Following his announcement of Tesla's dramatic Supercharger station expansion, CEO Elon Musk touched on another pet project: Hyperloop. The rapid transit system would connect downtown Los Angeles with San Francisco, 380 miles away. Musk told the crowd that more details for the project would be available on June 20th.

"Even if I'm wrong about the economic assumptions, it would be a really fun ride."

Musk denigrated California's current high speed rail plans, pointing out that the bullet train currently under consideration will be both the slowest in the world and most expensive per mile — "not the superlatives you're looking for." In contrast, the Hyperloop would be "a cross between a Concorde, a rail gun, and an air hockey table." Musk joked, "even if I'm wrong about the economic assumptions, it would be a really fun ride."

It sounds far-fetched, but the billionaire inventor has been enthusiastic about the project for some time. Last year, Musk claimed that his imagined train system would go "3 or 4 times faster than the bullet train" or twice the speed of an aircraft, shuttling people from LA to San Francisco in under 30 minutes. It's possible that the Hyperloop could even be self-powering. "If you put solar panels on it, you generate more power than you would consume in the system. There's a way to store the power so it would run 24/7 without using batteries," he said.