Power Plants
From sc2k-reverse
Despite the listed nominal output of each power plant their true output is measured in "tiles powered" per individual power plant tile. In addition to this counter-intuitively the power plant itself "consumes" some of the electricity it generates at the same rate that all tiles do, meaning that while the full output of a Coal Power plant is 704, it's effective output is actually 688 due to the 16 tiles immediately consumed by the power plant itself (004679B6).