Understanding Time-of-Day and Seasonal Variations in Supply and Demand for Electricity in India

2019 Analysis Using High Temporal Resolution Data

Abstract

India’s electricity grid is moving from one dominated by coal to one where renewable energy (RE) will dominate supply, especially wind and solar. By 2030, the target is to triple non-fossil sources of power to 500 gigawatts (GW) of capacity. Wind and solar sources are intermittent, and given a power grid needs to balance supply to meet demand at all points in time, this raises immense challenges for planning and operations.

This paper studies the impacts of times-of-day and seasons on the different types of fuels for generation electricity, their output ramp (swing up or down) rates, daily swings between maximum and minimum output, and relative contributions of each fuel type. It also covers net demand (total demand excluding RE) separately to highlight RE’s interplay with other supply sources.

We focus on calendar year 2019, which was the last year before the impact of the COVID-19 pandemic. We analyse data at 5- and 15-minute resolutions not just to understand granular gridbalance requirements but also examine ramping requirements. The larger policy objective remains improving the integration of more variable renewable energy (VRE) sources into the electricity grid and cost-effectively balancing different fuel types during specific times and/or seasons.

A key insight is that the average numbers (e.g., for correlation) are misleading and one needs granular data to consider “worst case” time periods for which we need adequate and appropriate supply. We also find that RE places greater burden on the rest of the grid in terms of ramping requirements, measured through net demand, which is the remaining demand after subtracting variable RE.