The question of the timing for release of the Model Y would seem to be one almost entirely of production capacity. In a back and forth on a comment thread on ELECTREK- an article was brought to my attention about Fremont expansion.
Tesla gets the green light from the city for its massive factory expansion in Fremont
I guess I had sort of assumed this expansion was to
get to 500,000 vehicle capacity by 2018. But in fact the announced expansion concerns ultimately increasing the output of Fremont to
1mil vehicles by 2020.
Here is my thinking- Tesla needs to produce about 100,000 S & X each year, plus preorders for 400,000 Model 3 (and any additional Model 3 orders from here forward). So in Tesla's perfect world here's what the next 3 years could look like:
2017: 100K S&X, 100K M3 (200K total production)
2018: 100K S&X, 400K M3 (500K total production, Max Fremont capacity)
2019: 100K S&X, 400K M3 (500K total production, Max Fremont capacity)
2020: 100K S&X, 600K M3, plus 300K of additional capacity (1mil total production, Max Fremont stage 2 capacity)
A lot of how this will follow thru we can probably gauge by the end of this year with how many Model 3s they can actually get out the door. If it's only 20-50K, then they many not reach Max production output until mid 2018.
Regardless, I think by early to mid-2019 they will have passed existing preorders and then some. With that in mind, and knowing they're production capacity is going to be doubled the following year, I think it would be safe to start production of Model Y in 2019, even if it's only 50,000 cars, because it's a minor impact short term- and it would seem likely that as they open the expanded production that they tool for both M3 and MY simultaneously.
Just some thought rumbling around my brain.