Why does ferrochrome silicon require more energy to produce than other ferrochromium alloys?

Ferrochrome silicon requires more energy to produce than other ferrochromium alloys primarily because of the significant energy needed to reduce silica into silicon.2

While the production of high-carbon ferrochromium consumes approximately 4,600 kilowatt-hours per ton and charge ferrochromium consumes about 4,000 kilowatt-hours per ton, the smelting of ferrochrome silicon requires 7,600 kilowatt-hours per ton. This increased energy demand is a direct result of the chemical reduction process required to incorporate the high silicon content (38–42 percent) into the alloy.12