This page contains information regarding new Star Trek material, and thus may contain spoilers.
At one point, Earth nearly choked to death on pollution. However, its inhabitants woke up, and within a generation, everything from trucks to toasters were covered in solar panels. (DIS: "An Obol for Charon")
Schematics of the Mariner 2, Nimbus 1, and Ranger 5 spacecraft depicting the locations of the solar panels was stored in the USS Enterprise's library computer database. This database was accessed by the Talosians in 2254. (TOS: "The Cage")
Retconned material shows solar panels and solar platforms used aboard NASA's Mariner 2, Nimbus 1, and Ranger 5 space probes when they were launched in the mid-20th century. Solar panels were also included in the International Space Station.
Schematics of the Mariner 2 and Ranger 5 spacecraft were from the archives of the National Aeronautics and Space Administration - Jet Propulsion Laboratory.