Clarity Fuel Cell

I've learned something today--I did not realize that Toyota was selling Mirais outright now. I still suspect they're being produced at a loss (especially when you factor in the 3 years/$15K of included fuel and very low number being produced), but this is particularly significant because it means they're willing to let someone take one apart. That was and is presumably the main reason for going lease only, and indicates a level of maturity of the technology.

They actually fit the stack and power electronics under the hood even in the prototype FCHV-adv Highlanders a decade ago (admittedly somewhat larger vehicles), and the power density of the stack and durability appeared quite good; I assume the maturity level of their technology has progressed significantly since then.

The thing is, you're talking about today. And today, you're right--a FCV is currently limited to basically California anyway, adding plug-in isn't going to get you anywhere farther outside the H2 station range, most manufacturers are giving away the fuel during the lease period so the drastically higher per-mile cost of H2 isn't a factor (plus FCV drivers are almost by definition at least economically comfortable), and it's taken a fair amount of effort to cram 300 miles of range into a midsized sedan. Likewise the larger economics--the goal of Toyota and Honda is very much to try and build out a hydrogen fueling infrastructure, so they're doing everything they can to encourage that (such as my above suspicion of selling vehicles at a loss to seed the market and giving away huge amounts of fuel with purchase/lease). They're trying very hard to get ahead of the chicken-egg equation.

I'm talking about many years in the future with a much less fossil fuel dependent transportation fleet. At the scale of hundreds of thousands of unsubsidized vehicles, rather than a couple thousand of subsidized ones, the inherent roundtrip inefficiencies of hydrogen may (not will, but may) have a real impact at the generation end (you quite simply might have to build three times as large a wind farm to get the same number of commuter vehicle miles), and the per-mile fuel cost at the consumer level may be nontrivial. Of course some breakthrough like cheap industrial biofuel-produced H2 might change that equation, but it's certainly not a given.

Likewise for the technology--what would be cramped and eating up your trunk today might fit just fine with the battery technology and fuel cell advancements ten years from now. Certainly there have been staggering improvements in both over the past ten years.

There will be a significant market for long-haul transportation fuel (road trips, interstate trucking, etc), which hydrogen is much better suited to than battery energy, but it's a tough competition for city driving, and for those who don't want to or can't afford to own two cars (which is exactly why I have a PHEV today despite being able to do >90% of my driving EV only even with only a 50 mile range), a PFCEV (or whatever) may one day be a very viable alternative to a bifurcated transportation fleet.

Just to note, on the plugging in, I feel like maybe you were doing it wrong. I've been driving a PHEV for two years now, and only ever drove it wherever and plugged in once when I got home and parked in the driveway. It takes an extra 5 seconds, give or take, to plug/unplug the car when leaving/arriving home (if I don't know I'm leaving again later), but that's it. And the result was I only make maybe one trip to a gas station a month. With the extra 10 miles or so of range on the Clarity, that'll probably be once every three months. The time and hassle saved stopping to refuel compared to when I had a liquid-fueled vehicle is easily worth the tradeoff.

But of course to some it won't be, and you might be in that category. Assuming a more robust and unsubsidized BEV/FCV transportation system in which H2 fuel costs 3x as much as charging your car at home as part of a smart grid, some people will just choose to drive on H2 all the time because they can afford it and it's worth it to them. Some will drive BEVs because that suits their needs or they want to save money. Others, I'm guessing, want the same sweet spot PHEVs currently occupy--cheap fuel for commuting most of the time, but no range anxiety and the ability to drive longer distances with more expensive fuel if necessary. PHEV owners are willing to pay extra for that now, I'm guessing PFCV owners will be some day as well.

Things could be different for high-rise dwellers, but I suspect if the plug-in transportation economy fleshes out chargers will be a given at any residential parking space (in the garage or on-street), and a smart grid will time charging for the least expensive periods (and balance loads in the area), resulting in a fairly inexpensive source of fuel. Unsubsidized EV charging at low-load times is already substantially cheaper than gasoline, and it would take a fairly massive breakthrough in biofuel-produced hydrogen to be competitive with that.

 

M.M & Slowjet. Mercedes-Benz will in fact have a Plug-in fuel-cell SUV on the market later this year.

 

@wodor Whoa! Interesting! There's hope yet for other plug-in fuel cell vehicles! I just looked up the Mercedes GLC F-Cell you mentioned. However, it does highlight the practical issues that were discussed earlier. Namely, even with the large SUV form factor there's still only room for a 4.4 kg H2 storage tank (smaller than the 5kg combined tanks in Clarity FCV) and a 13.8 kWh battery pack (smaller than the 17 kWh pack in the Clarity PHEV). This gives it an estimated range of 437 km (270 mi) on hydrogen and 49 km (30 mi) on battery, though this is the European NEDC rated range, which tends to be much higher than with EPA testing.

