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There's been a lot of discussion about the impacts of lithium mining vs oil extraction (here for example). I'd like to quantify this.

How do the impacts of mining lithium for one electric vehicle (EV) for it's lifetime compare to the impacts of extracting oil for one internal combustion engine vehicle (ICEV) for it's lifetime?

In theory, the environmental impact of lithium mining and oil extraction can be quantified per unit of mass. For all the gasoline that a car uses in it's lifetime, what is the total impact of that oil extraction compared to the lithium mining to make one EV's battery?

I understand that from an energy perspective you can't compare lithium directly to oil. But the unspoken question that arises from the debate is -- since mining lithium is so bad, would we be better off burning oil? Thus as a first analysis, I want to understand the environmental impact of that mining, and by comparison, the extraction of oil for an ICEV.

Some assumptions:

  • Environmental impacts can include any of greenhouse gas emissions, water toxification, deforestation, air pollution, or others. It should include whatever is most significant for both lithium and oil.
  • Primary analysis should assume a 100% renewable energy source for EV charging (in order to limit the analysis to lithium vs oil extraction)
    • Secondary analysis can include extraction of fuel for EV charging (coal, natural gas, etc)
  • It's OK to ignore lithium processing and oil refining, but specify at what point in the supply-chain the analysis ends
  • Ignore end-of-life, such as vehicle emissions and battery disposal/recycling
  • Assume a standard four passenger sedan
  • Assume both vehicles are driven the same distance over their lifetimes
  • I am interested in hard numbers so please provide sources
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    This might be more complicated than you think. What mix of mined Li is envisaged hard rock mining or specific salt lakes. Also how recyclable is Li, % that can be recycled, energy used, waste products from recycling & what gets done with the waste from recycling? Do you want to include the cost of rehabilitating the mine sites once they're exhausted?
    – Fred
    Dec 19 '20 at 9:13
  • @Fred good questions. Let's ignore end of life for now. Regarding Li mining methods, which is more common? I'm fine with an answer that addresses either or both (probably whichever one has the best data).
    – LShaver
    Dec 19 '20 at 16:02
  • I came across this item concerning the cost of mining Li, Lithium Sector: Production Costs Outlook. Mining hard rock Li is cheaper than mining brine. The significant difference between the two is that brine produces a higher value product. So much so, some hard rock miners want to further process the spodumene concentrate to produce a higher value product.
    – Fred
    Dec 22 '20 at 15:59
  • The horrible impact of lithium mining on native and Aboriginal peoples is a serious problem. Lithium mining regularly takes place on their sacred grounds, destroying it forever. Oil drilling and pipelines often destroy native lands and sacred sites as well. The bottom line is that when something becomes desirable, the greedy scum of the earth often exploit it without concern for the impact on others. Often, governments collude with them. Dec 22 '20 at 22:14
  • It appears that currently, Li from batteries is not recycled, because it is only worth 6 euro per kg (9 USD per kg). The only metals recovered from Li batteries are the valuable ones such as cobalt, which has a current LME price of 32 USD per kg.
    – Fred
    Dec 29 '20 at 10:52
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This is quite a difficult question to answer with precision, because the impacts of mining depend a lot on how you do it. I can offer a few references which give a guide to the scale of the problem.

There are many environmental concerns around the impact of Lithium mines on the environment and local communities (e.g. Reuters article on Salar de Atacama).

Quantifying Impacts

The difference in scale, maturity and categories of pollution involved make a detailed comparison of all the toxins involved difficult. I will look at two broad areas of impact: the area of land taken up and the volumes of water used in the processing chain.

Assumptions

To make the comparison, consider a Nissan Leaf with a 40kWh battery. Taking the low end of Lithium content from wikipedia of 0.15kg per kWh (the efficiency of batteries is rapidly increasing, so we can expect improvements beyond this figure) we require 6kg of Lithium.

For our petrol car, consider a car driving 12,000 km per year (the UK average) at 6L per 100km, and hence consuming 2,000 L per year.

We will also consider a 10 year lifetime for the battery.

