Further to the discussion on climate change, in New Zealand now the argument is that we must reduce our greenhouse emissions by converting our vehicle fleet to electric vehicles. So, what about the world? Let us look at the details. Currently, there are estimated to be 1.2 billion vehicles on the roads, and by 2035 there will be two billion, assuming current trends continue. However, let us forget about such trends, and look at what it would take to switch 1.2 billion electric vehicles to electric. Obviously, at the price of them, that is not going to happen overnight, but how feasible is this in the long run?
For a scoping analysis, we need numbers, and the following is a “back of the envelope” type analysis. This is designed not to give answers, but at least to visualise the size of the problem. To start, we have to assume a battery size per vehicle, so I am going to assume each vehicle will have an 85 kWh battery assembly. A number of vehicles now have more than this, but equally many have less. However, for initial “back of the envelope” scoping, details are ignored. For the current purposes I shall assume an 85 kWh battery assembly and focus n the batteries.
First, we need a graphite anode, which, from web-provided data will require approximately 40 million t of graphite. Since Turkey alone has reserves of about 90 million t, strictly speaking, graphite is not a problem, although from a chemical point of view, what might be called graphite is not necessarily suitable. However, if there are impurities, they can be cleaned up. So far, not a limiting factor.
Next, each battery assembly will use about 6 kg of lithium, and using the best figures from Tesla, at least 17 kg of cobalt. This does not look too serious until we get to multiplying by 1.2 billion, which gets us to 7.2 million tonne of lithium, and 20.4 million t of cobalt. World production of lithium is 43,000 t/a, while that of cobalt is 110,000 t/a, and most of the cobalt goes to other uses already known. So overnight conversion is not possible. The world reserves of lithium are about 16 million t, so there is enough lithium, although since most of the reserves are not actually in production, presumably due to the difficulty in purifying the materials, we can assume a significant price increase would be required. Worse, the known reserves for cobalt are 7,100,000 so it is not possible to power these vehicles with our current “best battery technology”. There are alternatives, such as manganese based cathode additives, but with current technology they only have about 2/3 the power density and they can only last for about half the number of power cycles, so maybe this is not an answer.
Then comes the problem of how to power these vehicles. Let us suppose they use about ¼ of their energy on high-use days and they recharge for the next day. That requires about 24 billion kWhr of electricity generated that day for this purpose. World electricity production is currently a little over 21,000 TWh, Up to a point, that indicates “no problem”, except that over 1/3 of that came from coal, while gas and oil burning added to coal brought the fossil fuels contribution up to 2/3 of world energy production, and coal burning was the fastest growing contribution to energy demand. Also, of course, this is additional electricity we need. Global energy demand rose by 900 TWh in 2018. (Electricity statistics from the International Energy Agency.) So switching to electric vehicles will increase coal burning, which increases the emission of greenhouse gases, counter to the very problem you are trying to solve. Obviously, electricity supply is not a problem for transport, but it clearly overwhelms transport in contributing to the greenhouse gas problem. Germany closing its nuclear power stations is not a useful contribution to the problem.
It is frequently argued that solar power is the way to collect the necessary transport electricity. According to Wikipedia, the most productive solar power plant is in China’s Tengger desert, which produces 1.547 GW from 43 square kilometers. If we assume that it can operate like this for 6 hrs per day, we have 9.3 Gwh/day. The Earth has plenty of area, however, the 110,000 square km required is a significant fraction. Further, most places do not have such a friendly desert close by. Many have proposed that solar panels of the roof of houses could store power through the day and charge the vehicle at night, but to do that we have just doubled the battery requirements, and these are strained already. The solar panels could feed the grid through the day and charge the vehicles through the night when peak power demand has fallen away, so that would solve part of the problem, but now the solar panels have to make sense in terms of generating electricity for general purposes. Note that if we develop fusion power, which would solve a lot of energy requirements, it is most unlikely a fusion power plant could have its energy output varied too much, which would mean they would have run continuously through the night. At this point, charging electric cars would greatly assist the use of fusion power.
To summarise the use of electricity to power road transport using independent vehicles, there would need to be a significant increase in electricity production, but it is still a modest fraction of what we already generate. The reason it is so significant to New Zealand is that much of New Zealand electricity is renewable anyway, thanks to the heavy investment in hydropower. Unfortunately, that does not count because it was all installed prior to 1990. Those who turned off coal plants to switch to gas that had suddenly became available around 1990 did well out of these protocols, while those who had to resort to thermal because the hydro was fully utilised did not. However, in general the real greenhouse problem lies with the much bigger thermal power station emissions, especially the coal-fired stations. The limits to growth of electric vehicles currently lie with battery technology, and for electric vehicles to make more than a modest contribution to the transport problems, we need a fundamentally different form of battery or fuel cell. However, to power them, we need to develop far more productive electricity generation that does emit greenhouse gases.
Finally, I have yet to mention the contribution of biofuels. I shall do that later, but if you want a deeper perspective than in my blogs, my ebook “Biofuels” is 99c this week at Smashwords, in all formats. (https://www.smashwords.com/books/view/454344.) Three other fictional ebooks are also on discount. (Go to https://www.smashwords.com/profile/view/IanMiller)
