Elon Musk master plan for Tesla, next generation platform for cheaper vehicles.

 Elon Musk master plan for Tesla, next generation platform for cheaper vehicles. 

The electric-car maker will outline "the path to a fully sustainable energy future for Earth" during its March 1 investor day, Musk tweeted. Tesla has already said its expansion plans and next-generation platform for cheaper vehicles will be on the agenda.

Tesla Inc. will present a third version of Elon Musk's "master plan" next month, almost a full year after the chief executive officer said he was working on a next edition.

The electric-car maker will outline "the path to a fully sustainable energy future for Earth" during its March 1 investor day, Musk tweeted. Tesla has already said its expansion plans and next-generation platform for cheaper vehicles will be on the agenda.

Musk first published a master plan for Tesla in 2006, outlining ambitions to build a high-performance sports car and use proceeds from that product to gradually build more affordable electric vehicles. Ten years later, he authored "part deux," which detailed ambitions to build solar roofs, expand into all major auto segments and develop self-driving capability.

Much of the second master plan remains unfinished business. The rollout of the solar roof was a bust, Tesla has just four vehicles in volume production and its cars aren't autonomous. Tesla's claims about self-driving capabilities and Musk's role in shaping them are now subject to investigations by the US Justice Department and Securities and Exchange Commission.