Our solar energy glossary offers a collection of key terms and phrases, explained simply and concisely. 


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Alternating Current (AC) 

A type of electrical current that circuits and appliances in most homes utilize.
Expressed as a sine wave, the current of AC passes through zero when it changes direction, which makes it a safer electrical current. 
Alternating Current (AC)


The direction that your roof faces (in the context of solar). The azimuth is measured in degrees, representing the angle between your roof and true north.



A mode of operation for the solar inverter that uses a battery or batteries to provide backup energy in the event of grid failure.


A device that is used to store energy using chemical reactions and has a positive and negative charge. Batteries store energy in DC form, and inverters convert the current to AC for general use. When selecting a battery for a PV system, a number of factors should be considered: (a) battery capacity should meet the household’s demand and the PV system’s production rate so that energy is not lost (b) the battery’s charging and discharging rate should be fast enough to meet energy needs (c) the battery should be warranted for outdoor and indoor installation.

Battery Capacity

The total amount of electrical energy a battery can deliver. Because many batteries can be damaged if they are completely discharged, a battery’s capacity is usually higher than its usable capacity. Battery capacity is measured in kilowatt hours (kWh), which shows how much total energy the battery can provide.

Battery Coupling

This refers to the way in which solar inverters are coupled with a battery. AC coupling converts solar energy to AC before converting it back to DC for battery storage, which results in lost energy and the inverter acting as an energy bottle neck. With DC coupling, the inverter directs energy directly from solar panels to batteries without converting it. DC coupling has multiple advantages, such as less conversions, higher efficiencies and supporting PV oversizing.

Bypass Diode

A bypass diode, located in the junction box, allows underperforming solar panels to be bypassed in order to prevent them from dragging down the production of the other panels in the same string. This is a standard component in PV panels.


BOS (Balance of System)

Components and equipment in a PV system excluding the modules. (inverters, optimizers, wiring, conduit, combiner box).


CEC Weighted Efficiency

A standard measure of solar equipment efficiency industry-wide based on California Energy Commission's standards. Inverter efficiency is measured as the ratio of DC input power to the AC output power as a weighted average in different solar irradiance scenarios.

Cell Card

The component inside the SolarEdge inverters that links them to the network and the SolarEdge monitoring portal through cellular communication.


The process of assuring that all systems and components of a PV plant are designed, installed, tested, operated, and maintained according to the operational requirements of the project’s owner or final client.

Community Solar

A solar power system which generates electricity that is used by more than one household. Sometimes called a solar garden, it allows members of a community who cannot (or do not wish to) install solar on their property to enjoy the benefits of solar.


When the DC solar system output exceeds the maximum capacity of the inverter and power is lost.


Direct Current (DC)

type of electricity created by solar modules when solar rays hit them. This energy is converted into Alternating Current (AC) electricity to be used in our home.

DC/AC Ratio

the ratio of installed solar DC capacity to the Alternating Current (AC) power rating of the inverter. Example: 6kW DC solar array paired with a 5kW rated inverter would have an DC/AC ratio of 1.2.


Energy Storage

The capture of energy produced at one time for use at a later time. Households can use batteries to store solar energy generated by solar energy systems during the day for use during the evening. By storing energy in batteries, users can increase their energy independence, self-consumption, and the ROI of their solar energy system.


Stands for Engineering, Procurement and Construction. These are companies that assist in facilitating large commercial solar contracts. They serve as the middleman between the client and solar component manufacturers and builders to negotiate contracts.



Uility infrastructure that is responsible for the transmission and distribution of electricity to consumers.

Grid-tied Solar Systems

The majority of residential solar is grid tied, meaning that we use the utility infrastructure to measure production of energy produced by the solar system. When we use more energy than is produced by the solar system, the energy from the utility grid will keep the lights on in our home.

Ground Mount Systems

Rather than installing solar panels on your roof, a ground mount solar system is a system where solar panels are attached to a racking system with its foundation directly in the ground.



Family of inverters that is 25% smaller than the standard inverter and has 99% efficiency. SetApp enabled Home-Wave inverters do not have an LCD screen, and instead are remotely accessed using SetApp.

Home-Wave Technology

software associated with our Home-Wave family of products.



(Investment Tax Credit) Federal Tax Credit that is associated with installing solar on your home. Currently valued at 26% of solar system purchase, given in the form of a tax credit towards your tax liability. Tax credit for homeowners is slated to step down year over year until it reaches 0% in 2024. It is regarded as the most significant financial incentive for solar in the U.S.

Solar ITC Schedule


I-V curve

A graphical presentation of the current (I) versus the voltage (V) from a photovoltaic device as the load is increased from the short circuit (no load) condition to the open circuit (maximum voltage) condition. The shape of the curve characterizes cell performance.


