Glossary by "L"

  • 345

    Least-cost planning

    See: Integrated resources planning
    Source: ESA Technical Working Group
  • 346

    Levelized cost

    See: Levelized cost of energy
    Source: ESA Technical Working Group
  • 347

    Levelized cost of energy

    Acronym(s): LCOE

    A common metric used to compare the “levelized” or “annuity equivalent” cost per unit to generate electric energy, over a specified period (number of years), given assumed cost-of-capital, start year prices and cost/price escalation rates. The two primary components are 1) capital plant and equipment related cost and 2) expense related costs such as maintenance and fuel. Importantly, LCOE is used to make comparisons between generation alternatives assuming comparable bases. So they reflect relative cost—and are unlikely to reflect actual cost—for a specific alternative or circumstance.

    Source: ESA Technical Working Group
  • 348

    Life extension

    Actions taken to extend the useful life of utility equipment, primarily by reducing peak demand served by the equipment. For most equipment types that involves reducing the equipment’s maximum and on-peak operating temperatures. For underground power cables a key result is reduced ground faults.

    Source: ESA Technical Working Group
  • 349

    Limiting element

    The element within a “system” that: 1) is operating at its appropriate rating or 2) would be following the limiting contingency.  Thus, the limiting element establishes a system limit.

  • 350

    Line fault

    See: Fault
    Source: ESA Technical Working Group
  • 351


    An end-use device or an end-use customer receiving electric power and using electric energy from the electrical system (grid). Note: The term load is sometimes treated as a synonym for demand, which is the measure of power that a load receives or requires.

    Source: ESA Technical Working Group
  • 352

    Load center

    A specific geographical area where electric load is concentrated, especially areas within a utility’s service area where demand is highest.

    Source: ESA Technical Working Group
  • 353

    Load management

    See: Demand side management
    Source: ESA Technical Working Group
  • 354

    Load shape

    A graphical representation of electric demand over time.

    Source: ESA Technical Working Group
  • 356

    Load-serving entities

    Acronym(s): LSE

    Utilities, marketers or aggregators who provide electric power to a large number of end-use customers.

  • 357

    Local publicly owned electric utilities

    A municipal corporation, a municipal utility district, an irrigation district or a joint power authority (which can include one or more of the agencies mentioned above) furnishing electric services over its own transmission facilities, or furnishing electric service over its own or its members

  • 358

    Locational marginal price

    Acronym(s): LMP

    A method of setting prices in an ISO market whereby prices at specific locations on the grid are determined by the marginal price of generation of power available to that specific location. Prices vary from location-to-location based on transmission congestion and losses.

  • 359

    Long-term fixed contract

    A bilateral transaction, often for an extended period of time at a set amount. Contracts may be one, five or 10 years and could be for peak or off-peak hours or a full-day contract.