What a sweet little car!
I have several questions though: What is NVH?
Looking at the diagram of FEV assessment, is bigger better, or smaller? I looks to me as though bigger is better, but in that case why is the still costly fuel cell REm (whodat?) given as having favorable costs?

It is impressing to see a 20kW generator with such a small engine only 295 cc. No wonder that the Wankel engine is superior with regard to weight and packaging when compared to cylinder engines or fuel cells. It is also good to hear that it is superior with regard to noise and vibration (NVH). As it has been licensed for road traffic I presume that the engine is currently euro 5 compliant. The Wankel engine’s cost disadvantage must be related to economics of scale. Do a million of these engines per year and I doubt it would cost more to make than a cylinder based engine of comparable power.

A wild guess on costs.

The Fiat 500 would probably sell for 14000 USD in the US and 4000 USD would be expenses for the powertrain. The PHEV Fiat 500 would probably cost 22.000 USD in the US where 12000 USD would be for powertrain cost with 6000 USD for the 12 kwh battery, 2000 USD for 60kW electric motor and power electronics and another 4000 USD for the Wankel motor with generator and power electronics. For these cost to be realistic it needs to be produced at over 50000 units per year.

Would it sell? I my opinion, yes, as it will easily achieve over 200 mpg in annual consumption for the average driver when factoring in that it will run on electricity in over 80% of the miles driven. Also it will be superior in terms of noise and vibration when compared to ICE vehicles. It will still not be economics for the vehicle owner but people buy vehicles for many other reasons than to be economical. Moreover, in the US and everywhere else the 22.000 USD price will be subsidized with several thousand USD because drivers of such vehicles will have to be compensated for their contribution to minimize emissions and making their economies independent of oil price chocks and oil embargoes.

Rotary engine = low weight and small size, but also poor thermal efficiency (even compared to a standard otto cycle engine)

If he wankel has poor thermal efficiency, it still manages 60/gallon, although of course the 500 is a very small car, and the acceleration above 37mph may be poor.

The EREV logic goes that most of the time your driving will be covered by the battery, but the rare occasion that you need to drive longer distances the genset helps out.. so that it does not really pay to spend too much (weight, bulk, money) to achieve a few more miles per gallon.

I've got my head around the assessment diagram at last
REM = Range Extending Motor.
The further the point is from the center, the better.
(What confused me is that it sometimes is more, sometimes less in numeric terms, as they have gone for a qualitative ranking instead)

The only thing the wankel is lot worse on is fuel consumption, but at least for this small car it still turns out very respectable figures.

295 cc Wankel

It depends on how you rate displacement. The RX7 was 1200 cc but with the three lobes it was more like 2400 cc. Either way, it is a nice small engine.

Looking at the ratings against the fuel cell version, it is not clear to me if they are simply comparing plug-in units to generate the power, or if they have allowed for the several parts of the system which could be discarded by going all electric with a fuel cell.
This could substantially alter the balance in weight, packaging and costs towards the fuel cell/battery plug in.

From all the positive comments - put it on the market. Profits and volume will do the rest.

Small turbines run at perhaps 3 kHz, not 100 kHz. At 100 kHz you'd need a wheel smaller than your pinky fingernail or it would blow up. Leakage and friction at that scale would make for abysmally low efficiency.

I share the distaste for inefficient Wankels (the very high surface area of the combustion chamber guarantees high heat losses), but if the car runs on wall power 80% of the time the average fuel economy hits 300 MPG. If the entire US fleet could achieve that, the ~3 trillion miles/year driven by light vehicles would require only 10 billion gallons of gasoline compared to the current 100+ billion. OPEC would cease to exist and Hugo Chavez would be strangled and hung on a meathook in Caracas.

The small Wankel engine is small and light for its power output. Since the engine/alternator can run in the engine's "sweet spot" the efficiency is much better than acceleration from a stop through clutch and transmission. The diagram shows that it is not the cleanest nor most efficient method, but when cost, size and weight are considered it is not bad.

This is the right size genset for a vehicle of this size. With the engine operating continuously, the car becomes a Battery Buffered Vehicle (BBV) providing range only limited by refueling opportunities.

I would rather have a trade-off of reduced battery size for a more efficient engine than the Wankel, perhaps an OPOC HCCI (opposed piston opposed cylinder homogeneous charge compression ignition), or a single-cylinder true Atkinson cycle, with double crank, version of Fiat's 900 cc Multiair twin.

Treating the vehicle as a BBV would reduce initial price, the greatest impediment to consumer acceptance of efficient vehicles, while providing real world liquid fuel economy of over 100 mpg.

BUILD THIS CAR !!!! Folks will buy gas when affordable.