Monsoon 2020 – Impact on India’s Wind Sector
Considering the importance of renewable energy resources in a warming world, India has seen a steady increase in the penetration of renewables, including wind energy, in the overall mix. Present installed wind capacity stands at 38.6 GW as of December 2020, and is targeted to increase to 60 GW by 2022. Wind resource availability in India is uneven in its distribution, both in terms of geography and time of the year. While western and southern part of the country is wind rich, the wind speeds attain a peak in the months of June-September due to the southwestern monsoon flow over India. Owing to this seasonal variability, power generation is maximum during monsoon when wind power producers usually secure a large portion of their revenue. In a competitive renewable energy market, where producers bid to offer the lowest possible price for electricity, wind power producers are reliant on maximizing generation in the peak season in order to achieve lower wind tariffs. If the resource availability during the peak season is lesser than expected, the producers incur losses. The year 2020 was one such year where the peak season generation underwent a drop, due to low southwest monsoon winds. With this anomalous event as the backdrop, CEEW (Council for Energy, Environment and Water) and REConnect Energy Solution Ltd. undertook a diagnostic analysis of the event in order to understand its causality, using reanalysis datasets provided by the European Centre for Medium-Range Weather Forecasts (ECMWF).
The year 2020 witnessed a drop during a season of peak energy generation, due to low southwest monsoon winds. The western and southern regions experienced a 29 and 17 percent decline in wind power generation, respectively, in the monsoon season. The cause of occurrence of such events is important to understand since unpredictability of wind resources could lead to diminished revenues and increased reliance on fossil fuel based energy resources in order to compensate for the shortfall.
Relevant atmospheric variables were examined for 2020 and compared with long period averages of the past decades to capture the deviation. It was observed that the north Indian ocean had anomalously high sea surface temperature (SST) in the pre-monsoon period of 2020. This resulted in generation and intensification of cyclones Amphan and Nisarga and brought rainfall along its path. The period also experienced events meteorologically known as western disturbances that caused widespread rainfall in the northern parts of the country.
The fact that monsoon circulation is driven by the land-ocean thermal contrast of Indian landmass and adjoining Indian ocean has been studied well and reported in the scientific literature. The temperature difference creates a pressure contrast and intensifies the southwest monsoon wind flow. It was observed that the land-ocean temperature contrast was low (i.e surface temperature of North Indian landmass dropped by 1.5 to 20C and North Indian Ocean warmed up by 0.5 to 10C) in 2020 (when compared with the 1979-2010 climatology), with both warmer ocean and cooler land contributing to it, while suggesting that the low land temperatures might have been caused by the rainfall events that occurred in the pre-monsoon period. This anomaly caused the strength of monsoon circulation over India to decrease.
The wind drought experienced in 2020 should not be brushed aside owing to the scale of impact such incidents pose (to the wind energy sector) along with the fact that extreme events are poised to increase in frequency owing to climate change. It is observed that the wind speeds have been decreasing steadily over some parts of India, with studies also reporting that the rise in sea surface temperatures of the Indian Ocean due to climate change would cascade and manifest as depressed land-ocean thermal contrast and could thereby result in further weakening of monsoon circulation and wind speed magnitude.
In order to make the wind energy sector climate resilient, it is necessary to understand the factors which affect the availability of wind resource, build a capability to predict the deviations well ahead of time so that the power producers are well prepared for the consequences, and invest into the research that promote a deeper understanding of the underpinnings and implications of future climate and promote development of storage technologies to effectively integrate variable renewable energy into the grid.into the research that promote a deeper understanding of the underpinnings and implications of future climate and promote development of s
The full report with in-depth analysis of underlying factors and implications for the wind sector can be accessed here.
Authored by Kaustabh Desai and Tarun Joseph