A hand to Walmart to get involved in the development and operation of advanced more efficient trucks.

The same approach would give improved results with large inter-city and city buses (with larger batteries)

45.5 kWh! how far can a class 8 truck travel on that?

dursan, it's a series hybrid, not EV.

Walmart has reach the saturation point typical of all big box stores, like K-mart. Their only way to continue to grow is through technological advancement, and moving production to cheaper copuntries. Although, it's hard to believe they could find anything cheaper than china. So, really, they need to change the technology of operations. It would be nice too if they could get the toxic fume smell out of their stores. It's one thing to sell toxic waste because some people think it makes them smell better, it's another to expose all your customers to a high dose of toxic brain rotting fumes as they seek less toxic products.

The other use for the batteries and capstone is to provide power for heating & cooling when the driver is resting.

Roger, like you I cannot believe a series hydrid Gas Turbine/Electric could beat the SFC of a modern diesel AT CRUISE. If that were true why haven't we seen GE shift from Diesels to gas turbines in their locomotives?

I'm with CarCrazy and Herman.  Something like the HyperBar boosted low-compression diesel would have a substantial efficiency advantage over a Capstone.  Heck, you might be able to use a Capstone C30 as its turbocharger.  The batteries would eliminate the need to operate at low load very much (if at all).

I see a lot of focus on just the microturbine vs the diesel engine. It just may be the overall machine makes it more efficient. I noticed it was air bearings, so there is no motor oil needed for lubrication. This would be a cost savings in maintenance. No intake for a radiator was needed resulting in 10% efficiency gain in fuel mileage. The diesel engine needs a radiator intake which lowers the efficiency of the truck going down the road. Another seems to be lower emissions, although I see no specs on this yet. As I look at a capstone website, they are looking at 25 million hours of reliability. That would be a big cost savings to Walmart there. The turbine seems to be quite simple. Is it possible to use waste heat and turn it into useable energy for refrigeration, further propulsion.

@Jeff,
The radiator of a semitractor takes up only a small portion of the total frontal drag. As such, it can easily be blended into the frontal area without incurring any drag penalty. The portion of air that flows thru the radiator is very small in comparison to the total amount of air that is deflected and passed on by, so, the radiator contributes very little to the overall aerodynamic drag of a semi truck, on order of less than 1% in my estimation.

Let's wait and see the mpg figure of this new hybrid design, if they will ever release the mpg figure at all. Our prediction is that the efficiency of this new Walmart contraption will fall far short of the 10-mpg that the state-of-the-art Diesel + aerodynamic-optimized semitruck is capable of!

@gryf,
Fuel cell + reformer + gas turbine + electric drive train seems way too complicated for the 60% efficiency quoted on the referenced link. Advanced turboDiesel with turbocompounding is hitting close to 50% efficiency already.
Future trucks will just simple use carbon-free H2 in tanks + FC stack at ~60% efficiency and be done with.

Of course, if the gas turbine is paired with something like an organic Rankine cycle engine bottoming cycle to generate useful power from the waste heat, you've got to have a condenser and the cooling drag problem is right back in your face.

There are many examples of fuel cell reformer research on the web. Most involve SOFC and Natural Gas, e.g. Bloom, Tokyo Gas, Redox Power Systems, Ceramic Fuel Cell Systems - BlueGen, and UTC. If the fuel cell is a PEM or HT-PEM they could use alcohol based fuels, possibly using a reformer similar to the Monsanto exhaust driven reformer (http://www.greencarcongress.com/2013/08/20130820-sall.html).
NOTE: Diesel efficiency gains have usually involved adding waste heat utilization (check Directions in Engine-Efficiency and Emissions Research (DEER) proceedings) or other fuels - Reitz, Bengt Johansson (Lund U.), this adds more complexity, e.g. Turbocompounding or a Rankine bottoming cycle.
Delphi has spent years researching an SOFC APU for Class 8 trucks using diesel fuel reformers (http://www.hydrogen.energy.gov/pdfs/review13/h2ra002_hennessy_2013_o.pdf).
and http://www.netl.doe.gov/publications/proceedings/01/seca-workshop/pdf/mukerjee.pdf) and could be added to the Walmart truck.
Even if H2 is the fuel (we hope produced using solar energy or renewable fuel), the best approach is to reduce the size of the fuel cell like the GE bus (http://gofuelcellbus.com/uploads/GE_IFCBW_2011.pdf) or the Vision Motors Tyrano truck and use batteries for the predominant energy source, remember all FCEV are electric vehicles.
Finally, the GE patent also discusses using the fuel cell with an ICE (described here http://spectrum.ieee.org/energywise/energy/fossil-fuels/ge-to-muscle-into-fuel-cells-with-hybrid-system).

Let's review: Advanced Diesel = diesel engine, e.g. Cummins ISX12 (3000 lbs) + SCR (think reformer) + turbocompound (think gas turbine w/o burner). Still needs a 1000 lb transmission and gets 50% efficiency. Or fuel cell + reformer (1000 lbs) + gas turbine (250 lbs) + battery (~1000 lbs) and nearly 70% efficiency.

@Bernard,
The 1/3 rule of thumb was formulated when air was allowed to flow into and out of the radiator regardless of cooling needs. A radiator is sized for much much higher cooling needs (120 kW of engine power) than for just the power used at hwy cruise, or just barely about 15kW of power. New cars with controllable louvers to drastically reduce air flow into the radiator are realizing significant reduction in aerodynamic drag. In a semitruck, the trailer is formidable in size and contributes the bulk of aerodynamic drag.

@gryf,
The SCR and the turbocompounder are tiny and are included in the wt. of the engine.
On the FC + reformer + Gas turbine + battery, you forgot to mention the electric motor and motor controller. The latter items probably won't weigh any more than the transmission, however, they are much more costly. For trucking use, cost is more important than weight. However, for aircraft use, weight is more important than cost.

Roger,

Cooling needs are proportional to overall drag. That's because the engine is creating the torque to overcome that drag. Think about it: the trailer creates tremendous drag. The engine generates enough power to overcome that drag. The engine is less than 50% efficient, so over half of the fuel's energy is dissipated as heat, using radiators. Radiators are air-cooled, which creates drag.

The 1/3 rule applies at speed (no one cares about drag at idle!). Variable radiator louvers lower drag somewhat, but not by >97%, as you assumed. The efficiency gain is in the single digit range.

Then again, if you really have worked-out a system that limits cooling drag to under 1%, you should patent it and let the planet benefit. You will make millions, and the world will save billions.