The economic feasibility of both photovoltaic (PV) stand alone and grid connected systems have been studied taking into account the prices of PV components in 1984 dollars. For stand alone PV systems, a comparative economic analysis with diesel generators is given. Different types of loads to be supplied by the stand alone PV or diesel systems are considered. Each load type is characterised by the ratio between energy demand during day time to that during a complete day. This ratio is denoted by "load factor". The load factor plays a major role in determining both array and storage size. A fixed array tilted at an appropriate angle is considered for stand alone systems to minimize maintenance and operating costs for applications likely to be in remote areas where no technician is available. The impact of power availability on PV system cost has been thoroughly investigated herein.
For PV grid connected central power plant a rather sophisticated, elaborate and efficient tracking system is considered to minimize the overall cost of 1 kWh produced by the power plant. The major factor in grid connected systems is how much oil can be saved by installing such a power plant so that a developing country government can export more oil (or decrease their oil import) to improve its balance of payment. The advantages of large scale PV grid connected systems are :(1) no storage batteries are needed and (2) prices of PV modules drastically drop when large systems (MW range) are required. An extremely important factor for a large scale PV grid connected power plant is that about 50% of the overall cost can be paid in local currency. Such costs are installation cost, labour cost, wiring cost, power tower cost, tracking motors cost,.., etc.