Electricity can be generated from the sunlight1 via photovoltaic (PV) and concentrated solar power technology (CSP) also known as solar thermal power plant.
Photovoltaic turns solar light into electricity. The word photovoltaic is derived from the Greek words photo (light), and voltaic (electricity), which literally means light-electricity. Therefore a PV system (solar modul/panel), converts light energy directly into electrical energy using PV-grade semiconductor materials such as silicon. PV technology is complicated in every sense of it, and it takes an understanding of what's going on at the atomic level when sunlight shines on a solar cell, to understand how photovoltaic device converts light directly into electricity2. More so, the PV cells are very expensive, requiring expensive manufacturing plant to produce PV-grade silicon. The efficiency of PV cells is still very low for a cheap utility scale power (at least a few hundreds of Mega Watts). Material costs for solar thermal power systems are less than that of photo voltaic systems hence return on Investment for solar thermal power plant is faster than a PV power plant of equal capacity.
CSP turns solar heat into electricity. CSP technology in comparison is simple, and involves using mirrors to concentrate (beam) sunrays to a surface to generate heat. The heat is then used for the production of steamto be used by a conventional turbine to generate electricity.
Another draw back of photovoltaic is the fact that the conventional solar cells (p,n-junction or mono juction) in the solar modules (panels) respond differently to the different wavelengths, or colors, of light. For example, PV grade crystalline silicon can use the entire visible spectrum (Violet-Red), plus some part of the infrared spectrum (right of red). But energy in part of the infrared spectrum, as well as longer-wavelength radiation (UV), is too low to produce current flow. Higher-energy radiation can produce current flow, but much of this energy is likewise not usable. In summary, light that is too high or low in energy is not usable by a cell to produce electricity. Rather, it is transformed into heat, which affects PV efficiency and life span. This is why PV cells work relatively efficiently in cold conditions with ample sunlight, whereas CSP works better in hot conditions with ample sunlight such as the desert.