The final production version of Toyota’s long anticipated Prius Plug-in Hybrid Electric Vehicle –or PHEV for short- will make its first public appearance at the upcoming Frankfurt Motor Show on the 15th of September.

The Japanese automaker has been field-testing the Prius PHEV for quite some time now, but starting from next Spring, it will go on sale in Europe as well as other markets including select dealerships in the U.S. with a nationwide launch to follow in 2013.

The addition of a compact lithium-ion battery with plug-in capability increases both the efficiency as well as the car’s all-electric driving range to around 13 miles or 21 km at speeds of up to 62mph (100km/h). Once the battery is depleted the PHEV reverts to its hybrid mode and operates as a regular Prius.

According to the automaker, the Prius Plug-in Hybrid vehicle can be fully charged in approximately three hours from a standard 110-volt electrical outlet, and in 90 minutes with a 220-volt connection.

Toyota said that based on the European homologation cycle, the Prius PHEV returns up to 128.4mpg UK (equal to 106.9mpg US and 2.2lt/100km) with corresponding CO2 emissions of 49 g/km, almost half the standard model.

“While some debate the relative merits of electric cars, the new Prius Plug-in Hybrid offers drivers the best of both worlds; extended EV driving range for shorter journeys in towns and cities, while the efficient hybrid petrol engine gives the car uncompromised long range capability and the very low fuel consumption of the standard Prius,” Toyota said in a statement.

In Europe, the new Prius Plug-in will join an expanded Toyota hybrid range consisting of the Prius, the British-built Auris hybrid, the new, seven-seat Prius+ and the soon-to-be-released Yaris hybrid.