Junction Box

The output interface installed on the back of each solar panel. Each junction box includes a bypass diode that wires the PV panel connectors together and keeps the power flow going in one direction.



Unit of energy or power measured over a period of time. We are charged by the utility company in an amount per kWh.   Example: The amount of power that ten 100W lightbulbs use in one hour


kW is a unit of power. 1kW is equivalent to 1000W of power. Solar systems are measured in kW.


Levelized Cost Of Energy (LCOE)

A way of calculating the cost of generating a unit of electricity from a specific energy production system. It is calculated by dividing the overall cost of the system (including operation and maintenance costs) by the number of energy units the system is expected to produce during its lifetime. In many locations, the LCOE of solar energy is lower than that of energy from the grid – this means that solar has reached grid parity.



Module level power electronics. What microinverter and optimizer technology is often referred to as.


Maximum Power Point Tracking is a used to maximize power extraction from PV systems. Since each panel performs at a different level, due to a variety of factors, MPPT is an algorithm that finds the maximum power point of the panels. For example, if the panels are soiled, covered in snow, leaves, or bird droppings, shaded, have a different manufacturing tolerance, or age at different rates, their energy production will vary. Some inverters perform MPPT at the string level, while other inverters perform MPPT at the panel level. String-level MPPT leads to panel-level mismatch which causes energy losses. However, when MPPT takes place at the panel-level, the energy loss from panel-level mismatch is eliminated.


The energy meter is a device that is used to measure and monitor production, consumption, and import/export of energy to the grid.


NEC 2014/NEC 2017

Electrical codes that govern all electrical equipment and construction in the U.S. Newest rapid shutdown requirement that states conductors around the solar array must be de-energized to 30V or less within 30 seconds of initiating rapid shutdown, and that the system must be shut down within 1’ in all directions of the solar array.

Net Metering

Process of obtaining credits from the utility company for your solar system production. You will receive a net meter when you go solar that measures the amount of electricity that comes into your home as well as the amount that the solar system sends “back to the grid”. This allows you to generate credits with the utility company when your solar system produces more energy than the house is consuming and that excess electricity is sent to the Grid.


Older SolarEdge inverters that had to be programmed via an LCD screen on the inverter.



A type of solar PV system that runs independently from the utility grid. Off-grid systems feature enough solar panels and battery storage to generate sufficient energy onsite, without access to utility-generated electricity.

Operations and maintenance (O&M)

The ongoing operational needs of a solar energy system, including cleaning, repairs, replacement of parts, bill management and so on; primarily refers to larger-scale commercial and utility-scale solar systems.


A way to increase the output of a solar energy system. Oversizing a solar energy system means that solar production has a higher peak capacity than the inverter rating. Simply put, oversizing is a cost-effective way to maximize a solar energy system’s production by increasing the total capacity of the solar panels so that it is higher than the capacity of the inverter. While energy will be lost at peak production, more energy will be harvested throughout the day. Oversizing can also be a good way to increase solar energy production in areas where inverter size is restricted.


Panel Mismatch

Panel mismatch occurs when lower performing panels pull down the performance of neighboring panels in the same string. The causes of panel mismatch vary and include manufacturing tolerance, panels aging at different rates, shading, soiling, bird droppings, snow, and fallen leaves blocking the sunlight. Panel mismatch reduces the output of solar energy systems, which decreases system ROI.

Peak Demand

The maximum energy demand or load in a specified time period.

Photovoltaic (PV) Panel

A PV panel, also referred to as a solar panel, is comprised of photovoltaic solar cells connected in a series. PV panels are installed on the rooftop where they absorb photons (light energy) to generate electricity. PV panels are connected in a string to form a complete solar-power-generating unit called a PV array.

Power purchase agreement (PPA)

Contract with a solar company to have a solar energy system installed on your roof. With a solar PPA, you agree to pay the company a per kilowatt-hour rate for the electricity produced by the solar panels.

PRISM Technology

It is the software that allows for an ever-growing range of products to be easily connected to The SolarEdge Home Hub inverter. Spectrum of capabilities includes EV charging, battery storage, consumption monitoring/production metering, and smart energy devices, now and in the future.


Permission to Operate. Authorization from the utility company that a solar system has passed inspection and can be turned on and connected to the grid.

PV Array

A Photovoltaic solar system. A linked collection of solar panels on a roof is called an ‘array’.

Power Density

Power density is the amount of power per mass. PV inverters are measured by power density. The higher the power per mass, the better the inverter.

Power Optimizer

Connected by installers to each solar panel, power optimizers are a DC-to-DC converters designed to maximize energy harvest from PV systems by individually tracking the maximum power point of each individual panel. Advanced power optimizers turn every solar panel into a smart panel. Power optimizers are also responsible for monitoring the individual panels performance.