It could be argued that this comparison is too pessimistic about the Lithium because it SHOULD be recycled and have a much longer lifetime than 10 years. However, current recycling rates in, for example, Australia are 2% (Inst. Energy Research) .. so we should not count this benefit too early.

I have not dealt explicitly with petroleum extraction: if done cleanly the extraction itself is the major cause of concern for petroleum, though it would be for coal or shale gas. Toxic chemical spills are a problem. Because of the much lower volume of Lithium needed compared to oil, we can expect spillage to be a smaller concern. We might hope that the high value to weight ratio will lead to a cleaner processing chain and reduced damaging spillage, but this hope cannot be verified at this stage.

Water Use

The Institute for Energy Research say that Lithium mining (from salt flats ... see comments on open cast mines below) requires 500 gallons (2,250L) per kg of Lithium. Most of the environmental problems are associated with waste water that is heavily loaded with a toxic mix of chemicals.

We can compare this to water use in petroleum refining, according to fluence, of about 0.5L per litre of petrol.

This means that the 2,250 L/kg * 6 kg = 13,300 kg of water usage for the electric vehicle should be compared with 2,000 L/yr * 10 yr * 0.5 kg/L = 10,000 kg of water usage to create petroleum for the conventional car.

In both cases, this is much less than the typical domestic usage of 40,000 kg per person per year in the UK. The problem is that this may be heavily polluted water and the usage may be concentrated in very small and sensitive areas.

Area of Land Needed*

Lithium battery factories have a huge scale, how does this compare with oil refineries?

The Tesla giga-factory in Nevada aims to produce 50GWh of batteries per year, enough for 1.25 million 40kWh cars, and covers 180,000m2. Taken over our 10 year period reference period, this means 0.18/12.5 = 0.014 m2/car. Seen like this, it is not taking up much space.

By comparison, the world's largest oil refinery at Baton Rouge, Lousiana covers 8,000,000 m2 and produces 80,000,000 L of petrol per day. The typical car described above needs 2L per day, so Baton Rouge is supporting 40,000,000 cars, or 0.2 m2/car.

Both these numbers indicate that the area of the fuel/battery processing plant is small on a per/car basis. In terms of emissions, battery factories do not appear to have significant waste outputs. The refineries, on the other hand, have a long list of toxic by-products and problems associated with leakage in the input supply chain.

We should also look at the spatial footprint of Lithium mines. Their are two categories of mine: open cast mines from which a solid ore is extracted and brine deposits. The brine deposits, such as in Salar de Atacama (Chile), currently provide the cheapest source, but many countries are developing large open cast mines, such as at Thacker Pass (Nevada, US).

The Salar de Atacama brine pools are visible in google maps from which I estimate their area as 25 km2. This site produced 80,000 tonnes of Lithium per year in 2017 (e.g. Reuters article on Salar de Atacama). The life-time of the site is unclear, but even with a conservative estimate of 10 years, this will supply 130 million car batteries, approximately 0.2m2 per car, as for the Baton Rouge site.

The main concern at the Salar de Atacama site appears to be the rate of extraction brine, which is lowering the local water table. If this is restricted, there will be limits in Lithium supply. This is no doubt one factor leading many countries to invest in open cast mines.

The Thacker Pass open cast mine referred to above is expected to have spatial footprint of 23 km2 (close to that of the Atacama brine pools) an produce enough Lithium for 100 million cars (see mining.com -- 3.1 million tonnes of Lithium carbonate implies 0.6 million tonnes of Lithium), and hence 0.23 m2 per car.

The Thacker pass mine will not use brine pools, but there is concern in the environmental impact assessment that there are unknown impacts because of new methods being used.

Energy Use

Finally, on energy efficiency and CO2 emissions. The Nissan Leaf is rated at 114 mpg-e by the EPA , or 19kWH per 100km. If this electricity is taken from the UK grid, with 233 kg/kWh implies 4.27 kg CO2e per 100km.

