles. [1]
Terrestrial sites rich in any one of these resources are currently used to mine materials before sending them to be processed and finally distributed for manufacturing. With global electrification driving up mineral demand; in addition to terrestrial sites, the prospect of extracting these resources from the seabed has suddenly gained economic attention. A large suppply of important minerals have been known to be found at the bottom of the ocean, from Cu for electricity production and distribution, Ni, Co, and silver (Ag) for electronic batteries, Mn and Zinc (Zn) for steel and iron processing, and tin (Sn) for solder in technology industries. [2] In fact, the mineral reserves on the ocean floor are so abundant that the United States Geological Survey recently predicted that seafloor mining could provide up to 45% of global mineral needs by 2065 - if a petroleum-production-like trend were followed. [3]
In the case of nickel (Ni), cobalt (Co), and manganese (Mn), it has been estimated that in a single zone of the ocean floor contains more of these minerals than in all known terrestrial reserves. [4] This seabed region is called the Clarion-Clipperton Zone (CCZ). It stretches roughly 4.5 million square kilometres between Mexico and Hawaii, and is about as wide as the lower 48 states. These Ni, Mn and Co metals are critical for EV manufacturing. What is unique about these seafloor resources is that they can all be found inside one, potato-like mineral deposit called a polymetallic nodule. Mining polymetallic nodules in the CCZ has thus received extra commercial attention by allowing an entity to explore collapsing two to three separate mining operations into one.
Polymetallic nodules (PMNs) are concentrated at depths of 3500-6000 meters in regions of the CCZ where low sedimentation rates allow minerals in the water column to precipitate out and grow around a solid seed substrate, layer by layer, at very slow rates on the order of 1-2 mm every million years. While there are other mineral deposits on the seafloor, none are known to be as concentrated as the nodules in the CCZ. This region of seafloor therefore lies at the center of a potential new mining industry. [1]
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| Fig. 2: Annual global EV demand predictions. [6,7] (Source: G. Clark) |
This new frontier for telluric mineral extraction begs the question, if mined, just how far would the seabed's resources carry anthropogenic material demands into the future. This question will be explored by analyzing the rate of cobalt extraction needed to meet electric vehicle demand over the next two decades. Using this rate of cobalt demand, the longevity of a potential cobalt source like the CCZ will be estimated along with the rate at which the seafloor ecosystem would be disrupted if seabed mining were to occur.
The focus is placed on cobalt because this metal is at the center of a severely complex and delicate resource dilemma. Cobalt plays a crucial role in current cathode technology for high energy density batteries and roughly 60% of global cobalt demand is being met by the Democratic Republic of Congo (DRC). A good discussion of cobalt mining in the DRC including socio-economic implications can be found in other works. [5]
Cobalt supply and demand is monitored very intensely making it a substantive element with which to analyze resource supply and demand dynamics between the concept of seafloor mining and the growing demand for electric vehicles. While other topics are of utmost importance on this subject, this report does not discuss social or economic feasibility, political or commercial support or opposition, nor the siginificant destruction of seafloor ecosystems, that are tied to nodule mining.
In this section, the rate of cobalt extraction required to meet global EV demands will be calculated. The total mineral demand for a single EV is shown in Fig. 1. [1]
Four separate predictions of EV demand over the next two decades will be used to provide upper and lower bounds for Cobalt extraction rates. The first trend comes from extrapolating historical rates of EV production as reported by the the International Energy Agency (IEA), while the latter three of these trends come from the global development scenarios laid out by the IEA: [6]
Historical Data Trend: Historical global EV stock data from 2010 to 2021 are fit with an exponential trendline to estimate growth in EV sales. [6]
Stated Environmental Policies Scenario (STEPS): EVs will reach 20% of annual global vehicle sales by 2030. This is the most conservative estimate. [6]
Announced Pledges Scenario (APS): EVs will reach 30% of annual global vehicle sales by 2030. This is a mid-tier estimate. [6]
Net Zero Emissions by 2050 Scenario (NZE): EVs will reach 60% of annual global vehicle sales by 2030. This is an aggressive estimate. [6]
Each of the four trends are compared and limited to an approximate rate of global vehicle sales such that no prediction can exceed the global rate of vehicle sales. The global rate of vehicle sales was estimated assuming a linear growth rate of 2 million vehicles per year. [7] This rate is on par with estimates from online sources and databases.
