Smart Grid Glossary

Can you talk the smart grid talk? Use this guide to common smart grid terms and acronyms to make sure you're speaking the lingo of the smart grid when meeting with prospective partners and customers.


Advanced battery systems - New generations of batteries that feature improved efficiency and power, and fast charging.

Advanced metering infrastructure (AMI) - All components of the infrastructure relating to electric metering and communications. Includes meters capable of two-way communication.

Appliances - In the smart grid context, appliances go well beyond the kitchen and laundry room and generally refer to residential items, tools, and systems powered by electricity, including heating and cooling, lighting, refrigerators, washers/dryers, computer systems and electronics.

Asset management - Procedures and policies intended to control costs, reduce risk, enhance performance, improve investment and project scheduling decisions, and deal with older equipment.

Automated meter reading (AMR) - Sensor-equipped meters capable of retrieving and transmitting power consumption and other information.


Battery electric vehicle (BEV) - A vehicle that runs exclusively on power stored in on-board batteries.

Biomass - A renewable fuel source for power generation. Includes wood and wood waste, municipal solid waste, crops and biogas.

Broadband over power line (BPL) - Broadband Internet access available over standard power lines.

Building automation system (BAS) - A system capable of computerized monitoring and control of a building’s lighting and mechanical systems, and monitoring for performance and potential failure. Installations typically focus on improved energy efficiency, reliability and reduced costs.

Business case - A decision-making process to determine how a specific decision will affect profitability, and how cash flow, costs and revenue will change.


 Capacity - The measurement of a quantity of energy a battery provides in one discharge.

Charge coupler - The connector and vehicle receptacle for hybrid and all-electric vehicle charging.

Cogeneration - The reuse of thermal energy by connecting thermal electric generation with a thermal process, such as an industrial application.

Command and control - Control centers able to monitor and manage the smart grid, providing remote diagnosis, and remote repair in some instances.

Communications - Generally refers to an integrated, two-way communications and networking platform essential to the operation of a smart grid. Also, communications is an intensely competitive market among wireless, cellular and networking vendors.

Compressed air energy storage - Air that has been compressed, frequently stored in mines or salt caverns, for use on demand.

Congestion - A condition in which there is not enough transmission capacity to handle all of the simultaneous demands on a system satisfactorily.

Critical infrastructure protection (CIP) - Administered by the North American Electric, CIP standards are used to safeguard the North American bulk power system from attack and ensure utility compliance.

Customer information system (CIS) - A software application for handling customer calls, billing and other related functions.

Cycle life - The lifespan of a rechargeable battery used in an EV before it starts to lose its ability to hold a charge. Batteries that are no longer useful in EVs still have capacity, and an after market is being developed to use them in other applications such as energy storage. (See secondary use.)


Demand response - A smart grid practice that allows consumers to reduce or change their electrical use patterns during peak demand, usually in exchange for a financial incentive. The concept of reducing demand rather than increasing supply.

Demand side management (DSM) - Programs used to encourage customers to change the levels and patterns of their electricity consumption.

Department of Energy (DOE) - The federal agency charged with ensuring the continuation of national, economic and energy security of the United States. Smart grid stimulus and demonstration project grants are administered by DOEl

Distributed generation - Relatively small sources of power generation located throughout the system and closer to the end user (as opposed to generation from a large centralized source). For example, rooftop solar panels or small-scale wind systems installed at homes and businesses. Microgrids also could be considered distributed generation.

Distribution - Power delivery from the substation to the end user (residential, commercial, industrial).

Distribution automation - Programs and technologies designed for an intelligent grid and used to ensure consistent power quality and reliability and accommodate two-way power flows.

Distributed generation - Small-scale power generation facilities, particularly renewables, close to consumers to boost efficiency while lowering costs and reducing environmental risks. Also refers to residential and commercial renewable energy sources, such as wind turbines and solar panels.


Electric Power Research Institute (EPRI) - An independent public interest energy and environmental research organization that focuses on issues and challenges related to electric power.

Electric vehicle (EV) - Originally, the term referred to vehicles that operate exclusively on electric power. More recently, the term describes the entire family of vehicles that use electricity as a power source including plug-in hybrid electric vehicles and battery electric vehicles.

Energy Independence and Security Act - Enacted by Congress in 2007 to direct national energy policy.

EV charging infrastructure - Integrated residential, public and commercial equipment, software, systems and management tools required to provide charging facilities for electric vehicles.

EV charging station - The location where EV battery charging is provided, including residential, public and other facilities.

