[gallery link="none" columns="1" size="full" ids="47662"] source: Audi UK As Audi prepares to launch a range of new plug-in hybrid electric models in the UK, we take a look back at the company’s first hybrid model, the 100 Avant quattro Duo of 1989 Audi Duo paved the way for hybrid technology three decades ago Plug-in charging and energy-regenerative braking pioneered in 1989 Audi 100 Avant quattro Duo, which was followed by Audi 100 Avant Duo in 1991 and Audi A4 Avant Duo in 1997 Lessons lea...