the energy required to make steel when compared with primary steelmaking from ores. Another benefit is flexibility: while blast furnaces cannot vary their production by much and can remain in operation for years at a time, EAFs can be rapidly started and stopped, allowing the steel mill to vary production according to demand. Although steelmaking arc furnaces generally use scrap steel as their primary feedstock, if hot metal from a blast furnace or direct-reduced iron is available economically, these can also be used as furnace feed. As EAFs require large amounts of electrical power, many companies schedule their operations to take advantage of off-peak electricity pricing. A typical steelmaking arc furnace is the source of steel for a mini-mill, which may make bars or strip product. Mini-mills can be sited relatively near the markets for steel products, so the transport requirements are less than for an integrated mill, which would commonly be sited near a harbor for better access to shipping. Electric arc furnace steelmaking results in lower carbon dioxide emissions of around 0.6 ton CO2 per ton of steel produced, which is significantly lower than the conventional production route via blast furnaces and the basic oxygen furnace. In theory, electric arc furnaces can be powered used only low-carbon energy sources such as wind, solar, hydroelectric and nuclear power. This would even further reduce the emissions and embodied energy associated with steelmaking, or any of the many other materials requiring furnaces, including glass. This makes EAF's an attractive option for green industry. Issues Although the modern electric arc furnace is a highly efficient recycler of steel scrap, operation of an arc furnace shop can have adverse environmental effects. Much of the capital cost of a new installation will be devoted to systems intended to reduce these effects, which include: Enclosures to reduce high sound levels Dust collector for furnace off-gas Slag production Cooling water demand Heavy truck traffic for scrap, materials handling, and product Environmental effects of electricity generation Because of the very dynamic quality of the arc furnace load, power systems may require technical measures to maintain the quality of power for other customers; flicker and harmonic distortion are common power system side-effects of arc furnace operation. Other electric arc furnaces For steelmaking, direct current (DC) arc furnaces are used, with a single electrode in the roof and the current return through a conductive bottom lining or conductive pins