Solar Electric Terms

Alternating current (AC)

Abbreviated as AC, it describes one kind of flow of electric charges. The AC stream of charges periodically reverses itself, whereas direct current (DC) describes a stream of electrons that moves in one direction only. AC is the standard electric current for power grids worldwide. When solar electric cells capture particles of light, they convert them into DC electricity. An inverter translates DC into AC so that consumers can use it in their homes and businesses.

Ampere (Amps)

Abbreviated as amp, this unit is used to measure electric current.


Balance-of-system (BOS) costs refer to costs of all aspects of installing the solar electric system with the exception of the solar electric modules and inverters themselves. BOS costs include all wiring and miscellaneous materials along with soft costs such as time and administrative costs associated with selling and signing a contract, system design and permitting, installation labor and component costs, inspections, travel to and from the installation site, and other costs of doing business. These costs can account for as much as 50 percent of the total solar electric system installation. New York State has focused on reducing BOS costs to efficiently reach its solar goal of producing 3 gigawatts of solar energy by 2023.

Direct current (DC)

Abbreviated as DC, it describes the flow of direct-charge electricity that is constant, unlike alternating current, which periodically reverses direction. A solar electric system comes equipped with an inverter that translates DC power into AC, the standard electric current for power grids worldwide.

Energy payback

An energy payback gauges how long it will take to recover the energy originally required to manufacture a solar electric system. Because most solar electric systems last 20 – 25 years, there is a pronounced net environmental benefit over the system’s life span. The U.S. Department of Energy estimates an energy payback of 1 – 4 years for rooftop solar electric systems. The original energy used is often referred to as embedded energy.

Feed-in tariff

Feed-in tariffs (FITs) are long-term generation This contracts that have has favorable terms designed to encourage the use of renewable energy by individuals and businesses. FITs are typically offered for long periods of time, such as 10, 15, or 20 years. On Long Island, FITs are used to incentivize mid- to large-sized solar installations.


This key component in a solar electric system converts direct current (DC) electricity into alternating current (AC) the standard current in the U.S.


Abbreviated kW, this unit of measure equals 1,000 watts and is the main mechanism for measuring a solar electric system size. The watt is named after Scottish inventor and mechanical engineer, James Watt (1736 – 1819).


Abbreviated kWh, one kWh is equivalent to the electricity generated or consumed at a rate of one thousand watts over the period of one hour.


K-Solar is a joint partnership between the New York Power Authority (NYPA) and the New York State Energy Research and Development Authority (NYSERDA). Working with the State Education Department, K-Solar provides school districts—at no cost and no obligation—with the tools and expertise necessary to bring solar energy to their facilities and reduce their energy costs.

Net metering

With a grid-connected solar electric system, a solar electric system owner can earn credits on future energy bills when the solar electric system generates more electricity than is needed at that time. The extra credits can be used later when homeowners need power from the local utility, such as at night or on cloudy days.

Power purchase agreement (PPA)

A power purchase agreement (PPA) is becoming a popular way for homeowners to take advantage of solar power without the financial responsibility associated with installation costs. Under the agreement, a third party installs the solar electric system, and the contract secures a rate for the homeowner to buy the energy that is typically lower than the utility rate.

PV (Photovoltaic)

Photovoltaics (PV) is the name of a method of converting solar energy into direct current electricity using semiconducting materials that exhibit the photovoltaic effect, a naturally occurring phenomenon in which photons of light emitted from the sun, knock electrons off their valence shell, into a higher state of energy, creating electricity. A photovoltaic (PV) electric system employs solar panels, composed of a number of solar cells to converts sunlight directly into electricity.

A photovoltaic (PV) electric system converts sunlight directly into electricity. Also referred to as solar electric.

PV Cells

Photovoltaic cells are thin layers of semiconducting material, usually made of silicon. When the silicon is exposed to light, an electrical charge is generated. Solar PV cells form the basis of a solar electric panel, which together make up a solar electric (PV) system.

Solar electric

A solar electric system converts sunlight directly into electricity. Also referred to as solar photovoltaic or PV. A solar photovoltaic system is made up of solar panels, which are made up of a number of solar cells.

Solar thermal

A solar thermal collector can be used to heat water for personal use or home heating. In contrast to a solar electric system, a solar thermal system requires heat from the sun to work.