The eia article U.S. government energy consumption continues to decline by Fred Mayes (7/25/19) has a half dozen charts showing U.S. government energy consumption. For example, the chart copied here provides energy consumption by defense and civilian agencies by type (vehicles/equipment or buildings).
The U.S. federal government consumed 915 trillion British thermal units (Btu) of energy during the 2017 fiscal year (FY), or 20% less than a decade before. The slight decline in FY 2017 marks the fifth consecutive decline in annual federal government consumption.
To put this in some perspective, the eia article In 2018, the United States consumed more energy then ever before by Allen McFarland (4/16/19) shows that the U.S. consumed almost 100 quadrillion BTUs in 2017.
Primary energy consumption in the United States reached a record high of 101.3 quadrillion British thermal units (Btu) in 2018, up 4% from 2017 and 0.3% above the previous record set in 2007.
So, the U.S. government consumes about 1% of overall energy. Both articles have links to the data.