Arc Furnace II
An Arc Furnace II is a direct upgrade from the Arc Furnace machine. It carries twice the Worker and Electricity requirement in addition to Water, some of which can be recovered by passing the byproduct Steam Lo through Cooling Towers. In exchange, it doubles throughput of Silicon smelting without increasing the need for Coal or Graphite.
Additionally, it incorporates smelting recipes for Iron Ore Crushed, Copper Ore Crushed, and Glass Mix similar to those available in the Blast Furnace II which make it possible to replace all Blast Furnace II machines on the island. These recipes switch 15 Coal for 12 Water and 3 Graphite (plus 4 Tflop and 1.4 MW power consumption), whilst generating 12 Steam Lo and reducing Exhaust output by 24/min. Assuming that all Graphite is made from Coal and Chlorine, this amounts to a 90% reduction in Coal usage.
While Nuclear Reactors, Solar Panels, or Solar Panels (Mono) are strongly recommended for powering the Arc Furnace II, Boiler (Coal) is still a viable option. Even with coal power, overall Coal usage still drops by 22.8-32.8% relative to a Blast Furnace II, depending on how efficiently the Steam Lo byproduct is used. Similarly, Exhaust drops by 0.84-3.84 per furnace.