August 4, 1977

The Department of Energy is created when President Jimmy Carter (D-USA) signs the Department of Energy Organization Act.

The reasons given for this:

Sec. 101. The Congress of the United States finds that—
(1) the United States faces an increasing shortage of nonrenewable
energy resources;
(2) this energy shortage and our increasing dependence on foreign
energy supplies present a serious threat to the national security of the
United States and to the health, safety and welfare of its citizens;
(3) a strong national energy program is needed to meet the present
and future energy needs of the Nation consistent with overall national
economic, environmental and social goals;
(4) responsibility for energy policy, regulation, and research, development
and demonstration is fragmented in many departments and agencies
and thus does not allow for the comprehensive, centralized focus
necessary for effective coordination of energy supply and conservation
programs; and
(5) formulation and implementation of a national energy program require
tie integration of major Federal energy functions into a single
department in the executive branch. (91 Stat. 567; 42 U.S.C. $71 11)

And some highlights of its defined purpose:

(2) to achieve, through the Department, effective management of energy
functions of the Federal Government, including consultation with
the heads of other Federal departments and agencies in order to encourage
them to establish and observe policies consistent with a coordinated
energy policy, and to promote maximum possible energy
conservation measures in connection with the activities within their respective
jurisdictions;
(3) to provide for a mechanism through which a coordinated national
energy policy can be formulated and implemented to deal with the
short-, mid- and long-term energy problems of the Nation; and to develop
plans and programs for dealing with domestic energy production and
import shortages;
(4) to create and implement a comprehensive energy conservation strategy
that will receive the highest priority in the national energy program;
(5) to carry out the planning, coordination, support, and management
of a balanced and comprehensive energy research and development pro
gram, including—
(A) assessing the requirements for energy research and development:
(B) developing priorities necessary to meet those requirements;
(C) undertaking programs for the optimal development of the various
forms of energy production, and conservation; and
(D) disseminating information resulting from such programs, including
disseminating information on the commercial feasibility and
use of energy from fossil, nuclear, solar, geothermal, and other energy
technologies;

[…]
(9) to promote the interests of consumers through the provision of an
adequate and reliable supply of energy at the lowest reasonable cost;

If those are the defined reasons and purposes, I think we can all agree that the Department of Energy has been a dismal failure.