A methodology to select the generation plants connected to the Argentinean electricity network and their operating loads is presented, minimizing life cycle greenhouse gases (GHG) emissions and operating cost. Mixed integer linear programming problems are formulated and solved in GAMS. The electricity generation grid has different fossil fuel thermoelectric, hydroelectric, nuclear, solar photovoltaic and wind power plants. Binary operating variables represent discrete decisions to select the power plants connected to the grid and the type of fossil fuel burnt in thermoelectric plants. Continuous operating variables allow the selection of the optimal load for each generation unit. Significant reductions in life cycle GHG emissions and operating cost are achieved in the operation of the Argentinean electricity network, providing relevant information to support a decision-making process. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.