Just how big a deal is the " gigafactory" that Tesla Motors says it's going to build to make batteries for its electric cars?

-- It's projected to cost $5 billion between now and the year 2020. Tesla expects to invest about $2 billion. Partners — who it's rumored could include Apple and Panasonic — would invest the rest.

-- The plant would eventually employ about 6,500 people, Tesla says.

-- At its peak the factory would produce 500,000 vehicle batteries per year, the company projects. That's more than the current combined output from all such factories in the world.

-- The facility would cover about 10 million square feet. That's more than twice the size of the Mall of America.

-- There's surely going to be stiff competition from the four states that Tesla says are its finalists to be the factory's location: Texas, New Mexico, Arizona and Nevada. Bloomberg News says there's going to be "a bidding war."

-- This huge investment is one of the keys, analysts say, to Tesla's effort to keep cutting the cost of its cars, which now start at $71,000. It's hoping to debut a model that retails for about $40,000 sometime next year.

As veteran auto writer Micheline Maynard writes for Forbes, Tesla founder Elon Musk is "taking on a manufacturing project that might give pause to companies with much more experience." She also notes, though, that "whether it's shooting rockets into space, or building a $70,000 electric luxury car ... Musk has never shied away from a challenge."

He's a big dreamer, as All Tech Considered has said before: " A Closer Look At Elon Musk's Much-Hyped Hyperloop."

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