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| Fig. 1: A lithium mine in Silver Peak, Nevada. (Source: Wikimedia Commons) |
One of the key issues in the transition from fossil fuels to renewable electricity is the dilemma of energy storage. Fossil fuels, including coal, oil, and natural gas, contain energy that can be stored and transported essentially as is. In contrast, if electricity is to be stored, it is stored in a battery. Lithium-ion batteries are a popular kind of battery, and they require lithium mining as depicted in Fig. 1. We will thus investigate comparisons of energy content between fossil fuels and lithium-ion batteries with consideration of the limitations on both specific energy and resource availability of lithium.
In 2021, approximately 82% of global primary energy consumption was in the form of oil, coal, and natural gas. [1] A transition from fossil fuels to renewable energy in the form of electricity would thus require reformatting the majority of our energy economy. We will here explore the theoretical storage of the equivalent of all fossil fuel energy in lithium-ion batteries.
Of the primary energy consumption across the globe in 2021, 184.21 EJ (1 EJ = 1.0 × 1018 J) were in the form of oil, 145.35 EJ in the form of natural gas, and 160.10 EJ in the form of coal. [1] This amounts to a total of 489.66 EJ of the world's energy consumption in the form of fossil fuels.
The specific energy of a commercial lithium-ion battery is approximately 9.54 × 105 J/kg. [2] This means that the theoretical storage of the equivalent of all 2021 fossil fuel energy would be given by
| 489.66 × 1018 J 9.54 × 105 J kg-1 |
= | 5.13 × 1014 kg of Li-ion batteries |
Lithium itself makes up about 7% of the mass of lithium-ion batteries. [3] Thus, storing this amount of energy would require about 3.59 × 1013 kg of lithium itself.
In 2022, the global consumption of lithium was on the order of 1.22 × 108 kg. [4] In total, this means that the hypothetical lithium-ion battery storage of the energy equivalent of global fossil fuels in 2021 would require approximately 295,000 times more lithium than was consumed globally in 2022. Furthermore, the sum total of lithium reserves on Earth is estimated by the USGS at 98 million tons, or equivalently, 8.89 × 1010 kg. [4] This estimate is 3 orders of magnitude smaller than the required amount to store the energy equivalent of global fossil fuels in 2021.
The storage of the entire global energy supply need not necessarily be in the form of lithium-ion batteries. This paper in no way seeks to suggest that electrification is implausible. Instead, we seek merely to bring to attention the limitations on specific energy and resource availability of lithium. These limitations suggest lithium-ion batteries alone would be an impractical or insufficient solution to electrification, and that further research into renewable energy storage would be advisable toward such an end.
© Nathanael Cadicamo. 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] "BP Statistical Review of World Energy 2022," British Petroleum, June 2022.
[2] K. M. Abraham, "Prospects and Limits of Energy Storage in Batteries," J. Phys. Chem. Lett. 6, 830 (2015).
[2] M. Pagliaro and F. Meneguzzo, "Lithium Battery Reusing and Recycling: A Circular Economy Insight," Heliyon 5, e01866 (2019).
[4] "Mineral Commodity Summaries 2023," United States Geological Survey, January 2023.
