Advantages of Photovoltaic Power
Photovoltaic solar power is one of the most promising renewable energy sources in the world. Compared to nonrenewable sources such as coal, gas, oil and nuclear, the advantages are clear: it is totally non-polluting, has no moving parts to break down and does not require much maintenance. A very important characteristic of photovoltaic power generation is that it does not require a large-scale installation to operate, as do conventional power generation stations. Power generators can be installed in a distributed fashion (on each house, business or school) using area that is already developed and allowing individual users to generate their own power, quietly and safely.
Rooftop power can be added as more homes or businesses are added to a community, thereby allowing power generation to keep in step with growing needs without having to overbuild generation capacity, as is often the case with conventional large scale power systems. But even when photovoltaic power is compared to other renewable energy sources such as wind power, water power and even solar thermal power, there are some obvious advantages. First, wind and water power rely on turbines to turn generators to produce electricity. Turbines and generators have moving parts that can break down, require maintenance and are noisy. Even solar thermal energy needs a turbine or other mechanical device to change the heat energy of the sun into mechanical energy for a generator to produce electric power. Photovoltaic power, by contrast, is generated directly from the sun. PV systems have no moving parts, require virtually no maintenance and have cells that last for decades.
Most commercial PV cells are manufactured from crystalline silicon, although research is identifying other suitable materials, some of which are now being marketed. The individual cells are grouped into modules and encapsulated between a sheet of glass and a backing material (also often glass) within a frame. Modules are then connected together to provide the voltage and current levels required to meet a particular load.
A complete PV system incorporates a wide range of other components, such as cabling, batteries and inverters. These "balance of system" components provide the necessary interface between the PV modules and the electricity distribution grid or other specific application.
PV systems are both reliable and environmentally friendly. Furthermore, costs have fallen, efficiencies have improved and the more advanced crystalline silicon cells achieve efficiencies of more than 24 percent under laboratory test conditions and 15 percent in commercial applications.