Photovoltaic power generation is based on the principle of photovoltaic effect, using solar cells to directly convert solar energy into electrical energy. Whether it is used independently or connected to the grid for power generation, photovoltaic power generation systems are mainly composed of solar panels (components), controllers and inverters. They are mainly composed of electronic components and do not involve mechanical components. Therefore, photovoltaic power generation equipment Extremely refined, reliable, stable, long life, easy to install and maintain. In theory, photovoltaic power generation technology can be used in any occasion where power is needed, from spacecraft, down to household power sources, as large as megawatt power stations, as small as toys, and photovoltaic power sources are everywhere.
In 1839, a young French experimental physicist named Henry Becquerel discovered the photoelectric effect. When he experimented with two metal electrodes in an electrically conductive solution, he found that the device was exposed to light to increase the voltage. Until the end of the 1800s, some researchers, including Werner Siemens and others who were equally prestigious, had great hopes for the potential benefits of photovoltaic power generation, although many of them carried out selenium-related work (Willoughby. Smith, 1873; Charles Fritz, 1880), its photoelectric conversion rate is less than 1%. However, these researchers had to overcome the credibility problem because photovoltaics seemed to violate the laws of physics known at the time.
It was not until 1904 that Einstein published a paper on the photoelectric effect. Since then, the entire scientific community no longer regards photovoltaics as a scientific hoax. Einstein won the Nobel Prize in Physics in 1921, not because of his theory of relativity or other work.
Unfortunately, due to the low conversion efficiency and high production cost of selenium, the technology was left out until the 1950s. Researchers at Bell Laboratories developed silicon-based photoelectric conversion devices in the United States, and they were quickly engineered. And achieve a conversion efficiency of 6% (research work on the photovoltaic characteristics of other materials is still continuing in the RCA laboratory and other places).
After a period of initial craze and some ground applications, relative to the expected benefits, photovoltaic technology was once again cold due to its high cost. After that, in 1958, the first orbiting satellite powered by photovoltaics was successfully launched (“Voyager I”,
March 18, 1958), thus photovoltaics created a new era and a considerable market-science and technology. Regardless of cost, there is simply no other way to provide long-term, reliable power for the space vehicle. Moreover, almost all orbiting space vehicles have used photovoltaics as their power source since then.
The status quo of aerospace as the only market for photovoltaic applications lasted for 15 years. Although some ground systems were installed in the mid to late 1960s, including the buoy system in the sea of Tokyo Port, Japan, this market did not generate much interest until 1973, when the oil embargo caused energy interruption, countries around the world The government began to look for alternative energy sources. Coincidentally, as soon as the news of the oil embargo came out, the first meeting of ground-based photovoltaic power generation was held in Cherry Hill, New Jersey, USA. Later, from the early 1970s, when the capacity of photovoltaic modules was only a few hundred kW/a, it increased to nearly 200MW/a in 2000 (mostly used in rural and remote power systems). After 15 years of growth in the photovoltaic industry, by 2007, the total installed photovoltaic capacity increased from 100MW in 1992 to 7,800MW in 2007 (IECPVPS T12008 photovoltaic application trend report).
Today, the technology is widely used, from world communication networks, satellites, relay stations, and remote power supplies for communication equipment, to large-scale solar power plants, grid-connected residential and commercial buildings, to rural and remote lighting and pumping systems. Figure 1 shows the cumulative grid-connected and off-grid installed capacity of the countries in the report.