Optimal Power Flow (OPF) is a non-convex and highly constrained optimisation study which is used to find the most economical power export allocation from different generating resources. Policies to produce green electricity have led to the integration of non-conventional generating resources into the networks. However, non-conventional generators, like solar and wind, have intermittent power export due to their stochastic nature. This paper presents an OPF approach for modern grids integrated with conventional and non-conventional generating resources considering environmental impacts. Different loading and generation scenarios are considered for solving the probabilistic OPF using MATPOWER for an IEEE 30-bus transmission network. The results highlight the most economical mix of different generators thereby reducing the overall operational cost of the system.