Featured Toyota Launches Production Model Fuel Cell Bus

A world first, a successful fuel cell bus.

Bob Wilson

 

This has the potential to approach a rare practical application of a fuel cell vehicle.

A bus is typically used on a fixed metropolitan route/loop with many hours of operation a day. Advantages compared to passenger fuel cell vehicles include that it can be supplied by very limited fueling infrastructure - consisting of just a single (very expensive) H2 station which could also supply dozens of like vehicles. Rapid refueling could also be advantageous compared to current battery charging speeds.

 

Lots of fuel cell buses. I'm not sure what makes this one successful. Hopefully the 2020 Tokyo Olympics fuel cell bus experiment will go better than the 2010 Vancouver olympic fuel cell bus. That had hydrogen trucked in quebec. I wonder if these will have hydrogen shipped in from australia. Who knows? I'm sure the experiment will go better as Tokyo has more people and the government already knows some of British Colombia's mistakes.

This experiment has been run dozens of times. BEV buses have won every time. The difference here may be that Japan after Fukishima has a very poor electrical grid, where hydrogen may help especially if lots of Olympic dollars are put into it. Really the cost disadvantages of hydrogen aren't going to affect a city Tokyo's size with only 100 busses. Let the experiment continue.

 

But, but, ... hydrogen!

 

Everything old is new again? These were everywhere in the city when I was growing up.

What the original Red Rocket looked like in Toronto

 

They are fuel cell, so have a battery to capture regen braking energy. They aren't hybrids though; that is Toyota marketing. There is just the one motive source, electric motor(s).

An BEV bus will have a larger battery, and could recapture more brake energy. Then batteries are getting cheap. There is going to be savings in maintenance for the BEV bus. Hydrogen tanks require annual inspections, and have a set expiration date like CNG. In addition, there is the fuel lines and the fuel cell itself to think of.

Steam was the more powerful choice for locomotives, but lost out to diesel-electrics much lower operation costs.

 

BEV buses make way more sense than fuel cell. Range is not an issue. Recharging is not an issue. Hmmm.... and save a hell lot more money in fueling and maintenance cost.

Toyota still trying to push their non EV support. GM, the past biggest fuel cell supporter, is not marketing (I mean lying) anymore.

 

An engine motivates. Even if that motion doesn't result in physically moving around the place. You got chemical energy being converted to heat energy, and that then converted to kinetic energy. Have that kinetic energy spin a generator, and you get electrical energy, which can be converted back into kinetic energy by a motor. That is the basic energy flow of a series hybrid. The hybrid term applies because it has two devices devices that produce motion; the motor than provides propulsion and the engine that spins the generator.

A fuel cell does not motivate. It converts chemical energy directly to electric. The way it works is very close to a battery. The only device making motion on a FCEV is the motor propelling it. One motive source means it is not a hybrid. If it was, BEVs would be hybrids too.

Toyota applied the HSD trademark to their FCEVs in the hopes that the Prius success would transfer. They are the only one to apply the hybrid term to a FCEV.

 

The main problems with fuel cell buses so far have been operating costs and downtime. At least currently fuel cells can't quickly shift power so they do require a fairly big battery to perform like a task like this. In the case of toyota's fuel cell bus, it looks like they are using 2 mirai fuel cells (2x114 KW) and probably 3.2 kwh nimh battery. IMHO that battery is still too small to provide full efficiency;-) Let's say a bus uses a 40 kwh lithium pack and a plug instead of that nimh pack which would cost around $10,000 more to the manufacturer (price of a diesel bus is around $450K, these fc busses are probably at least twice that). DOE has found fc busses in the US fleet get around 6.5 mpge, there goal is 8 miles/kg and maybe the new toyota does that. I doubt the toyota will do much better unless you do jc08 instead of real world.

The protera bev bus gets 21 mpg and byd bev bus's gets 19 mpge. That means that electricity needs to cost at least twice as much for fueling cost for a fc bus to be lower. At least if you add a plug fuel economy would go up a great deal. In Japan a GGE of electricity costs about $9 US, this is much higher than the US but still not very high for a bus given the efficiency (a byd bus would cost $0.5/mile in fuel).

Maintenance costs and down time are also much higher for fuel cell busses than bev busses. Hopefully toyota can get closer here than in the past. A fuel cell bus needs all the stuff of an electric bus + high pressure hydrogen tanks, gas regulators, and fuel cells - all of these add to maintenance and down time.

Its a tough slog for a fuel cell bus, and it looks worse if renewable energy is used. My guess is if you put in a 40 kwh battery pack and plug, the average fuel economy after electriicty is used up would be around 12 mpge only running the fuel cells in their most efficient range and mostly directly to the motors. A camry engine as purely a generator might get 8 mpg in charge sustain mode in such a set up.

This is an experiment though, and undoubtedly if you add bigger batteries and a plug, and make the fuel cells and tanks more affordable and reliable you can get it to work. I'm not sure it will work in the next 10 years though. Hell once you have a 40 kwh plug-in hybird fuel cell bus, I wonder how much lower maintenance would be if you replaced the fuel cell stack and hydrogen tank with a camry engine, generator, and gas tank?

Actually it can't operate well without a battery given current fuel cell technology, the fuel cells take too long to change power levels. It would be more like accelerating a ship, than what a bus driver expects, and that could cause hazzards if the busses are sharing the road with other vehicles. Here the battery acts like a buffer, providing for acceleration while the fuel cell gets working, and storing energy when the fuel cell is slow to slow down.

 

A fuel cell most resembles a primary battery, a one-way discharge device versus a bi-directional battery. So calling it a hybrid makes sense. The battery provides the primary power to the motor and regenerative braking. The fuel cell maintains the battery SOC within the operating range.

I like seeing the Miria fuel-cell power assembly in other vehicles with depot fuel and maintenance. But that doesn't solve the economic problem of hydrogen.

In high pollution areas like the Port of Los Angles, it sort of makes sense except for the cost per ton-mile. Railroad engines would be another good application. Large boats would also make some sense. But all of these are subject to the same economic problem, the cost of hydrogen.

Better solutions are methane fuel cells and/or hydrogen from a liquified carrier like methane or my favorite, ammonia. Highly compressed hydrogen just doesn't make sense.

Bob Wilson

 

Only if you stretch the use of the hybrid term beyond how it is applied to vehicles. In them, hybrid is used to refer to a vehicle having two different types of devices making motion or producing a force. Usually an ICE and an electric motor, but it also includes trucks with an ICE and hydraulic motor.

Batteries and fuel cells don't produce a force; they are just energy supplies. Under technical and regulatory definitions they are treated as fuel tanks. Put a plug on a FCEV and you can call it bi-fuel like an ICE with gasoline and CNG tanks, or BEV with a secondary and primary battery.

What makes the Prius a hybrid isn't the gas tank and battery, but the ICE and motor.

A Volvo group does have a working fuel cell that runs off diesel. The plan is to offer it as a replacement to generators on sleeper cab trucks and boats.

Fuel cells should be a good fit for locomotives and other large series hybrids. The huge diesels in ships already approach 50% thermal efficiency though. Fuel cells would have to really drop in cost to replace one of those directly driving the propeller.