The cost of the PbC once it scales up to auto production level would be about 250 dollars. That is in range of a high end lead acid battery.

Compare the cost of a NiMH battery (3k or so) or a Li-ion battery (10-20k). The savings for a simple change far outclasses what heavy hybrids or full electrics can do dollar for dollar.

The numbers you are comparing are not even close to the same energy capacity.

LiFePO4 can be bought for ~$.33/Wh

A flooded golf cart battery is the very cheapest per Wh, and they are about $.10/Wh assuming 100% capacity (which you can actually only use 50-80% of, boosting cost to $.13-.22/Wh).

The whole point of a "mild hybrid" such as what's discussed in the article is that you can get some of the benefits of a hybrid with a much smaller battery and motor.

You can spend a bunch of money on a full hybrid system and get large increases in fuel economy, or you can spend a small amount of money on a "mild hybrid" system and get a small increase in fuel economy. What he's saying is that, for the small amount of money involved, a 15% gain is pretty decent.

15% better fuel economy is certainly noticeable even if it's not huge. Lots of car buyers prioritize fuel economy these days. Not every improvement has to be an order of magnitude.

Moreover in many countries the taxes are related to CO2 emissions, which will result in savings as well.

As electric cars become more popular, expect taxes on them to go up as well. Germany recently scrapped fuel tax breaks for biofuel. In the long run, it's unlikely for tax breaks to be maintained on popular items of consumption.

Rational tax policy would levy taxes in proportion to the externalities produced by any given activity. Cars which emit air pollution generally produce more external costs than those which don't, so it would be reasonable to expect taxes on them to remain higher forever.

How about a full-electric car - 100% co2 reduction. Why make this car, with its dual power systems. When on gas, its lugging the electrics around - has to hurt gas mileage. The electrics have to lug the gas engine around. All for 15% reduction, when 100% reduction was possible. Why do it? Because its some profit point for the manufacturer.

No,not fuel economy. CO2 reduction.

What are you proposing the difference would be here? CO2 emission is directly proportional to gasoline consumption in a gas-powered car.

No amount of carbon reduction is noticeable in any meaningful sense to the driver of the vehicle. Doesn't mean it's not important.

Well, it's strongly correlated with your spending on fuel, and that's potentially quite noticeable :-).