From Wikipedia, "Swanson's law is the observation that the price of solar photovoltaic modules tends to drop 20 percent for every doubling of cumulative shipped

From Wikipedia, "Swanson's law is the observation that the price of solar photovoltaic modules tends to drop 20 percent for every doubling of cumulative shipped volume." (Swanson's law is a special case of Wright's law for more general manufacturing costs, and is a misnomer.) https://en.wikipedia.org/wiki/Swanson%27s_law https://en.wikipedia.org/wiki/Swanson%27s_law