Elon Musk recently did an interview while in Copenhagen, Denmark. The whole thing was pretty good, and many interesting topics were covered, from the philosophical to the practical. The most news worthy revelation probably has to do with battery capacity. When asked when an electric car would be able to drive 1,000 kilometers (612 miles), Musk says that a Model S has already been driven about 800 kilometers (500 miles), though that was at relatively slow speeds. So he expects that a thousand KMs will definitely be possible in 2017, maybe even next year.
Then when asked how far he thought his EVs would be able to go in 2020, he answers that he expects that 1,200 KM (746 miles) will be possible. From the context, it's not entirely clear if he's still talking about a record at slow speed or if he meant the official range ratings for regular driving, but late he does say that he expects battery technology to improve at about 5-10% a year. Even if we take the upper bound of that prediction, we wouldn't get from the current 300 miles of range of the top-of-the-line P90D (300 miles) to 746 miles, so he was probably talking about how far things could be pushed rather than what Tesla owners would get in regular driving.
Still, at 5% improvement per year just in the batteries (they could also make other parts of the vehicle more efficient and squeeze more range that way), we get from today's 300 miles of range to 382 miles in 2020, and at 10% per year, we get to 483 miles in 2020. That's more than enough for almost everyone, especially with Supercharger stations sprinkled all around the world.
Here's the video of the interview:
Another interesting discussion during the interview is about Musk's philosophy for his company. When asked about how he feels about the increasing competition from other automakers who are announcing electric cars (such as Porsche), Musk says that he's pleased about it, and that his goal is to accelerate the advent of electric transportation, which is why he made all of Tesla's patents available for free to any competitor who wants to use them.
That's quite a refreshing perspective in this world where most companies seem to care more about having a market to themselves to maximize profits rather than to accelerate the rate of progress.
Another interesting tidbit from the interview: Musk expects fully autonomous self-driving cars to be ready within about 3 years, but he thinks it'll take a few more years for regulators to allow them.
They also discuss the importance of stationary battery storage to make wind and solar power more dependable, and how a large fleet of electric vehicles can help the grid absorb a lot of that intermittent energy, especially if variable pricing serves as an incentive.