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Feb 3rd 2015

Solar Power Glossary of Terms

Technical terms related to solar power and photovoltaic (PV) technologies can be confusing (don’t worry, you’re not alone). Acronyms and lexicon used in the solar industry are numerous; the following solar power glossary just scrapes the surface defining terms and vocabulary related to all things solar. For a more in-depth look, has provided an exhaustive list of solar terminology and definitions. Below is an introduction to the solar terms you most need to know. So, let’s dive right in and learn the lingo!


In a photovoltaic device, the material that readily absorbs photons to generate charge carriers (free electrons or holes) is considered the absorber.


Horizontal angle measured clockwise from true north; 180° is true south.


A solar cell is the basic component of solar modules that produces electricity from light. Cells are the building blocks for modules and are manufactured from wafers.


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.

Conversion Efficiency

This measure gauges the percentage of solar (light) power reaching a module that is converted into electrical power. Expressed in percent, it is the ratio of output power (or energy) to input power (or energy).


Solar power crowdfunding campaigns are gaining traction and may allow companies to diversify and expand their capital sources – changing how renewable energy is financed.

Crystalline Silicon

A type of PV cell made from a single crystal or polycrystalline slice of silicon.

Customer Load

The amount of power a particular location uses. Load may be expressed in kilowatts (capacity) or kilowatt-hours (energy). A location’s peak kilowatts generally refers to when electric demand requirements are highest.

Energy Payback

The amount of time required for a solar panel to generate the amount of energy it took to manufacture it.


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 unit of electromagnetic wave frequency that is equal to one cycle per second.


Since sunlight varies by region, insolation measures the solar radiation energy in a given region. It is usually expressed as the intensity of light energy per unit of land area (kilowatt-hours per square meter).


The inverter electronically converts Direct Current (DC) power into Alternating Current (AC) power and is required for grid-connected solar power systems.

• Micro inverters can be installed on each solar module. The cost is typically higher, but they provide certain advantages for very small or geometrically complex PV systems.
• String inverters are the most common type of inverter for residential and small commercial PV systems.
• Central inverters are used for very large PV systems.

Kilowatt Hour (kWh)

The abbreviation for kilowatt-hours, a unit of energy is kWh. One kWh represents a 1,000 watt load operated over a period of one hour. Electricity rates are most commonly expressed in cents per kilowatt hour.


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.


Commonly called a “solar panel,” a PV module is composed of multiple solar cells that are electrically connected to increase the total power output. This integral unit is encapsulated in an environmentally protective laminate with tempered glass for weather protection.


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.

Megawatt (MW)

The abbreviation for megawatt, a unit of power or capacity of a generator is MW. 1 MW = 1,000 kW = 1,000,000 W.

Mounting Equipment

Equipment/apparatus used to fasten PV modules to the roof or ground.


Net-metering allows the solar electric system to send excess electricity back through the electric meter to the utility. The meter actually runs in reverse! Your utility company will bill you for the net (kWh used minus kWh generated).

Peak Watt

Peak Watt is a unit used to rate the performance of solar cells, modules, or arrays; the maximum nominal output of a photovoltaic device, in watts (Wp) under standardized test conditions, usually 1,000 watts per square meter of sunlight with other conditions, such as temperature specified.


A photon is a particle of light that acts as an individual unit of energy.

Photovoltaics (PV)

Photo = light; Volt = electrical potential — literally: electricity from light.


Also known as multicrystalline, polycrystalline is a semiconductor (photovoltaic) material composed of variously oriented, small, individual crystals.

Solar Cell

The solar cell is the basic photovoltaic device which generates electricity when exposed to sunlight.

Solar Energy

Electromagnetic energy transmitted from the sun (solar radiation). The amount of solar power that reaches the earth is equal to one billionth of the total solar energy generated, or the equivalent of about 420 trillion kilowatt-hours.


The basic material used to make solar cells. It is the second most abundant element in the earth’s crust, after oxygen.

Tilt angle

The tilt angle is a fixed angle measured from the horizontal to which a solar array is tilted to maximize the array output. Depending upon latitude, season and time of day this angle will vary.


A wafer is a thin sheet of semiconductor (photovoltaic material) made from cutting it from a single crystal or ingot. It is used as the starting point for manufacturing a solar cell.


The rate of energy transfer equivalent to one ampere under an electrical pressure of one volt. One watt equals 1/746 horsepower, or one joule per second. It is the product of voltage and current (amperage).

Zenith Angle

The Zenith angle is the angle between the direction of interest (of the sun, for example) and the zenith (directly overhead).


KMB Design Group is at the forefront of the escalating solar industry, and is considered a leading consulting firm in the renewable energy field providing photovoltaic design and engineering services. Our Solar engineers will give you full analysis and let you know how much energy can be drawn with considerations such as location, obstructions and orientations. We will also provide you with the best commercial solar power designs tol give you maximum output. Licensed in 49 states, we have the ability to work nationally without limitations.