| Value | Category |
|---|---|
| 00 | NIU (not in universe) |
| 01 | None |
| 02 | Electricity |
| 03 | Fuel oil, kerosene, other liquid fuels |
| 04 | Kerosene/paraffin |
| 05 | Diesel |
| 06 | Gas |
| 07 | Bottled gas, in tank, liquified |
| 08 | Solid fuel |
| 09 | Coal |
| 10 | Wood |
| 11 | Wood or coal |
| 12 | Solar |
| 13 | Animal dung |
| 14 | Charcoal |
| 15 | Biofuel |
| 16 | Other |
| 17 | Multiple sources |
| 99 | Unknown |