The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear weapons program, nuclear reactor production for the United States Navy, energy-related research, and energy conservation.

The DOE was created in 1977 in the aftermath of the 1973 oil crisis. It sponsors more physical science research than any other U.S. federal agency, the majority of which is conducted through its system of National Laboratories. The DOE also directs research in genomics, with the Human Genome Project originating from a DOE initiative.

The department is headed by the secretary of energy, who reports directly to the president of the United States and is a member of the Cabinet. The current secretary of energy is Jennifer Granholm, who has served in the position since February 2021. The department's headquarters are in southwestern Washington, D.C., in the James V. Forrestal Building, with additional offices in Germantown, Maryland.

In 1942, during World War II, the United States started the Manhattan Project to develop the atomic bomb under the U.S. Army Corps of Engineers. After the war, in 1946, the Atomic Energy Commission (AEC) was created to control the future of the project. The Atomic Energy Act of 1946 also created the framework for the first National Laboratories. Among other nuclear projects, the AEC produced fabricated uranium fuel cores at locations such as Fernald Feed Materials Production Center in Cincinnati, Ohio. The Energy Reorganization Act of 1974 split the responsibilities of the AEC into the new Nuclear Regulatory Commission, which was charged with regulating the nuclear power industry, and the Energy Research and Development Administration, which was assigned to manage the nuclear weapon, naval reactor, and energy development programs.

The 1973 oil crisis called attention to the need to consolidate energy policy. In 1977, President Jimmy Carter signed into law the Department of Energy Organization Act, which established the Department of Energy. The new agency, which began operations on October 1, 1977, consolidated the Federal Energy Administration, the Energy Research and Development Administration, the Federal Power Commission, and programs of various other agencies. Former Secretary of Defense James Schlesinger, who served under Presidents Nixon and Ford during the Vietnam War, was appointed as the first secretary.

President Carter proposed the Department of Energy with the goal of promoting energy conservation and energy independence, and developing alternative sources of energy to reduce the use of fossil fuels. With international energy's future uncertain for America, Carter acted quickly to have the department come into action the first year of his presidency. This was an extremely important issue of the time as the oil crisis was causing shortages and inflation. With the Three Mile Island accident, Carter was able to intervene with the help of the department. Through the DOE, Carter was able to make changes within the Nuclear Regulatory Commission, including improving management and procedures, since nuclear energy and weapons are responsibilities of the department.

In December 1999, the FBI was investigating how China obtained plans for a specific nuclear device. Wen Ho Lee was accused of stealing nuclear secrets from Los Alamos National Laboratory for the People's Republic of China. Federal officials, including then-Energy Secretary Bill Richardson, publicly named Lee as a suspect before he was charged with a crime. The U.S. Congress held hearings to investigate the Department of Energy's handling of his case. Republican senators thought that an independent agency should be in charge of nuclear weapons and security issues, rather than the DOE. All but one of the 59 charges against Lee were eventually dropped because the investigation proved the plans the Chinese obtained could not have come from Lee. Lee filed suit and won a $1.6 million settlement against the federal government and news agencies. The episode eventually led to the creation of the National Nuclear Security Administration, a semi-autonomous agency within the department.

In 2001, American Solar Challenge was sponsored by the DOE and the National Renewable Energy Laboratory. After the 2005 race, the DOE discontinued its sponsorship.

Title XVII of Energy Policy Act of 2005 authorizes the DOE to issue loan guarantees to eligible projects that "avoid, reduce, or sequester air pollutants or anthropogenic emissions of greenhouse gases" and "employ new or significantly improved technologies as compared to technologies in service in the United States at the time the guarantee is issued". In loan guarantees, a conditional commitment requires to meet an equity commitment, as well as other conditions, before the loan guarantee is completed.

In September 2008, the DOE, the Nuclear Threat Initiative (NTI), the Institute of Nuclear Materials Management (INMM), and the International Atomic Energy Agency (IAEA) partnered to develop and launch the World Institute for Nuclear Security (WINS), an international non-governmental organization designed to provide a forum to share best practices in strengthening the security and safety of nuclear and radioactive materials and facilities.

