Let me start by copying the numbers that Plug In Cars published...
Everything is, I think, in grams of CO2 equivalent per mile.
Conventional ICE gasoline......451
HEV gasoline........................323
FFV corn ethanol E85............371
FFV switchgrass E85............119
CNG ICE..............................391
Diesel ICE............................386
Renewable diesel-soybean......92
Electricity EV U.S. Mix..........333
Electricity EV CA Mix............172
Electricity EV Coal................579
Electric EV NGCC.................243
Then yours...
Electricity EV German Mix..........160
Combustion Car ...............320
Average of All New Cars........208
VW Polo Diesel Blue Motion........132
That right?
EV on CA and German grids are about the same (172 and 160).
Average of all new cars is 208, higher than 172 and 160. And the 172/160 numbers will drop as grids transition to more renewables.
Plug In is using US cars which are not as efficient as European cars. And data from 2012, which might make a difference. The 451/208 difference is not surprising. Our fleet mileage in 2012 was probably below 25 MPG.
VW Polo at 132 is cleaner than an EV on CA and German grids. Of course that's the absolutely cleanest sold ICEV that we know about. And we're comparing it to grids which aren't the cleanest we have.
How about all the countries that have very clean grids? If we're going to compare to the best ICEV shouldn't we also use EVs on the cleanest grids? Best:Best.
There are at least 17 countries with 90% renewable grids and about half a dozen with 100% renewable grids.
http://k.lenz.name/LB/?p=6525