Container-glass hybrids and full-electric furnaces are in operation; flat glass is harder. The switch happens at rebuild and pays only on a clean grid.
From our guide: Decarbonizing Glass — 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: