Historical clue formulations

• Component of a green house? — 2024-04-15
• Something that turns light green? — 2021-07-01
• Provider of green juice? — 2018-09-16
• Green energy source that might go on top of a house — 2018-06-25
• Green energy source — 2011-01-14
• Environmentally-friendly energy source — 1999-05-21