A comprehensive glossary of solar industry terms

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A Complete Solar Term Glossary

Welcome to Simple Energy's complete solar term glossary containing definitions for technical terms related to solar energy and power generation by technologies like photovoltaics (PV) / solar panels. If you are considering going solar or you want to gain a better understanding of the solar industry, this glossary is designed to help you understand key industry terms 


Annual Solar Savings - The annual solar savings of a solar building is the energy savings attributable to a solar feature relative to the energy requirements of a non-solar building.

Array -  See photovoltaic (PV) array.

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Battery Backup -  A solar battery backup is a battery that stores energy from a solar PV system. The system's panels absorb energy from the sun and convert it to electricity which then passes through the inverter for your home to use. Also see solar battery storage

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Charge Controller -  If you have a battery backup, a charge controller regulates the electricity going into the battery, and protects the battery charge during off hours. A charge controller is needed because a battery can be damaged by a fluctuating charge, which would happen if the battery were connected directly to the solar panel system

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Days of Storage -  The number of consecutive days a solar system will meet a defined load without solar energy input from the sun. 


Direct Current (DC) -  A type of electricity transmission and distribution by which electricity flows in one direction through the conductor, usually relatively low voltage and high current. To be used for typical 120 volt or 220 volt household appliances, DC must be converted to alternating current, its opposite.

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Electric Bill -  The bill that a local utility issues to a homeowner for the electricity that their home consumes.

Electrical Grid - An integrated system of electricity distribution, usually covering a large area


Electrical Panel Upgrade -  Electrical panels divide incoming electrical power from the grid into subsidiary circuits to distribute power throughout the building. With a 25-40 year lifespan and an ever-growing reliability on electricity, these panels need upgrading and replacement.

Energy Audit - A survey that shows how much energy used in a home, which helps find ways to use less energy.

Energy Storage - When a battery stores power from a PV (photovoltaic) solar system.


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Federal Solar Tax Credit -  Commonly referred to as the investment tax credit (ITC), the federal solar tax credit gives homeowners a dollar-for-dollar reduction against their federal income tax. It is regarded as the most significant financial incentive for solar in the U.S.

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Gigawatt -  A unit of electrical power equal to one billion watts or 1000 megawatts

Greenhouse Gases - Gases that trap heat in the atmosphere increasing the rate of climate change

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Hybrid Solar System -  Hybrid solar systems generate power in the same way as a common grid-tie solar panel system but use special hybrid inverters and batteries to store energy for later use. This ability to store energy enables most hybrid systems to also operate as a backup power supply during a blackout.

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Inverter -  A solar inverter or PV inverter, is a type of electrical converter which converts the variable direct current output of a photovoltaic solar panel into a utility frequency alternating current that can be fed into a commercial electrical grid or used by a local, off-grid electrical network.

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Joule - A metric unit of energy or work; 1 joule per second equals 1 watt or 0.737 foot-pounds; 1 Btu equals 1,055 joules.


Junction Box - The solar panel junction box is an enclosure placed at the underside of the solar PV module (solar backsheet). It is an important part through which two or more solar PV panels are interconnected

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Kilowatt (kW) -   A standard unit of electrical power equal to 1000 watts, or to the energy consumption at a rate of 1000 joules per second.

Kilowatt-hour (kWh) -   1,000 thousand watts acting over a period of 1 hour. The kWh is a unit of energy. 1 kWh=3600 kJ.

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Life-cycle cost - The estimated cost of owning and operating a photovoltaic system for the period of its useful life.

Local Utility - Where homeowners buy grid electricity and where power is generated at a local level

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Megawatt (MW) - 1,000 kilowatts, or 1 million watts; standard measure of electric power plant generating capacity.

Megawatt-hour (MWh) - 1,000 kilowatt-hours or 1 million watt-hours.

Meter - A meter is what monitors the energy production of your home solar system. You’re probably familiar with the traditional meter, but if you get solar panels, you’ll need a bi-directional or digital meter.

Microinverter - A device that converts the generated solar energy into usable electricity for a home

Mounting System - is the foundation that holds your solar array in place. Mounts are used to attach solar panels to the roof, ground, or another surface on your property. With proper installation, a sturdy mount secures your panels in harsh weather and protects your investment.

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Net Energy Metering - A practice in which the utility company will credit you for the excess electricity generated by your solar panels. You can then draw upon these credits when your installed solar panels do not produce enough electricity to match your use; most commonly in the night when the sun is not shining. When excess electricity is produced by your solar system, it is sent back to the grid and the electric company must buy that energy from you.​

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Off-grid - The power grid refers to the network that delivers electricity to your home An off-grid system is designed to help people function without the support of this network.

