An electrolyzer assembly includes an electrolysis unit having: a hermetically-sealed case made at least partially from a durable dielectric polymer material, the case having a gas outlet and an electrolyte inlet; at least one set of series-coupled, equally-spaced, rectangular, vertically-oriented metal plates installed within the case, each set having first and second end plates, each plate having each side edge sealed to a case wall panel and a bottom edge sealed to the bottom panel; a ground connection to each first end plate; and a voltage connection to each second end plate that is non-zero with respect to the ground connection, thereby providing at least a 1.5 voltage differential between each pair of adjacent plates when gaps between each adjacent pair of plates are filled with electrolyte.