Fig. 2 shows the spread from 2022 to 2040 of the four EV demand scenarios. Demand predictions based on (1) historical EV stock data in red, (2) the IEA's STEPS scenario in orange; (3) the IEA's APS scenario in dark blue; and (4) the IEA's NZE scenario (4) in yellow. Linear trends were fitted to the IEA's scenarios to extrapolate them. Note that once trend (1) in red hits the total predicted annual global demand for vehicles it is set to equal the global demand instead of exceeding it. When this occurs, 100% of new vehicle demand is for electric vehicles. For a sense of scale, total vehicle sales today hovers around 80 million vehicles and the cumulative global fleet as of 2022 is roughly 1.4 billion vehicles.
Notably, these estimates do not include the demand associated with 2 and 3 wheeled electric vehicles or sport utility vehicles.
A mass-based Co demand rate can be calculated based on the four annual EV demand predictions using the earlier statistic that an average electric vehicle requires 13 kg of Co per vehicle using Eq. (1). [1] The results are shown in Fig. 3. By 2040, the annual Co demand for each scenario is listed in the first column of Table 1.
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(1) |
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| Fig. 3: Predicted annual cobalt demand by scenario. (Source: G. Clark) |
What do the above rates of cobalt production required to meet the demand of electric vehicles mean if the Clarion-Clipperton Zone (CCZ) were to become the world's primary source of this metal? Estimates of Co reserves are used to compute a 2D nodule and cobalt density in the CCZ [kg/m2] because this resource is two dimensional, meaning Polymetallic nodules (PMNs) are not expected to extend appreciably below the seafloor into the substrate.
Three key assumptions are made in this section. The first is that Polymetallic nodule mining will begin by 2026 at the earliest, and 2030 at the latest. The second is that when seafloor mining begins in this model, it is assumed that the CCZ provides 100% of Cobalt demand for EVs. The third is that there is a 100% yield of useful Cobalt from the mined polymetallic nodule (PMN) in practice, some percentage of this Co would be lost in processing, increasing the required rate of nodule extraction than what is estimated here. Any other assumptions made in the analysis will be made explicit throughout the section.
While PMNs are non-unform in composition, the average composition of key metals in a polymetallic nodule by weight is reported as Co 0.20%, Ni 1.30%, Mn 28.09%, Cu 1.10%. [8]
The CCZ is roughly estimated to be 4.5 million square kilometers. A conservative estimate of the total mass of extractable PMNs in the region is 21.1 billion metric tonnes. [8] The resource density of PMN material can therefore be calculated using Eq. (2):
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(2) |
Next, using the percentage of Co in a nodule by mass, the kg of Co extracted per square-meter mined can be computed (again assuming 100% Co extraction efficiency) using Eq. (3):
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(3) |
Therefore, since one car requires 13 kg of Cobalt, it would require you to mine 1386 square meters of seafloor to produce enough Cobalt for one EV. The area footprint of a Tesla Model 3 is nine square meters. This means if you parked 159 Tesla Model 3s door-to-door, end-to-end, the total area they would cover is roughly equivalent to the amount of seafloor that needs to be uprooted to supply enough Co for just one of those electric vehicles.
Finally, we can estimate at how long the CCZ could supply the global EV demand with cobalt. The estimated Co reserves in the CCZ is pinned at 42.2 Mt using the percent-composition of Co found in one nodule and the total nodule tonnage. [1,2] Looking at cumulative cobalt demand from 2030-2040 by integrating Fig. 3 from 2030 to 2040, an estimated decade's worth of demand for each scenario is as follows (this assumes that the International Seabed Authority and its member states allow the entirety of the CCZ to be mined, without preserving any seabed habitat), can be found in column two of Table 1.
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| Table 1: Annual Co Demand, as given by Eq. (1); Co Demand per Decade (adding 2030/2040 data from Fig. 3); CCZ Co Reserve Lifetime from Eq. (4). |
The resulting four consumption rates [Mt/decade] of cobalt per decade can then be assumed to stop growing for the following decades, e.g., 2040-2050, 2050-2060, to give an extremely conservative computation of the number of years until the 42.2 Mt of Co reserves in the CCZ are depleted are shown in the third column of Table 1 and shown in Eq. (4).
