Michigan Environmental Education Curriculum Support (MEECS) Michigan Environmental Education Curriculum Support (MEECS) Energy Resources Unit Lesson 3 How does electricity get to our homes? Created by Heather Luoto Copyright 2005 Central Michigan University

There are three phases of electric power supply: Generation is defined as the production of electric energy from other energy sources. Transmission is the delivery of electric energy over high- voltage lines from the power plants to the distribution areas. Distribution includes the local system of lower voltage lines, substations, and transformers, which are used to deliver the electricity to end-use consumers. Source: United States Department of Energy. Energy Information Administration. Electricity. The U.S. Electric Power Industry Infrastructure: Functions and Components. Washington, DC. Retrieved March 8, 2004, from

Source: Lower Colorado River Authority

Generation Electricity is generated at power plants and generating facilities using energy resources. Photo Sources: Edison Sault Electric Company, DTE Energy, Village of Mackinaw City

Transmission Electricity leaves the power plant and travels along wires to a step-up substation (high voltage switch yard) where the voltage is increased using transformers to reduce energy (heat) loss during transmission. Photo Credit: Heather Luoto

The electricity leaves the substation and enters the network of high voltage transmission lines called the electric power grid. Most of the Upper Peninsula is connected to the MAIN: Mid-America Interconnected Network. The Lower Peninsula is connected to the ECAR: East Central Area Reliability Coordination Agreement.

The Main Interconnections of the U.S. Electric Power Grid and the 10 North American Electric Reliability Council Regions Note: There is no “national power grid” in the United States. The continental United States is divided into three main power grids. Source: North American Electric Reliability Council

The electricity then travels on high voltage transmission lines to step-down substations near the final destinations. Photo Credit: Heather Luoto

Distribution Small step-down transformers in substations reduce the voltage so it can be carried on smaller distribution lines to customers. Photo Credit: Heather Luoto

Transformer and Distribution Lines in an Upper Peninsula Neighborhood Photo Credit: Heather Luoto Small transformers on poles or on the ground reduce the voltage to volts for residential use. The electricity travels to homes on either above ground or underground wires.