Tesla CEO Elon Musk has said he wants his company to be building 500,000 electric cars a year by 2018.

That's an ambitious goal, but at least one necessary piece of the puzzle is already in place.

Tesla's factory in Fremont, California, previously produced that many cars when it was a joint operation of General Motors and Toyota.

DON'T MISS: Tesla's new manufacturing chief has a lot on his plate (Model 3, mostly)

But Tesla employment at the site could soon exceed levels from the old GM-Toyota days, suggests SiliconBeat.

That's because the Fremont City Council recently approved a major expansion of the Tesla plant, which is expected to boost employment.

The current Tesla factory was previously owned by New United Motor Manufacturing Inc. (NUMMI), which built mostly compact cars like the Chevrolet Prizm, Toyota Corolla, and Pontiac Vibe.

Tesla Model S undergoing assembly

Tesla Model S undergoing assembly

It was shut down in 2010, and Tesla took over that same year after negotiating a deal with Toyota. The electric-car maker also received a government loan to cover costs of converting the facility to electric-car production.

When it closed in 2010, NUMMI employed 4,700 people, but Tesla now has about 6,200 workers at the 5.3-million square-foot site.

The expansion signed off by the Fremont City Council will reportedly add 4.6 million square feet, and add 3,100 jobs.

ALSO SEE: Does Tesla have plant, permits to build 500,000 electric cars a year?

No timeline for completion of the expansion was discussed in documents filed with the city, however.

It would make sense for Tesla to aim for completion in time for the ramp up of Model 3 production.

With a promised 215-mile range and $35,000 base price (before federal, state, and local incentives), the Model 3 is expected to make up the bulk of Tesla's expanded production.

Tesla Model 3 design prototype - reveal event - March 2016

Tesla Model 3 design prototype - reveal event - March 2016

Tesla unveiled a prototype of the car in April, and has said it will start production sometime next year.

The Model 3 generated considerable consumer interest, with Tesla receiving around 400,000 reservations within a month and a half of the unveiling.

But Tesla has not yet hit its first announced production deadline for any of its three preceding models.

MORE: New orders for Tesla Model 3 won't be filled until mid-2018

The Model 3 launch is also complicated by the need for Tesla to ramp up lithium-ion battery pack production at its "gigafactory" near Reno, Nevada.

The gigafactory is needed to produce enough packs to meet Model 3 demand, and afford economies of scale to keep the car's base price low.

Any schedule that emerges for the expansion of its Fremont factory may give further clues to how quickly the company can ramp up Model 3 production after it starts.


Follow GreenCarReports on Facebook and Twitter