The SPV (solar photovoltaic power) system is the simplest form of converting solar energy to electricity. However, its high capital cost makes it one of the costliest resources of energy, ostensibly with implications of high fixed charges. Despite is high cost, over the last 40 years, the price of the module, which is the main ingredient of SPV, has fallen from $99.61 per watt in 1975 to $3.84 in 2007.