Possible Solution: doesn't transfer energy but instead you can make a minecart track that teleports minecarts (including chest minecarts wink wink hint hint) into the nether with an item i dunno being maybe a battery? either way this nether-portal block would be crafted with three power rails over the top two Advanced circuits on the sides of the middle a flint and steel in said middle and 2 obsidian on the sides of the bottom with one dirt in the middle. it would be "powered" by nether portal next to it teleport the cart instantly and create a track on the other side. Would probably be a pain to code but then you wouldn't need and inv. full of crystals leaving you to carry building supplies for that reactor you decide is safer in the nether.