Finland's underground data centers heat entire city blocks using server waste heat In Finland, several data-centres now feed their waste heat into municipal district-heating networks instead of simply dumping it into the air. For example, waste heat generated by data-centre cooling is captured and transferred into the district-heating grid, providing carbon-neutral heat to thousands of homes and public buildings. This reuse of thermal energy helps reduce reliance on fossil-fuel heating, cuts emissions, and turns the by-product heat from digital infrastructure into a genuine resource rather than waste.