Let's analyse how Aluminium would work out as hydrogen for transport:Assumptions
Density of Gasoline = 737.22 kg.m-3
= 2.7907 kg/gallon
Efficiency of Internal Combustion Engine (ICE) = 35%
Efficiency of H2
Fuel Cell (FC) = 60%
|Substance|| ||Energy Density|
|1. ||Hydrogen Gas||120 MJ/kg|
|2. ||Ethanol ||23.4 MJ/kg|
|3. ||Gasoline ||45 MJ/kg|
|4. ||Diesel ||45 MJ/kg|
|Vehicle Type||Petrol Mileage|| ||ICE Consumption|| ||FC Consumption|
|1. ||Passenger Car||22.4 Miles/Gallon||2.769 kJ/Mile||1.615 kJ/Mile|
|2. ||Vans, Pickups, SUVs ||16.2 Miles/Gallon||3.828 kJ/Mile||2.233 kJ/Mile|
|3. ||Trucks ||06.7 Miles/Gallon||9.259 kJ/Mile||5.402 kJ/Mile|
|4. ||All Vehicles ||17.1 Miles/Gallon||3.627 kJ/Mile||2.116 kJ/Mile|
|On a basis of 1000 miles|
|Vehicle Type||H2 Required||H2O Required||Al Required||Gasoline Required|
|1. ||Passenger Car||0.0135 kg||0.1215 kg||0.1214 kg||124.6 kg|
|2. ||Vans, Pickups, SUVs ||0.0186 kg||0.1674 kg||0.1673 kg||172.3 kg|
|3. ||Trucks ||0.0450 kg||0.4050 kg||0.4047 kg||416.5 kg|
|4. ||All Vehicles ||0.0176 kg||0.1584 kg||0.1583 kg||163.2 kg|
There is storage space available for 158g of water and 158g of Aluminium. Their total space storage would be so much less than the space required for 163.2 kg of gasoline (58 gallons).
Based on the price peak (US$3000 / 25 tons) in the above chart, the price of aluminium for topping up an average vehicle is $0.02. However, if one to take in account of the effect of supply and demand of Aluminium for transport, I would not be surprised that Aluminium price would grow to at least 50-70X its current price. Taking in account of logistics, tax and profit, one might expect the the price increment of $100-200/kg. A more realistic price for Aluminium at "petrol" kioks would be $2-4 per 1000 miles, compared to $1.50/gallon for petrol.
But there are definitely challenges in implementing this technology.
1. The availability of Gallium to store Aluminium in the form of a liquid alloy
2. Will the liquid alloy freeze in winter?
3. Controlling hydrogen production rate at the micro-gram level in a car
4. Separating Al2
from the Gallium alloy
5. Can Aluminium be regenerated via electrolysis in liquid Gallium?
1. Energy Density Data: http://hypertextbook.com/facts/2003/
2. Transport Consumption (USA, 2004): http://www.eia.doe.gov/emeu/aer/txt/ptb0208.html