In an old wind farm in the wind-rich region of Kayathar in the Thoothukudi district of Tamil Nadu, there are 30 wind turbines, each with a 200-kilowatt capacity. Many of these turbines are nearing the end of their lifecycle of 20 years-25 years. Generally, the wind turbine generators at the end of service life exhibit high breakdown rates, require repairs and are likely to suffer from a shortage of relevant replacement parts as the technology has improved significantly over the years.

What if these turbines could be removed and replaced with the latest technology wind turbine generators that are taller and more efficient? The six megawatts wind power plant would then generate 16.2 megawatts, finds a 2021 study that conducted an economic investigation of repowering existing wind farms, with Kayathar as a case study.

This is just one old farm. If all the old wind farms in the southern Indian coastal state with rusty turbines and obsolete/low functioning components were to be removed and replaced with newer turbines, it would be a huge boost in terms of renewable targets. However, Tamil Nadu has thousands of turbines installed before the year 2000, with less than 550-kilowatt capacity and the state faces many challenges in repowering.

Through the years, the technology has improved, and the wind farms located in Tamil Nadu, that were installed in the 1990s, are functioning below their capacity. The obsolete components in these turbines result in significant maintenance costs and time inefficiencies, and increased downtime, which lowers average energy production, says the study. Looking into the future of these old wind farms is crucial because not only have they completed their life cycle, but they also occupy the best wind sites of the state.

It was in 2016, that the Union Ministry of Renewable Energy released a policy for “repowering” of the wind power projects in India. The policy stated that initially, the wind turbine generators of one-megawatt capacity and below would be eligible for repowering. Each state’s nodal agency or the organisation involved in the promotion of wind energy in the state was in charge of implementing repowering plans. Six years later, Tamil Nadu, with the country’s oldest onshore windfarms, is yet to start repowering.

Tamil Nadu is home to about 25% (close to 9.86 gigawatts) of India’s total installed wind power capacity of 40.35 gigawatts. Moreover, India aims to install 140 gigawatts of wind power capacity by 2030. The Tamil Nadu Generation and Distribution Corporation Limited, the state’s electricity distribution company aims to install 24 gigawatts of onshore wind by the year 2050 with “determined effort”. To meet this target and lead by example for other states, Tamil Nadu must take the right steps forward in repowering, according to wind energy experts.

Improved energy capacity

“Repowering basically means that old turbines will be uprooted and replaced with newer turbines,” said K Balaraman, Director General, National Institute of Wind Energy, while explaining the benefits of repowering to Mongabay-India. “The old machines generate less energy and the new ones that come with an increased hub height and a larger rotor diameter, can harvest wind energy with increased electricity generation. In many cases, in the place of 20 turbines, around three to four turbines would be enough.”

According to a 2018 study, supported by the Ministry of New and Renewable Energy, in India more than 10 gigawatts of old wind turbines with less than 1 megawatts capacity are installed in wind-abundant sites.

Repowering these sites with modern turbines will quadruple the energy generation. However, there is no state-specific repowering policy in Tamil Nadu, although the Ministry of New and Renewable Energy’s repowering policy says that states would implement these plans.

What is the state government’s stance? In 2021, the Tamil Nadu Electricity Regulatory Commission issued a clarification on the Ministry of New and Renewable Energy’s repowering policy replying to some frequently asked questions by different stakeholders.

It said that “TANGEDCO [the power distribution company] and the state are benefited by way of optimum utilisation of natural resources and existing transmission infrastructure erected by way of realising additional generation,” recognising the benefit of repowering. However, the Tamil Nadu Electricity Regulatory Commission also said that “The power distribution company does not intend to make the repowering procedure mandatory as has been understood by many of the stakeholders. It is an option left to the generator.”

Therefore, since repowering has not been made “mandatory” it is being left to the choice of the wind turbine owners to decide whether old turbines need to be repowered.

Challenges in repowering

Repowering was going to be the next big thing, in 2016, when the Ministry of New and Renewable Energy announced the policy but the progress since then has been slow. Even if a few owners wish to repower their wind farm, apart from the fact that repowering is not mandatory, fragmented land ownership and turbine ownership also stand as major challenges.

“Similar to agricultural lands, the wind farm lands are also small and fragmented and owned by multiple people,” shared DV Giri, Secretary General, Indian Wind Turbine Manufacturers Association. “Micrositing, the process of choosing the specific location of wind turbines which is determined by multiple factors like existing wind resource, distances from other wind turbines, becomes an obstacle.”

Although the Ministry of New and Renewable Energy has relaxed the rules for micrositing, the site can be repowered only with the consensus of all land and turbine owners of a large area.

“In a thickly populated site like Muppandal, this becomes a challenge, ” Balaraman told Mongabay-India. “It needs permission from many sources.”

“It has been a really tricky business trying to repower,” said a wind farm manager from the Kanniyakumari district, on condition of anonymity. “It involves negotiations from multiple stakeholders and there needs to be more clarity. Also, the power distribution company is yet to pay us the debt it owes. We need financial incentives to begin repowering.” The company owes a total of Rs. 20,828 crores to the electricity generators.

An additional challenge is that the repowered turbines would require stronger evacuation facilities. Power evacuation is a facility that allows the electricity generated, to be transferred to the grid from the turbine. These facilities need to be upgraded if individual turbines with 1MW, 2MW or 3MW capacities are installed. “The power distribution company must augment the evacuation facility and the grid,” said Giri while adding that “If the state augments the grid, it will be doubling the energy production; it will be like a multiplier effect.”

