Electricity can be produced from sunlight through a process called photovoltaics (PV). "Photo" refers to light and "voltaic" to voltage. The term describes a solid-state electronic cell that produces direct current electrical energy from the radiant energy of the sun. Photovoltaic cells are made of semi-conducting material, most commonly silicon, coated with special additives.

In this section we discuss the following technical issues of photovoltaics (PV):

• How it works
• The solar resource
• Photovoltaic cells
• Photovoltaic modules and systems
• Inverters to convert direct current into alternating current
• Environmental considerations, including energy payback time

Besides we pay attention to the application of photovoltaic systems. PV system applications basically fall into one of two categories:

• Stand-alone applications: systems operating independently of the grid network
• Grid-connected applications: systems are tied into the grid network

Finally we discuss deployment issues for both stand-alone systems as grid-connected systems