Those infograms do a great job. Thanks Erasmo.
By "are we bothered?" I was wondering if anyone had a good argument supporting hydrogen. Or perhaps they might be concerned that hydrogen might become dominant with all the backing it has. The 'we' also inferred this community of motorcyclists and EV enthusiasts. There are lots of applications for hydrogen out there. I should have qualified the topic a little better or thought of a different title. Apologies.
Here are some arguments in support of hydrogen fuel cells. The comparison targets are 200-300 mile battery EVs with 100+ kW DCQC, similar in capability if much cheaper than Model S today.
Quick Refueling InfrastructureFor: A single FCEV can recharge quickly, about as fast as gas. 50+ miles of range added per minute, or 10x as fast as a Tesla Supercharger. This also means a single "refueling" bay can service many more cars per day.
Against: Until home natural gas reforming becomes common and cheap, most people will "fill up" a FCEV at public infrastructure. Tesla Model S owners charge about 10% of their total miles using Superchargers, so you still need roughly the same total number of bays to support a given number of vehicles. 10x as fast per "refill" but need to charge 10x the total number of miles using public infrastructure. Hydrogen has better "surge" capacity, in theory. Imagine thousands of vehicles needing to fill up as people depart a large sports game or
other gathering - this may overwhelm the slower charging infrastructure.
Fuel cell filling stations are also expensive to build, relative to DC quick charging. Ballpark figures: 8 bays at a hydrogen filling station cost around $2M, 8 bays at a Tesla DC QC station cost around $200k. Hydrogen filling stations will suffer the same chicken-or-egg problem as DC quick charging - who will build the stations if there are no cars? Who will buy the cars if there are no stations? Maybe state-level actors or natural gas companies will step in to kickstart the refueling network, in the same way that Tesla has done with the Supercharging network.
Producing hydrogen on-site with electrolysis is inefficient, and requires significantly more total grid energy to day from the grid than DC quick charging (though demand can be smoothed and generated using off-peak electricity). DC quick charging can be smoothed as well, using storage batteries ($$$ - 500 kWh of gigafactory cells may add $100k to cost of each SC station).
Cheap CapacityFor: The fuel cell stack is expensive, but increasing the total amount of energy stored is relatively cheap - simply add more or larger tanks. Passenger vehicles have volume limitations, but volume is almost a non-issue for grid storage applications. Even given relatively low round-trip efficiency, it's better than idling wind turbines when renewable generating capacity exceeds demand.
Against: Depending on the ratio of storage capacity to power requirements (typically 3:1 or lower), battery storage may still be less expensive than fuel cells. And if V2G becomes a practical application, storage capacity may be
nearly free.
One video I watched covered a brewery that had a few self contained hydrogen generators. They took a feed of natural gas, created the hydrogen and generated electricity from it. They also captured the carbon dioxide and used it in the bottling process. I guess it must be more efficient than just generating electricity using a gas turbine.
It's not more efficient. If it was more efficient (more energy per kg of natural gas) then we'd use it in generating plants today.
Hydrogen might be the better option in lorries and buses. Even ships perhaps? At that scale it would make sense to store hydrogen in its liquid state. Expensive though. It's a shame nuclear is so hazardous.
Buses, sure. Planes may run into the same volumetric limitations as batteries, though the weight is less of a concern. Ships, maybe?
What I find rather comical is that hydrogen fuel cells still require a big battery to act as a reservoir. They can't just be switched on and throttled up and down like a petrol engine. The battery provides the power until the fuel cell has had chance to get up to speed and so on. So you end up with all the engineering required for a battery powered EV plus an expensive fuel cell and all the plumbing and extra safety measures for the hydrogen tank! Bonkers or what?
Not necessarily. Some early FCEVs had large battery packs due to low power density / output of the fuel cell stack. Most recent FCEVs have small batteries - the Toyota Mirai has a 1.6 kWh onboard battery for example, similar in size to the closed-loop Prius (and like the standard Prius, provides no way to charge the battery from the grid).
I think the more likely practical FCEV will actually be an EREV. A moderate-sized onboard battery (10-20 kWh should be relatively cheap soon) paired with a small fuel cell stack (30-50 kW) and large hydrogen tanks, not unlike the BMW i3 REX. This gives the convenience of home-charging as with a traditional EV, but also the reduced infrastructure demands and increased charging speeds of hydrogen and petrol filling stations for trips.
final end-state will be an extended range EV: a moderate-sized onboard battery (15-30 kWh) providing 50-100 miles of "everyday" range, and then a small fuel cell stack (30 kW)