"Tesla is incredibly important for the future of sustainable transport and energy generation. The fundamental purpose, the fundamental good that Tesla provides is accelerating the advent of sustainable transport and energy production," Musk said told Recode's Kara Swisher . "The success of Tesla is, by far, the biggest forcing function for the other car makers to get into … electric cars."

So why does Musk push himself? To hear Musk tell it, he is trying to save planet Earth. Literally. Musk wants Tesla to be successful so the world moves away from driving cars that run on petroleum-derived fuel.

This from a man who is already worth more than $20 billion, according to Forbes .

In late October Musk finally said he was working a much more manageable schedule of 80 to 90 hours a week.

Providing alternative methods for mass transportation that do not depend on petroleum-derived fuel is key to slowing global warming.

"Yes. It's very important for the future of the world. It's very important for all life on Earth. This supersedes political parties, race, creed, religion, it doesn't matter. If we do not solve the environment, we're all damned," Musk told Swisher.

We know we'll run out of dead dinosaurs to mine for fuel & have to use sustainable energy eventually, so why not go renewable now & avoid increasing risk of climate catastrophe? Betting that science is wrong & oil companies are right is the dumbest experiment in history by far …

Building an electric car company that will one day mass produce electric vehicles is not easy, even for an entrepreneur like Musk.

"It's trivial to start a car company," Musk tells Swisher. "It is insanely difficult to make it successful. … So as a startup, a car company, it is far more difficult to be successful than if you're an established, entrenched brand. It is absurd that Tesla is alive. Absurd! Absurd."

Musk attributes Tesla's survival to this point to "excruciating effort" and "hundred-hour weeks by everyone," he told Swisher.

"There wasn't some other way to do this, Kara," Musk insisted.

Musk has said he would give over the job of running and building Tesla if there was someone who would be better at it.

"If you have anyone who can do a better job, please let me know. They can have the job. Is there someone who can do the job better? They can have the reins right now," Musk told The New York Times in August.

Currently, Tesla's patents are available for anyone to access.

"The whole point of Tesla is to accelerate the advent of electric vehicles. And sustainable transport and trying to help the environment. We think it's the most serious problem that humanity faces. I'm not sure if you know it, but we open sourced our patents, so anyone who wants to use our patents can use 'em for free," Musk told Lesley Stahl on CBS' "60 Minutes" in December.

"If somebody comes and makes a better electric car than Tesla and it's so much better than ours that we can't sell our cars, and we go bankrupt, I still think that's a good thing for the world," Musk said.

See also:

Elon Musk on working 120 hours in a week: 'However hard it was for [the team], I would make it worse for me'

Elon Musk is stressed, says he's sleeping on Tesla factory floor and has no time to go home and shower

Elon Musk: Up all night, at times depressed, taking the blame for Tesla production delays