A thermodynamic analysis is presented to upgrade "waste heat" with chemical heat pumps for hydrogen production by thermochemical water decomposition. Low-grade waste heat refers to low-temperature heat that typically has limited or no utility in practical applications. in this paper, low-grade thermal energy is upgraded by releasing heat at successively higher temperatures in exothermic reactors of salt/ammonia and MgO/vapor chemical heat pumps. If waste heat is partly recovered to produce electricity by a heat engine, then this electricity can be used to drive compressors that pressurize vapor in the chemical heat pumps and supply heat for high-temperature processes in a copper-chlorine thermochemical cycle of hydrogen production. A Second Law analysis of the system is examined and results for the coefficient of performance (COP) are presented for the heat pumps. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.