| from natural gas | 8 | location |
| always | 2 | temporal |
| from the steam reforming of hydrocarbons | 2 | other |
| hydrogen → be → refined | 4 |
| hydrogen → be → synthesized | 4 |
| hydrogen → be → processed | 3 |
| negative | neutral | positive |
| 0.164 | 0.747 | 0.088 |
| Raw frequency | 11 |
| Normalized frequency | 0.242 |
| Modifier score | 1.000 |
| Perplexity | 80.717 |