Glossary by "I"

  • 313


    Energy losses associated with current flow through electric transmission and distribution systems. Also known as resistive losses. resistive losses. As the name implies: I

    Source: ESA Technical Working Group
  • 314

    Incremental cost

    The cost of the next kilowatt-hour of generated energy, also referred to in the industry as the next unit. Incremental costs change as production increases or decreases, but these changes don’t always occur in a predictable pattern. As an example, incremental costs typically decrease as production rises to comfortable capacity. But once that limit is reached, incremental costs increase because additional costs (construction of new facilities, costs of stressing production facilities, etc.) need to be factored into the cost of the next unit. Incremental cost is often used interchangeably with marginal cost, but incremental cost is a strict value applied to the next unit only, whereas marginal costs are often expressed as averages of large numbers of next units.

    Source: ESA Technical Working Group
  • 316

    Independent power producer

    Acronym(s): IPP

    A generation company that is not part of a regulated vertically-integrated utility company that sells output under a long-term contract.  

  • 317

    Independent system operator

    Acronym(s): ISO

    An organization formed at the direction or recommendation of the Federal Energy Regulatory Commission (FERC) to coordinate, control and monitor operation of the electrical power system. An ISO’s jurisdiction may be for one state or multiple states. Note: RTOs typically perform similar or the same functions as ISOs, but RTOs tend to have jurisdiction over larger geographic areas than ISOs. Some ISOs and RTOs also administer the marketplace for wholesale electricity.

    Source: ESA Technical Working Group
  • 318

    Independent System Operator New England

    Acronym(s): ISO-NE

    A non-profit organization that ensures the constant availability of electricity by 1) ensuring the day-to-day reliable operation of New England’s bulk power generation and transmission system, 2) overseeing and ensuring the fair administration of the region’s wholesale electricity markets, and 3) managing comprehensive, regional planning processes.

  • 331

    Induce (current)

    See: Inductance
  • 332


    The ratio of the voltage to the rate of change of current, which has units of henries (H).

    Source: Wikipedia
  • 333


    A passive two-terminal electrical component which resists changes in electric current passing through it. It consists of a conductor such as a wire, usually wound into a coil. When a current flows through it, energy is stored in a magnetic field in the coil. When the current flowing through an inductor changes, the time-varying magnetic field induces a voltage in the conductor, according to Faraday

    Source: Wikipedia
  • 322

    Institute of Electrical and Electronics Engineers, Inc.

    Acronym(s): IEEE

    IEEE a professional association that is “dedicated to advancing technological innovation and excellence for the benefit of humanity” and to “inspir[ing] a global community through IEEE’s highly cited publications, conferences, technology standards, and professional and educational activities.”

  • 323

    Integrated gasification combine cycle plant

    Acronym(s): IGCC

    IGCC power plants add to the electricity supply, replace aging coal power plants and replace expensive natural gas power plants. Using coal, IGCC plants produce a synthetic gas, the pollutants are removed and electricity is generated using combined cycle technology.

  • 324

    Integrated resources planning

    Acronym(s): IRP

    A holistic/comprehensive electric resources planning framework that addresses all existing and possible electric supply resources including those owned and controlled by entity doing the planning and other resources that can be provided by other providers. Addressed are supply and demand side alternatives. The objective is to identify the most optimal portfolio of electric resources (i.e. the mix that yields to the lowest possible cost, possibly including environmental and societal externalities). Historically IRP was used as a  

    Source: ESA Technical Working Group
  • 325


    Energy transfers that cross Balancing Authority boundaries.

  • 326

    Interchange authority

    The responsible entity that authorizes implementation of valid and balanced Interchange Schedules between Balancing Authority Areas, and ensures communication of Interchange information for reliability assessment purposes.  

  • 327

    Interchange schedule

    An agreed-upon Interchange Transaction size (megawatts), start and end time, beginning and ending ramp times and rate, and type required for delivery and receipt of power and energy between the source and sink balancing authorities involved in the transaction.  

  • 328

    Interchange transaction

    An agreement to transfer energy from a seller to a buyer that crosses one or more Balancing Authority Area boundaries.

  • 329


    The physical and electrical connection between an electricity source and an external power system (i.e. the electric power grid).  

    Source: ESA Technical Working Group
  • 330

    Interconnection reliability operating limit

    Acronym(s): IROL

    A system operating Limit that, if violated, could lead to instability, uncontrolled separation, or cascading outages that adversely impact the reliability of the bulk electric system.

  • 334

    Intermediate generation

    One of three types of generation, intermediate generation moves up and down throughout the day.

  • 335

    Internal resistance

    The resistance to the flow of electric current within an electrochemical cell or battery.

    Source: ESA Technical Working Group
  • 336

    Interruptible load or interruptible demand

    Demand that the end-use customer makes available to its Load-Serving Entity via contract or agreement for curtailment.  

  • 337

    Inverted block rate

    An energy pricing structure involving prices for energy prices that increase commensurate with increasing energy use. Typically; inverted block rates apply to energy delivered to customers that use a large portion of energy during peak demand periods, especially if additional capacity is needed to meet the customer’s electricity needs. The opposite of declining block rate.  

    Source: ESA Technical Working Group
  • 338

    Investor owned utility

    Acronym(s): IOU

    A utility whose assets are owned by investors (as distinct from public power agencies, cooperatives and municipal utilities).

  • 339


    See: Electrical island

    The process of operating an electrical island.  

    Source: ESA Technical Working Group