Cost will certainly be high, and it appears that it will not actually come to market until late 2019 in the US, possibly earlier in other countries (source). I hope it achieves at least some degree of success, enough to inspire other manufacturers to design a similar hybrid.

 

I have no idea how the station you're using is set up, but unless it's a direct-fill compressor type, the fill you get is based entirely on the pressure level in the tanks at the station. If it's a heavily used station, it's possible that the high-pressure stage (I'm assuming here it's a multi-stage station, which it may not be) wasn't at full pressure, which would explain an incomplete fill, but it wouldn't have anything to do with the cost of pressurization, just the throughput on whatever is adding gas to the high-pressure-stage tanks (or that the tanks were getting low because there hadn't been an H2 delivery recently).

The power used by a compressor as a factor of pressure doesn't vary much, and certainly not enough to be worth stopping at 90%. For reference, I am assuming, possibly incorrectly, that your station is not a slow-fill one because to the best of my knowledge the station we built was the only one that existed, and you'd probably notice because it would take quite a while to complete the fill (it also used to be difficult to get Toyota to certify a direct-fill station for use with their vehicles due to cryogenic requirements).

Question: The way you worded it sounds kind of like you're making a connection between 66mi/kg and the level of fill in the tank. Were those two separate pieces of information, or were you somehow inferring one from the other?

Interesting! Looks like this was actually announced two years ago, which shows how much I've been keeping up with the industry. Glad to see it, and it'll be interesting to see how it works. I vaguely remember Mercedes-Benz having a prototype FC vehicle way before Toyota or any other automaker did (something like 20 years ago), so I'm actually a little surprised that other automakers seem to have ramped up more quickly than them.

 

I confess to being satisfied that word-of-Honda confirms my educated guess.

Having a mile/kg readout is sure an improvement. We needed to write down the kg per fill and mileage and used that to manually calculate fuel efficiency.

 

My 4th fill up was on 6th. Total of 17kg for 1095 miles for a 64.4 m/kg. For me, it has been consistently showing a range of 315-325 miles.
The car gives the best mileage in city traffic (40-50mph). When driven above 70mph, the efficiency drops quite a lot. I was driving in 75-80mph range on a flat highway and the available range was dropping lot faster than the odometer was rising. I have backed off a bit and drive 70-75mph now.

 

The curve will vary depending on the drivetrain design and aerodynamics of the vehicle, but keep in mind that any car, including ICEs, are generally most efficient around 50mph and take a huge hit in fuel economy once you get above 60 (probably 30% decrease between 55 and 75mph).

So really, it's behaving impressively well--if the efficiency isn't dropping off until 70mph, Honda has done an exceptionally good job with the aerodynamics and drivetrain design.

This page has a graph comparing the efficiency curve on a Sonata and Ford F-150. The truck peaks way down at 30mph because of the horrific aerodynamics (and maybe an engine optimized for low-end torque?), but both suffer a precipitous drop starting way down at 55mph. I think people lack an appreciation for just how much impact on fuel consumption speed has because in the past vehicles just didn't provide much real-time feedback on how much fuel was being used.

 

Yes, the drop in efficiency seems to be gradual between 60 and 70mph and then becomes steeper at higher speeds. This was a good feedback for me because I was planning a ~280 miles round trip with no access to FC refueling station along the way and now I'll drive around 65mph to avoid running out of fuel.

 

M.M., I might have to question that “any car”. The author you cited even states that at low speeds the mpg suffers due to tranny not being in highest gear ratio. With the Clarity in EV mode this is not a concern and you have to factor in more regen at lower speed city vs hwy driving. Indeed I see better mpge at speeds under 40 than over. But of course there is no way to factor out the regen.
So in electric cars, slower is more efficient since there are essentially no gear ratio inefficiencies, more regen is avaiable, and aerodynamic drag is lower. However I concede your point if we’re talking about conventional ICE vehicles.

 

You're correct, and I worded that badly; the point I was really trying to make is that any car sees a dropoff once you get above 60mph. As even the graph I linked to shows, while the peak in an ICE passenger car is around 50mph (which I think is common), the peak in a truck was half that, and will depend entirely on vehicle aerodynamics and drivetrain. EVs, as you note, tend to do better the slower they go, though even if that were 100% true there is bound to be an inflection at a point where parasitics outstrip improvements in energy going to the wheels and the efficiency drops again.

I ran across a calculation of theoretical optimum speed per parasitic load on a Volt; with no climate control or lights it's something like 20mph, and with the heater on it's closer to 40.

 

I forgot to add... thanks for the great info you are sharing w us on this and other threads.

 

Has anyone driven from SF to LA?

I'm thinking the red is the best color for fuel cell version. I have the vortex blue on the electric version.