An energy flow diagram shows the movement of energy used by a specific consumer or set of consumers from source to usage. In the example below, the flow energy is shown for the United States.
This chart shows the sources of energy consumed in the United States and how they are used. The left side of the chart shows the various sources of energy and how much of total energy consumed each source represents. If you look at trends in recent years, you will see some reduction in the use of coal and an increase in the use of renewables.
Electric power is shown in the center. If you follow the lines from the various energy sources to the electric power sector, you can see how much of each source is used to generate electricity. On the right side of the chart are the sectors that use these energy sources and electricity. As an example, 3% of the natural gas consumed in the U.S. is used for transportation (CNG in cars and vehicle fleets), 33% of the natural gas consumed in the U.S. is used by the industrial class (boilers and process heat), 15% of the natural gas consumed in the U.S. is used by residential customers, and 10% of the natural gas consumed in the U.S. is used by commercial customers (space and water heating for both of these end-use sectors). The remaining 38% of the natural gas consumed in the U.S. is used to generate electric power.
The numbers on the right side of the infographic show the percentage of total energy consumption each energy source accounts for. For instance, for the transportation sector, 91% of the energy used comes from petroleum with lesser amounts from natural gas and renewables. Currently less than 1% of the energy used in transportation comes from electricity, though this is likely to change in the future.
In this graphic, a quadrillion is 1,000,000,000,000,000 (10 to the 15th).