Electrical resistance heating (ERH) is an intensive  environmental remediation method that uses the flow of alternating current electricity to heat soil and groundwater and evaporate contaminants.  Electric current is passed through a targeted soil volume between subsurface electrode elements. The resistance to electrical flow that exists in the soil causes the formation of heat; resulting in an increase in temperature until the boiling point of water at depth is reached.  After reaching this temperature, further energy input causes a phase change, forming steam and removing volatile contaminants. ERH is typically more cost effective when used for treating contaminant source areas.