Is hydrogen fuel-injection more potent than hydrogen fuel cell?

Question

BMW has made a hydrogen fuel-injection based car, meaning this is not a hydrogen fuel cell, but the same engine used for burning gasoline, but now it burns hydrogen instead. The car is found here.

http://www.cars.com/go/features/autoshows/vehicle.jsp?vehicletype=concept&autoshowyear=2007&vehicle=concept_bmw_7hydrogen&make=BMW&model=Hydrogen+7+Prototype

What I am wondering is, that if hydrogen gas when burned is the same potent as gasoline, then shouldn't a fuel injection engine be more powerful than a fuel-cell electric engine? My particular interest if the two are different energies (battery cell vs. hydrogen combustion). If hydrogen combustion produces more horsepowers, then that extra energy could theoretically make up for the 30-40 percent energy loss in making hydrogen.

What is the energy difference (energy output) in hydrogen burning in a fuel injection (combustion) engine and hydrogen used in producing electricity in hydrogen fuel cells? Gasoline power is stronger.

Answer 1

--------
The key is when you point out the 30 to 40 percent efficiency loss that results from making hydrogen in the first place; there is no way to recover this lost efficiency, even if you managed 100% efficiency from the hydrogen itself.
*
Since fuel cells are about 50% efficient (ideally), and internal combustion engines can only manage as much as 30% efficiency (ideally), the fuel cells would still win. But combine this with the loss from converting the hydrogen, and the best you can hope for is a 35% overall efficiency.
*
I'm going to do something unexpected, and compare this to an electric vehicle. It's true that about half our electricity comes from coal, but fuel burns very efficiently in large powerplants (about 85% efficient in newer plants.) Transmitting energy by wire to charge electric cars is 95% efficient (beats the wasted efficiency of trucking gasoline around the country.) Battery storage is about 90% efficient, and electric motors are also about 95% efficient.
*
Multiplying these numbers out gives us an efficiency of about 69%. But the number is even better than this, since not all electricity comes from fossil fuel, and EVs can also recover braking energy to charge batteries while stopping.
*
The poor electric vehicle has almost been forgotten, but much progress on batteries has been made in the last few years. Take a look at this car:
*
http://phoenixmotorcars.com/models/fleet.html
*
The Phoenix can travel up to 250 miles per charge, carries 5 passengers plus cargo at 95mph, charges in only 10 minutes, and has batteries that will last well over 200,000 miles (for the life of the car.) Yes, it's a real car, orders have been taken and they begin building cars this month.
----------

Answer 2

Hydrogen fuel cells are enormously expensive and don't last long.  This is a far bigger problem than their effluent. Water vapor is the biggest greenhouse gas (on average) by weight, but only accounts for about half the total greenhouse effect (mostly in the tropics, very little at the poles - this is why AGW warms the poles much more than the rest of the earth).  Also, water vapor only lasts about 9 days in the atmosphere before it precipitates out as rain or snow.  Adding or subtracting water vapor has a very small influence on climate; the movers and shakers are the things which drive the amount of water which stays, how much forms high clouds vs. low clouds vs. vapor, etc.

Answer 3

Do apples taste better than oranges? You are comparing two entirely different systems here. In the long run it won't matter because there is very little chance they will produce a vehicle that costs more to run on a fuel that is almost impossible to get that the public will be willing to pay a higher price for.

Even the link you supplied shows the chances of having it produced are next to none.