Porsche Files Patents for a Fuel Cell Vehicle

I can see a possible advantage for having a hydrogen source and hydrogen burning engine at the vehicle, but I don't really see the overall system-wide or nationwide advantage of using hydrogen as a fuel.

Other fuels, notably methane, diesel, and gasoline, are obtained by extracting them from the Earth. The energy needed in converting the crude material into a usable fuel is fairly small. Not so with hydrogen; it is not simply extracted from the Earth.

With hydrogen, energy needs to be expended to separate hydrogen from some other molecule, such as water. If the system was 100% efficient, the energy obtained when burning hydrogen would be exactly the same as the energy put in, in 'creating' the hydrogen. But systems aren't 100% efficient, the energy produced in the vehicle's engine will never be as much as what was needed to extract the hydrogen and get it to the vehicle. Thus hydrogen is not functionally different from a battery, i.e., refilling the tank with hydrogen is, in an overall systems viewpoint, not much different than recharging a battery.

I know that in terms of energy density hydrogen is far superior than any battery technology, but that's only a small part of the overall system. Tesla Motors looked at hydrogen and went with battery technology. I think that says a lot about the comparative technologies.

Fuel cells have a major advantage over battery-based systems (at present) - they can re-charge in the same time as a petrol ICE vehicle takes to fill the tank.

Not that that has any bearing on your argument for fossil-fuel based systems.

Yes, that's a good point. One of my co-workers has an all-electric vehicle and as soon as he gets to work he plugs it in, to be sure he has enough charge to get home. Luckily for him he's able to park close to the building near a power outlet.

Thanks.

Nevermind all this crap about hydrogen, it is also a loser, somewhere of the same ken as ethanol.

When the aluminum rechargable battery comes out next year in all electric vehicles, everyone will see what I am talking about: complete re-charge in 3-4 minutes. Minimum of 7000-10000 charging cycles before change-out (all of this is way beyond the lithium ion battery). Also, did I mention the aluminum battery will not catch fire?

If one insisted on running the batteries to dead state, there could still be a small onboard conventional gas ICE to get from point D (dead) to point R (re-charge).

I think there might not be much weight penalty at all for this battery, as it relies on metallic state aluminum, and Al3+ ions in complexes. There is potential energy in the redox couple, as well as charge storage in the intercalated carbon cathode.

OR one could have an onboard hydrogen fuel cell system (that thermally strips hydrocarbons to C + H2, and then capture the carbon (soot). The soot could be turned in later for credit - like bottle caps?

Efficiency of turning fossil fuels at a power station into electricity - about 35%, efficiency of using electricity to make hydrogen from water - about 75%, efficiency of turning hydrogen into electricity in a fuel cell - about 50%, efficiency of electric motor - about 85%.

Overall from fossil fuel to motor output about 11.1% - ugh! Then there's the problems of storing and transporting hydrogen. Unless someone can come up with a method of making hydrogen very cheaply, it just isn't viable.

On the other hand: "German Wind-to-Hydrogen Plant Takes Car-Fuel Battle to Tesla."

http://www.renewableenergyworld.com/news/2015/07/german-wind-to-hydrogen-plant-takes-car-fuel-battle-to-tesla.html

But 100 kM (62 miles) costs 10 Euros ($ 12) from water to hydrogen to fuel cell to motive power. Still a way to go before it's worth it.

I see several problems with Hydrogen vehicles right off.

First, it is far more explosive and much easier to ignite than gasoline and much harder to contain since pressurizing is required to carry any meaningful amount. (several racing organizations have looked into this and abandoned it as an unnecessary safety risk)

Next, it is much more expensive. Both to produce and to transport, store, and of course sell. The cost at the pump will be unmarketable without heavy subsidies. (we already subsidize oil companies enough imho) Much like E85, it is not really viable without government subsidies to keep the price competitive and now that oil is down in the $60 a barrel range, not even close given its really poor mileage compared to straight gas.

People always like to point to the lack of charging stations when arguing against electric vehicles. So, how many Hydrogen filling stations are there anyway? Compared to electric? Look at the cost to install a hydrogen station and its required safety equipment compared to the cost of a charging station. Also look at foot print of the physical installation with the necessary safety set backs, fire suppression, and these will not be able to be self serve in most locations. Not really viable in most cities.

I am not sure what the attraction is.

possible.... but the pressure containers are probably more safer than a petrol tank.

Expense is always an issue on 'new' technology that doesn't have a infrastructure.