Brush Up On Your Residential Solar Power Lingo
Glossary of Terms
Glossary of Terms
Alternating Current (AC) – The flow of electricity that constantly changes direction between positive and negative sides. Almost all power produced by electric utilities in the United States moves in current that shifts direction at a rate of 60 times per second.
Ampere (Amp) – The unit of measure that indicates how much electricity flows through a conductor. It is like using cubic feet per second to measure the flow of water. For example, a 1,200-watt, 120-volt hair dryer pulls 10 amperes of electric current (amps = watts/volts).
Annual Solar Savings – 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.
Azimuth Angle – The angle between true south and the point on the horizon directly below the sun.
Balance of System (BOS) – In listing all the hardware and system components that make up a PV system, CPF Tools lists PV Modules, Inverters, and Balance of System. So in this case, BOS refers to all the other hardware line items (“the balance”) not specified such as racking system, flashing materials, enclosures, conduit, cabling, wires, and fasteners. For other references, B05 is everything but the modules themselves.
Demand – The level at which electricity is delivered to end-users at a given point in time. Electric demand in measured in kilowatts.
Direct Current (DC)– The flow of electricity that flows continuously in one direction. Frequency – The number of cycles through which an alternating current moves in each second. Standard electric utility frequency in the United States is 60 cycles per second, or 60 Hertz (Hz).
Electrical Grid – The electricity transmission and distribution system that links power plants to customers through high-power transmission line service.
Electric Distribution Company (EDC) – EDCs deliver electricity from electricity suppliers to end users such as homeowners and businesses. These companies manage the electric wires seen on the sides of streets and are regulated monopolies. There are only four EDCs in New Jersey (JCP&L, PSEG, Atlantic City Electric, and Rockland Electric) and customers must use the company present in their area for electricity delivery. Customers can choose to have the electricity supplied by the same distribution company, or they can opt to purchase from a different supplier.
Energy – The capability of doing work; different forms of energy can be converted to other forms, but the total amount of energy remains the same.
Interconnection – The linkage of transmission lines between two utilities, or between a utility and an end-user, enabling power to be moved in either direction.
Inverter – A device that converts direct current electricity to alternating current either for stand-alone systems or to supply power to an electricity grid.
Investment Tax Credit (ITC) – The ITC is a 30 percent tax credit for solar systems on residential and commercial properties.
Kilowatt (kW) – 1,000 watts. A unit of measure of the amount of electricity needed to operate given equipment. For example, a one kW system is enough power to illuminate 10 light bulbs at 100 watts each. (volts x amps = watts)
Kilowatt-hour (kWh) – The amount of kW produced over a period of time, or one kilowatt of electricity supplied for one hour. For example, a one kW system, if operating at full capacity for 5 hours will produce (or use) 5 kWh of electricity.
National Electrical Code (NEC) – Contains guidelines for all types of electrical installations. The 1984 and later editions of the NEC contain Article 690, “Solar Photovoltaic Systems” which should be followed when installing a PV system.
Net Metering – Net metering is a billing mechanism that credits solar energy system owners for the electricity they add to the grid. For example, if a residential customer has a PV system on the home’s rooftop, it may generate more electricity than the home uses during daylight hours. If the home is net-metered, the electricity meter will run backwards to provide a credit against what electricity is consumed at night or other periods where the home’s electricity use exceeds the system’s output. Customers are only billed for their “net” energy use.
Orientation – Placement with respect to the cardinal directions, N, S, E, W; azimuth is the measure of orientation from north.
Photovoltaic Cell or Module or Panel (PV) – A device that produces an electric reaction to light, thereby producing electricity.
Photovoltaic (PV) Array – An interconnected system of PV modules that function as a single electricity-producing unit. The modules are assembled as a discrete structure, with common support or mounting. In smaller systems, an array can consist of a single module.
PPA – A Power Purchase Agreement (PPA) is a financial arrangement in which a third-party developer owns, operates, and maintains the photovoltaic (PV) system, and a host customer agrees to site the system on its roof or elsewhere on its property and purchases the system’s electric output from the solar services provider for a predetermined period. The homeowner pays based on the actual power produced by the system.
Renewable Portfolio Standard (RPS) – New Jersey’s Renewable Portfolio Standard (RPS) was first adopted in 1999 and has been updated several times. The total RPS requirement in NJ including solar carve out is 24.39% by 2028. The RPS includes two separate provisions for renewable energy. The first provision, which was part of the initial RPS goal requires each supplier/provider serving retail customers in the state to procure 20.38% of the electricity it sells in NJ from qualifying renewables by 2021. The solar specific provision was added 2010. This provision requires suppliers and providers to procure an additional 4.1% of sales from qualifying solar electric generation facilities.
Solar Energy – Heat and light radiated from the sun.
Solar Lease – Homeowners pay a fixed monthly payment for their solar system, and can get started with no money down. A solar lease can make it possible to switch to clean, solar power for less money than homeowners currently pay for electricity.
Solar Panel – Devices that collect energy from the sun (solar energy). This is usually solar photovoltaic (PV) modules that use solar cells to convert light from the sun into electricity.
SREC – The SREC program provides a means for Solar Renewable Energy Certificates (SRECs) to be created for every megawatt (1000 kW) of solar electricity created. SRECs are sold separately from the electricity and their value is determined by market supply and demand. Facilities must be certified by a state to sell SRECs.
Volt (V) – The amount of force required to drive a steady current of one ampere through a resistance of one ohm. Electrical systems of most homes and offices use 120 volts. (volts – watts/amps) (volts = amperes x resistance)
Watt (W) – Electric measurement of power at one point in time, as capacity or demand. For example, light bulbs are classified by wattage. (1,000 watts = 1 kilowatt).