In December 2024, the Loan Programs Office announced it would extend the largest loan ever sanctioned – a $15 billion (US) low-interest loan to support the modernization of Pacific Gas & Electric’s hydroelectric power structure, enhance transmission lines critical for renewable energy integration, data center operations, and the growing fleet of electric vehicles. Initially requested as a $30 billion (US) loan, the amount was reduced due to concerns over the company’s repayment capacity.

The department announced a reorganization with new names of under secretaries in 2022.

Program
Secretary of Energy	Deputy Secretary of Energy *Associate Deputy Secretary of Energy
	Assistant Secretary of Energy (International Affairs)
	Assistant Secretary of Energy (Congressional and Intergovernmental Affairs)
	Office of the General Counsel
	Office of the Chief Financial Officer
	Advanced Research Projects Agency-Energy
	Energy Information Administration
	Federal Energy Regulatory Commission
	Enterprise Assessments
	Energy Policy and System Analysis
	Intelligence and Counterintelligence
	Public Affairs
	Office of Management
	Office of Project Management
	Chief Human Capital Officer
	Chief Information Officer
	Economic Impact and Diversity
	Hearings and Appeals
	Assistant Secretary of Energy (Environmental Management) *Legacy Management
	Small and Disadvantaged Business Utilization
Under Secretary for Science and Innovation	Arctic Energy Office
	Office of Critical and Emerging Technologies (CET)
	Assistant Secretary of Energy (Energy Efficiency and Renewable Energy)
	Assistant Secretary of Energy (Electricity)
	Assistant Secretary of Energy (Fossil Energy and Carbon Management)
	Assistant Secretary of Energy (Nuclear Energy)
	Office of Science
Under Secretary of Energy for Nuclear Security	National Nuclear Security Administration
Under Secretary for Infrastructure	National Laboratory Operations Board
	Associate Under Secretary of Energy (Environment, Health, Safety and Security)
	Office of Clean Energy Demonstrations
	Office of Federal Energy Management Programs
	Grid Deployment Office
	Office of Cybersecurity, Energy Security, & Energy Response
	Indian Energy Policy and Programs
	Loan Programs Office
	Office of State and Community Energy Programs
	Bonneville Power Administration
	Southeastern Power Administration
	Southwestern Power Administration
	Western Area Power Administration

The department is under the control and supervision of a United States Secretary of Energy, a political appointee of the President of the United States. The Energy Secretary is assisted in managing the department by a United States Deputy Secretary of Energy, also appointed by the president, who assumes the duties of the secretary in the secretary's absence. The department also has three under secretaries, each appointed by the president, who oversee the major areas of the department's work. The president also appoints seven officials with the rank of Assistant Secretary of Energy who have line management responsibility for major organizational elements of the department. The Energy Secretary assigns their functions and duties.

Excerpt from the Code of Federal Regulations, in Title 10: Energy:

The official seal of the Department of Energy "includes a green shield bisected by a gold-colored lightning bolt, on which is emblazoned a gold-colored symbolic sun, atom, oil derrick, windmill, and dynamo. It is crested by the white head of an eagle, atop a white rope. Both appear on a blue field surrounded by concentric circles in which the name of the agency, in gold, appears on a green background."

"The eagle represents the care in planning and the purposefulness of efforts required to respond to the Nation's increasing demands for energy. The sun, atom, oil derrick, windmill, and dynamo serve as representative technologies whose enhanced development can help meet these demands. The rope represents the cohesiveness in the development of the technologies and their link to our future capabilities. The lightning bolt represents the power of the natural forces from which energy is derived and the Nation's challenge in harnessing the forces."

"The color scheme is derived from nature, symbolizing both the source of energy and the support of man's existence. The blue field represents air and water, green represents mineral resources and the earth itself, and gold represents the creation of energy in the release of natural forces. By invoking this symbolism, the color scheme represents the Nation's commitment to meet its energy needs in a manner consistent with the preservation of the natural environment."

