Solar Terminology: A Glossary of Solar Energy Terms
As with any industry, the solar business has its own jargon — words which may not be familiar to you. Solar terminology can get confusing, so we created a glossary of common solar terms to help you make sense of your solar energy investment.
Conversion efficiency: Conversion efficiency refers to how much available sunlight a panel converts into electrical power. Conventional cells now range in the high teen percentages, although theoretical and laboratory conversion efficiencies are often much higher.
Crystal: A crystal is a solid with molecular building blocks, such as atoms or ions that have arranged themselves in an identically repeating pattern along all three spatial dimensions. In solar manufacturing, these crystals are usually silicon.
Grid parity – This phrase refers to the point at which energy costs the same regardless of whether it comes from solar technology or fossil fuels
Insolation – Because sunlight can vary so much from region to region, it helps to have a method of expressing the change. Insolation is a measure of the solar radiation energy in a given region. It is usually expressed as the intensity of light energy per unit of land area. The United States, particularly in the southwest and southeast states, offers strong insolation, meaning it’s quite sunny. Germany on the other hand, which is the PV industry’s leader, gets just a bit more sun than Alaska.
Micron – Most Americans are more than fluent with inches and centimeters, but our manufacturing dimensions are so precise that they’re measured in microns. In the metric system, a micron is one millionth of a meter, or one thousandth of a millimeter – much smaller than the human eye can see. To give you a better idea, a human hair measures about 100 microns across.
Module – While the common term outside the industry is “solar panels,” internally we call these structures modules because they can be linked together evenly and interchangeably use electrical connectors to form a circuit within an array, with a building or with a utility grid.
Net metering – Net metering refers to a solar power configuration in which the system is tied into the main power grid. It allows solar power producers to generate and use power with the same pricing using just a single meter. For example, when a residential solar system makes more power than it uses, the meter on the home rolls backward, decreasing the net consumption of electricity from the main power grid (and the home’s bill).
Photon – Neither a wave nor a particle, a photon is a packet of light energy. Solar radiation strikes the surfaces of photovoltaic cells (and the earth as a whole) in the form of photons. These photons provide the main energy that activates cells to produce electricity.
Photovoltaic – The word photovoltaic stems from the words photo, meaning light, and volt, meaning electricity. In short, the term photovoltaic translates to electricity from light.
Silicon carbide: Silicon carbide (SiC) is created when silicon is bonded with carbon. It is one of the many types of silicon materials used in the solar industry, but it’s also used in a variety of other applications including as an abrasive for everything from grinding to sandblasting. At SolarWorld, crushed SiC is mixed into a water slurry and applied to saw wires, which are used when slicing wafers for solar cells. In this process, it is actually silicon carbide, not the wire, that does the cutting.
Tool – In the solar industry, the word “tool” has a special meaning. Rather than referring to a single piece of equipment like a screwdriver or hammer, “tools” in our world are entire machines or assembly lines. One common example is the spider-like device that is used to lift and move silicon wafers and cells on and off conveyor belts.