SOLAR TERMS, & TECHNOLOGY
Whether you are contemplating PV or Thermal, Commercial or Residential, let SunEarth explain some of the Industry jargon.
An abbreviation for carbon dioxide. CO2 is well-known as a “green-house gas.” When people talk about “Carbon Footprint,” they are usually referring to CO2 emissions.
This measure gauges the percentage of solar (light) power reaching a module that is converted into electrical power. Conventional cells now range in the high percentage teens. Theoretical and laboratory conversion rates typically are much higher than rates from mass production.
A grid-connected solar electric system generates its own electricity and feeds its excess power into the utility grid for later use. Grid-connected solar electric systems are eligible for many incentives and rebates
The abbreviation for kilowatt-hours, a unit of energy. One kWh represents a 1,000 watt load operated over a period of one hour—that's the amount of energy an average plasma TV uses. Electricity rates are most commonly expressed in cents per kilowatt hour.
Commonly called a “solar panel,” a PV module is composed of multiple solar cells that are electrically connected to increase the total power output and are encapsulated in tempered glass for weather protection and ease of handling.
The abbreviation for megawatt, a unit of power or capacity of a generator. 1 MW = 1,000 kW = 1,000,000 W.
Systems are designed to function without the support of remote infrastructure, such as an electrical grid.
A photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. Solar radiation arrives on the surface of photovoltaic cells in the form of photons, providing the main energy that activates cells to produce electricity.
The basic material used to make solar cells. It is the second most abundant element in the earth’s crust, after oxygen.
A sawn silicon disc, used as the starting point for manufacturing a solar cell.
Any of various devices for the absorption of solar radiation for the heating of water or buildings or the production of electricity.
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.
The amount of time required for a solar panel to generate the amount of energy it took to manufacture it. Modern PV panels have an energy payback of 1 to 3 years depending on where they’re installed; over a 30+ year life, a PV system will return 10 to 30 times the energy that went into making them.
Sunlight varies by region. 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. As a whole, the U.S., especially the sunny Southwest and Southeast, offers strong insolation. By comparison, Germany, the PV industry’s leader, gets little better sun than Alaska.
In cell production, manufacturing steps occur in dimensions measured in microns. In the metric system, a micron is one millionth of a meter, or one thousandth of a millimeter. For reference, a human hair measures about 100 microns across.
Silicon is a metal and, therefore, its atoms are organized into a crystalline structure. Monocrystalline refers to silicon that is pulled as a single, completely homogenous crystal, as SolarWorld does in the USA. Monocrystalline PV cells are generally the most efficient and reliable available.
Net-metering allows the solar electric system to send excess electricity back through the electric meter to the utility. The meter actually runs backwards! Your utility will bill you for the net (kWh used – kWh generated). While most utilities will not pay you cash if you generate more than you use, many will carry forward a credit toward your next bill.
Photo = light; Volt = electrical potential — Literally: electricity from light. Einstein won the Nobel Prize for discovering that when light shines on certain materials (like silicon), an electrical current is generated. Learn how a PV module (solar panel) works.
Energy generated by these systems is stored in batteries and then subsequently used. Also known as “off-grid,” these systems are not connected to the utility grid.