The chief executive of Tesla is, in a post-Steve-Jobs world, the stand-out visionary voice in Silicon Valley. There’s no question about that.

But with each product launch – or, in this case, a building launch – it seems he needs both more time and more money to realise his own ambitions.

The more he achieves, the bigger the task, and budget, seems to get.During a typically scorching Tuesday afternoon in the Nevada desert, near Reno, Mr Musk told a group of journalists about his global manufacturing ambitions.

We had just had a tour of the new Gigafactory, Tesla’s $5bn (£3.8bn) 3,200-acre battery-manufacturing plant that has already begun production but will not be in full swing until about 2020. At that point, it will have the largest physical footprint of any building in the world.

By making battery cells here, Mr Musk hopes he will be able to innovate faster and cut out about 30% of the cost.

The factory is a tie-up with the company that already makes Tesla’s cells, Panasonic.