Historical clue formulations

• Certain renewable energy — 2026-03-11
• Higher power? — 2025-12-20
• Kind of power using rooftop panels — 2025-06-02
• ___ power — 2025-04-01
• Clean energy option — 2025-03-04
• Kind of farm — 2024-08-11
• Like some panels and flares — 2024-02-06
• Kind of green energy — 2023-09-26
• Fossil fuel alternative — 2023-09-14
• Sun-related — 2023-01-02
• With 41-Across, a celestial event ... or a hint to four squares in this puzzle — 2022-04-21
• Energy alternative to wind — 2021-06-14
• Kind of energy — 2020-12-22
• Word before system or power — 2020-11-30
• Go ___ (be green, in a way) — 2020-04-16
• Word before system or panel — 2020-03-18
• Type of clean energy — 2019-09-30
• Green, in a way — 2019-02-24
• Like some clean energy — 2018-12-02
• Renewable kind of energy — 2018-11-20
• ___ panel (rooftop installation) — 2018-09-04
• Like the Gregorian calendar — 2018-09-02
• Kind of cell — 2017-08-05
• Alternative to wind — 2017-07-16
• Kind of renewable energy — 2017-06-07
• Kind of energy with panels — 2015-10-05
• ___ power — 2015-08-12
• Green energy option — 2015-04-26
• Renewable option — 2014-10-16
• Certain renewable — 2014-07-01
• Sunny? — 2013-07-07
• Like panels on some racecars — 2012-12-28
• Alternative energy option — 2012-05-13
• Green option — 2011-06-29
• Kind of energy or eclipse — 2011-01-03
• Alternative energy type — 2009-03-15
• Like the Julian calendar — 2008-03-14
• Kind of year — 2008-01-11
• Kind of wind — 2007-06-22
• Alternative to fossil fuels — 2006-06-28
• Kind of panel — 2006-06-25
• Kind of energy — 2005-12-21
• Like some panels — 2005-09-13
• ___-powered — 2005-09-12
• Kind of cell — 2005-04-22
• Kind of cycle — 2003-04-18
• Kind of collector — 2003-02-21
• Kind of power — 2002-02-12
• Kind of energy — 2002-01-22
• Under Helios's influence — 2001-06-10