With most of the best windy sites nearing saturation in Tamil Nadu, there is large potential for small wind energy and the authors say government policies and schemes should be formulated favouring this.

A Small Wind TurbineAuthor: Derek Jensen/ Wikimedia Commons/ CCBY2.0
Voices Energy Tuesday, October 26, 2021 - 15:42

Wind is a clean and inexhaustible source of energy. It is harnessed on site and is a free resource. The resource has been tapped over centuries primarily for grinding grain, pumping water, propelling ships and more recently for generating electricity. The International Electrotechnical Commission defines small wind turbines (SWT) as wind power plants with swept areas less than 200 sq m, corresponding to a sub 50 kW rated power. In India, wind turbines up to a rated power of 100 kW can be classified as small.

SWTs are an adaptive and flexible option for generating sustainable electricity. They are popular in farmhouses, remote and rural areas, telecommunication towers, houses and tall buildings, operating as standalone or grid connected units. SWTs are easier to install and operate than their larger counterparts and are located close to areas where there is a requirement for energy. They can also be installed at locations with a reasonable wind resource that are geographically unsuitable for large wind projects due to terrain, logistics or infrastructure related constraints.

In India, the current installed capacity of both SWTs and small wind-solar hybrid systems is not more than 3.3 MW (Ministry of New and Renewable Energy Annual Report 2018-2019) as opposed to countries like China and USA with installations of 732 MW and 161 MW respectively (Small Wind World Report 2017). This is due to the early adoption of SWTs in these countries, supported by the right policies, incentives and standardisation methods.

Some of the reasons for the low popularity of SWTs in India are complexities in the installation process, difficulties in maintenance, lack of skilled technicians, unavailability of a comprehensive resource mapping study and competition from solar PV technologies. Other factors are to do with the need for supporting business models and policy frameworks.

The Ministry of New and Renewable Energy (MNRE) announced a scheme for small wind energy and hybrid systems in 2010 with a target of 25 windmills and 500 kW of aerogenerators. The scheme also offered financial assistance of up to Rs 1.5 lakh per kW of installation of SWTs for all categories of users. The scheme was modified in 2013 and again in 2016, and the financial assistance offered was reduced to Rs 1 lakh per kW, that too only for community-based users. The tenure of the schemes expired in 2017 and since then the progress on small wind energy has been slow.

Why small wind energy for Tamil Nadu

Wind rich states like Tamil Nadu with large utility scale wind farms and experience in the execution of wind power projects do not have matching installations of small wind. The installed capacity of small wind systems in Tamil Nadu is only about 257 kW (MNRE Annual Report 2018-2019), ranking third in India.

Maharashtra and Andhra Pradesh, with 1833 kW and 271 kW respectively (MNRE Annual Report 2018-2019), are the states with higher installed capacity than Tamil Nadu. The significantly higher installations in Maharashtra are partly due to an active off-grid power generation programme that includes small wind energy systems and the availability of supporting regulations for rooftop renewable energy generation. Many of the major SWT suppliers are also located in Maharashtra, reducing lead times and fast-tracking the installation process. This also ensures timely servicing and maintenance of the turbines, increasing their overall life and popularity.

With most of the best windy sites nearing saturation in Tamil Nadu, it is essential that decentralised renewable options like small wind be considered. This can increase the renewable capacity in the state’s energy mix.

Examining the wind speed maps published by the National Institute of Wind Energy, multiple regions across Tamil Nadu with sufficient wind resource for SWT deployment can be identified. Here they can be deployed as both grid-connected and off-grid units. In the off-grid mode, SWTs can be used for mechanical power or electricity generation. Mechanical power can be used for water pumping, grinding grain and other agriculture related applications. Turbines generating electricity can be used for illuminating common spaces, treating water and desalination, heating and cooling, and cooking. It could also be used for food conservation, remote housing, telecom towers, and so on.

It is evident that there is large potential for small wind in Tamil Nadu due to the presence of wind rich areas with matching energy needs. Government policies and schemes should be formulated favouring small wind energy. They must ensure a level playing field among options such as solar photovoltaics for decentralised applications. Since SWTs are not limited to the daytime for power generation, they can effectively complement solar PVs in the hybrid mode. Renewable targets by the government can set aside a fixed capacity for small wind and mandate the use of small wind for applications such as telecom towers in windy areas. Additionally, policies must incorporate financial assistance for those opting for SWTs.

SWTs must also be positioned competitively in the market to enable seamless purchase, installation and maintenance. Local technicians need to be upskilled with small wind specific training programmes. Business models could be explored where the manufacturer owns and maintains the machines, selling the electricity generated to the user. A detailed state-wide resource mapping study would highlight regions conducive for SWT deployment. Suitable measures for the optimum utilisation of wind resources across Tamil Nadu would increase the share of renewables in the state. It would also allow for the use of affordable, easy to deploy technologies like SWTs, which require low maintenance and have minimum impact on the environment.

Vaisakh Suresh Kumar and Kajol are researchers at the World Resources Institute, India’s energy programme. They can be contacted at vaisakh.kumar@wri.org and kajol@wri.org respectively.

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