This pv magazine writer must stand corrected. In our prior coverage of Tesla’s developing solar power system, we projected that the rooftop would only be able to hold ~100,000 solar modules on a 43 acre structure that was about 1.9 million square feet. Further research has taught us that the structure will approach 5.8 million square feet of rooftop space, and it is now clear that this will indeed be a monstrous 70 MW rooftop system.
To back up our new information, we’ve attached a roughly drawn Helioscope system analysis: Tesla Gigafactory – 70 MW – Section 1 of 27 (PDF download).
A tweet from Tesla started this analysis, in which the company showed a picture of an east-west racking structure utilizing ~350 W 72 cell solar modules, based on Tesla suggesting approximately 200,000 modules would fill out the 70 MW facility.
Gigafactory 1 will have the largest rooftop solar array in the world upon completion – 70MW or roughly ~200,000 solar panels pic.twitter.com/OMkfXg3r7a
— Tesla (@Tesla) September 13, 2018
In the Helioscope analysis above, a single portion of the Gigafactory structure was modeled. This subsection held 7,510 modules, to total 2.59 MW of capacity. The site can be found here on Google Maps.
This one chunk of the building is greater than 200,000 square feet, and with an end structure size of 5.8 million square feet – that means an additional 27 units of this size are expected, getting us to the 70 MW value. The east-west solar module alignment will allow Tesla to maximize the number of solar modules on a limited amount of roof space. While the PV system will produce less electricity than if they were aimed due south and at the optimal angle, the low price of solar modules means it still makes great economic sense – and it is probably the model that gets the most electricity out of the rooftop.