With such concentrator photovoltaic systems, such as the one depicted in the photograph below, the costs per electricity Watt peak drop approximately in two times due to the substitution of the expensive Si-material through cheap Fresnel lenses and small area high efficient MJ solar cells.



An essential advantage of the concentrator technology is the fact, that the space and investment costs required are only about half those of traditional silicon based arrays. This leads to costs which are coming close to the ones of fossil power plants at peak hours. Much attention is given to heterostructure solar cells in the national programs of the USA, Japan and European countries. The works are carried out on both space and terrestrial arrays. In the nearest years launching of several hundreds of communication satellites equipped with solar arrays with highly efficient cascade solar cells based on the III-V compound is planned. In the national programs on the terrestrial photovoltaics, much attention is also given to the investigations and developments of power installations and powerful photovoltaic plants on the base of highly efficient cascade solar cells and sunlight concentrators. For highly effective conversion of the 500-1000x concentrated sunlight the most promising are the solar cells based on wide-gap compounds, first of all on the gallium arsenide – indium – gallium - phosphide system. Limiting values of the efficiency of the solar cells based on these materials are 25-27% for 500-1000x concentrated sunlight in solar cells with a single p-n junction and higher than 35% in a cascade solar cells. Much less semiconductor material is required to fabricate solar cells, when high concentration of the sunlight is used. For this reason, in spite of the more expensive gallium arsenide, the specific cost of concentrator photovoltaic installations with gallium arsenide solar cells will be approximately in 2 times lower.

Photovoltaic solar vs concentrator modules