CAIDI

Customer Average Interruption Duration Index

This power reliability indicator shows the average outage time experienced by a consumer over the course of one year.

DER

Distributed Energy Resources

These are small-scale electricity supply or demand resources that are interconnected to the electric grid.

DFA

Distribution Fault Anticipation

Technologies that can provide information on impending circuit failures, which allows utilities to improve power reliability.

EER

Energy Efficiency Ratio

The measurement of the efficiency of an air conditioning system.

EIA

U.S. Energy Information Administration

Statistical agency of the Dept. of Energy, which provides policy-independent data, forecasts and analyses to promote sound policy making, efficient markets and public understanding regarding energy.

FERC

Federal Energy Regulatory Commission

Independent agency that regulates the interstate transmission of electricity, natural gas and oil.

ISO

Independent System Operator

An independent organization that handles electric grid operations, market facilitation (for certain electric markets) and bulk electric system planning.

LIHEAP

Low Income Home Energy Assistance Program

This program lowers the energy burden for households by helping with energy bills—heating costs during the winter and cooling costs during the summer––for those who qualify.

PMAs

Power Marketing Administrations

The four administrations (BPA, WAPA, SEPA and SWPA) that operate electric systems and sell the electrical output of federally owned and operated hydroelectric dams in 34 states.

REC(s)

Renewable Energy Certificate(s)

Market-based instruments that represent the property rights to environmental, social and other non-power attributes of renewable electricity generation.

RTOs

Regional Transmission Organizations

Non-profit, public-benefit corporations created as a part of electricity restructuring in the U.S., beginning in the 1990s. RTOs cover about half of the U.S. and manage roughly two-thirds of annual electricity demand.

SAIDI

System Average Interruption Duration Index

SAIDI is calculated by multiplying the average duration of consumer (power) interruptions by their total number, then dividing by the total number of consumers in the system.