Abstract: Apparatus, compositions and methods provide cathodic protection to a structure by placing an anode layer (10) directly between the structure (22) and its underlying foundation (30). Structures contemplated to be protected in this manner include especially very large structures such as above ground storage tanks. In one aspect of preferred embodiments, the anode layer (10) comprises sheets of at least 85% aluminum with other alloying elements such as magnesium (0.05 to 6%), zinc (0.1 to 8%), indium (0.005 to 0.03%) and tin (0.05 to 0.2%) added for the purposes of optimizing current yield, polarization and ease of manufacturing the sheet.