This is good for stop and go driving but using hydrogen as a supplemental fuel - via an on board hydrogen production unit would be useful for highway driving.

Please note: hydrogen as a supplemental fuel means that the diesel and the hydrogen fuels get mixed in the engine. This mixture not only increases the truck's highway mileage but it also keeps the engine running cooler and cleaner.

A nice "accident" about hydrogen supplemental fuel units is that they improve the cold weather capabilities of bio-diesel burning vehicles.

Seems like this would also help a lot with reducing pollution from diesel soot, which seems to be produced in greatest quantity when engine load and/or RPM changes suddenly.

I'm also curious about whether heavy trucks like this can potentially capture more energy from regenerative breaking than hybrid cars. They rely heavily on engine breaking, though this is often banned in urban areas. Also, given their high payload capacities, having two or even 3x as many batteries to capture more breaking energy would have a much smaller impact on overall weight (and volume) than they would in a passenger car.

Hydrogen is not the silver bullet to all our problems. Never will be.

A rarely mentioned thing about hydrogen generation from water is that it requires distilled water, not tap water. Otherwise you end up with a tank resembling a shower head with too much hard water ran through it. Distilling water requires energy, reducing the overall efficiency.

Batteries aren't that bad of a storage device, and having a large battery bank could allow the truck to run air conditioning or heat without idling the engine, something which truckers often resort to. This alone would make it a worthwhile setup.

I never offered it as a silver bullet, only as a means to improve highway mileage of large vehicles.

While you are correct about the hydrogen units working better with distilled water - the amount of energy required for the water distillation is fairly low compared to the overall increase in the vehicle's efficiency.

This of course assumes that the distilled water is being produced by reasonable means.

Don't semis spend most of their time on the freeway? I guess a truck that's delivering stuff to NYC would be good for this, though. If I were to redesign trucks, I'd make them pure electric and set up a rail system of sorts on the freeway (maybe add a few electrified lanes, to keep the cost down?) to increase an electric truck's range. This has far reaching implications, because many truckers need to spend the night in the truck on their trip, and on some nights, the weather is so inclimate that they need the engine to idle overnight so they get A/C or heating. Electric vehicles do this with much less electricity, and a properly designed electric truck could probably do that overnight while still absorbing a decent charge.

As for electricity costs, maybe add RFID or a data rail to explain who the bill goes out to?

These hybrid trucks will help a great deal, even if there are few highway advantages. I work in the trucking industry (parts department) and the majority of our customers use their trucks in stop-and-go situations; road paving, city garbage, county garbage, concrete pouring/pumping, construction, and farming (our biggest customers). If one of our largest customers was to switch all of their 500 trucks to these Kenworth hybrids (the majority of their trucks are already Kenworths too) there would be HUGE savings.

Well, there maybe a whole bunch of commentaries from which I can extract that there would be even greater improvements possible, but I do indeed congratulate Kenilworth and this attempt to sober up parts of the huge fleet that crusades across the U.S., 24/7.....

Let's get the ball rolling, you can count on that the next big manufacturer is going to find an even more impressive way to generate savings and a smaller environmental footprint for the Company.

That's the good thing about hitting Global Warming from this end. It makes you save money - and makes you feel better, too!!

We owe this much - and much more, to our kids!

Most trucks work on in-town deliveries, such as running between construction sites, delivering bottled water, etc.

As anyone who has passed a big rig going up a long hill, only to have it fly past you on the other side knows, these things generate a ton of kinetic energy, especially when hooked to a heavy trailer. Riding a regenerative brake on the way down would recapture a TON of it. GE has already started doing this with trains, I'm glad Kenworth is finding a way to make it happen in big trucks! The gains will be huge! Plus the fuel savings to the user will be pretty damn big too. Win win! I wonder what the cost premium is.

As others have already stated, this is perhaps a small net gain for long haul situations, but could be very helpful in short hauls. Utilizing a larger bank of batteries could also help with reducing idling, a major issue that trucking companies are trying to reduce for fuel cost savings.

As a city dweller, though, I'd be happiest to see lower volumes of particulates from cleaner diesels and the acceralation assist that the hybrid electric design allows. Acceleration from a dead stop is always a huge producer of particulate pollution from older dirty diesels.

Just google "hybrid garbage truck" several related items will pop up.
2 trucks are being tested in NYC. These are Oshkosh, I believe.
Also, Peterbilt will sell them starting next year.
UPS is testing them also.
Of course that would work for School buses, postal trucks or any delivery truck. The more stops, the higher the savings...
Some of these are diesel/hydraulic rather than diesel /electric, same idea. in stop n go traffic a lot of energy is needed to accelerate, then wasted as brake heat when stopping.
All these concepts use regenerative braking, then apply that saved energy to re-accelerate.
Estimated savings are between 30 to 50 %, depending on route and such.