This paper proposes a probabilistic approach for economic/emission management of Micro Grids (MGs). In order to meet the electrical and thermal loads while having lower emission production in a more economical manner, combining heating and power along with hydrogen production and utilization strategies are employed. A PEMFCPP (Proton Exchange Membrane Fuel cell power plant) is considered as the prime mover of the Combined Heat and Power (CHP) system. The surplus power of PEMFCPP is managed to produce hydrogen. An electrochemical model for representation and performance evaluation of the PEMFC is applied. Using this model, the output voltage and power of the PEMFC are calculated as a function of current, constructive and operational parameters. The proposed probabilistic optimization method includes 2m + 1 point estimate method to cover the uncertainties and a modified multi-objective algorithm based on the Modified Gravitational Search Algorithm (MGSA) to find Pareto-optimal front of the operation management problem. The study considers the uncertainties in forecasted values of: the hourly market tariffs, electrical and thermal load demands, available output power of the PhotoVoltaic (PV) and Wind Turbines (WT) units, fuel prices, hydrogen selling price, operation temperature of the FC, and pressure of the reactant gases of FC. (C) 2012 Elsevier B.V. All rights reserved.