NRG Glossary of Industry Terms

Glossary of Industry Terms

At Reliant, we're so into what we do that we sometimes use language that doesn't make sense to people outside the industry. Get the definitions of some commonly used industry terms below.

Building envelope
The structural elements (walls, roof, floor, foundation) of a building that encloses conditioned space; the building shell.

Circuit
The complete path electricity follows from a source through a connection to an output device. For example: A circuit can be made from a battery (source) through a copper wire (connection) to a light bulb (output device) and back to the battery.

Connection fee
A fee charged by your transmission and distribution service provider (TDSP, your area's poles/wires or utility company) to connect and start electric service at a particular address.

Customer choice/electricity choice
In deregulated retail electricity markets like Texas, customer choice means you can choose a retail electricity provider (REP) and an electricity plan to meet your specific needs. While just one company maintains the poles and wires that deliver your electricity, many companies compete to sell you the electricity that runs over the poles and wires. As a result, you get to choose the type of plan and REP you prefer.

Demand charge
Charge based on the rate at which electricity is delivered to your system at a particular instant or averaged over a designated period in the billing cycle. Typically, the energy demand for your business or residence is determined by finding the highest amount of electricity your property uses and maintains for 15 minutes. This is measured so power generators know how much electricity needs to be available for all locations on the grid. A demand charge is used more typically for businesses than for residential addresses.

Deregulation (electricity deregulation)
The move from a regulated electricity system, where customers may not have a choice about which electricity company they use, to a competitive electricity market. Electricity deregulation means you can choose a retail electricity provider (REP) and an electricity plan that meet your specific needs. One company (your TDSP) maintains the poles and wires that deliver your electricity, but many companies compete to sell the electricity that runs over the poles and wires.

Disconnect/reconnect fee
A fee charged by your TDSP (e.g., your area's poles/wires or utility company) to disconnect or reconnect electric service.

Distributed renewable generation (DRG)
On-site, customer-owned renewable power systems, such as solar panels or wind turbines, that supply a portion or all of a customer's electricity requirements. These systems are typically connected to the power grid and can send excess electricity into the grid.

Distribution system
The part of the electricity supply system that delivers electricity from electricity generation facilities to consumers.

Electric current
A measure of the amount of electrical charge transferred per unit. It represents the flow of electrons through a conductive material. A common unit of current is the ampere.

Electric energy
The ability of an electric current to produce work, heat, light or other forms of energy. It is measured in kilowatt hours.

Electric Reliability Council of Texas (ERCOT)
The state’s largest electricity management agency that oversees the electric grid. ERCOT serves 23 million Texas customers, representing 85% of the state’s electric load and 75% of the state’s land area.

Electric service identifier (ESID or ESI ID)
A unique 17- or 22-digit number number in the ERCOT market given to an electricity delivery point by the TDSP, usually visible on your electric meter. You can find this number on your electricity bill. (Same as ESI I.D. below.)

Electric utility
A regulated electric power company, often referred to as a public utility, which engages in the generation, transmission, distribution and sale of electricity.

Electrical grid
A network of transmission and distribution lines, substations and transformers that delivers electricity to consumers.

Electricity
The supply of electric currents to a house or other building for heating, lighting or powering appliances.

Electricity demand
The amount of electricity being consumed at any given time. Demand rises and falls throughout the day in response to the time of day and other environmental factors.

Electricity facts label (EFL)
A document required by the Public Utility Commission of Texas that provides customers with information on pricing, contract length, cancellation fees, sources of power generation and emissions along with other disclosures in a standardized format. 

Electricity generation
The process of producing electricity using a natural resource or a renewable source, such as coal, natural gas, nuclear energy, solar, wind, water or biomass.

Electricity usage
On your electricity bill, this is the amount of electricity used in a billing cycle, measured in kilowatt-hours (kWh).

Emergency backup generation
Alternative means of generating electricity used only during temporary interruptions of normal power supply.

Energy audit
A review of your home or place of business to find out how much energy you are using and identify ways to reduce energy usage. The audit could be performed in person or by reviewing energy usage data for your residence or business property.

Energy charge
A portion of your total charge for electricity service; the total number of kilowatt-hours consumed within the billing cycle times the price you pay per kWh.

Energy efficiency
Using less energy to provide the same level of performance, comfort and convenience. The goal of energy efficiency is to reduce energy use, which may result in cost savings and the conservation of natural resources.

EnergyGuide Label
Yellow and black labels found on appliances that can help you compare the energy use of similar models while you shop. The Federal Trade Commission's Appliance Labeling Rule requires appliance manufacturers to put these labels on:

  • Refrigerators, freezers, dishwashers, clothes washers, televisions
  • Water heaters, furnaces, boilers, heat pumps
  • Central air conditioners, room air conditioners
  • Pool heaters
  • Certain light bulbs, plumbing products and ceiling fans

Energy source
The primary source used to generate power. The energy could be converted to electricity through chemical, mechanical or other means. Common energy sources include coal, petroleum, gas, water, uranium, wind, sunlight, geothermal, etc.

ENERGY STAR®
ENERGY STAR is a U.S. Environmental Protection Agency program that helps individuals and businesses identify energy saving products. Products that earn the ENERGY STAR label are independently certified to save energy without sacrificing functionality.

ESI I.D. (electric service identifier)
A unique 17- or 22-digit number number in the ERCOT market given to an electricity delivery point by the TDSP. You can find this number on your electricity bill.

