Friday, September 11, 2020

Lithium reserves: enough for 1-5 generations of "cars across the world" and nothing else

Lithium-battery electric cars are a niche market and they will always be. And if most cars were replaced by lithium-battery cars, mankind would run out of lithium after the first generation of cars would be produced. Or soon afterwards. And it's possible that other materials such as cadmium (reserves are estimated at half a million tons only) are even more constraining.

First, note that the number of cars in the world has surpassed 1.4 billion. How much lithium do we need for 1.4 billion electric cars with 70 kWh lithium-based batteries?

Well, in 2017, the estimate was that 1 kWh in a Tesla had 0.8 kg of lithium carbonate per kWh of batteries. With 70 kWh, this means 56 kg of lithium carbonate, Li2CO3. About 19% of the mass of this molecule is lithium itself which is a bit over 10 kg per a 70 kWh battery pack. (I did confuse lithium with the lithium carbonate in a previous calculation but the factor of 5 doesn't really change any qualitative conclusions.)

Now, despite the fantasy and hype, you can't really go well below 10 kg for a 70 kWh battery pack by changing the other compounds accompanying lithium. Why? It boils down to the basic atomic physics. You may calculate a very simple thing called the Faraday constant. Note that Faraday lived centuries ago and he sucked in mathematics so you should really be able to understand these basics. The Faraday constant tells you "how many coulombs you get per mole" and is simply the product of the elementary electric charge and Avogadro's constant. The numerical value is some 96,500 coulombs per mole, OK?

A lithium atom has one loosely bound electron (note that there are two electrons in 1s and one in 2s) and that's the electron you may remove to get the Lithium+ ion. This ion is the ideal situation you may get. As you may read in this section about Li-ion electrochemistry, those 96,500 coulombs per mole may be divided by 6.941 gram per mole (the molar weight of lithium) and you get 13,901 coulombs per gram. Multiply it by a voltage like 3V and you get 41.7 kJ per gram of lithium which is the same as 11.6 kWh per kilogram of lithium. You need more than 6 kg of lithium even if you had the perfect positive ions but you will never quite reach this idealized ionized lithium in the batteries. The lithium in 70 kWh batteries will likely stay closer to 10 kg of pure lithium than to the idealized limit of 6 kg.

Great. So how many cars worth of lithium does the Earth have? The known lithium reserves were 14-17 million tons in 2017-2020 (Czechia's Ore Mountains, near the Saxon border, have the highest European reserves of 1.5 million tons or so) while the highest 2020 estimate on that page is 80 million tons. I think it's extremely likely that only the initial 14-17 million tons are easy to get, the rest would be much more difficult and expensive to extract. At any rate, we have 14-80 billion kg of pure lithium. Divide it by 10 kg per car and you get 1.4-8.0 billion cars (with a 70 kWh battery pack each).

That's between 1-5 generations of cars for the world, assuming no significant recycling. If we used all the Earth's lithium for cars, we could indeed replace all the currently operating world cars by cars with 70 kWh battery packs, and maybe five times if we use the optimistic estimated reserves. Then we would run out of lithium. In reality, the pro-lithium hype doesn't affect just cars. People want to have lithium batteries to store their electricity produced from solar panels, pinwheels, and other ludicrous sources of energy. Because cars produce some 20% of the CO2 emissions, it's reasonable to expect that they would only be "assigned" 20% of the world lithium, too. With this counting, we have enough lithium for 0.2-1.0 generations of electric cars.

An electric car manufacturer (e.g. Tesla) guarantees something about the batteries for 8 years or 150,000 miles, whatever comes first. So "one generation" is at most 8 years. Beyond that, the batteries are assumed to be mostly unusable. So the lithium reserves are enough for 8-40 years of electric cars for the world if you don't allow the lithium to be spent by anything else; or 2-8 years if you do.

All the numbers may be adjusted a little bit, improved by some hype etc. But at any rate, it is spectacularly clear that the switch to lithium-based batteries is not a long-term solution to any hypothetical "problem" (there is really no problem but I don't want to discuss this here). For example, if you were brainwashed and considered the CO2 emissions a "problem", the electric cars would only delay the "problem" by a few years (2-40 years according to the estimates above).

