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d
Degree Day of Deficiency
A measure of the coldness of the weather experienced, based on the extent to which the daily mean temperature falls below a reference temperature, usually 60° F.
Demand
The rate at which electric energy or natural gas is delivered to or by a system at a given instant or averaged over a designated period, usually expressed in kilowatts or megawatts (electric); Mcfs or MMBus (natural gas).
Demand Charge
A charge based on the maximum demand (highest consumption peak) during the billing period. The Demand Charge portion of rate design is expected to recover the costs associated with the level of demand for the particular service and will be paid even if no service is taken by the customer; a reservation charge. Included in demand charges are capital-related costs and the cost of operation and maintenance of generation, transmission and distribution.
Demand Interval
Time period over which electric billing demand is measured (typically 15, 30 or 60 minute intervals).
Demand Ratchet
A ratchet allows utilities to bill based on a customer’s maximum present or past demand rather than actual lower demands that might exist during the billing period.
Demand-Side Management (DSM)
A term for all activities or programs undertaken by an electric system or its customers to influence the amount and timing of electricity use. Included in DSM are the planning, implementation and monitoring of utility activities that are designed to influence consumer use of electricity in ways that twill produce desired changes in a utility's load shape, such as, among other things, direct load control, interruptible load and conservation.
Deregulation
The elimination of regulation from a previously regulated industry or sector of an industry.
Derivative Instruments/Products
Futures, options and other contracts derived from underlying instruments such as securities, commodities or financial instruments.
Direct Access
The ability of an end user of electricity to contract with the supplier of choice for electricity services.
Disaggregation
The breaking up of the traditional electric utility structure from a totally bundled service to an a la carte service.
Distributed Generation
Electric power produced elsewhere than a central station generating unit, such as that using fuel cell technology or on-site small scale generating equipment.
Distribution
The ability of an end user of electricity to contract with the supplier of choice for electricity services.
Distribution (Electric)
The system of lines, transformers and switches that connect between the transmission network and customer load. The transport of electricity to ultimate use point such as homes and businesses. The portion of an electric system that is dedicated to delivering electric energy to an end user at relatively low voltages.
Distribution (Gas Utility) Company
A company that obtains the major portion of its natural gas operating revenues from the operation of a retail gas distribution system and that operates no transmission system other than incidental connections within its own system or to the system of another company.
Distribution (Gas)
Mains, service connections and equipment that carry or control the supply of natural gas from the point of local supply to an including the sales meters.
Distribution Line
Network-like pipeline that transports natural gas form a transmission line to an end-user's service line or to other distribution lines. Generally, large pipelines are laid in principal streets, with smaller lateral lines extending along side streets and connected at their ends to form a grid; sometimes lateral lines are brought to a dead end.
Distribution Loss
Natural gas lost though leakage or condensation in delivering natural gas to customers through distribution mains.
Distribution System (High Pressure)
A system that operates at a pressure higher than the standard service pressure delivered to the customer; thus, a pressure regulator is required on each service to control pressure delivered to the customer.
Distribution System (Low Pressure)
A system in which the pressure of the natural gas in the mains and service lines is substantially the same as that delivered to the customers' appliances; ordinarily a pressure regulator is not required on individual service lines in a low-pressure natural gas distribution system.
Distribution Utility (DISCO)
The regulated electric utility entity in a competitive world that would construct and maintain the distribution wires connecting the transmission grid to the final customer. The DISCO could also perform other services such as aggregating customers, purchasing power and providing and offering other regulated or non-regulated energy services to retail customers. The “wires” and “customer service” functions provided by a distribution utility could be split so that two totally separate entities are used to supply these two types of distribution services. These two functions could also remain within the same company but customers could have an option to choose the services or not.
Downstream
ommercial gas operations which are closer to the market, as opposed to upstream, which is closer to production.
Downstream Pipeline
A pipeline receiving natural gas from another pipeline at an interconnection point.
Dual Fuel Capacity
The capacity of an energy burning facility to use more than one kind of fuel, alternatively.
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