Active tiles: Tiles imbedded with SRS Energy solar technology that enables the tiles to convert the sun’s energy into grid-friendly, green electricity.

Alternating current (AC): An electric current whose direction reverses cyclically, as opposed to direct current (DC), whose direction remains constant. AC is the form of electricity that is delivered to a home or business. Solar photovoltaic systems produce DC power, which must be converted to AC by an inverter.

Amorphous silicon (s-Si): The non-crystalline form of silicone often referred to as “thin film” offers multiple advantages, including flexibility.

Azimuth: The horizontal angular distance between the vertical plane containing a point in the sky and true south.

Building integrated photovoltaic (BIPV): Refers to photovoltaic technology that forms part of the structure to which they are affixed. Typically integrated into the roofing system, BIPV products can provide architectural interest and/or unobtrusive installation.

California Solar Initiative (CSI): Part of the Go Solar California campaign, building on 10 years of state solar rebates and incentives offered to customers in California’s investor-owned utility territories.

Capacity rating: The rating given to a PV system by its manufacturer denoting the load the system is able to meet or supply when operating at full capacity. For a solar system, this will occur when the system is in direct sunlight.

Conversion efficiency: The amount of the sun’s energy that a solar cell can convert into electricity. The balance is lost as heat or reflected light.

Curb appeal: Typically refers to the attractiveness of the exterior of a residential or commercial property; the initial appeal of a property to prospective buyers.

Direct current (DC): An electric current whose direction remains constant, as opposed to alternating current (AC), whose current reverses cyclically. Solar photovoltaic systems produce DC power, which must be converted to AC by an inverter to power household electronics.

Electrical distribution grid: A system that provides electricity to most homes and businesses. A network power stations, transmission circuits and substations conduct electricity to consumers. Under most governmental incentive programs, eligible renewable energy systems must be permanently interconnected and operating parallel to the electrical distribution grid.

Green: Of or pertaining to a process or system that is environmentally friendly or environmentally conscious.

Greenhouse gases (GHG): Gases responsible for trapping heat from the sun within the Earth’s atmosphere. GHGs include water vapor, carbon dioxide, methane, ozone, chlorofluorocarbons and nitrogen oxides, and are released from industrial processes such as power generation from fossil fuels.

Grid: Term used to describe an electrical distribution network.

Grid-connected or grid-tied photovoltaic system: A photovoltaic (PV) system in which the PV array is wired into buildings or residences that are connected to the utility grid. To receive incentives under government programs, PV systems must be connected to the utility’s grid, allowing excess solar energy to flow back onto the grid, which produces a bill credit.

Insolation: The amount of solar energy that shines on a building or area, equivalent to energy and usually expressed in annual kilowatt hours per square meter.

Interconnection agreement: A legal document between the homeowner and their electric utility authorizing connection of the customer’s solar system to the utility’s grid.

Interval data recorder: A metering device that stores data on energy production, usually in hourly or 15-minute intervals.

Inverter: A device that converts direct current (DC) electricity produced by a solar system into alternating current (AC) electricity that can be used in a home or building. Some energy is lost when this conversion takes place.

Inverter efficiency: Alternating current (AC) power output of the inverter divided by the direct current (DC) power input. Inverter efficiency is lowest when operating at low loads, thus it is important inverters of the proper size are selected relative to the photovoltaic array.

Kilowatt (kW): A unit of electrical power equal to 1,000 Watts, which constitutes the basic unit of electrical demand. The Watt is a metric measurement of power (not energy) and is the rate (not duration) at which electricity is used.

Kilowatt hour (kWh): A unit of electrical energy, equivalent to the use of 1 kilowatt of electricity for one full hour. Utilities measure customers’ electric energy usage on the basis of kilowatt-hours, and electricity rates are most commonly expressed in cents per kilowatt hour.

Load: The amount of power carried by a utility system or the amount of power consumed by an electric customer at a specific time. Base load is the minimum constant level of electricity required by utility customers. Peak load is the amount of electricity required at the time of greatest demand.

Megawatt (MW): Unit of electric power equal to 1,000 kilowatts, or 1 million Watts.

Meter: A device used to measure and record the amount of electricity used or generated by a consumer.

Net energy metering (NEM) agreement: An agreement with the local utility that allows customers to receive a credit at the retail price of electricity for surplus electricity generated by certain renewable energy systems. Under net metering, the electric meter runs backward as a customer’s solar system generates surplus electricity.

New Solar Homes Partnership (NSHP): A statewide program that is managed by the California Energy Commission and works with homebuilders to accelerate photovoltaic installation on new residential construction.

Orientation: A term used to describe the direction that the surface of a solar module faces. The two components of orientation are the tilt angle (the angle of inclination a module makes from the horizontal) and the azimuth (the compass angle that the module faces, with north equal to 0 degrees and south equal to 180 degrees).

Photovoltaic (PV): The technology that uses a semiconductor to convert light directly into electricity.

Power conversion efficiency: The ratio of output power to input power of the inverter. Efficiency of stand-alone inverters will vary significantly with the load. Values found in manufacturers' specifications are the maximum that can be expected.

Renewable energy credit (REC): Renewable energy certificates (RECs), also known as green certificates, green tags or tradable renewable certificates—represent the environmental attributes of the power produced from renewable energy projects. By installing a renewable energy system (such as solar), you become the owner of these environmental attributes, or RECs.

Silicon: A chemical element (Si) that is the most common semiconductor material used in making solar photovoltaic cells.

Solar irradiance: Radiant energy emitted by the sun, particularly electromagnetic energy.

Solar pathfinder: A device used in photovoltaic site assessment for charting the sun's path through the sky for all months of the year, calibrated by the hours of the day. Also provides other critical, detailed site data.

Solar thermal: The process of concentrating sunlight on a relatively small area to create the high temperatures needed to vaporize water or other fluids to drive a turbine for generation of electric power, heat water for domestic or industrial hot water, or space conditioning (heating or cooling).

SRS: An acronym for solar roofing system, as in SRS Energy.

Stand-alone photovoltaic system: An autonomous or hybrid photovoltaic system not connected to a grid (as opposed to grid-connected)

Sustainable: Of or pertaining to a process or system that is environmentally friendly or environmentally conscious; a system or process that reduces energy consumption or generates energy.

UL certified: Refers to Underwriters Laboratories Inc. (UL), a U.S. nonprofit privately owned and operated product safety testing and certification organization that develops standards and test procedures for products, materials, components, assemblies, tools and equipment, chiefly dealing with product safety.

Time-of-use (TOU) meter: An electric meter that measures and records the times during which a customer consumes or generates electricity. This type of meter is used for customers who are on time-of-use rates.

Time-of-use (TOU) rates: Electricity prices that vary depending on the time period in which the energy is consumed or produced. In a time-of-use rate structure, higher prices are charged during utility peak-load times. Such rates can provide an incentive for consumers to curb power use during peak times. Solar tiles tend to produce power during peak times, so they have high value when used in conjunction with time-of-use rates.

Watt: A unit of measurement of electric power, named after physics pioneer James Watt.

Watt-hour (Wh): A unit of energy measurement, equal to one Watt of power used for one hour.