Volkswagen has taken the diesel-electric running gear and plug-in charging system of its previous Golf V based TwinDrive hybrid, and transferred it into the new Golf VI.

In addition to giving its fuel-sipping hybrid prototype a fresh new look, VW has allocated 20 of the Golf TwinDrives to be entered into a German government-sponsored trial designed to determine the efficiency and feasability of a renewable-energy-powered transport infrastructure.

In VW’s TwinDrive system, the electric motor does the bulk of the work, with the diesel engine only cutting in when the electrons run out. With the plug-in system allowing the Golf TwinDrive to be charged from a mains outlet, overall efficiency (and maximal eco-friendliness) can be also be achieved - particularly if the electricity used comes from renewable sources. Fuel usage of as little as 2.5 litres per 100km is reportedly possible with the TwinDrive system.

The German government trial will see all 20 cars being used in regular day-to-day driving, with the mains electricity being used to charge them generated from renewable sources. The trial is slated to begin in early 2009, and, if all proves successful, VW hopes to bring a production version to market soon after.