The electricity demand is increasing day by day and that is exhausting limited conventional energy resources rapidly. Thus, renewable energy is becoming very attractive source of electricity to meet the load and prevent the global warming threat. The challenges in integration of renewable energy sources are its intermittency and old existing power system infrastructure. Renewable energy sources collocated with energy storage facilities can mitigate the effect of renewable energy uncertainty. However, high penetration of green energy is only possible by upgrading the existing power system network. Most of the time transmission lines are under loaded from its actual power handling capacity, as worst possible power handling capacity of line is considered while scheduling power to generators. Actual power capacity of line depends on many environmental factors and changes accordingly with the weather conditions. This article elucidates the impact of weather variation on economic operation of a practical Indian 75 bus power system network placed at Uttar Pradesh, India. The simulation is carried out by accounting the proposed solar power plants in that region and the effect of dynamic line rating on renewable curtailment, thermal power fuel cost and line congestion has been studied.