If 2020 had any saving grace, it came perhaps in the form of a bountiful monsoon. Rainfall in the June-to-September southeast monsoon period—at 109% of the long-period average—was above the 50-year mean for the second year in a row in a country where seasonal rains water half the cropland.
However, no such silver lining lay in store for the wind energy sector. Typically, the monsoon brings along with it wind speeds that range between 23 kilometres and 29 kilometres per hour, fuelling the turbines that harness the whimsical force of nature in order to generate electricity. Last monsoon, the average wind speed was 20-27kmph, the slowest on record. Around two-thirds of wind energy in India is generated during the four months ending September.
Naturally, the average capacity utilization factor (CUF) of wind turbines, a measure of efficiency that indicates the extent to which installed capacity is deployed, declined. At the end of the financial year in March 2021, CUF was 17% compared with 20% in the previous two years.
Wind speeds were below normal across most areas, particularly in July and September, resulting in widespread deficits in CUF across much of India during the monsoon months, according to consultant UL.
“Wind speed was one of the lowest last year in a 100 years,” said Praveer Sinha, chief executive officer and managing director of Tata Power Ltd, quickly adding: “These are aberrations, and one has to look at weather patterns on a longer term. It can’t be predicted based on short-term occurrences.”
“Climate change is happening, and wind patterns are changing. These are cyclical changes that are happening globally and in India also—be it wind speeds or solar irradiance. It can’t be a standard. Last year, the wind speed was the lowest. However, it averages out over a period of time,” Sinha added.