Energy density - The amount of energy in a source of fuel, such as lithium-ion, nickel metal hydride or lead acid batteries.

Efficiency - The term refers to the practice of using less power without affecting the services provided (heating, cooling, lighting, etc.). It is included here as efficiency is considered a form of conservation, the ultimate sustainable resource.


Federal Energy Regulatory Commission  (FERC) - An independent agency responsible for regulating interstate transmission of electricity, high-voltage transmission systems, wholesale electricity sales, and aspects of oil, gas, and hydroelectric operations.

Flow battery - Rechargeable high power and very high storage capacity battery, and used to level loads on the electrical grid.


Geographic information system (GIS) - Digitally stores, analyzes, manages, and relays location-oriented data. Numerous GIS software applications are available.

Geothermal energy - Taps the heat energy from fluids deep within the earth, and used directly for heating or for electricity production.


Home area network (HAN) - Includes computer networking within the home and bundled data, voice, and video services provided by telephone companies. Usually refers to a short distance, low power approach such as Zigbee and WiFi.

Home automation network - Monitoring and control systems for residential use such as heating and lighting controls, security, and appliance and electronics power consumption.

HomePlug – Developed by the HomePlug Powerline Alliance, the term refers to a variety of power line communications standards that support networking over a home’s existing electrical wiring.


Independent system operator (ISO) - An organization established by the Federal Energy Regulatory Commission to control and monitor electric power system operations, typically within one state.

In-home display – Tools designed to provide energy consumers with real-time information on household consumption. There are a variety of them on the market with varying levels of complexity and smart device integration.

Integration and management - The process of bringing power from renewable sources into the electric grid. The integration and management of renewable energy sources is critical because of the intermittent nature of sources like wind and solar which do not provide power at a constant level.

Interoperability - The concept that devices, software and programs from different sources can function together seamlessly.

Interruptible load - Electricity providers can, with prior agreement with the customer, interrupt power delivery to accommodate the occasions when the highest demand for power (peak load) occurs. This practice usually involves large-scale industrial and commercial customers.

Investor-owned utility (IOU) - A privately held utility (not operated by a government entity or a consumer cooperative).

Islanding - The ability to use distributed generation to provide power when storms or other events have knocked out the utility’s ability to provide power.


Line loss - Electric power lost during the process of transmission, typically in the form of heat.

Lithium-ion battery - An increasingly popular and relatively lightweight and high-capacity battery. Also referred to as Li-ion. Used in EVs and many electronics.

Load management - A collection of strategies intended to reduce or move demand from peak to off-peak periods. Another term is load shifting.


Machine-to-machine (M2M) – This refers to various wired and wireless technologies that allow communication between devices on a network.

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

Meter data management (MDM) - As smart meter rollouts continue, utilities are swamped with unprecedented amounts of data that can be used to improve customer relationships, utility operations and business intelligence.

Microgrid - Community-scale system built to automatically separate itself from the primary electric grid during outages or completely independent of the primary grid. The U.S. military is strongly interested in microgrids as a way to improve reliability on its bases and increase security.


National Institute of Standards and Technology (NIST) - A U.S. Department of Commerce agency charged with identifying and evaluating standards and technologies relevant to smart grid adoption. NIST has other responsibilities, as well.

Net metering - Net metering allows consumers who contribute power to the grid to receive credit for at least a portion of that electricity.

nEV - A “neighborhood” EV, intended for short trips.


Off peak - A period of reduced electrical demand.

Outage management - Incorporates technologies such as GIS and smart meters to quickly locate and manage power outages.


Peak demand - Periods when the demand for power is at its highest, such as early morning and early evening or during extremely hot or cold weather.

Peaker plant - Generally, these are older, low-efficiency power plants brought online only during periods of peak demand. Because of their age, inefficiency and intermittent use, peaker plants are extremely expensive to operate.

Phantom load - Refers to power use in appliances after they are turned off. Most electronics and related devices continue to consume power, even when turned “off.”

Phasor measurement unit (PMU) - Phasor measurement units help detect and mitigate congestion at various points on the grid by sampling voltage and current several times a second. Also referred to as synchrophasor.

Photovoltaic system (PV) - Solar cells grouped in panels, then linked together in arrays to transform sunlight into electricity.

PEV – Plug-in electric vehicle

PHEV – Plug-in hybrid electric vehicle

Public utility commission (PUC) - A state agency responsible for setting rates and regulating services and other activities of electric, gas and telecommunications utilities operating within its state boundaries.

