Tesla Weighs New York, Arizona, Idaho to Lift Solar Cell Output

Tesla Inc. isn’t waiting around to see if Elon Musk’s 100-gigawatt solar ambition is feasible — it’s already acting on it. The company is evaluating multiple sites across the US to begin manufacturing solar cells, according to people familiar with the matter, turning what sounded like a moonshot just weeks ago into an active industrial push.

One component of the plan: expanding production at its Buffalo, New York, factory, said the people, who weren’t authorized to speak publicly. Capacity there could reach 10 gigawatts, they said, which would be equivalent to 10 nuclear plants.

Longer-term, another scenario would involve ...