BMW may have already greenlighted plans to build an eco-friendly, "breakthrough green supercar" that will be available to the public by the end of 2012, according to AutoWeek, confirming earlier reports. To be clear, it will not look exactly like the BMW M1 Homage Concept displayed above, although the supercar will draw inspiration from it, a source privy to early design proposals said in the article; there are also more details this time.

The source said that the new BMW supercar "would be a modern-day M1, with high levels of performance, lively dynamics and fuel consumption and emissions ratings" on par with or better than those of a 5-series, according to the report. "The idea is to take the supercar to a whole new level of environmental compatibility using technology and materials already in wide use today," the source said.

What does that mean? In a nutshell: an all-aluminum spaceframe that's a sturdier version of the one in the Z8; carbon-fiber body panel technology; and a reworked version of the twin turbo six in the 335i with variable vane turbochargers and a more advanced fuel injection system.

On the green tech front: "Alternatively, BMW may also look at employing an electric motor and lithium-ion battery pack similar to that proposed for its new 7-series hybrid to lift the new supercar's overall output even more," the report said. "Other technology under consideration is a kinetic-energy recovery system similar to the setup BMW is developing for use in F1 next year." There's no word yet even on the basic layout of the car (will it be mid-engine, rear-drive? probably, but that's not confirmed).