The Department of Energy operates a system of national laboratories and technical facilities for research and development, as follows:

Other major DOE facilities include:

Airstrip:

• Pahute Mesa Airstrip – Nye County, Nevada, part of Nevada National Security Site

The DOE/NNSA has federal responsibility for the design, testing and production of all nuclear weapons. NNSA in turn uses contractors to carry out its responsibilities at the following government owned sites:

• Research, development, and manufacturing guidance: Los Alamos National Laboratory and Lawrence Livermore National Laboratory
• Engineering of the non-nuclear components and system integration: Sandia National Laboratories
• Manufacturing of key components: The Kansas City Plant, Savannah River Site and Y-12 National Security Complex.
• Testing: Nevada Test Site
• Final weapon and warhead assembling and dismantling: Pantex

• 1920 – Federal Power Act
• 1935 – Public Utility Holding Company Act of 1935
• 1946 – Atomic Energy Act PL 79-585 (created the Atomic Energy Commission) [Superseded by the Atomic Energy Act of 1954]
• 1954 – Atomic Energy Act of 1954, as Amended PL 83-703
• 1956 – Colorado River Storage Project PL 84-485
• 1957 – Atomic Energy Commission Acquisition of Property PL 85-162
• 1957 – Price-Anderson Nuclear Industries Indemnity Act PL 85-256
• 1968 – Natural Gas Pipeline Safety Act PL 90-481
• 1973 – Mineral Leasing Act Amendments (Trans-Alaska Oil Pipeline Authorization) PL 93-153
• 1974 – Energy Reorganization Act PL 93-438 (Split the AEC into the Energy Research and Development Administration and the Nuclear Regulatory Commission)
• 1975 – Energy Policy and Conservation Act PL 94-163
• 1977 – Department of Energy Organization Act PL 95-91 (Dismantled ERDA and replaced it with the Department of Energy)
• 1978 – National Energy Act PL 95-617, 618, 619, 620, 621
• 1980 – Energy Security Act PL 96-294
• 1989 – Natural Gas Wellhead Decontrol Act PL 101-60
• 1992 – Energy Policy Act of 1992 PL 102-486
• 2000 – National Nuclear Security Administration Act PL 106-65
• 2005 – Energy Policy Act of 2005 PL 109-58
• 2007 – Energy Independence and Security Act of 2007 PL 110-140
• 2008 – Food, Conservation, and Energy Act of 2008 PL 110-234

On May 7, 2009 President Barack Obama unveiled a $26.4 billion budget request for DOE for fiscal year (FY) 2010, including $2.3 billion for the DOE Office of Energy Efficiency and Renewable Energy (EERE). That budget aimed to substantially expand the use of renewable energy sources while improving energy transmission infrastructure. It also proposed significant investments in hybrids and plug-in hybrids, smart grid technologies, and scientific research and innovation.

As part of the $789 billion economic stimulus package in the American Recovery and Reinvestment Act of 2009, Congress provided Energy with an additional $38.3 billion for fiscal years 2009 and 2010, adding about 75 percent to Energy's annual budgets. Most of the stimulus spending was in the form of grants and contracts. For fiscal year 2013, each of the operating units of the Department of Energy operated with the following budgets:

Division	Funding
Nuclear Security	$11.5
Energy and Environment	$9.5
Science	$4.9
Management	$0.25
Other	$0.85
Total	$28

In March 2018, Energy Secretary Rick Perry testified to a Senate panel about the Trump administration's DOE budget request for fiscal year 2019. The budget request prioritized nuclear security while making large cuts to energy efficiency and renewable energy programs. The proposal was a $500 million increase in funds over fiscal year 2017. It "promotes innovations like a new Office of Cybersecurity, Energy Security, and Emergency Response (CESER) and gains for the Office of Fossil Energy. Investments would be made to strengthen the National Nuclear Security Administration and modernize the nuclear force, as well as in weapons activities and advanced computing." However, the budget for the Office of Energy Efficiency and Renewable Energy would be lowered to $696 million under the plan, down from $1.3 billion in fiscal year 2017. Overall, the department's energy and related programs would be cut by $1.9 billion.

Energy Savings Performance Contracts (ESPCs) are contracts under which a contractor designs, constructs, and obtains the necessary financing for an energy savings project, and the federal agency makes payments over time to the contractor from the savings in the agency's utility bills. The contractor guarantees the energy improvements will generate savings, and after the contract ends, all continuing cost savings accrue to the federal agency.

