Energy Grid & Transmission

Energy Grid & Transmission


The national electricity grid is made up of three main components.

1. Generators, which generate electricity, such as hydropower plants, coal and gas power plants, solar panels, or wind turbines.

2. Transmission and distribution, which ensures that power gets transported to the end consumer. A transformer converts power into higher voltages, and electricity then travels over cables to another transformer, which reconverts it into lower voltages so that it can reach the end consumer. Transmission cables carry very high voltages (equal to or above 110,000 V, as opposed to the 120 V that homes in the U.S. typically require) because they reduce the amount of electricity that is lost in transit due to resistance in the metal wires it travels through (around 5% of electricity is lost in transit ).

3. Consumer use or “load.” This is the amount of electricity that is being consumed at any given point in time. One factor that will likely reduce grid load in years to come will likely be behind-the-meter generation, which refers to energy that is consumed at the same location it is produced, without passing through a meter. It includes systems such as roof-top solar panels, small wind turbines, as well as gas or diesel generators. When solar or wind systems generate more power than is consumed on-site, producers in most states can be credited for the excess energy they supply to the grid through what is called net metering.

According to the U.S. Energy Information Administration (EIA), there are more than 9,700 power plants, hundreds of thousands of miles of high-voltage power lines, and millions of miles of low-voltage power lines and transformers, that distribute power to more than 153 million customers in the U.S. The electric power generation sector employs approximately 896,800 workers, and 417,600 are employed in transmission, distribution and storage.

There are three principal transmission networks in the country, which operate independently from each other:
1. The Western Interconnection, which covers the area west of the Rocky Mountains;
2. The Eastern Interconnection, which encompasses states to the east of Rocky Mountains, as well as a part of Texas;
3. The Electric Reliability Council of Texas (ERCOT), which covers most of Texas.

Network structures are highly interconnected, in order to create redundancy and ensure that power can flow to multiple routes. This ensures reliability of the system and helps prevent interruptions in supply.

To learn more about the energy grid and transmission, visit the EIA website.