 Another key design decision was to develop the concept car based on a new family of common powertrain components for electric propulsion , which initially was called the E @-@ Flex Systems , “ E ” stands for electric drive and “ Flex ” for the different sources of electricity , but later was renamed Voltec drive system . The E @-@ Flex or Voltec powertrain is an attempt to standardize many components of possible future electrically propelled vehicles , and to allow multiple interchangeable electricity @-@ generating systems . The E @-@ Flex powertrain has the potential to adapt the vehicles to pure battery electric , to fuel cell @-@ powered or to several other sources of energy to create electricity on board , such as engine @-@ generator sets ( genset ) fueled by gasoline , diesel , biodiesel , ethanol fuel ( E100 ) , or flex @-@ fuel ( E85 ) . Regenerative braking would also contribute to the on @-@ board electricity generation . On October 2006 the E @-@ flex powertrain was selected for the new propulsion architecture and the name Volt was chosen by General Motors . 