Overproduction - The energy that is generated above the committed level in a customer's agreement


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Panel - See photovoltaic (PV) panel.

Photovoltaic (PV) - Pertaining to the direct conversion of light into electricity.

Photovoltaic (PV) array - An interconnected system of PV modules that function as a single electricity-producing unit. The modules are assembled as a discrete structure, with common support or mounting. In smaller systems, an array can consist of a single module.

Photovoltaic (PV) cell - The smallest semiconductor element within a PV module to perform the immediate conversion of light into electrical energy (direct current voltage and current). Also called a solar cell.

Photovoltaic (PV) system - A complete set of components for converting sunlight into electricity by the photovoltaic process, including the array and balance of system components.

Polycrystalline - PolyCrystalline or MultiCrystalline solar panels are solar panels that consist of several crystals of silicon in a single PV cell. Several fragments of silicon are melted together to form the wafers of polycrystalline solar panels. ... These solar panels absorb energy from the sun and convert it into electricity. Also see multicrtalline

Power Purchase Agreement (PPA) - Pay a per kilowatt-hour rate for the electricity produced by the solar panels. Solar PPA and solar leases are so similar that there is no easy answer to which one is best for an individual homeowner. You do not own the solar panels on your roof with a PPA. Instead, you send a monthly payment to the PPA company for each kilowatt hour of solar energy you use.

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Quad - Unit of heat equal to one quadrillion Btu. One quadrillion Btu (1,000,000,000,000,000 Btu).

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Rated Battery Capacity - The term used by solar battery manufacturers to indicate the maximum amount of energy that can be withdrawn from a battery under specified discharge rate and temperature. 

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Service Transfer - If you sell your home, a service transfer refers to the process of transferring your solar system service to the new owner. The new home owner will be able to take advantage of solar incentives like net metering, more predictable electric bills, and clean, renewable energy for their family.

Solar Array - Combining several solar panels creates a solar array, which is part of a solar system. The typical residential solar array consists of 20–25 solar panels to cover 100% of its energy consumption.

Solar Battery Storage - A battery that reserves energy for later consumption that is charged by a connected solar system. The stored electricity is consumed after sundown, during energy demand peaks, or during a power outage. 

Solar Farm - A solar farm is often referred to as a solar ranch, solar field, or solar park. Spanning between an acre and 100 acres of solar panels, a solar farm allows a community to reap the benefits of a solar electricity system without purchasing, installing, or maintaining individual systems. 

Solar Cells - A solar cell, also known as a photovoltaic (PV) are used to convert sunlight into direct electricity and are grouped together to make solar panels

Solar Cell Efficiency - The direction in which your home faces determines the efficiency of your solar cells (which are collected into solar panels). The more sunlight that hits the cells, the more electricity they produce.

Solar Incentive - Homeowners are offered financial incentives from federal, state, and local governments to install solar systems on their homes. Many solar energy companies also offer their own incentives to homeowners for going solar.

Solar Lease - A solar lease is a financing option that lets you essentially “rent” your solar panels from a solar leasing company for a set cost each month.

Solar Loan - A loan that allows you to purchase a solar-energy system and pay it off over time with interest

Solar Panel Performance Warranty - A performance guarantee from the solar panel manufacturer or installer. An industry leading performance warranty is 30 years.

Solar Panel Product Warranty - A guarantee from the solar panel manufacturer or installer that covers the solar panels. An industry leading warranty is 25 years.

Solar Rack System - Also known as a photovoltaic mounting systems is used to safely fix solar panels to various surfaces such as roofs, building facades, or the ground.


Solar Renewable Energy Credit - For every unit of electricity that a solar system generates, an associated SREC is created. In some states you can sell your SREC's for additional income. 


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Time of Use - A method of measuring and charging a homeowner for energy consumption based on when the energy is used.

True South - To gain the maximum energy benefits from the sun, you’ll want your solar panels to face true south (not magnetic south). A solar panel system facing true south will operate at 100% of expectations. An East or West-facing panel will operate at around 80% of expectations. A North-facing panel will only operate at around 60% of expectations.

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Underproduction - The energy that is generated below the committed level in a customer's agreement

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Value of Solar - A methodology that takes a uniform approach to establish the true value of the electricity produced by the distributed energy systems.

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Watt - 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).

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Simple Energy Solar Incentives

In addition to the 2021 26% federal investment tax credit (ITC) that homeowners can deduct from the cost of their solar panel system, Simple Energy offers even more incentives for homeowners that choose to install solar panels with us. Contact us today to find out what incentives are available to you.

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