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(4) |
Finally, another way to visualize the rate of CCZ resource depletion is to look at the total area of seafloor that is mined between 2026 and 2040 under the four demand scenarios (assuming mining begins in 2026). The results can be seen in Fig. 4. From the most conservative Stated Policies Scenario for EV demand (STEPS) in orange, to the most aggressive trend based on historical EV stock data in red, 12% to 53% of the CCZ seabed respectively will need to be mined by 2040 to produce the world's electric vehicles under the assumptions in this analysis. Most notably, on the IEA's path required to meet net zero global emissions by 2050, the EV demand is such that 40% of the CCZ seabed would need to be mined by 2040 if the CCZ were used to supply the needed Co. The black dashed line in Fig. 4 indicates the total area of the CCZ.
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| Fig. 4: Amount of CCZ seabed required to be mined each year for cobalt to satisfy the demand in Fig. 3. (Source: G. Clark) |
The original question asked, how far could the seabeds' resources meet material demands into the future? One answer to this question is provided above. If we want to supply the cobalt demand of electric vehicles by mining the CCZ in a net zero emissions global scenario, all mineable regions of CCZ will contain nothing but lander tracks and settled plumes in 3.1 decades. All estimates neglect the Cobalt demands for other battery applications, such as consumer electronics, industrial energy projects, and two and three wheeled electric vehicles.
A keen reader would correctly argue that this estimated longevity is far better than what global terrestrial reserves could provide against such a Cobalt demand. This point simply highlights the severity of the pressure put on mineral supply chains as electrification increases. Neither terrestrial nor subsea reserves appear to be enough. Considering this realization, perhaps rather than asking how to extract more and more resources, a better question to ask is, what solutions are needed to meet demands in the long term? Other avenues of exploration to reduce mineral demands include:
New battery chemistries: if supply chain constraints on minerals drive prices too high, other battery chemistry options will become more attractive that do not rely on Co, but switching chemistries often comes at the cost of energy density. [6]
Shift in demand to smaller vehicles and reduced range requirements such that energy density is less of a driving force on mineral demands.
Circular Economy: many innovators are already working on recycling and recovering metals from battery electric vehicles and devices.
Alternative transport and public transport: anything that can contribute to an overall flattening of vehicle demand curves.
As discovered in the introduction, electric vehicles are extremely mineral intensive. While EVs play an indubitable role in meeting environmental goals in the face of a warming climate, this report uses the analysis of cobalt supply and demand to underscore the new challenges posed by increased EV demand. The problem of tailpipe contents of a fleet of new vehicles moves into the past, while the challenge of equitably and responsibly obtaining the materials needed to bring a fleet of vehicles into existence in the first place emerges.
© Gibson Clark. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] "The Role of Critical Minerals in Clean Energy Transitions," International Energy Agency, May 2021.
[2] K. A. Miller et al., "An Overview of Seabed Mining Including the Current State of Development, Environmental Impacts, and Knowledge Gaps," Front. Mar. Sci. 4, 418 (2918).
[3] J. R. Hein and K. Mizell, "Deep-Ocean Polymetallic Nodules and Cobalt-Rich Ferromanganese Crusts in the Global Ocean," in The United Nations Convention on the Law of the Sea, Part XI Regime and the International Seabed Authority: A Twenty- Five Year Journey, ed. by A. Ascencio-Herrera and M. H. Nordquist (Koninklijke Brill, 2022).
[4] O. Heffernan, "Deep-Sea Dilemma," Nature 571, 465 (2019).
[5] B. K. Sovacool, "The Precarious Political Economy of Cobalt: Balancing Prosperity, Poverty, and Brutality in Artisanal and Industrial Mining in the Democratic Republic of the Congo," Extr. Ind. Soc. 6, 915 (2019).
[6] "Global EV Outlook 2022," International Energy Agency, May 2022, p. 221.
[7] É. Latulippe and K. Mo, "Outlook for Electric Vehicles and Implications for the Oil Market, 2019," Bank of Canada, 2019.
[8] J. R. Hein et al., "Deep-Ocean Mineral Deposits as a Source of Critical Metals for High- and Green-Technology Applications: Comparison with Land-Based Resources," Ore Geol. Rev. 51 114 (2013).