hey ive played Pokemon leaf green before and was really close to finishing it so I thought I knew the locations of all the important stuff, but everybody is talking about the Zapdos in the powerplant. I don't recall going there before, and Im at the elite four right now, so I must have already passed it. Where is this thing? You obviously don't NEED it to beat the game, since I already passed it, but is there anything to do there other than getting a legendary Pokemon(Zapdos), like the Seafoam Islands? Thank you!
No not seafoam islands.
Remember rock tunnel? Go up from there till you see water. Surf where it takes you. You'll reach the power plant.
Hope this helps!
Unless you want to collect the items, catch new Pokemon, or get Zapdos, there isn't a lot to do in the Power Plant. The Pokemon in there are very mediocre, with Zapdos being the only good one. Here is all the encounters and items in the Power Plant: https://bulbapedia.bulbagarden.net/wiki/Kanto_Power_Plant
All the items are mediocre too. You are almost finished, so your Pokemon should be at a high enough level to beat the game, so you probably don't need Zapdos because it would mean you would have to grind it a lot.