Wort boiling, then pasteurisation and CIP. Vapour-energy recovery on the kettle is the sector's signature retrofit.
From our guide: Decarbonizing Brewing — full context, charts and sources there.
Boilers, kilns, heat exchangers, valves and steam lines lose energy continuously. Inzonex makes patented (UK GB2508992.1) removable modular insulation — snap-fastened covers engineered per temperature tier, not generic off-the-shelf jackets: