solar panels

basics

how it works and process

The amount of sunlight that strikes the earth’s surface in an hour and a half is enough to handle the entire world’s energy consumption for a full year. Solar technologies convert sunlight into electrical energy either through photovoltaic (PV) panels or through mirrors that concentrate solar radiation. This energy can be used to generate electricity or be stored in batteries or thermal storage.

Solar Energy 101

Solar radiation is light – also known as electromagnetic radiation – that is emitted by the sun. While every location on Earth receives some sunlight over a year, the amount of solar radiation that reaches any one spot on the Earth’s surface varies. Solar technologies capture this radiation and turn it into useful forms of energy.

A solar panel works by allowing photons, or particles of light, to knock electrons free from atoms, generating a flow of electricity, according to the University of Minnesota Duluth. Solar panels actually comprise many, smaller units called photovoltaic cells — this means they convert sunlight into electricity. Many cells linked together make up a solar panel.

Each photovoltaic cell is basically a sandwich made up of two slices of semi-conducting material.

Intricacies

To work, photovoltaic cells need to establish an electric field. Much like a magnetic field, which occurs due to opposite poles, an electric field occurs when opposite charges are separated. To get this field, manufacturers “dope” silicon with other materials, giving each slice of the sandwich a positive or negative electrical charge.

A couple of other components of the cell turn these electrons into usable power. Metal conductive plates on the sides of the cell collect the electrons and transfer them to wires, according to the Office of Energy Efficiency and Renewable Energy (EERE) (opens in new tab). At that point, the electrons can flow like any other source of electricity.

Materials

Solar cells are usually made from the element silicon (atomic #14 on the periodic table). Silicon is a nonmetal semiconductor that can absorb and convert sunlight into electricity – we also use silicon in almost every computer on the planet. There are a few different types of semiconductors typically used in solar cells, and silicon is by far the most common, used in 95 percent of solar cells manufactured today. Cadmium-telluride and copper indium gallium diselenide are the two main semiconductor materials used in thin-film solar panel production.

Types of Technologies

There are two main types of solar energy technologies—photovoltaics (PV) and concentrating solar-thermal power (CSP).

Photovoltaics: You’re likely most familiar with PV, which is utilized in solar panels. When the sun shines onto a solar panel, energy from the sunlight is absorbed by the PV cells in the panel. This energy creates electrical charges that move in response to an internal electrical field in the cell, causing electricity to flow.
Concentrating solar-thermal power (CSP) systems use mirrors to reflect and concentrate sunlight onto receivers that collect solar energy and convert it to heat, which can then be used to produce electricity or stored for later use. It is used primarily in very large power plants.

Can We Go Greener?

Yes! Organic solar cells are a separate type of thin-film solar cell that use carbon-based materials as a semiconductor. These types of organic photovoltaics (OPV) are also sometimes referred to as “plastic solar cells” or “polymer solar cells”, and are produced by dissolving organic compounds in ink and printing them onto thin plastics.

the evolution of

solar technology