The 2013 Volk­swa­gen Eco Up!, which runs on nat­ural gas, bio­methane, or gaso­line, was launched in Europe but it’s not com­ing to the US. The alt-fuel car comes with a 1.0L three-cylinder engine mod­i­fied to run on nat­ural gas, and is one of six natural-gas pow­ered vehi­cles in Europe. Edmunds thinks a case could be made bring­ing at least some NGVs to the US.