It’s long been thought that the next model to emerge from BMW’s i division for enviro-friendly cars would be badged an “i5” (“i7” has also been rumored), positioning the vehicle somewhere between the electric-only i3 city car and plug-in hybrid i8 sports car. The last we heard is that the i5 will be a sporty sedan targeting the Tesla Model S, and now we have a few more details by way of a report in Germany’s AutoBild.

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Rather than go the electric-only route, the i5 is said to be adopting the plug-in hybrid system known as “Power eDrive” that BMW showcased in prototype form late last year. Power eDrive differs to current plug-in hybrid systems due to its reliance on high-power electric motors and next-generation high-density batteries.

BMW’s prototype version of Power eDrive combined a turbocharged 2.0-liter four-cylinder engine with two electric motors for a combined output in excess of 670 horsepower. One of the electric motors was integrated with the car’s transmission to help the engine power the rear wheels, and the other was used to power the front wheels.

In the i5, peak output is said to be capped at around 640 hp. The electric-only driving range, meanwhile, is said to be about 78 miles. Though this is considerably lower than the range of the Model S, it should make the i5 considerably lighter (due to a smaller battery) and thus more dynamic.

The basis of the i5 will likely be BMW’s modular “35up” platform debuting in the 2016 7-Series, with the car's overall size said to be similar to the long-wheelbase version of the current 5-Series sold in China. A 2018 arrival date is being reported.

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Note, BMW is not alone in targeting the disruptive Tesla Motors [NSDQ:TSLA] sedan, with both Mercedes-Benz and Porsche thought to be working on Model S rivals of their own. Another German automaker, Audi, is looking towards Tesla’s next model, the Model X, with an electric crossover of its own likely to be badged a “Q6”.