While ownership and technical upgrades are two primary challenges, the tariff structure lacks clarity too. The additional energy produced after repowering requires heavy investment in technology. The wind energy developers question if the same tariffs would be applied by the distribution companies.

In 2019, the Indian Wind Power Association in 2019 had stated, “The Tariff rates for Repowering have to be fixed prior to the announcement of the Repowering Policy.” The National Tariff Policy of 2016 recognised this additional investment required and even recommended a multi-year-tariff policy.

This mismatch in tariff requirements between stakeholders, the central and state governments, calls for negotiation talks and a clear repowering policy by the state that answers tariff-related questions.


Optimising land usage

According to the power distribution company, the land footprint required by 2050 for renewable energy projects is 318.2 million hectares. Although wind is only one component of the renewable energy basket, the sector must take note that “land” is a limited resource. In other parts of the country, land conflicts due to massive renewable energy projects have already become a common feature.

“The one thing we cannot create is land. Land is a national asset, and we need to maximise the potential of the available land before acquiring new land,” Giri told Mongabay-India.

During Mongabay-India’s interactions with the local communities in Tirunelveli, Thoothukudi and Kanniyakumari, what came out was that people were conflicted about the use of common lands and agricultural lands.

Although they are happy about the jobs generated for the youth of the region, they mourn the loss of agriculture and pastoralism in the region, as lands were sold off for wind farms when the land price appreciated.

Repowering existing wind farms, before acquiring new lands will not add to the worry of the residents in these districts. Repowering has a financial benefit too, in comparison to acquiring new lands for wind farms.

“The cost of dismantling and disposal of old turbines is less compared to the cost of land and evacuation and so in fact applying the feed in tariff of new machines to the repowered WEGs may be advantageous to the generators,” said the Tamil Nadu Electricity Regulatory Commission statement.

Rust visible on wind turbines along the Tirunelveli-Kanyakumari state highway road in Aralvaimozhi, Kanyakumari district, Tamil Nadu. Aralvaimozhi is located in the foothills of Western Ghats and it houses one of Asia’s largest wind farms. Photo credit: Narayana Swamy Subbaraman/ Mongabay

Questions remain

One of the important questions that need to be addressed when repowering begins full-fledged is “What happens to the old turbines?”.

Rajenthiran and Balakrishnan GR from the wind company Siemens Gamesa emphasised that their company is interested in repowering their old turbines too. They stated that if the policies are in place, recycling old wind turbines is very much feasible.

“Most of the components of a turbine can be recycled. Imagine the blades becoming shelters for bicycle stands. European countries have several case studies for successful recycling of wind turbines, and we are at the ready, to implement recycling plans if repowering begins/ is made mandatory,” they told Mongabay-India. The company is already pioneering in recycling turbine parts. It has produced recyclable blades at Siemens Gamesa’s blade manufacturing plant in Denmark.

An interdisciplinary research team called The Re-Wind Network, have started repurposing old wind turbine blades as public utility architectural elements like bike shelters, footbridges and skate parks.

Whether all wind companies can come forward to recycle and whether they have the finances and infrastructure to recycle, are other questions that must be answered by the companies. The old turbines cannot go to landfills, as they have electrical and other non-biodegradable components.

The European market is experimenting with mechanical, thermal and chemical recycling methods, each with its own pros and cons. For companies in India to take up recycling and for it to be viable for them, guidelines and policies must be implemented. But there is no policy yet on disposing or recycling clean energy-related waste.

A single blade of a wind turbine at a wind farm in Thoothukudi district. Photo credit: Narayana Swamy Subbraman/ Mongabay

Assessing biodiversity impacts

While studies on biodiversity impacts of wind farms are lacking in India, there are no studies/comparative studies of biodiversity impacts in an old wind farm versus a repowered wind farm in the country, as repowering in important wind sites is yet to begin.

Mitigating the biodiversity impacts of wind farms is essential because the challenge of climate change cannot be looked at as independent from biodiversity loss, as stated by the Intergovernmental Panel on Climate Change in its latest Assessment Report.

Regarding repowering and biodiversity, T Ganesh, Senior Fellow from the Ashoka Trust for Research in Environment and Ecology, said, “When the height of turbines increase, it can have impacts on high flying birds like storks and large raptors.”

“We need to conduct a proper study,” Ganesh told Mongabay-India. “And as for the location of these windmills, we should try to prioritise areas where there is less concentration of biodiversity or less concentration of important birds/animals. The location analysis and proper biodiversity impact assessments need to be done because we do not have this data in India.”

The state has many issues to tackle with respect to repowering, but to solve the preliminary issue of land ownership fragmentation, Giri suggests that the turbine owners come together to form a cooperative or a Limited company, where the land would be the equity and the owners can become shareholders. “A cooperative model for repowering would be the best way to move forward,” said Giri.

Painting a picture of what the future would look like if Tamil Nadu realises repowering, he said, “In the first shutter we can look at turbines that have crossed 20 years and in the second, we can look at the ones that have crossed 15 years. At one point, only high-capacity turbines would be left. We would have optimised land usage. A mini wind farm could power factories or residential townships.”

A 2021 study that looked at an overview of wind energy development and policy initiatives in India recommended that coordinated efforts between the Centre and the state may push repowering activities.

Queries sent by Mongabay-India to the Tamil Nadu government’s energy department to understand the recent steps taken for repowering remain unanswered at the time of publishing.

This article first appeared on Mongabay.