Solar photovoltaic panels have been developed for several years

The average dropped drastically for solar cells in the decades leading up to 2017. While in 1977 prices for cells were about $77 per watt, average spot prices in August 2018 were as low as $0.13 per watt or nearly 600 times less than forty years ago. Prices for and for c-Si were around $.60 per watt. Module and cell prices decline. [pdf]
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