An overestimation of long-term electricity demand will result in significant wasteful investment in excess power plants, whilst an underestimate will result in the insufficient generation and inadequate demand. According to the NEA annual report, the transmission line length in Nepal has increased from 279.50 km in Fiscal Year (FY) 2076/77 to 604.74 km in 2077/78. From this, it can be observed that the transmission system in Nepal is developing at an accelerated rate. For such a fast-developing system, classical forecasting methods give a poor performance, hence for such systems a computational method based on the knowledge-based expert system that takes into account the present situation of the power system, all electrical variables, and non-electrical variables are found to be more accurate. At the same time, scenario-based strategies for the optimum and reliable operation of the future power grid, backed by strong technical, financial and feasibility analysis is necessary to make the grid future-ready.