Friday, February 13, 2009
A brief survey of the Electric Vehicle landscape for beginners
Welcome to this humble blog. The idea is to make it a little bit easier for people trying to get an overview of the direction of the electric vehicle. I recently became very interested in the area, but had to do a lot of googling to get an insight into the issues associated with the expansion of the electric vehicle market. I'll try to distill this down.
We're all searching for the alternative to gasoline and diesel in the context of climate change and the suggested solutions are wide and varied. Here's a sample of the options:
Mechanically rechargeable; they would be swapped for fresh metal at a refueling station:
You plug them in to recharge them or charge them on the go:
Climate Change Context
Here is a chart of anthropogenic emissions:
Another chart showing more detail:
The 16% attributable to road transport is the most intractable slice of the pie. This is because of the millions of individual emitters, with no centralised facility. Electricity generation lends itself to wind, solar thermal, carbon capture etc; manufacturing to more efficient processing and so on. CO2 is an irreconcilable byproduct of gasoline or diesel cars. The cars can be made more efficient, but any gains will be at the margin.
The only way to make a significant reduction is to change to electric cars, drive less, or switch to public transport. The window for action to avert the worst consequences of climate change is, arguably, not that wide.
Each of them has their own advantages and disadvantages. The main issue I found that is common to most of them is that of scalability. There were some 53m cars produced in 2007 and that will only grow with the development of the Orient. The issue is climate change and to have an impact on CO2 emissions, electric vehicles must make inroads into that 53m figure.
There is much debate over which battery is the best. I believe any discussion should be impassionate and based on clear-headed analysis of the figures. Resource constraints appear to be a key handicap on the widespread adoption of EVs. Suppose Toyota comes out tomorrow with an all electric NiMH that gets 80mpg, is reliable and much cheaper than gasoline vehicles. Everyone would want one, right? So in what timeframe could Toyota deliver?
Let's look at the figures for how much of the building blocks for each battery type were produced last year(click for a clearer picture):
Would Toyota be able to deliver the goods? We know they use a Nickel Metal Hydride(NiMH) battery. The M in NiMH is predominantly Lanthanum, a rare earth metal. The next 2010 Prius will, for example, have 20kg of Lanthanum per vehicle. The motor in the electric vehicle contains a Neodymium-Iron-Boron(NIB) permanent magnet. A typical magnet contains 100 grams of Dysprosium. Both Dysprosium and Neodymium are rare earth elements. 95% of rare earth elements come from China. China is keenly aware of the value of rare earth elements and institutes export quotas and tarriffs. For the last two years they have lowered the amount they allow to be exported.
I don't know how many vehicles per year Toyota would be able to produce but to put it in context Toyota aim for 1 million hybrids in 2011; down from 2-3 million three years ago.
Here is an illustration of the problem along with commentary on the different battery types(click to read):
"Resource-based view of key components in EV supply chain"
(Height of disks vaguely sized to reflect 2008 production of each metal, the main purpose is qualitative, though)
This graph shows the constraints on Toyota were they to be asked to produce immediately. The question then becomes: As demand increases, can't supply of raw materials simply scale to match it?
In the case of rare earth metals the answer is a qualified no. There are small pockets of rare earth materials outside of China but they are firstly more expensive to extract and would at best only supplement not supplant Chinese dominancy. This would seem to place a ceiling on the expansion of NiMH absent any other consideration. I can't put a figure on it, others might, but it would probably be in the low millions.
Regarding lithium, figures are hard to come by although a recent report (NB: Author has a vested interest) shows demand outstripping supply by 2020. The same report puts the total EV market at 3.5m per year (how much is attributable to li-ion is not delineated). This again does not seem to show lithium impinging materially upon the 53m (it will be much greater by 2020) in the medium term.
Then there is the issue with neodymium and dysprosium in the permanent magnets of most EV motors. At 100 grams a pop and with 100 tons produced last year, it would indicate a current ceiling of 1m Priuses. Here are some good articles to get you up to speed on the difference between DC Brushless(Permanent Magnet) & Induction motors. Chorus claim to have a high efficiency low cost induction motor alternative although independent verification appears scant and it is not in any vehicles at present.
My study of the situation leads me to suspect that high volume production of electric vehicles in the short to medium term is unlikely. Stretching to the longer term, the scalability of lithium-ion and NiMH are dubious. A lead-acid battery or rechargeable zinc battery would thus represent the best options - purely from a resource perspective. There is also the zinc-air option which I haven't looked at but am intuitively skeptical of. I think I've said most of what I wanted to get across and hopefully one or two of you find it useful.
My sources are predominantly secondary or tertiary and all based online so a pinch of salt is perhaps required. I would welcome any corrections, clarifications or criticisms of what I've written - I'm still a neophyte in the EV area.