Public utility district (PUD) - A single-purpose district established for the generation, transmission and distribution of electricity or other services. Boundaries frequently extend beyond local jurisdictions.


Rate base - A utility’s property value that determines the utility’s permitted rate of return. That rate is set by a regulatory agency.

Rate case - A request filed by an electric utility for a consumer price increase with the appropriate state public utility commissions.

Real-time pricing - Charging consumers varying rates for a service to reflect frequent cost fluctuations occurring over time, as opposed to fixed pricing.

Regional transmission operator (RTO) - An organization established at the direction of the Federal Energy Regulatory Commission to control the electrical power transmission system in a service area that extends beyond state borders.

Reliability - The term refers to how well a device, technology, application or software functions within accepted standards. Typically, reliability addresses adequate power generation and transmission resources to ensure that enough power can be delivered to meet demand with enough in reserve to handle unforeseen circumstances. Another key reliability issue is security, that there will be enough power available even if outages or equipment failures occur.

Renewable energy (also renewables) - A variety of energy sources considered to be sustainable alternatives to oil, coal and natural gas. These sources include solar and wind, geothermal, marine and hydro and hybrid systems such as those incorporating geothermal and solar.

Rooftop PV (photovoltaic) - Solar arrays mounted on rooftops. Increasingly common in residential, commercial and industrial applications.


Secondary use - Using batteries previously used in electric vehicles and plug-in for stationary electric grid storage after they no longer have the capacity to meet the demands of use in a vehicle.

Security - With the smart grid’s more open forms of communications (such as the Internet), those communications are more vulnerable to outside attack and other disruptions. Because utilities are increasingly relying on those open networks for grid monitoring and control, reliable security is essential to reliable and safe smart grid operations.

Sensors - This term includes a variety of devices and/or software designed to monitor and report on conditions that could lead to power outages and damage to the electric grid. Sensors typically monitor temperature, line sag, the condition of transformers, physical security and equipment conditions.

Smart charging - A group of technologies and equipment  incorporated into EV charging infrastructure to ensure integration with the electric grid without causing unmanageable spikes in electricity demand.

Smart grid - While most industries in the energy sector may define it a bit differently, it is basically using  smart devices together with  smart communications and smart software to modernize the electric grid to conserve energy, reduce costs and increase reliability, security and energy independence.

Solar energy - Energy from the sun converted to electricity by a photovoltaic system incorporating sunlight gathering solar cells into panels.

Standards - Standards are critical to the smart grid initiative because they are the instruments used to ensure reliability, efficiency and interoperability throughout the electric grid. Standards are used to enforce those concepts to help guarantee that devices, applications and systems can efficiently work together.

Storage - Grid-scale energy storage is a booming smart grid market and includes a variety of storage technologies, such as compressed air, stationary batteries, ice, flywheels and molten salt to name a few. The ability to store energy is particularly critical with the growing popularity of wind and solar energy sources because they are intermittent power sources, and storage is necessary to avoid wide fluctuations of power brought into the electric grid.

Substation - The site where equipment for switching or regulating electrical voltage is located.

Supervisory control and data acquisition (SCADA) - A computer system that monitors an industrial, infrastructure or facility-based control process.


Transmission - The delivery of bulk high-voltage electricity from the generating plant to substations and the distribution system.

Time of day rate (TOD) - The rate charged to electric utility customers based on the varying costs of delivering service at different times throughout the day.

Time of use (TOU) - An energy cost reduction measure that permits consumers to shift power consumption to off-peak hours.


Ultracapacitor - A capacitor used in large-scale applications, such as powering a bus.


Volt/VAR optimization - Transmitting the correct voltage to each customer rather than sending higher voltages to all users as a “just in case” measure. Also referred to simply as Volt/VAR. There also are other variations in terminology.

V2G - The integration of EVs into the smart grid. In other words, the use of EVs as a backup source of power for the electric grid during periods of high demand.


WiFi - One of the wireless communications technologies favored in home area network device communications and other applications.

WiMax - Another wireless communications technology used to transmit data using a variety of transmission methods. Typically covers wider areas than WiFi.

Wind turbines - A modern day windmill, wind turbines harness energy from the wind to generate electric power. Wind farms They are often part of large land-based wind farms but wind turbines are also becoming more popular as devices to rein in offshore wind.


ZEV - A zero emissions vehicle.

Zigbee – A wireless technology designed as an open standard to promote interoperability in a wide variety of smart energy products.

This is a glossary of terms commonly used in the smart grid environment. Alternative definitions and synonyms are included where appropriate – as are commonly used acronyms.