Michigan Environmental Education Michigan Environmental Education Curriculum Support (MEECS)Curriculum Support (MEECS)

Energy Resources UnitLesson 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 http://www.eia.doe.gov/cneaf/electricity/chg_stru_update/chapter3.html#trans

Source: Lower Colorado River Authority http://www.lcra.org/energy/getpower.html

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. 2004.

The electricity then travels on high voltage transmission lines to step-down substations near the final destinations.

Photo Credit: Heather Luoto

DistributionSmall 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 NeighborhoodPhoto Credit: Heather Luoto

Small transformers on poles or on the ground reduce the voltage to 120-240 volts for residential use. The electricity travels to homes on either above ground or underground wires.