For petrol, with 2.3 kg CO2e per Litre, we have closer to 13kg CO2e per 100km. So, even with today's electricity supply, the electric car is doing significantly better.

As new generation capacity is dominated by carbon free energy sources, this balance will change increasingly in favour of electric vehicles.

Conclusions

(1) Pollution associated with Lithium mining is potentially significant. Care needs to be taken with water usage and disposal of waste water. These are not new challenges, but if this is going to be done in a "green" way, there needs to be a significant improvement in the quality of waste management compared to current standards in the fossil fuel industry.

(2) Lithium battery production is a clean and compact process.

(3) Electric vehicles have a lower carbon footprint than comparable petrol vehicles if charged using energy from the UK national grid. The carbon footprint will continue to decrease as the grid moves increasingly to zero carbon emissions.

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  • The land comparison is an interesting angle, but my understanding is that with horizontal drilling, oil extraction itself probably requires less land than lithium extraction? I understand that some lithium extraction involves pumping water underground to create a lithium-rich slurry, then pumping it back to the surface for evaporation, with the slurry just being left on the surface. Seems like this would take up a lot more land than an oil rig.
    – LShaver
    Dec 28 '20 at 17:53
  • True .. it may be worth trying to get an estimate of the land footprint of the Lithium mine. I think it would need to be compared with the land footprint of the refinery. You make a good point. In other words, the "dirty" part of the Lithium processing is at the mine, while the "dirty" part of the oil processing is at the refinery.
    – M Juckes
    Dec 28 '20 at 23:30
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    I've added a discussion of brine and open cast mines .... it becomes quite an essay. It may be instructive to compare against hydrogen cell technology ... but that is another question.
    – M Juckes
    Dec 29 '20 at 9:15
  • I think some headings, and numbers in the conclusions, would make this more readable. You've pulled together a lot of good info but it's not clear how it all relates.
    – LShaver
    Dec 29 '20 at 17:47
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    Fair comment (the answer is somewhat longer than I had hoped), I've added some headings.
    – M Juckes
    Jan 3 at 20:01
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How do the impacts of mining lithium for one electric vehicle (EV) for it's lifetime compare to the impacts of extracting oil for one internal combustion engine vehicle (ICEV) for it's lifetime?

There's one fundamental difference in the comparison that cannot be ignored. It is the impact of lithium recycling. Lithium as an atom cannot vanish so recycling is very efficient, nearly 100% (yes I know some isotopes of lithium can be transmuted to tritium for fusion reactions, but that requires neutron irradiation and thus can be ignored).

A car has a lifetime of 20 years. If we want to live on this planet for 2000 years, that means there will be 100 cars in this time multiplied by the number of car owners.

Let us assume that a battery electric car uses 1.6 kg of lithium per 10 kWh [1] and has a 75 kWh battery. It's 12 kg of lithium needed.

The lithium need is as follows:

  • The first car needs 12 kg of lithium.
  • The second car needs 0 kg of fresh lithium as the 12 kg of lithium comes from recycling
  • The third car needs 0 kg of fresh lithium as the 12 kg of lithium comes from recycling
  • ...
  • The hundredth car needs 0 kg of fresh lithium as the 12 kg of lithium comes from recycling

The total lithium usage is 12 kg.

Let us also assume that a petroleum fueled car uses 6.5 liters of fuel per 100 km, and has a lifetime of 300000 km.

The fuel use is as follows:

  • The first car needs 19500 liters of fuel (around 14 000 kg)
  • The second car needs 19500 liters of fuel (around 14 000 kg)
  • The third car needs 19500 liters of fuel (around 14 000 kg)
  • ....
  • The hundredth car needs 19500 liters of fuel (around 14 000 kg)

So that's comparing 12 kg of lithium with 1.4 million kg of fuel.

Of course, every stage of lithium recycling takes some energy input, but if that energy is in the form of electricity, it's trivial: we can already create green electricity, as you already assumed in the question.

