The electric power industry is going through deregulation. The current picture of a single utility controlling the market in a specific region will soon disappear. Instead, there will be power producers who sell their production to a power pool; and power suppliers who will buy power from the pool and sell it to their customers. As a result, generating companies are faced with increasing demand uncertainty and must consider volatile electricity prices in their operations. We study scheduling the generating units in the presence of uncertainty. The resulting models are large-scale mixed-integer programs. We investigate solving these models using branch-and-bound (CPLEX) and using Lagrangian relaxation.