So the preeminent difficulty with aluminum-air is the cost of aluminum. Going off phinergy's number (8 kWh/kg), and assuming Tesla-parity range of 260 miles for

So the preeminent difficulty with aluminum-air is the cost of aluminum. Going off phinergy's number (8 kWh/kg), and assuming Tesla-parity range of 260 miles for an 85 kWh fill-up, you need 10.5 kg Al per fill-up, which costs $1.80/kg on the London Metal Exchange as of today, costing about $20/fill-up, or -eep- eight cents a mile, before considering tax, transit, manufacturing etc. For comparison my 2009 Toyota Prius (yes, I -am- that lame) costs nine cents a mile for fuel (350 miles, nine gallons, $3.50/gal). So aluminum-air largely negates the cost advantage of an electric battery, unless phinergy can come up with a superior way of making aluminum, which is already one of the most optimized processes in modern industry: the cryolite process has absorbed millions of hours of human attention. If the power-density problems can be solved, zinc-air or similar may still be a good idea. Zinc is, unfortunately, quite heavy. Incidentally, I have put over 15k miles on my car this year alone. Some people drive a lot.