Glossary of Energy Terms

These are common terms that you may see on plan documents or your monthly electricity bill.


An entity registered with the PUCT to bring a group of customers together to buy electricity in bulk.

Base Charge

A charge assessed during each billing cycle without regard to the customer’s demand or energy consumption.

British Thermal Unit (BTU)

A measure of heat equal to the amount of heat necessary to raise the temperature of one pound of water one degree F.

Commercial Customer

One of three commonly used designations for classes of customers. The others are residential and industrial. Commercial customers are not involved in manufacturing. Examples of commercial customers are retail stores, restaurants and educational institutions.


Adding charges to a bill without a customer's approval.

Customer Charge

A charge assessed during each billing cycle without regard to the customer’s demand or energy consumption.


The amount of electricity used at any given instant or averaged over a designated period of time. Demand is usually in measured in kilowatts or Megawatts. The Peak Demand is the highest 15 or 30 minute recorded demand period over 12-months.

Demand Charge

A charge based on the rate at which electric energy is delivered to or by a system at a given instant, or averaged over a designated period, during the billing cycle.

Do Not Call List

The PUCT will establish a list for customers who do not want to receive telemarketing calls from REPs.

Electric Reliability Council of Texas (ERCOT)

A non-profit entity that is subject to the complete oversight and authority of the Public Utility Commission of Texas and is required to ensure reliability and proper accounting of electricity in the state.

Electricity Facts Label

An information sheet that provides customers with information on a REP's prices, contracts, sources of power generation and emissions, allowing customers to make an "apples-to-apples" comparison of REP offers.

Energy Charge

A charge based on the electric energy (kWh) consumed.

ESI-ID (Electric Service Identifier)

A unique number in the ERCOT market given to an electricity delivery point by the TDSP. You can find this number on your electricity bill.

Kilowatt (kW)

The standard unit for measuring electricity demand, equal to 1,000 watts.

Kilowatt Hour (kWh)

The standard unit for measuring electricity energy consumption, equal to 1,000 watt-hours.

Late Payment Penalty

A charge assessed for late payment in accordance with Public Utility Commission rules.

Miscellaneous Gross Receipts Tax Reimbursement (Gross Receipts Reimb.)

A fee assessed to recover the miscellaneous gross receipts tax imposed on retail electric providers operating in an incorporated city or town having a population of more than 1,000.

Municipally Owned Utility (Muni)

A non-profit utility that is owned and operated by the municipality it serves. In Texas, municipally owned utilities may opt into the competitive retail electric marketplace.

Provider of Last Resort (POLR)

A Retail Electric Provider offering a standard retail service package for each class of customer at a fixed, non-discountable rate. In the event that a REP fails to serve any or all of its customers, those customers may be transferred in mass to the provider of last resort, which may serve that customer the standard retail service package for that customer class, or may serve that customer under a competitive retail plan, in either case with no interruption of service.

Public Utility Commission of Texas (PUCT)

The state agency that regulates electric and telecommunications service. Under Electric Choice, the PUCT will regulate the delivery of electricity and enforce customer protections.

PUC Assessment

A fee assessed to recover the statutory fee for administering the Public Utility Regulatory Act.

Renewable Energy

Electricity that is made from "environmentally friendly" fuel resources, such as wind, water, biomass or solar. Sometimes referred to as "green" energy.

Residential Customer

One of three commonly used terms to differentiate customer classes. The other two are commercial and industrial. Residential customers include private households that utilize energy for such needs as heating, cooling, cooking, lighting and small appliances.


The reorganization of traditional monopoly electric service to require operations and charges to be separated or "unbundled" into generation, transmission/ distribution, and retail services. This allows customers to buy retail electric service from competing providers in areas of the state open to retail competition.

Retail Electric Provider (REP)

A person or company that sells electricity to customers at retail.

Rural Electric Cooperative (Co-op)

Customer-owned electric utility that distributes electricity to members. In Texas, co-ops can choose to opt into the competitive retail market.

Sales Tax

Sales tax collected by authorized taxing authorities, such as the state, cities and special purpose districts.


Switching electric service without a customer's approval.

TDU Delivery Charges

The total amounts assessed by a TDU for the delivery of electricity to a customer over poles and wires and other TDU facilities not including discretionary charges.

Transmission Distribution Surcharges (TDU Surcharges)

One or more TDU surcharge(s) on a customer’s bill in any combination. Surcharges include charges billed as tariff riders by the TDU.

Transmission and Distribution Service Provider (TDSP) or Transmission and Distribution Utility (TDU)

The company that delivers electricity to a customer's home or business along the poles and wires.

Terms of Service

Contract between a Retail Electric Provider and a customer that outlines fees, length of service and other important information.


An electrical unit of power or rate of doing work. It is analogous to horsepower or foot-pounds per minute of mechanical power. One horsepower equals 746 watts.

Your Rights As a Customer Disclosure

A document that informs you of your rights as mandated by the PUC. Retail Electric Providers must provide you with this disclosure.

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