Electric stone furnace
Available from game start.
Smelting speed: 1
Power consumption: 90 kW
Pollution: 1 per minute (2.5 including boiler emissions)
Electric steel furnace
Unlocked by researching Advanced material processing.
Smelting speed: 2
Power consumption: 180 kW
Pollution: 2 per minute (5 including boiler emissions)
Electric Furnace 1 (unmodified from base game)
Unlocked by researching Advanced material processing 2.
Smelting speed: 2
Module slots: 2
Power consumption: 180 kW
Pollution: 1 per minute (4 including boiler emissions)
Electric furnace 2
Unlocked by researching Advanced material processing 3.
Smelting speed: 3
Module slots: 2
Power consumption: 180 kW
Pollution: 1 per minute (4 including boiler emissions)
Electric furnace 3
Unlocked by researching Advanced material processing 4.
Smelting speed: 4
Module slots: 4
Power consumption: 240 kW
Pollution: 1 per minute (5 including boiler emissions)
Electric boiler
Available from game start. Requires 900 kW to run at full speed, produces 900 kW of steam. While you could conceivably use this as part of a solar/stored-steam setup, its intended function is to provide an alternative source of steam for any recipe that requires it (coal liquefaction, for example).