Assume that all the observed warming in the recent 100 years, which was occurring at the rate between 1.3 and 2.0 °C per century in recent 50 years, was due to fossil fuels. And generously assume that the switch to electric cars, solar panels, and pinwheels stops the CO2 emissions. (It's very generous, indeed, because most of the energy for electric cars is still produced from fossil fuels and it will be the case for a long time, anyway. Also, lots of energy is spent when the cars and batteries are being produced.) With these assumptions, the world lithium reserves are enough to build the new batteries for 8 years or so. That's between 0.10 °C and 0.16 °C of global warming... and then you run out of lithium. You will need to recycle the lithium from the old, no longer healthy, batteries and it may be very difficult. If you optimistically get 1/2 of lithium to be usable again, you will be able to double the total time over which the lithium "solution" helps (the doubling comes from the summation of a geometric series, feel free to adjust the coefficient).

We just saw that to sacrifice the world's known lithium reserves is equivalent to cooling the Earth (relatively to the business-as-usual scenario with fossil fuels) at most by some 0.1-0.2 °C and most of our assumptions were extremely generous so the actual temperature change is much lower than that. Do you think it is wise to sacrifice the Earth's reserves of the third lightest element just to delay some "allegedly harmful" global warming by 0.1-0.2 °C (we will have to return to fossil cars when there's not enough lithium for the batteries again)? We wouldn't be just depleting an important element on Earth. We would also be forcing each average prospective driver to work for two more years of his life just to pay for the expensive batteries.

Every sensible person must agree that this lithium "solution" to the hypothetical "problem" is insane. Lithium is the third lightest element. It's far more important than a 0.1 °C difference between two habitable temperatures. What seems even more amazing is when you compare these simple arguments of mine with the slogans of the ecoterrorists such as "coal belongs underground". If coal belongs underground, "doesn't lithium belong underground" as well? The case for "lithium belongs underground" is clearly much stronger because lithium is much closer to being a scarce resource (and it's also a less natural material which may be toxic). Our estimates showed that it's at most "good for decades" of the omnipresent global usage. The fossil fuels are demonstrably enough for additional centuries.

Note that physics really prevents you from improving these numbers much by choosing other materials. In your batteries, some elements must become the positive ions. Those are elements that can easily shed electrons. Hydrogen can do so and we may discuss the hydrogen cars with all their advantages (even more concentrated energy than in lithium), disadvantages, and risks (which are still much more promising than lithium in the long term because hydrogen is abundant). Helium is an inert gas so it can't easily sacrifice an electron. Then you have the lithium. Beryllium comes afterwards. Even if you could build batteries based on it, the reserves are estimated at just half a million ton, some 10-100 times lower than the lithium reserves.

The fifth element is boron whose reserves are huge, comparable to one or two billion tons, but it can't really replace lithium itself as far as we know today. Boron is used for electrodes. As you continue to heavier elements, you get increasingly "heavy stuff per electron" of the electrical charge (while the voltage is always several volts in an atom). You may continue and get to the sixth lightest element, carbon, which is abundant and has a very rich chemistry. But the energy content of hypothetical carbon-based, lithium-free batteries (think about graphene which is still hot enough among condensed matter physicists) is much lower than in the case of lithium. To remove lithium (and hydrogen) really means to try cars that are much heavier than today, perhaps 5 or 10 tons for a hatchback that can make 200 km.

Now think about the stocks that depend on the "lithium-powered revolution". Tesla is becoming absolutely uncompetitive now, e.g. after the stunning Škoda Enyaq iV was released last week (see a review at the top). So it will only have a tiny share of the electric car market in a year or two. Even if you really integrate its revenues and profits over a hypothetical rosy infinite future, Tesla will produce at most tens of millions of cars in total (other manufacturers could produce hundreds of millions of cars) before the lithium prices go up again and make this industry clearly infeasible again. They would need to make the profit $30,000 per car to justify the Tesla capitalization of $400 billion we saw just a week ago. Tesla doesn't make any real profit from a car let alone $30,000 which is the whole price where it must go now to sell almost anything. This whole "green industry", with electric cars and especially Tesla, is just a totally insane religious cult, something that is promised to revolutionize the world even though it is spectacularly obvious that such a revolution isn't possible and if it were realized, it would start the last decades of the civilization as we have known it. Electric cars, starting with Enyaq, will remain a niche market that may attract our eyes and promote other products by Škoda (or others) but they can't become the "dominant transportation technology" in the world.

And that's the memo.

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