Capstone Energy Services

Energy Basics

Terms A-Z

Day-Ahead Market

The forward market for electric energy and ancillary services for delivery on the next trading conducted by an Independent System Operator, a power exchange, or other Scheduling Coordinators.

Day-Ahead Schedule

A schedule prepared by a Scheduling Coordinator or the Independent System Operator before the beginning of a trading day. This schedule indicates the levels of generation and demand scheduled for each period of that trading day.


The act of ending federal government control over the wellhead price of new natural gas sold in interstate commerce. Also termed: "deregulation".

Delivery Point

Point at which gas leaves the control of a seller and enters the control of a buyer and the point that title changes hands.


The rate at which electric energy is delivered to loads and scheduling points by generation, transmission, and distribution facilities at a given instant or over a specific period of time. For gas, the rate at which gas is delivered to or by a system, part of a system, or a piece of equipment, expressed in cubic feet or therms or multiples thereof, for a designated period of time called the demand interval.

Demand Charge

The portion of a rate for gas service which is billed to the customer whether they use the service or not. Depending on the rate design this charge is based on actual or estimated peak usage, annual needs or a combination.

Demand, Billing

The demand upon which billing to a customer is based, as specified in a rate schedule or contract. It may be based on the contract year, a contract minimum, or a previous maximum and, therefore, does not necessarily coincide with the actual measured demand of the billing period.

Demand, Contract

The daily quantity of gas which the supplier agrees to furnish and for which the buyer agrees to pay, under a specific contract.


The elimination or reduction of regulation from a previously regulated industry or sector of an industry.

Direct Sale

Contract sale of natural gas by producer to end user or local distribution company, usually for a term of a year or longer.


Displacement transactions permit the lateral movement of gas through a transportation network. The configuration of many pipelines is such that it may not be apparent whether a given movement of gas is forward or backward from the point of receipt. It can be argued that all transportation service is performed by displacement as the physical delivery of the same molecules of gas is impossible.


The delivery of electricity to retail customers (including homes, businesses, etc.) at a low delivery voltage. For gas, the act or process of distributing gas from the city gate to consumers.

Distribution System

The portion of an electric system that is dedicated to delivering electric energy at low voltage to end users.


Any point in the direction of flow of a liquid or gas from the reference point.

Energy Facts

Energy Facts

Natural gas can be used as a raw material in a variety of products, including paint, fertilizer, plastics and medicines.

Natural gas produces fewer emissions than other fossil fuels, with less nitrogen, sulfur, carbon and fine particulates.

Texas produces the largest amount of natural gas in the USA.

The biggest consumer of coal in the US is the electric power sector.

There are 17,658 electric utility generators in the USA.

Energy Delivery Chains

Energy Delivery Chains

Find out more about how your energy is produced and delivered to your business.

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Energy & the Environment

Energy & the Environment

How we assist clients in responding to national environmental concerns.

  • Initiate and manage a "Green" energy procurement program
  • Evaluate national legislative and regulatory initiatives
  • Research state and local energy efficiency programs and incentives
  • Track energy use and related emissions estimate