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Green | May 2012

For a repowered India!

With many states facing power shortages and potential windy areas being used inefficiently, it is imperative to assess the potential of repowering old wind farms, says Ramesh Kymal.

For nearly two decades, the sector has witnessed a lot of changes, challenges and opportunities. Over time, the industry has made path-breaking enhancements in turbine efficiency and reliability. Today, we have turbines that offer a viable investment in low wind sites while also ensuring improved reliability. This advancement in technology also offers another lucrative opportunity – Repowering!

The development of wind power in India began in the 1990s and has significantly increased in the last few years. During the first three years of the 11th Plan period ending March 2010, India added 4.6 GW of wind power capacity. With over a year to go before the current plan period is over, it is very likely that Indian wind power installations will meet and exceed the 11th Plan period target, which will be a record of sorts as historically the targets have never been met through conventional thermal and hydro projects within the plan period. The Indian wind energy market grew by almost 68 per cent on a year-on-year basis with 2,193 MW of wind capacity installed between January and December 2010. This made India the third largest annual market after China and the USA for 2010. With more than 13 GW of the total installed capacity, India ranks fifth in the world in terms of cumulative installed capacity.

With many states facing power shortages and potential windy areas being used inefficiently, it is imperative for India to assess the potential of repowering old wind farms. The aim of repowering is to use existing renewable energy resources on site more efficiently, respectively in a technically adapted or improved manner. Repowering offers a significant increase in generation as modern turbines are more efficient at exploiting wind resources.

Repowering has been around for over two decades but the economic benefits lay only in theory and nobody was willing to try it. Besides, most of the old windmills are owned by people engaged in other businesses, such as textiles, and they were prized more for their tax-avoidance value rather than for electricity generation. As these machines still produce some profits — long after they have been milked for their tax value — few have the proclivity to invest in replacing them. Wind mills were regarded as mere ‘depreciation machines’ and investors put in only so much money as would be needed to save taxes, giving little thought to aspects such as efficiency. But today, economics is back and it has become financially viable beyond mere tax and depreciation benefits. The interest in repowering has increased significantly and progressive investors are keen to evaluate repowering.

Through repowering, wind power generation is multiplied without the need for additional land - making a more efficient use of potential land and more capacity addition per unit of land area. One can expect an increase in generation of over 100 per cent than the existing capacity. The use of existing electrical infrastructure save costs, however, extensive due diligence and disposal of old turbines is an additional expense. Considering the costs are same but generation is much higher, the cost of energy is very low.

Some major benefits of repowering are:
  • Fewer wind turbines: The number of turbines is greatly reduced while the natural landscape is maintained.
  • Higher efficiency, lower costs: Modern turbines make better use of available wind energy, thus improving the efficiency of the wind farm and lowering the operation cost. Repowering also gives more energy generation per unit of land area and per square metre of rotor area with improved economics.
  • Better performance: Modern turbines rotate at much lower speeds and thus reduce the noise levels.
  • Better power grid integration: Modern turbines offer much better grid integration since they use a connection method similar to conventional power plants and also achieve a higher utilisation degree.
  • Grid compliance: New machines would be able to fulfill the grid code requirements.
  • Reactive power: New machines will consume less reactive power and help in reduction of green house gases since multiple turbines are replaced with fewer turbines. The scope of earning more foreign exchange also increases through the sale of certified emission reductions.
  • National/state targets for renewable energy: Repowering can also be used as a tool to achieve targets for renewable purchase specifications (RPS) and renewable energy obligations (RPO) in India.
In India repowering old wind turbines is faced with a lot of technical, financial and policy-related issues. The policy uncertainty and fragmented wind-farm ownership is a key hindrance to growth of the repowering market.
  • Technical issues: Absence of continued O&M services for old wind turbines, turbine spacing, testing and certification and rating of wind turbines for repowering are some of the major technical issues faced.
  • Financial issues: Ownership and land costing – contiguous land required, de-commissioning cost, salvage value of old project, discounting factor, sale to EB v/s captive power projects, tariffs and incentives for repowering are some of the main financial issues concerning repowering. To make projects viable, additional financial support is required either in terms of separate feed-in-tariff or financial incentives through governments/utilities buying green power.
  • Government and policy issues: The challenges include securing the necessary approvals and licenses from authorities as well as ensuring a favourable policy and maintaining regulatory transparency and support.
For repowering to be successful and beneficial to the Indian power scenario, it would benefit the industry to replace inflexible, arbitrary and bureaucratic spacing requirements with more flexible, fact-based regulations. A lot of issues can be addressed by offering wind power projects having less than 300 kW or 500 kW turbine capacities for repowering. Stringent turbine spacing requirements as followed in few states (eg: Tamil Nadu) should be relaxed to develop the full repowering potential. All captive, third-party sale and sale to SEB projects should be considered for successful repowering programmes since above 75 per cent of the investors are in captive mode.

For permitting repowering, old existing projects should have a maximum balance life of 10 years and wind turbine capacity of each WTG < 500 kW, will be considered. The repowering ratio should be at least two which in turn will give more energy yield (>3 times). The same land area as per the existing project needs to be considered.

The repowering potential and its benefits offer an attractive opportunity to improve the quality of generation and efficiency of wind sites. The government should also encourage repowering through various forms of incentives for capacity addition such as increase in tariff, etc.

As far as repowering incentive options are concerned, feed-in tariff support should be given to companies engaged in repowering for 20 years. The right policy framework and incentives could significantly change the landscape of aging wind farms in India.

The author is CMD, Gamesa Wind Turbines. Views are personal.
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