If the lithium mining uses 100% green electricity, it has emissions of 0 kg CO2 per 12 kg of lithium. So in other words, there's nothing in lithium mining that inherently releases carbon dioxide. In contrast to cement manufacturing for concrete, the chemical reactions release carbon dioxide and burning fossil fuels release carbon dioxide. Similarly, some steel production methods release carbon dioxide although there are available methods such as direct hydrogen reduction that avoid the carbon dioxide emissions. We can assume the mining equipment made from steel can be created with hydrogen reduction, and we can assume the energy for mining comes from renewable sources.

If oil refining uses 100% green energy (such as hydrogen from renewable electricity for hydrocracking the oil), the 1.4 million kilograms of fuel create 4.6 million kilograms of CO2 emissions when burned in the car engine.

It is not realistic to create that fuel from renewable sources, as the CO2 emissions of cars are mobile so it's not realistic to capture the emissions, and the sustainable sources of CO2 (mainly those from forestry industry and biofuel plants) are not large enough to create enough synthetic fuels for the present oil consumption [2].

However, there probably is enough lithium to make all cars around the world electric [3]. There is not enough lithium for grid energy storage purposes, but for that purpose we will probably use other technologies such as hydrogen electrolysis and large gas turbines / internal combustion engine plants for converting back that hydrogen for electricity.

[1] https://en.wikipedia.org/wiki/Lithium_battery says that 0.15 - 0.3 kg of lithium is needed per kWh, and 1.6 kg / 10 kWh is in that range

[2] A general rule of thumb in the forestry industry is that one cubic meter of forest sequesters one tonne of carbon dioxide. One hectare of forest can grow perhaps around 5 cubic meters per year (forests in warm areas more, boreal taiga forests less). According to http://www.fao.org/state-of-forests/en/ the world forests are 4 billion hectares so they could grow 20 billion cubic meters per year. That's 20 gigatonnes of sustainable carbon dioxide sources. We are already emitting 36 gigatonnes of carbon dioxide, and if car usage in developing countries increases, the demand for fossil fuels skyrockets. Plus, a lot of the forests are tropical rainforests which we really don't want to disrupt in any manner. Besides, http://edepot.wur.nl/196265 tells that annual world wood production is only 1.7 billion cubic meters, so that's only 1.7 gigatonnes of sustainable carbon dioxide sources.

[3] If we assume 5 billion cars are enough, that requires 60 billion kilograms of lithium. According to https://en.wikipedia.org/wiki/Lithium#Reserves the lithium resources are over 80 million tonnes, more than those cars need.

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  • I understand the point about recycling, but as a primary analysis I want to understand how the impact of mining the 12 kg of Li compares to extracting the 14,000 kg of oil for the first car.
    – LShaver
    Dec 21 '20 at 0:39
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    No industrial process is 100% efficient, some Li will be lost during recycling. Most steel isn't made using hydrogen reduction. Most mine sites are in remote locations, the cost of using 100% green energy would be very high. The question needs to be answered with reference to actual practices that are currently being used, not what might happen in ideal situations. Significant amounts of Li are still being mined from hard rock, which means: drilling, blasting, trucking, process plant operations: crushing, grinding, flotation, drying, stockpile reclamation, haulage & addition processing. ...
    – Fred
    Dec 21 '20 at 3:10
  • ... Then there's manufacturing of the batteries & haulage to the car markers.
    – Fred
    Dec 21 '20 at 3:10
  • Recycling is definitely important .. I don't agree with @LShaver 's comment suggesting that it is fair to compare the 12kg of Li against the lifetime fuel use of a car, but 100% recycling is also unrealistic. There will be loss due to damage in collisions which makes recycling impractical, damage in house fires, cars being dumped, wastage at the recycling plants, and wastage in the manufacturing system. I don't know what the numbers are, but I doubt that you will get above 90% efficiency of recycling. It is also unclear whether anyone will want the Lithium in 50 years time.
    – M Juckes
    Dec 21 '20 at 22:55
  • @MJuckes I agree that recycling is important -- my point is that to understand how important, we first need to know the impact of mining. Then any amount you can recycle improves the comparison.
    – LShaver
    Dec 21 '20 at 23:18

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