There are two basic uses of solar energy - heat and generating electricity. Sunlight is captured and converted into either usable heat or usable electrical power. Light is composed of individual photons, each with a wavelength and an energy, and all travelling at the same velocity.
The photon’s wavelength determines the color, in the portion of the spectrum that we can actually see. The photon’s frequency determines the energy of a photon. The higher the frequency, the higher the energy.
PV cells convert light energy into electrical energy. All solar PV systems rely on a very simple process called the photovoltaic effect, which takes advantage of the fact that light photons act as both radiation and matter. Incident radiation hits the PV cell and the technology within the cell transforms the light energy into a raw electrical signal. Wires transmit this signal down to an inverter, which converts the power to usable electrical power.
The driving force behind the solar PV market is the underlying technology of semiconductors. Semiconductors are made of very carefully purified silicon which forms a crystalline structure with specific electrical properties. When a photon of light strikes a semiconductor, an electron is freed up from the crystalline structure, and this is what causes electricity to flow.