| Abbreviation | Definition |
|---|---|
| DEEP | Deep Earth Energy Production |
| DEEP | Department of Energy |
| DEEP | Department of Energy and Environmental Protection |
| DEEP | Department of Environmental Energy Protection |
| DELEG | Department of Energy Labor Economic Growth |
| DEMIS | Direct Energy Measurement and Information System |
| DEN | Decentralised Energy Network |
| DEN | The Distributed Energy Network |
| DENA | Duke Energy North America |
| DENIS | Dance Energy Nation In Soonchunhyang |
| DENNIS | Distributed Energy Neural Network Integration System |
| DEO | Dominion East Ohio (energy) |
| DEOP | Dominion Energy Overthrust Pipeline |
| DEPA | Domestic Energy Producers Alliance |
| DEPS | Directed Energy Professional Society |
| DER | Distributed Energy Resources |
| DERA | Danish Energy Regulatory Authority |
| DERBS | Dispatchable Energy Resource Balancing Service |
| DERI | Dominion Energy Reliability Investment |
| DERM | Diagnostic and Energy Reserve Module |