| Abbreviation | Definition |
|---|---|
| IET | Institute for Energy |
| IET | Institute for Energy and Transport |
| IETB | Installation Energy Test Bed |
| IETP | Innovative Energy Technologies Programs |
| IETP | Innovative Energy Technology Program |
| IEU | Industrial Energy Users |
| IEWE | Institute Of Energy Water And Environment |
| IFE | Institute for Energy |
| IFES | Integrated Food Energy System |
| IGCC | Integrated Gasification Combined Cycle |
| IGE | Integrated Green Energy |
| IHER | Irish Home Energy Rating |
| IIEC | International Institute for Energy Conservation |
| IIEE | Indonesian Institute for Energy Economics |
| IIEG | Iowa Industrial Energy Group |
| IIET | International Institute for Energy Training |
| IJFE | International Journal of Fusion Energy |
| IJGEI | International Journal of Global Energy Issues |
| IMEF | Integrated Modified Energy Factor |
| IMER | Institute for Mineral and Energy Resources |