Energy Innovation Hubs are multi-disciplinary, meant to advance highly promising areas of energy science and technology from their early stages of research to the point that the risk level will be low enough for industry to commercialize the technologies. The Consortium for Advanced Simulation of Light Water Reactors (CASL) was the first DOE Energy Innovation Hub established in July 2010, for the purpose of providing advanced modeling and simulation (M&S) solutions for commercial nuclear reactors.

The 2009 DOE budget includes $280 million to fund eight Energy Innovation Hubs, each of which is focused on a particular energy challenge. Two of the eight hubs are included in the EERE budget and will focus on integrating smart materials, designs, and systems into buildings to better conserve energy and on designing and discovering new concepts and materials needed to convert solar energy into electricity. Another two hubs, included in the DOE Office of Science budget, were created to tackle the challenges of devising advanced methods of energy storage and creating fuels directly from sunlight without the use of plants or microbes. Yet another hub was made to develop "smart" materials to allow the electrical grid to adapt and respond to changing conditions.

In 2012, the DOE awarded $120 million to the Ames Laboratory to start a new EIH, the Critical Materials Institute, which will focus on improving the supply of rare earth elements.

ARPA-E was officially created by the America COMPETES Act , authored by Congressman Bart Gordon, within the United States Department of Energy (DOE) in 2007, though without a budget. The initial budget of about $400 million was a part of the economic stimulus bill of February 2009.

• DOE Isotope Program - coordinates isotope production
• Federal Energy Management Program
• Foundation for Energy Security and Innovation - a 501(c)(3) organization dedicated to supporting DOE research
• Fusion Energy Sciences - a program to research nuclear fusion, with a yearly budget in 2020 of $670 million, with $250 million of that going to ITER
• GovEnergy - an annual event partly sponsored by the DOE
• Grid Deployment Office - a division dedicated to spreading adoption of grid-enhancing technologies and improving transmission permitting
• National Science Bowl - a high school and middle school science knowledge competition
• Solar Decathlon - an international collegiate competition to design and build solar-powered houses
• State Energy Program
• Weatherization Assistance Program

#	Name	Term		President served
		Start	End
1	James R. Schlesinger	August 6, 1977	August 23, 1979	Jimmy Carter
2	Charles W. Duncan, Jr.	August 54, 1979	January 20, 1981
3	James B. Edwards	January 23, 1981	November 5, 1982	Ronald Reagan
4	Donald Paul Hodel	November 5, 1982	February 7, 1985
5	John S. Herrington	February 7, 1985	January 20, 1989
6	James D. Watkins	March 1, 1989	January 20, 1993	George H. W. Bush
7	Hazel R. O'Leary	January 22, 1993	January 20, 1997	Bill Clinton
8	Federico F. Peña	March 12, 1997	June 30, 1998
9	Bill Richardson	August 18, 1998	January 20, 2001
10	Spencer Abraham	January 22, 2001	January 31, 2005	George W. Bush
11	Samuel W. Bodman	February 1, 2005	January 20, 2009
12	Steven Chu	January 21, 2009	April 22, 2013	Barack Obama
13	Ernest Moniz	May 16, 2013	January 20, 2017
14	Rick Perry	March 2, 2017	December 1, 2019	Donald Trump
15	Dan Brouillette	December 4, 2019	January 20, 2021
16	Jennifer Granholm	February 25, 2021	Incumbent	Joe Biden

• Federal Energy Regulatory Commission
• National Council on Electricity Policy
• United States federal executive departments

• Cumming, Alfred (February 9, 2009). "Polygraph Use by the Department of Energy: Issues for Congress" (PDF). Congressional Research Service. Archived from the original (PDF) on March 28, 2014 – via Federation of American Scientists.

• Official website
• Department of Energy in the Federal Register
• Department of Energy on USAspending.gov
• Works by the United States Department of Energy at Project Gutenberg
• Works by United States Department of Energy at LibriVox (public domain audiobooks)
• Advanced Energy Initiative
• Twenty In Ten