 The European version of the Volt , the Opel Ampera ( known as the Vauxhall Ampera in the United Kingdom ) , was unveiled at the Geneva Auto Show in March 2009 and also was exhibited at the 2009 Frankfurt Auto Show . Opel developed the battery control modules for the Ampera at the Opel Alternative Propulsion Center Europe in Mainz @-@ Kastel , Germany . The production version of the Ampera was unveiled at the 2011 Geneva Motor Show . The Ampera is assembled at the Detroit / Hamtramck Assembly plant , Michigan . 