PV Inverter

PV inverters were originally developed to convert direct current (DC) generated by PV panels to alternating current (AC) for use in the home or to feed into the grid. One of the most common types of inverters is a string inverter, which performs both conversion and MPPT at the string level.

Standard string inverters offer limited monitoring possibilities, create energy losses, limit design flexibility, and in some regions require the installation of additional safety hardware. Other types of inverters available are DC-optimized inverters and micro-inverters.

In recent years the role of the PV inverter has expanded into smart energy management, including storage, grid interaction, home energy, EV charging, monitoring, safety, and more.


PV Monitoring

A solar energy monitoring system offers information about the performance of the PV system, such as, how much energy is produced, consumed, and fed into the grid. Without high-resolution monitoring, it can be challenging to understand the PV system’s performance. Monitoring increases a system owner’s insight into their PV system’s performance and helps them understand if something needs to be repaired. Furthermore, monitoring often allows for installers to perform remote troubleshooting, which means quicker problem-solving and higher system uptime. There are different types of PV monitoring – embedded monitoring systems, add-ons, monitoring at the string-level, and monitoring at the panel-level. panel-level monitoring provides the highest resolution insight.



The mounting system used to affix solar panels to the roof, building surface, or ground.


(Return Merchandise Authorization) Customer request for a replacement product within warranty parameters.


SafeDC Technology

Used to describe all the aspects of safety compliance with the SolarEdge commercial system. Primarily focused on the ability to meet NEC2017 and NEC2014 requirements without the need for additional equipment. With the automatic rapid shutdown upon AC disconnect and optimizers designed to drop to less than 1V, our system is the safest option on the market.


When a household or business uses electricity generated by its own solar energy system, it is called self-consumption. Self-consumption can increase a PV system’s ROI, unless the system is in a net metering or FiT (feed-in tariff) market.


Installer app used to activate and configure inverters, which is done directly through a smartphone.

Single Phase Power

A type of alternating current (AC) in which all voltages vary in unison. Single phase power is the most common household power circuit. It is often used to power lighting, heating, televisions, and other appliances.

The Self-Generation Incentive Program (SGIP)

Provides cash incentives in select areas of California that can cover a majority of the costs of a battery and installation.


Solar Massachusetts Renewable Target. A Massachusetts program which offers monthly financial incentives to home and business owners who purchase and install a solar PV system. (Read more about SMART here.)

The SolarEdge Home Hub

SolarEdge’s most advanced, versatile residential solution — a next generation inverter designed to meet every home energy need

  • Home-Wave meets StorEdge to deliver record-breaking inverter efficiency, flexible whole home backup and superior performance
  • Integrates the capabilities of existing SolarEdge residential inverters in one future-ready solution for all homeowner needs

Solar Lease

Contract with a solar company to have a solar energy system installed on your roof. With a solar lease, you agree to pay the company a fixed monthly fee to “rent” the system in exchange for the benefits (i.e., the electricity) the system provides.

Step Down Transformer

a transformer designed to reduce the voltage from the primary winding to the secondary winding. These are used in the interconnection of transmission systems with different voltage levels.

String Inverter

An inverter that connects to a string of solar panels. String inverters are among the more common types of inverters used in residential solar energy systems today. Standard string inverters perform both DC/AC conversion and MPPT at the inverter level. This means energy losses, limited monitoring capability, and lack of design flexibility. Depending on local safety standards, string inverters may also require the installation of additional safety equipment.


A number of photovoltaic modules or panels interconnected electrically in series to produce the operating voltage required by the load.



Technology associated with our commercial inverter products i.e., Three Phase Inverter with Synergy Technology.


Three Phase Power 

A type of alternating current (AC) that ensures constant power supply. Unlike single phase power where electrons travel through one wire, here the electrons move through three wires at slightly different times. Three phase power is usually used by electrical grids to transfer electricity, or to power industrial machinery, large motors and other heavy loads. Essentially converting power over separate currents, out of phase with one another. Residential systems would utilize a single-phase solution.


Time of Use. A utility rate structure that charges consumers more at the highest demand times of day.

True Up Bill

The culmination of the energy credits generated by producing power from solar and the amount you owe the utility company for using power from the grid. This is reconciled for the total year and a bill from the utility company is sent to the homeowner for the power they used from the grid for the entire year.

480V & 208V

Size of grid capacity in a commercial system. 480V is required in large commercial systems, 208V can be utilized in a smaller commercial situation, such as restaurants and small businesses.


Watts (W)

A measure of power. Appliances, lightbulbs, as well as solar panels are measured in Watts. 1kW = 1,000 Watts.