| shale | 0.34 |
| coal beds | 0.34 |
| gaseous state | 0.32 |
| reservoir | 0.30 |
| generate electricity | 0.73 |
| replace coal | 0.70 |
| produce heat | 0.61 |
| surpass coal | 0.57 |
| produce carbon dioxide | 0.56 |
| dissipate into the atmo… | 0.54 |
| become cheap | 0.48 |
| replace oil | 0.47 |
| displace coal | 0.47 |
| occur in nature | 0.46 |
| More » |
| physical change | 0.35 |
| explosion | 0.34 |
| fire | 0.30 |
| little processing | 0.16 |
| asphyxiation | 0.32 |
| shortage | 0.25 |
| a fossil fuel | 0.71 |
| fuel | 0.65 |
| a greenhouse gas | 0.61 |
| gas | 0.57 |
| a bridge fuel | 0.53 |
| the cleanest burning fo… | 0.48 |
| clean fuel | 0.43 |
| powerful greenhouse gas | 0.42 |
| finite resource | 0.42 |
| primary fuel | 0.40 |
| More » |
| the solution | 0.43 |
| composed of methane | 0.74 |
| extracted | 0.72 |
| transported by pipeline | 0.72 |
| burned | 0.72 |
| used in the united stat… | 0.71 |
| used to generate electr… | 0.71 |
| produced | 0.71 |
| consumed in the united … | 0.71 |
| produced in the u.s. | 0.68 |
| used to heat home | 0.66 |
| More » |