A simple optimal balance control scheme for electrolysation plants is proposed. It can be realized through the use of a commercially available model predictive control (MPC) package. In most cases, much property data or information regarding disturbances, such as the deterioration of electrodes and ion exchange membranes, is necessary in order to calculate the optimal operating conditions for energy conservation. However, the proposed controller can achieve the optimal conditions without them. In this paper, it is proved that the resultant converged operating conditions of the proposed controller are identical to the actual optimal condition. (C) 2007 Elsevier Ltd. All rights reserved.