An apparatus for passing electrical current from a D.C. power source through an underground formation in the extraction of carbonaceous fluids from beneath the earth's surface comprises an anode and a cathode remote from the anode. The anode is comprised of a containment positioned proximate to the underground formation within which is placed layers of material suitable for conduction. First conductor means connect the conduction material and the first terminal of the D.C. power source. The cathode is comprised of a wire screen housing of electrically conductive material which is supported within a well bore proximate to the underground formation. Second conductor means connects the wire screen housing to the second terminal of the D.C. power source. Electrical current from the power source is passed along the first conductor means, through the anode, through the underground formation, through the cathode and back to the power source through the second conductor means.