Mechanically the two cars are essentially the same. They use the same battery pack, the same motor, and the same range extending engine. The platform architecture is shared between the two cars and they should feel more or less the same to drive.
Again, the differences are more subtle. We asked Opel how the car differs from the Volt, and the response was interesting.
A feature offered on the Ampera and not on the Volt is that of an EV charge-holding option. What this means is that in the Opel, you can delay using the EV mode until such a time as it suits your route. You can begin your journey with the range-extending engine providing the power, but should you then reach a city that (in Europe, particularly) might have restrictions on non-EVs, and cruise around the city using only the EV power.
This also means that should you have a longer commute, you're using the EV mode in the most logical manner, where local emissions are more important and the approximate 40 mile EV range will last a lot longer than it would on a freeway.
The mode has clearly been a decision of Opel based on how Amperas are likely to be used in Europe, though it wouldn't surprise us to see Chevrolet implement it in due course as it looks like being a very useful feature.
Money, money, money
We asked Opel what the price difference would be between the European market Ampera and the European market Volt, and the answer is about 1,000 Euros (about $1,400). This will mainly be down to trim level differences, though the benefit of that charge-holding option will likely be of use to buyers too.
There is still a large difference in price between the Ampera and Volt available in Europe and the Volt on sale in the U.S, though this can be explained in part by where all the vehicles are produced - initially at least, the European Volt and Ampera will have been produced in Michigan and imported (the Ampera then receiving a battery control module developed by Opel itself). There are plans to produce the Ampera in Europe in the future.
The Ampera should go on sale at around 42,900 Euros, which is about $59,900 at current exchange rates. This price is the German figure, and includes the sales tax or 'Value Added Tax' that many European countries pay on products. The U.S. Volt in comparison starts around $41,000. Both prices are quoted before governmental and local incentives that may lower the price. Some European countries will be able to apply for a rebate of up to 7,500 Euros ($10,500).
So similar and yet so different, it'll be interesting to see whether the Volt or Ampera comes out on top in Europe, and whether either can persuade people to part from their significantly cheaper and still highly efficient diesel cars.