| Abbreviation | Definition |
|---|---|
| EFE | Energy From the Electrical |
| EFEF | European Future Energy Forum |
| EFEM | Energy Finite Element Method |
| EFH | Energy Future Holdings |
| EFI | Energy Federation Incorporated |
| EFL | Energy Fiji Limited |
| EFM | Energy Friendly Microcontrollers |
| EFM | Energy-Friendly Microcontroller |
| EFMS | Energy and facility management software |
| EFRC | Energy Frontier Research Centers |
| EFRC | Energy Fusion Research Corp |
| EFRS | Energy Fishing Rental Services |
| EFS | Energy Finance Solutions |
| EFS | Energy for Sustainability |
| EFSB | Energy Facility Siting Board |
| EFSL | Energy Forum Sri Lanka |
| EFT | Energy Financing Team |
| EFW | Energy Food and Water |
| EFW | Energy From Waste |
| EFWB | Energy From Waste Biomass |