| NUC | Alternative to wind or solar |
| SOLAR | Alternative to wind or geothermal |
| ALTERNATIVEFUEL | Ethanol, uranium, wind, or solar |
| TREELINE | The edge of a habitat beyond which, due to cold, altitude, aridity, exposure to wind or other cause, only shrubs or smaller plants can grow (4-4) |
| SOIL | To wind or twist into spirals or rings |
| BORNE | Word attached to "wind" or "air" |
| ERODE | Wear away due to wind or water |
| BAG | Word attached to wind or hand |
| NUCLEAR | Greek character has obvious alternative to wind (7) |
| LIGHTS | Illuminations such as lamps, candles or solar rays; greenhouse panes; divisions of mullion windows; or, white squares reserved for answers in crosswords (6) |
| SPICULE | From "ear of grain", word for a needlelike particle, process or splinter of coral, crystal, ice, osseous tissue, sea sponge, silica or solar plasma (7) |
| YEAR | It can be lunar or solar |
| ENERGY | It may be nuclear or solar |
| PANEL | Word that can go after "control" or "solar" |
| ECLIPSE | Celestial event that may be lunar or solar |
| SYSTEM | Word with 'metric' or 'solar' |
| ATEN | Sun or solar disk |
| ATON | Sun or solar disk |
| EPACT | The excess of the calendar month or solar year over the lunar (5) |
| SORORAL | Or solar power could be regarded as being sisterly, perhaps? (7) |
