Economic Evaluation of Solar Power and Fossil Energy in a House in Mashhad

The need to use of renewable energies to achieve the more electrical energy production، is one of the most important and most basic fields to find the new resources of renewable energies. Among these resources، solar energy، for many reasons such as easy access and convenience of becoming electrical energy and so on، have more utility. Today، with economic and mass production of solar cells or photovoltaic (PV) system، the use of solar energy has been highly regarded to supply the energy needs of buildings and their independence and even sales the excess of that needed to power companies. In this study the feasibility of using a photovoltaic system to supply the electrical charge required for a residential unit in Mashhad city، has been investigated. For this purpose، technical - economic analysis of the use of this system has been analyzed using the COMFAR Software. The results show that providing the use of photovoltaic systems، the internal rate of return in a residential unit on an average consumption of 400 units per month is equal to 19. 15 percent and capital return period is 9 years and net present value is equal to 733. 14 million rials.