Fixed rate
You pay a certain rate for electricity, usually per kilowatt hour (kWh) of usage, each billing cycle. On a fixed rate plan, the amount you pay per kWh will stay the same for the duration of your contract. This is different from a variable price plan, where the price can change from one billing cycle to the next.

Generation
The production of electricity. In Texas, electricity is produced using a number of energy sources, including natural gas, coal, nuclear power, wind, water and solar energy.

Geothermal energy
Energy obtained by tapping underground reservoirs of heat, usually near volcanoes or other hot spots on the surface of the Earth.

Hydroelectricity
Hydroelectricity or hydroelectric power is the electricity obtained by harnessing the power of water flowing down from a high level. It is a timeless and renewable resource. Huge generators convert the potential energy of falling or fast-moving water into electrical energy.

HVAC
An abbreviation for the heating, ventilation and air-conditioning system, which is the system or systems that condition air in a building.

Kilowatt (kW)
A standard unit that measures electrical energy (1,000 watts = 1 kW).

Kilowatt hour (kWh)
A unit or measure of electricity supply or consumption equaling 1,000 watts operating for one hour. Ex: 1 kWh = ten 100 watt bulbs all burning at the same time for one hour; 10 bulbs x 100 watts each x 1 hour = 1 kWh

Local wires company
The company that transmits and delivers electricity to a customer's home or business along the electrical poles and wires. The local wires company is responsible for maintenance and repair of these poles and wires and is also referred to as the transmission and distribution service provider (TDSP).

Lumens
A unit of measurement of light energy. Specifically, lumens measure the amount of light a lamp produces in all directions.

Meter
A device that measures the amount of electrical energy consumed by a residence, business or an electrically powered device. Utility companies (or TDSPs) read meters to determine how much electricity each customer used. Types of electricity meters include digital meters and smart meters.

Nuclear power
The energy produced by splitting atoms in a nuclear reactor.

Off peak
A period of relatively low system demand for electricity. These periods often occur in daily, weekly and seasonal patterns. The use of smart meter technology has allowed electricity companies to offer new products that take advantage of off-peak pricing periods

On peak
Periods of relatively high system demand for electricity. These periods often occur in daily, weekly and seasonal patterns.

Phantom load
The consumption of electricity when a device or appliance is plugged into an outlet but not turned on.

Prepaid plans
Prepaid electricity plans provide electricity service on a pay-as-you-go basis. These plans allow customers to decide how much electricity to purchase, as opposed to a traditional plan that delivers a bill at the end of a billing cycle.

Public Utility Commission of Texas (PUC or PUCT)
The state agency responsible for the regulation and oversight of electricity and local telecommunication services in Texas. In Texas' deregulated market, the PUC still regulates the delivery of electricity and enforces customer protections.

R-value
A measure of the resistance of an insulating or building material to heat flow, expressed as R-11, R-20 and so on. The higher the R-value, the greater the resistance to heat flow and better insulating capability.

Rate
The amount you pay for your electricity is the rate, and it is usually an amount per kilowatt hour (kWh).

Renewable energy
Electricity made from resources that rely on fuel sources that naturally regenerate over a short period of time, such as the sun, wind, moving water, biomass or biomass-based waste products, or the earth’s heat (geothermal). A renewable energy technology does not rely on energy resources derived from fossil fuels, waste products from fossil fuels, or waste products from inorganic sources.

Retail electric provider (REP)
In Texas, a REP is a company that sells electricity to consumers and is responsible for sending a monthly electricity bill.

Solar power
Heat radiation from the sun that is converted into electrical power.

Smart energy
The term smart energy comes from the philosophy of using the most cost-effective approach to meeting your electricity needs while maintaining the lowest environmental impact.

Smart home
A home equipped with lighting, heating and electronic devices that can be controlled remotely by phone or computer. Smart homes use a variety of tools to make their residents’ lives easier and more efficient, while also allowing for a smaller impact on the environment.

Smart meter
A type of electricity meter that has continuously available, remote, two-way communication and information storage capability. Smart meters record and store your electrical usage in 15-minute intervals and communicate that usage information back to your local wires company. Unlike traditional electric meters that only measure total consumption, smart meters show when the energy was consumed.

TDSP
The transmission distribution service provider, which is in charge of maintaining electrical poles and wires.

TDSP delivery charges
The cost of delivering electricity to your home, charged by your transmission and distribution service provider (TDSP). All delivery charges are approved by the Public Utility Commission of Texas and apply to all customers within a TDSP's service area, regardless of electricity provider.

Thermal energy
A rising air current caused by heating from the underlying surface.

Transformer
A device used to transfer electric energy from one circuit to another.

Transmission and distribution service provider (TDSP)
The local wires company responsible for the poles and wires that transmit and deliver electricity to your home or business. TDSPs are responsible for the maintenance and repair of these poles and wires.

Usage
The amount of electricity you used during a specified billing period listed in kilowatt-hours (kWh). This is listed on your electric bill as kWh used.

Usage charge
A monthly account fee, if applicable.

Variable price
On a variable price electricity plan, your price can vary according to a method determined by your retail electric provider.

Volt
A unit that measures the force used to produce an electric current. Also the push or force that moves electric current through a conductor.

Watt
A unit that measures electric power. 1 kW = 1,000 watts. 1 Megawatt (MW) = 1,000,000 watts

Wattage
The rate of electric energy being used by lights or appliances.

Wind power
A form of energy conversion in which turbines convert the kinetic energy of wind into electrical energy that can be used for power.

Wind turbine
A device that converts kinetic energy from the wind, also called wind energy, into electrical energy in a process known as wind power.

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