Solar Energy Glossary

Solar Energy Glossary

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

A dopant material, such as boron, which has fewer outer shell electrons than required in an otherwise balanced crystal structure, providing a hole, which can accept a free electron.

The period of time, at a specified temperature, that a charged battery can be stored before its capacity falls to an unusable level.

 The voltage(s) at which a charge controller will take action to protect the batteries.

A feature allowing the user to adjust the voltage levels at which a charge controller will become active.

dopant material, such as boron, which has fewer outer shell electrons than required in an otherwise balanced crystal structure, providing a hole, which can accept a free electron.

Equal to the cosine of the zenith angle-that angle from directly overhead to a line intersecting the sun. The air mass is an indication of the length of the path solar radiation travels through the atmosphere. An air mass of 1.0 means the sun is directly overhead and the radiation travels through one atmosphere (thickness).

A type of electrical current, the direction of which is reversed at regular intervals or cycles. In the United States, the standard is 120 reversals or 60 cycles per second. Electricity transmission networks use AC because voltage can be controlled with relative ease.

The temperature of the surrounding area.

 A non-crystalline semiconductor material that has no long-range order.

A unit of electrical current or rate of flow of electrons. One volt across one ohm of resistance causes a current flow of one ampere.

Services that assist the grid operator in maintaining system balance. These include regulation and the contingency reserves: spinning, non-spinning, and in some regions, supplemental operating reserve.

The angle that a ray of sun makes with a line perpendicular to the surface. For example, a surface that directly faces the sun has a solar angle of incidence of zero, but if the surface is parallel to the sun (for example, sunrise striking a horizontal rooftop), the angle of incidence is 90°.

 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.

The positive electrode in an electrochemical cell (battery). Also, the earth or ground in a cathodic protection system. Also, the positive terminal of a diode.

A thin coating of a material applied to a solar cell surface that reduces the light reflection and increases light transmission.

The electrical current produced by a photovoltaic array when it is exposed to sunlight.

The voltage produced by a photovoltaic array when exposed to sunlight and connected to a load.

 The quality or condition of a photovoltaic system being available to provide power to a load. Usually measured in hours per year. One minus availability equals downtime.

Represents all components and costs other than the photovoltaic modules/array. It includes design costs, land, site preparation, system installation, support structures, power conditioning, operation and maintenance costs, indirect storage, and related costs.

A metered segment of the power system, maintained by a balancing area authority, that ensures the total of all electrical generation equals the total of all system loads.

 In a semiconductor, the energy difference between the highest valence band and the lowest conduction band.

The energy given up by an electron in penetrating the cell barrier; a measure of the electrostatic potential of the barrier.

The average amount of electric power that a utility must supply in any period.

Typically coal or nuclear generating units that are committed and dispatched at constant or near-constant levels with minimum cycling. They are often the sources of lowest-cost of energy when run at very high capacity factors.

Two or more electrochemical cells enclosed in a container and electrically interconnected in an appropriate series/parallel arrangement to provide the required operating voltage and current levels. Under common usage, the term battery also applies to a single cell if it constitutes the entire electrochemical storage system.

The total maximum charge, expressed in ampere-hours, that can be withdrawn from a cell or battery under a specific set of operating conditions including discharge rate, temperature, initial state of charge, age, and cut-off voltage.

 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.

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.

The chemical element commonly used as the dopant in photovoltaic device or cellmaterial.

The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit; equal to 252 calories.

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.

 A chemical element used in making certain types of solar cells and batteries.

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.

A battery having an immobilized electrolyte (gelled or absorbed in a material).

The negative pole or electrode of an electrolytic cell, vacuum tube, etc., where electronsenter (current leaves) the system; the opposite of an anode.

A method of preventing oxidation of the exposed metal in structures by imposing a small electrical voltage between the structure and the ground.

A single unit of an electrochemical device capable of producing direct voltage by converting chemical energy into electrical energy. A battery usually consists of several cells electrically connected together to produce higher voltages. (Sometimes the terms cell and batteryare used interchangeably). See also photovoltaic (PV) cell.

A free and mobile conduction electron or hole in a semiconductor.Toggle Content