This is a tricky question for reasons that hearken back to mention of where panels are assembled vs. where their components get made.
In addition, we can use several metrics to quantify a company’s size, and depending on which one you choose to go with, you’ll get different answers.
Based on annual sales, First Solar, an Arizona company we’ve already discussed, boasts yearly sales of over $250 million. That’s far and away the highest sales. Unsurprisingly, First Solar also leads in the number of gigawatts sold, which sits at 1.9GW yearly.
If you’re just looking for name recognition and the neat-o factor, the answer would have to be Tesla. The company continues revolutionizing most things it gets involved with, and its solar roof looks great and seems to produce a lot of happy customers and solar power.