The hybrid wins in the hybrid vis-a-vis full electric, UNLESS all of the charging is done with solar, wind power, hydro or nuclear sources.

Why? The conversion efficiency or heat rate of a fossil fuel electric plant is only 30-35% less transmission loss of 8% and battery losses of 10%, recharging power supply losses of 8% or so. In addition, an electric car simply moves the point of pollution to the power plant.

A petroleum burning hybrid converts 70- 80% of the BTU value of fuel to the motion of the vehicle. So if your goal is to get the pollution out of the cities to the power plants elsewhere, EV's will do that. If you want to minimize CO2 per mile, hybrids do that at least three times more effectively.

So, why is EV cheaper per mile? In dollar-cost it is cheaper because coal is cheaper than petroleum per BTU, MUCH CHEAPER. Coal is not cheaper on a tons of CO2 per mile basis (note: about 49% of the US electricity is produced with coal).

So if you drive an EV with grid based recharging, you are really driving a 50% coal-burning car.  You won't feel it or see it, but the environment will.

Though I haven't analyzed a VW diesel vehicle that gets 50+ MPG, I suspect that that would be less polluting on a CO2 basis, than a 2009 Prius. However, the nasty micro particles of high-compression combustion of diesel is a whole 'nother hidden health issue, that may rival the mercury-from-coal-in-fish problem.

( I mostly ride a bike )