The opening episode focuses on solar cells. Today, solar PV is the fastest-growing energy source in the world. Yet that wouldn’t have been possible without a history of innovation spanning decades. From the breakthrough discovery of a practical silicon solar cell at a US phone company in the 1950s to the rapid scaling up of solar panel manufacturing in China in the 2000s, these advances – along with supportive policies – have made solar energy cost competitive globally. (Source: IEA)