U
- U.S. Department of Energy (DOE)
- U.S. Energy Information Administration (EIA)
- U.S. Refiner Acquisition Cost of Imported Crude Oil
- Ultimate Customer
- Ultra Large Crude Carrier (ULCC)
- Ultra-low Sulfur Diesel (ULSD) Fuel
- Ultraviolet (UV)
- Unaccounted for (crude oil)
- Unaccounted for Natural Gas
- Unbundling
- Uncompleted Wells, Equipment, and Facilities Costs
- Unconsolidated Entity
- Unconventional Oil and Natural Gas Production
- Underground Mine
- Underground Mining Equipment
- Underground Mining Methods
- Underground Natural Gas Storage
- Underground Natural Gas Storage Injections
- Underground Storage
- Underground Storage Withdrawals
- Undifferentiated/Unspecified Reserves and Production
- Undiscovered Recoverable Reserves (Crude Oil and Natural Gas)
- Undiscovered Resources (Coal)
- Unfilled Requirements
- Unfinished Oils
- Unfractionated Streams
- Unglazed Solar Collector
- Uniform System of Accounts (USOA)
- Union of Soviet Socialist Republics (U.S.S.R.)
- Union of Soviet Socialist Republics (U.S.S.R.)
- Unit Price
- Unit Value, Consumption
- Unit Value, Wellhead
- United States
- United States Army Corps of Engineers (USACE)
- United States Bureau of Reclamation (USBR)
- Unleaded Midgrade Gasoline
- Unleaded Premium Gasoline
- Unleaded Regular Gasoline
- Unprocessed Gas
- Unregulated Entity
- Unscheduled Outage Service
- Uprate
- Uranium (U)
- Uranium Concentrate
- Uranium Deposit
- Uranium Endowment
- Uranium Hexafluoride (UF6)
- Uranium Hexafluoride (UF6)
- Uranium Importation
- Uranium Mill
- Uranium Mill Tailings
- Uranium Mill Tailings Radiation Control Act (UMTRA) of 1978
- Uranium Mill Tailings Remedial Action (UMTRA)
- Uranium Ore
- Uranium Oxide
- Uranium Property
- Uranium Reserves
- Uranium Resource Categories (International)
- Usage Agreement
- Used and Useful
- Useful Thermal Output
- Utility
- Utility Demand-Side Management Costs (DSM Costs)
- Utility Distribution Companies (UDCs)
- Utility Generation
- Utility-Sponsored Conservation Program