noun
private power generation; in-house electricity generation
Refers to generating one's own electricity, typically via solar panels or a generator, rather than relying on the grid.
この工場は自家発電で電力をまかなっている。
This factory covers its electricity needs with in-house power generation.
noun
Jocular slang likening self-pleasure to generating one's own power. Used humorously, often among close friends or online.
「昨日は自家発電してたよ」と彼は冗談っぽく言った。
"I was doing some private power generation last night," he said jokingly.
Compound of 自家 (self, one's own) and 発電 (power generation). The slang sense is a metaphorical extension.