Scenario Analysis of Integrated Nepal Power System for Energy Banking between Nepal & India from Nepalese Perspective for Projected Ten Years

Abstract

The surplus – deficit energy analysis for projected ten years of Integrated Nepal Power System (INPS) gives ideas about the monthly energy status in different scenarios and helps in better planning for Energy Banking between Nepal and India from Nepalese perspective and also in increasing the opportunities of internal consumption within the country. Energy banking between power systems of Nepal and India will enhance the power system security and reliability of Nepal power system. The real problems created by delays in commissioning of upcoming generation projects due to different delaying factors such as delays in commissioning of projects from their PPA concluded date and delays in completion of transmission projects will change the pattern and amount of generations in upcoming periods which results into difficulty in planning purpose. Similarly, the increase in both the generations and expected energy consumption also impacts the INPS in future as well. This thesis presents the scenario analysis of surplus – deficit energy for projected ten years period with the consideration of different scenarios in both the generation and consumption sector and simulates the load flow analysis of planned INPS after the saturation of new generation projects for fiscal year 084/85 in most likely generation scenario i.e. Shift IPP and NEA Plants scenario. Three scenarios viz. commissioning of upcoming projects in accordance with the Power Purchase Agreement (PPA) concluded date, with one year delay for projects coming under Independent Power Producers (IPPs) & additional three years delay in projects coming under Nepal Electricity Authority (NEA) and its sister organization are considered in generation sectors. The consumption sector is introduced with five scenarios viz. Normal, Growth with Categorization of Consumption, Intervention with Induction Chulo, Intervention with Electric Vehicle and Combined Intervention of Induction Chulo and Electric Vehicle. Surplus – Deficit (S – D) ratio has been used for studying the relative dominance of surplus or deficit energy over a year. For the projected ten years period, the surplus – deficit energy of each month of those fiscal years are determined. This study clearly decides for monthly energy banking scenario between two countries in both the normal load consumption growth in Nepal and also with opportunities of increasing use of electrical energy. This study also models and simulates the planned INPS after generation saturation in “Shift NEA and IPP Plants” scenario for five scenarios to predict the import export options in five energy consumption scenarios as well. iv When the energy demand is expected to grow at the rate of 8% per annum, the maximum export of energy has been observed for months of Ashoj. The study shows the Dhalkebar – Muzzafarupur 400 kV line has been fully used upto its capacity and around 2094 MW power export has been observed through 400 kV Butwal – Gorakhpur cross border transmission link. When the energy demand is expected to grow as per growth rate with categorization of consumption, the maximum import (in the month of Falgun) is achieved with four import lines viz. Dhalkebar – Muzzafarpur 400 kV line, Tanakpur – Mahendranagar 132 kV transmission line, Butwal – Gorakhpur 400 kV line and Kusaha – Katiya 132 kV line. Similarly, when the energy consumption policy is implemented as intervention with induction chulo or combined intervention of both induction chulo and electric vehicle for maximum import in these scenarios with monthly peak demands of about 5803MW and 6139 MW respectively for fiscal year 084/85, six import lines in accordance with cross – border planning have been neede to accommodate the total import peak demand within their loading capacity. These lines are Tanakpur – Mahendranagar 132 kV line, Butwal – Gorakhpur 400 kV line, Dhalkebar – Muzzafarpur 400 kV line, Kusaha – Kataiya 132 kV, Parwanipur – Raxaul 132 kV line and Duhabi – Purnea 400 kV lines. However, Amlekhgunj – Kamane – Pathlaiya – Parwanipur – Birgunj – Simara – Amlekhgunj loop is provided with additional capacitor banks to compensate for convergence problem cause by reactive power need in latter two import scenarios. When the export scenario is analyzed with electric vehicle integration policy in the months of Ashoj, only Dhalkebar – Muzzafarpur 400 kV line is needed to accommodate the export demand which is in the range of capacity of this line (i.e.1200 MW). The transformers of Balaju, Bhaktapur, Chapali, Dhalkebar, Hetauda, Suichatar, Khimti and Parwanipur grids is found critically overloaded in all scenarios and should be upgraded once the upcoming generation projects saturates in INPS. The 66 kV and 132 kV transmission lines of Kathmandu sub – system and Amlekhgunj – Kamane – Pathlaiya – Parwanipur – Birgunj – Simara – Amlekhgunj sub – sytem is found critically overloaded in all scenarios. Similarly, all the 66 kV and 132 kV in buses in INPS have been found to operate with critical bus voltages in all scenarios after generation saturation in planned INPS indicating vulnerability of our INPS as well.