Solar Energy and Solar Cells

Solar energy is energy derived from the light and heat of the Sun. It reaches the Earth continuously and in enormous quantity, making it one of the most abundant renewable resources. The energy can be used in two broad ways: directly as heat, for warming water or buildings, or by conversion into electricity. Because the supply depends on daylight and weather, solar systems generate power intermittently and are often paired with storage or connected to a wider grid.

The most familiar method of producing electricity from sunlight uses solar cells, also called photovoltaic cells. A solar cell is typically made from a semiconductor such as silicon. When sunlight strikes the cell, it transfers energy to electrons in the material, freeing them to move and creating an electric current. This is known as the photovoltaic effect. Individual cells produce only a small voltage, so many are wired together and sealed into a solar panel, and panels in turn are combined into larger arrays to generate useful amounts of power.

Solar power is one of several renewable technologies, alongside wind energy and hydropower, that aim to generate electricity without burning fossil fuels. Photovoltaic panels have no moving parts and produce no emissions or fuel costs while operating, which suits them to applications ranging from small devices and rooftop installations to large utility-scale power stations. Solar production complements other renewable sources, since output peaks at different times depending on the weather and season.

Frequently asked questions

How does a solar cell turn sunlight into electricity?

Sunlight striking the semiconductor in the cell frees electrons, which then flow as an electric current. This conversion is called the photovoltaic effect.

What is the difference between a solar cell and a solar panel?

A solar cell is a single small unit that produces a low voltage, while a solar panel is many cells wired together and sealed into one module to generate more usable power.

Why does solar power output vary?

It depends on sunlight, so production falls at night and in cloudy weather and changes with the season, which is why solar is often combined with storage or a grid connection.