There was a great episode of the Planet Money podcast they recently re-ran that got into at least one of the factors of the drastically cheaper solar availabili

There was a great episode of the Planet Money podcast they recently re-ran that got into at least one of the factors of the drastically cheaper solar availability: https://www.npr.org/2019/08/14/751234092/episode-616-how-solar-got-cheap https://www.npr.org/2019/08/14/751234092/episode-616-how-sol... As I recall -- there was a boom of manufacturing plants for the solar cells in China as they were forecasting a drastically growing demand. The plants came online and boosted the supply greatly before the demand was high enough, so the prices sank. There's also apparently been a number of improvements to tooling in regards to the labor required to install solar panels that has generally lowered labor costs.