Wind energy heralded India’s renewable energy journey. The country’s first grid-connected wind energy project was commissioned in 19851, decades before solar energy arrived on the scene. With continuous central and state government support, the wind energy sector has grown tremendously over the years. However, growth in recent years has been muted and has notably lagged behind solar. One of the reasons is the fast depletion of sites with attractive wind resources. Wind repowering can address this challenge by facilitating increased generating capacity on sites with such attractive wind resources.
Replacing outdated wind turbines with modern and updated turbine technology is known as wind repowering. It is further classified as full and partial repowering. In full repowering, the existing wind turbines are dismantled, and new wind turbines are installed. In contrast, in partial repowering (lifetime extension), some components, such as the generators of existing wind turbines, are upgraded. Full repowering usually results in an increase in generating capacity on the same land footprint.
In India, wind energy projects installed before 2000 at the best wind sites predominantly have a capacity below 500 kW and a hub height of 50 m or lower. This results in maximum achievable plant load factors (PLF) of below 20 per cent. However, significant increases in capacity and PLF are achievable at higher hub heights.
For example, the National Institute of Wind Energy (NIWE) estimated India’s gross wind power potential in seven windy states2, namely, Gujarat, Rajasthan, Maharashtra, Tamil Nadu, Madhya Pradesh, Karnataka, and Andhra Pradesh. At 100 m, NIWE pegs the potential to be 302 GW. It further estimates that increasing hub height by a mere 20 per cent to 120 m can result in a potential capacity increase of over 100 per cent to 695.50 GW.
To promote the optimum utilisation of wind energy resources and address evolving challenges regarding land availability, the Ministry of New and Renewable Energy (MNRE)3, released a repowering policy for wind power projects in 2016. According to this policy, wind turbine generators of 1 MW or below capacity are eligible for repowering. Eligible projects will receive incentives such as interest rate rebates from the Indian Renewable Energy Development Agency (IREDA) and other benefits that are available to Greenfield wind energy projects.
At the state level, Gujarat, Rajasthan, Maharashtra, Andhra Pradesh, and Tamil Nadu have also identified the value of repowering their old wind power projects. For example, in 2018, Tamil Nadu Generation and Distribution Corporation Limited (TANGEDCO) released its own draft repowering guidelines4. The very same year, Gujarat also released its state wind repowering policy5. Separately, Rajasthan6, Maharashtra7, and Andhra Pradesh8 have included references to repowering in their wind power policies.
Internationally, many countries have initiated wind repowering; the key markets in Europe for repowering are the United Kingdom, Germany, Denmark, Spain, Italy, Portugal, and France. In addition, wind repowering is also becoming a common phenomenon in the United States9.
The wind energy sector is expected to play a prominent role in India’s energy sector transition. Consequently, the adoption of wind repowering becomes inevitable. As per the updated Nationally Determined Contribution (NDC)10, India committed to transitioning to 50 per cent cumulative installed power generation capacity from non-fossil-fuel-based resources by 2030. Additionally, the Central Electricity Authority’s report (launched in January 2020) on the optimal generation capacity mix for 2029–30 highlights that solar and wind energy are expected to contribute 280 GW and 140 GW, respectively11.
Wind project developers
Wind original equipment manufacturers (OEMs)