National Iranian Oil Engineering and Construction Company is responsible for implementation of all infrastructure projects in the downstream sector of the petroleum industry including refining, storage and distribution of crude oil and petroleum products across the country.
Since the past, the activities of the company have started by designing and constructing oil storage and sale place for the oil and have been continued by construction of the first refinery in Tehran and oil and gas pipeline during 1960’s as the management of specific projects in National Iranian Oil Company continued.



National Iranian South Oil Company, the largest subsidiary of National Iranian Oil Company, is a symbol of one century experience in the oil industry of the country and the largest producer of oil in IRI. The company is responsible for supplying the feed to the refinery and for the great part of the country's oil exports through organizations and subsidiaries.
Iranian Falat-Ghare Oil Company was established early September 1980 to meet the practical and scientific objectives for development, exploration and exploitation of crude oil and natural gas in the Persian Gulf. Among the company's goals and policies, we can mention the followings:
Iranian Offshore Engineering and Construction Company was established in 1993 as the first general contractor in construction and installation of offshore structures in oil and gas industry, and in 1999 by establishment of pipes concrete-coating plant was significantly developed. Since then, the company has successfully expanded its offshore services and using equipped naval fleet supports offshore projects during piping, installation, pre-commissioning and commissioning operations.
The Department of Energy is responsible for managing the supply and demand for water, electricity, energy, and water and wastewater services, promotion of education, research and technology, and providing infrastructures for development of goods and services market for utilities industry. The department plays its effectively key role in the preservation of national resources, preservation of environmental, promotion of public health, social welfare and self-reliance for sustainable development of the country.