white coal

Noun

dated uncountable

(dated) water that is being used to generate power

Japanese Meaning

発電に利用される（使用中の）水。

The engineers called the rushing river white coal, the source of energy that powered the mills.

技術者たちは激しく流れる川を発電用の水と呼び、その水が製粉所を動かすエネルギー源だった。

Sense（1）

(dated) water that is being used to generate power