What is Solar Photovoltaic?
Photovoltaics are best known as a method for generating electric power by using solar cells to convert energy from the sun into electricity. The photovoltaic effect refers to photons of light knocking electrons into a higher state of energy to create electricity. The term photovoltaic denotes the unbiased operating mode of a photodiode in which current through the device is entirely due to the transduced light energy. Virtually all photovoltaic devices are some type of photodiode.
Solar cells produce direct current electricity from light, which can be used to power equipment or to recharge a battery. The first practical application of photovoltaics was to power orbiting satellites and other spacecraft, but today the majority of photovoltaic modules are used for grid connected power generation. In this case an inverter is required to convert the DC to AC. There is a smaller market for off-grid power for remote dwellings, boats, recreational vehicles, electric cars, roadside emergency telephones, remote sensing, and cathodic protection of pipelines.
Perhaps not unexpectedly, a significant market has emerged in off-grid locations for solar-power-charged storage-battery based solutions. These often provide the only electricity available. The first commercial installation of this kind was in 1966 on Ogami Island in Japan to transition Ogami Lighthouse from gas torch to fully self-sufficient electrical power.
World solar photovoltaic (PV) installations were 2.826 gigawatts peak (GWp) in 2007, and 5.95 gigawatts in 2008, a 110% increase. The three leading countries (Germany, Japan and the US) represent nearly 89% of the total worldwide PV installed capacity. According to Navigant Consulting and Electronic Trend Publications, the estimated PV worldwide installations outlooks of 2012 are 18.8GW and 12.3GW respectively. Notably, the manufacture of solar cells and modules had expanded in coming years.
Germany was the fastest growing major PV market in the world from 2006 to 2007. By 2008, 5.337 GWp of PV was installed, or 35% of the world total. The German PV industry generates over 10,000 jobs in production, distribution and installation. By the end of 2006, nearly 88% of all solar PV installations in the EU were in grid-tied applications in Germany. Photovoltaic power capacity is measured as maximum power output under standardized test conditions (STC) in "Wp" (Watts peak). The actual power output at a particular point in time may be less than or greater than this standardized, or "rated," value, depending on geographical location, time of day, weather conditions, and other factors. Solar photovoltaic array capacity factors are typically under 25%, which is lower than many other industrial sources of electricity. Therefore the 2008 installed base peak output would have provided an average output of 3.04 GW (assuming 20% � 15,200 MWp). This represented 0.15 percent of global demand at the time.
The EPIA/Greenpeace Advanced Scenario shows that by the year 2030, PV systems could be generating approximately 1,864 GW of electricity around the world. This means that, assuming a serious commitment is made to energy efficiency, enough solar power would be produced globally in twenty-five years� time to satisfy the electricity needs of almost 14% of the world�s population.
