Photovoltaic Conversion Efficiency Terms +

(solar electricity technical terms applying to electricity, power generation, concentrating solar power, or CSP, solar heating, solar lighting, and solar electricity)

battery capacity, system storage
The maximum total electrical charge, expressed in ampere-hours, which a battery can deliver to a load under a specific set of conditions.
battery cell
The simplest operating unit in a storage battery.

It consists of one or more positive electrodes or plates, an electrolyte that permits ionic conduction, one or more negative electrodes or plates, separators between plates of opposite polarity, and a container for all the above.

battery cycle life
The number of cycles, to a specified depth of discharge, that a cell or battery can undergo before failing to meet its specified capacity or efficiency performance criteria.
battery energy capacity
The total energy available, expressed in watt-hours (kilowatt-hours), which can be withdrawn from a fully charged cell or battery.

The energy capacity of a given cell varies with temperature, rate, age, and cut-off voltage. This term is more common to system designers than it is to the battery industry where capacity usually refers to ampere-hours.

battery energy storage
Energy storage using electrochemical batteries.

The three main applications for battery energy storage systems include spinning reserve at generating stations, load leveling at substations, and peak shaving on the customer side of the meter.

battery life
The period during which a cell or battery is capable of operating above a specified capacity or efficiency performance level.

Life may be measured in cycles and/or years, depending on the type of service for which the cell or battery is intended.

blocking diode
A semiconductor connected in series with a solar cell or cells and a storage battery to keep the battery from discharging through the cell when there is no output, or low output, from the solar cell.

It can be thought of as a one-way valve that allows electrons to flow forwards, but not backwards.

boron (B)
The chemical element commonly used as the dopant in photovoltaic device or cell material.
A sausage-shaped, synthetic single-crystal mass grown in a special furnace, pulled and turned at a rate necessary to maintain the single-crystal structure during growth.
British Thermal Unit; BTU, Btu
The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit; equal to 252 calories.
building-integrated photovoltaics; BIPV
A term for the design and integration of photovoltaic (PV) technology into the building envelope, typically replacing conventional building materials.

This integration may be in vertical facades, replacing view glass, spandrel glass, or other facade material; into semitransparent skylight systems; into roofing systems, replacing traditional roofing materials; into shading "eyebrows" over windows; or other building envelope systems.

bypass diode
A diode connected across one or more solar cells in a photovoltaic module such that the diode will conduct if the cell(s) become reverse biased.

It protects these solar cells from thermal destruction in case of total or partial shading of individual solar cells while other cells are exposed to full light.

cadmium telluride; CdTe
A polycrystalline thin-film photovoltaic material.
cadmium; Cd
A chemical element used in making certain types of solar cells and batteries.
capacity factor
The ratio of the average load on (or power output of) an electricity generating unit or system to the capacity rating of the unit or system over a specified period of time.
The information for the entries in this unit were compiled primarily from data
provided in the following source:

"U.S. Department of Energy, Energy Efficiency and Renewable Energy"
consisting of definitions of many important terms having to do with electricity,
power generation, concentrating solar power (CSP), solar heating, solar lighting,
and solar electricity, also known as photovoltaic (PV).

Information was also compiled from the

Academic Press Dictionary of Science and Technology; Edited by Christopher Morris;
Academic Press; Harcourt Brace Jovanovich, Publishers; New York; 1992;
as well as,
McGraw-Hill Dictionary of Scientific and Technical Terms, 4th edition;
Sybil P. Parker, editor in chief; McGraw-Hill, Inc.; 1989.

Index of additional Scientific and Technological Topics.