Published by EIA
Getting electricity from power generating stations to our homes and workplaces is quite a challenging process. Electricity must be produced at the same time as it is used because large quantities of electricity cannot be stored effectively.
High-voltage transmission lines (those lines between tall metal towers that you often see along the highway) are used to carry electricity from power generating stations to the places where it is needed. However, when electricity flows over these lines, some of it is lost. One of the properties of high voltage lines is that the higher the voltage, the more efficient they are at transmitting electricity â€” that is, the lower the losses are. Using transformers, high-voltage electricity is “stepped-down” several times to a lower voltage before arriving over the distribution system of utility poles and wires to your home and workplace so it can be used safely.
History of the Electric Power Grid
Around the beginning of the 20th century, there were over 4,000 individual electric utilities, each operating in isolation. Almost all of those used low-voltage connections from nearby generating power plants to the distribution lines serving their local customers.
As the demand for electricity grew, particularly in the post-World War II era, electric utilities found it more efficient to interconnect their transmission systems. In this way, they could share the benefits of building larger and, often, jointly-owned generators to serve their combined electricity demand at the lowest possible cost, and to avoid building duplicative power plants. Interconnection also reduced the amount of extra capacity that each utility had to hold to assure reliable service. With growing demand and the accompanying need for new power plants came an ever-increasing need for higher voltage interconnections to transport the additional power longer distances. Over time, three large interconnected systems evolved in the United States.
Read More About How U.S. Electrical Systems Are Now Interlinked