Efficiency of solar cells and modules
Every year, the problems of energy shortage and environmental pollution are getting worse and worse: fossil resources are being depleted, and human consumption of electricity is constantly growing. In this context, it is not at all surprising that scientists continue to improve alternative methods of generating electricity.
Along with other clean sources, such as wind, tides, sea waves, heat of the earth and others, do not lose their importance and solar power plants, traditionally built from batteries based on photovoltaic cells. The main requirement for solar cells is the highest possible efficiency, the highest possible efficiency of the conversion of solar radiation into electricity.
The catch with solar cells is that although the radiation flux (radiating from the Sun and reaching the Earth) has a specific power at the upper limit of the atmosphere in the region of 1400 W / m2, nevertheless in cloudy weather near the Earth's surface on the European continent it turns out only 100 W / sq.m. and even less.
Efficiency of a solar cell, module, array — The ratio of the electrical output of a solar cell, module, battery to the product of the solar energy flux density per area, respectively, of the cell, module, battery.
Efficiency of the solar power plant — The ratio of the electrical energy generated to the solar energy received during the same time interval to the surface, which constitutes the projection of the area of the solar power plant on a plane normal to the sun's rays.
The most popular solar panels today make it possible to extract electricity from the sun's rays with an efficiency of 9 to 24%. The average price of such a battery is about 2 euros per watt, while industrial production of electricity from photovoltaic cells today costs 0.25 euros per kWh. Meanwhile, the European Photovoltaic Association predicts that by 2021 the cost of industrially generated "solar" electricity will drop to €0.1 per kWh.
Scientists from all over the world are trying to improve the efficiency of theirs photocells… Every year there is news from various institutes, where again and again scientists manage to create solar modules with record efficiency, solar modules based on a new chemical composition, solar modules with more efficient concentrators, etc.
The first high-efficiency solar cells were publicly demonstrated in 2009 by Spectrolab. Then the efficiency of the cells reached 41.6%, while at the same time the beginning of the industrial production of solar cells with an efficiency of 39% was announced in 2011. As a result, in 2016 Spectrolab started the production of solar panels with an efficiency of 30, 7% for spacecraft.
In 2011California-based Solar Junction achieved an even higher efficiency of 43.5% with a 5.5mm by 5.5mm solar cell, surpassing the record recently set by Spectrolab. The multi-layered three-tiered elements were planned to be manufactured in a plant, the construction of which required a loan from the Ministry of Energy.
Sun Simba solar system that includes optical concentratorand with an efficiency of 26 to 30%, depending on the illumination and the angle of incidence of light, was presented in 2012 by the Canadian company Morgan Solar. The elements included gallium arsenide, germanium and plexiglass. This development allowed a widow to increase the efficiency of traditional silicon solar cells.
Sharp trilayer cells based on indium, gallium, and arsenide, measuring 4 by 4 mm, show an efficiency of 44.4%. They were demonstrated in 2013. But in the same year, the French company Soitec, together with the Berlin Center. Helmholtz and specialists from the Fraunhofer Institute for Solar Energy Systems have completed the development of a Fresnel lens photocell.
Its efficiency is 44.7%. And a year later, in 2014, the Fraunhofer Institute obtained an efficiency of 46%, again on a Fresnel lens element. The solar cell structure contains four junctions: indium gallium phosphate, gallium arsenide, gallium indium arsenide and indium phosphate.
The cell's creators claim that the battery, consisting of 52 modules, including Fresnel lenses (16 sq. cm each) and ultra-efficient receiving photocells (only 7 sq. mm each) can, in principle, convert 230 suns of light into electricity ….
The most promising alternative to what we have now, analysts see the creation in the near future of photovoltaic cells with an efficiency of about 85%, working on the principle of correcting the current caused by the electromagnetic radiation of the Sun (after all, sunlight is electromagnetic wave with a frequency of about 500 THz) on a small nanoantenna with a size of a few nanometers.