Smart Grid 101: Terminology

A subset of terms that may be helpful in better understanding Smart Grid concepts appear below. For a more extensive glossary, see the link at the bottom of this page.

·      Alternative energy:  A vague term that usually refers to non-conventional sources, including fuel cells, waste-to-energy and renewables other than hydro.

·      Demand response: Cutting demand instead of increasing supply. Typically refers to programs that aggregate small reductions from many different users and then present that reduction to the system as a block of power.

·      Distributed generation: Smaller sources of generation scattered throughout the system and located closer to the end user (as opposed to large centralized generation)

·      Distribution: Medium-voltage distribution lines move power from substations to the customer premise, where it is stepped down to lower voltages (typically 220v or 110v).

·      Energy storage: Storing energy for later use via batteries, capacitors, compressed air, flywheels, fuel cells or pumped storage. Typically, the use of this term implies storage large enough to have an impact on the grid.

·      Generation: Converting energy into electricity, typically in large central facilities. Roughly 95% of all U.S. electricity is generated in centralized plants. In the U.S., coal is the most common fuel, followed by natural gas and nuclear.

·      Home area network (HAN): Includes simple computer networking within the home and bundled data, voice, and video services provided by telephone companies. Usually implies a low-power, short-distance approach such as ZigBee, though WiFi and other computer networking standards can also be used.

·      Load management: A collection of strategies intended to reduce or move demand from peak to off-peak periods.

·      Metering:  Generally refers to any type of metering system, such as old electromechanical meters, and the advanced two-way smart meters that are replacing them.

·      Microgrid: Refers to community-scale infrastructure built to automatically island itself from the big grid during outages and reattach when power comes back.

·      Net metering: Allows consumers who contribute power to the grid to receive credit for at least a portion of that electricity by (in essence) “spinning the meter backwards.”

·      Power marketing: Power is often earmarked for a particular utility. In other cases, it is marketed to other utilities or to large industrial users and wheeled (transmitted) over the grid. Power from privately owned plants is sold through power marketers. Power from federally owned hydroelectric dams is allocated through power agencies.

·      Renewable energy: Energy from sustainable, non-fossil sources such as wind, solar, geothermal, marine and hydro.

·      Sensor: Sensors report on conditions or send an alert when conditions go outside specified boundaries. They are used to monitor many conditions: temperature, line sag, transformer condition, physical security, equipment condition and many others. They are an integral component of a Smart Grid.

·      Standards: Critical to the industry, codified and administered standards ensure reliability, efficiency, and interoperability. Typically administered by government entities such as FERC and state PUCs.

·      Storage: A general term for a variety of power storage technologies, including pumped storage, fuel cells, batteries, flywheels, and more.

·      Transmission: High-voltage transmission lines move power from generating plants to substations, where the voltage is stepped down for distribution.

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Deepen your understanding

The following documents provide more detailed information on the barriers to the Smart Grid: