How a Hydrogen Fuel Cell Engine Works
rybrook.co.uk
rybrook.co.uk
I figure, hydrogen's technological downside is a fuel that's hard to store and handle (can't fill a portable tank and carry around like with gasoline, can't fill at home like with batteries). Pure battery's downside is shorter range and longer time to "fill". Hydrogen's economical downside is a more complex system with more parts to assemble. Battery's downside is the cost of large amounts of batteries.
In both cases it seems that hydrogen has the upper hand in the short term, if they solve the cost of the fuel cell itself. But in both cases it seems to me like pure batteries have downsides that are likely to improve over time.
It would be interesting to know where the break-even point is, given we have a cheap fuel cell.
I'm worried that the hydrogen fuel cells are a bit of a blind alley for cars. Heavy trucks and cargo ships is another matter though. But then maybe biofuels aren't so bad if we can just combust them cleanly enough.
There's also plug-in hybrid cars which would fill the gaps that pure EV don't yet cover better than fuel cells, by allowing short commutes or restricted city centres to be pure electric with no emisions, while still allowing for quick refuels on longer journies and defeating range anxiety.
I think you missed this part ", if they solve the cost of the fuel cell itself. "
Until they solve the high cost of the fuel cell, no, they don't have an advantage at all. But I feel like it's reasonable to assume that it can be solved.
That is, I want to give hydrogen the benefit of doubt, but even then I see issues.
There could be niche usecases though, such as long range trucks or buses - if energy density is more important than fuel cost.
I think it's more likely we'll see a renewables-to-methanol/ethanol solution than a hydrogen economy. There are various proposed processes for this, including the USAF's nuclear-to-jetfuel one which claims $6/USgal amortised cost.
This claims that it is not yet competitive with untaxed natural gas from fossil fuels though:
http://www.biosng.com/fileadmin/biosng/user/documents/report...
Presumably, the taxes in Sweden are sufficient to make it feasible.
Natural gas is cheaper to make in a renewable manner than diesel (Europe is already mass producing natural gas from biomass) and has higher energy densities in J/g, which makes it suitable for transportation. The lower combustion temperatures do lower efficiency, but they also lower NOx emissions, which are a difficult problem for diesel.
As far as aviation is concerned, natural gas could be more efficient not only due to the lower weight, but also due to the fuel being "precooled" in its liquid state:
It has better energy density than ethanol and absorbs less water than ethanol and is not as good a solvent as ethanol (so engine parts last longer).
Has anyone calculated the maximum in KW/H or such that a normal house hold could sustain from standard street connections?
I don't feel like this is very relevant. The number of people who can't charge their daily need within 8 hours on a 10kW connection is on the order of one in every 10'000, if not less.
Or maybe you assume people charges at home in the same pattern as how they fill gasoline? I.e., they only charge when the battery is down to like 30%? That's probably not gonna be the case. If you have the option to charge at home, there's no reason not to plug it in every night.
A significant number of people will need to drive long distance 2 or more days in a row, every once in a while, so that has to be solved by rapid charging stations.
We will end up with ~350kW rapid chargers (the rough physical limit with water cooled cables), which is almost fast enough that it'd feel like filling gasoline does. But yeah, that will be dedicated facilities with grid storage scale batteries to smooth power consumption.
Just ended up taking the other car we had, if I needed to I could have just hung out at the supercharger for another 15 minutes.
So with the larger panel, a bit more than 40 kW.
And maybe 15 kW with the smaller panel if you want to be able to run other stuff. So 6.5 hours is enough to fully charge the biggest Tesla packs using a normal connection. Install a bigger service and you can do 200 kW in that time (I guess charging might slow down, but that's the facile napkin math).
It's also likely to be acceptable to only add 500 miles of range in the first night of charging.
Can somebody describe how - and why - oppositely charged particles get separated?
https://en.wikipedia.org/wiki/Fuel_cell#Types_of_fuel_cells....
Very tricky system.
An example of how a catalyst works can be presented in terms of energies. If a set of atoms (like, two atoms of hydrogen) can be in several different states (like, as a molecule or as two separate atoms), and there is an energy barrier between those two states, then the system "sits" in a potential hole. In order to get to another state, it has to increase energy to overcome the barrier. Catalyst can help with that, providing a new path between two energy states which doesn't require that high jump in energy.
However, when initial state (the molecule) has much lower energy than the final state (two separate atoms), catalyst doesn't help. There can't be a "low energy path to the top of the energy mountain".
Here we don't have splitting of neutral molecule into neutral atoms... but I'd still listen to an explanation.
I am afraid I won't dig into this now due to time reasons (I have to go back and read up stuff), but I just would like to give a remark regarding the concept you have sketched out:
The different states you describe do not have to be on different energy levels. A catalyst provides an alternative reaction mechanism that might have a different activation energy. It can result in a molecule of similar energy state, and, yes, you can have a reaction towards an energetically higher state.
I am sure there is many a publication that models the electronic transitions that occurs when gas molecules react with metals. Funky stuff, which involves number crunching with models of atomic/molecular orbitals or bands, and even more funky spectroscopic real time measurements of reactions.
Chemistry has gone a long way since alchemy, and there are many abstraction layers to get through if you want to have an explanation that would satisfy a physicists. At the end, you will move from empirical knowledge towards a world of quantum chemistry/physics. That is the beauty (or curse) of the discipline that is chemistry.
Now, if you are curious how such a thing works, I suggest look up the "Wilkenson catalyst" (a Rhodium based catalytic hydrogenation agent) as an example. It gives you an idea how organometallic compounds work at various levels of depth.
Where does that extra chemical energy come from? Other degrees of freedom of a molecule?
In general, I'd expect the reaction H2 -> 2H+ + 2e- not to be anything like dominant. It's the separation of charges which is the source of energy of the cell, and the energy is released along the path of those charges recombining. Or am I missing something here?
> there are many abstraction layers to get through if you want to have an explanation that would satisfy a physicists.
Yes, I'm interested in the actual physics of the process, not in the net chemical result...
Today I learned.
https://en.wikipedia.org/wiki/Hydrogen_internal_combustion_e...
It's not as safe as diesel, but no worse than gasoline, or even large Lithium batteries.
2016 he says the same thing. Fuel cells will never be the fuel for cars and no clear viable application. The issue is that you can't just go with hydrogen into a magical filter and split the hydrogen atoms and get energy without it costing multiple more then gas or electric.
Then you add platinum which you get from the contract with the devil.