How repowering can breathe new life into existing wind farms

Our wind farms are ageing. According to the Australian Energy Market Commission, the average age of Australian wind farms is approaching 15 years, with some even surpassing the 20–30-year mark.

To date, no Australian wind farm has been repowered. The cheaper route is to squeeze out a few more years of life using advanced sensing tools to avoid component failures and predictive maintenance to keep turbines running marginally longer. But it’s a stopgap. These ageing wind farms face operational challenges, reduced capacity and increased costs, making them potentially unprovisioned liabilities in the balance sheet.

There are other hurdles to overcome when developing new greenfield sites, with the approvals process presenting numerous challenges for proponents. However, our ageing wind farms present a valuable opportunity. Their existing infrastructure and proven wind quality offer a solid foundation for repowering projects, providing a new lease on life and significant economic and environmental benefits.

So, when a wind farm comes to its end of life, what are the options?

When a wind farm reaches its end of life, the options are clear but varied. The baseline option is decommissioning – dismantling turbines, removing infrastructure, and returning the land to its original state. Acknowledging that some sites have inherent issues that make them unsuitable for further investment, outright decommissioning is a net lost option.

Life extension

In cases where turbines are in good condition, minimal investment can extend their life beyond the design limit of 25-30 years. While cost-effective, this option offers limited gains in energy production.

For high production and widely installed turbine models, there is a global abundance of spare parts and even replacement turbines in case of catastrophic failure. However, spare parts are becoming increasingly difficult to source for less common models, making it hard for upgrades to meet the Australian Energy Market Operator’s network controls and operating standards.

Partial repowering

Partial repowering involves upgrading certain parts of the wind turbines while retaining the existing towers. It strikes a balance between cost and performance improvement, though the energy generation gains might be modest.

Full repowering

Full repowering is the most comprehensive option and involves rebuilding the wind farm with newer, more efficient technology. While the initial investment is significant, the returns in terms of capacity and efficiency are substantial. Modern turbines can generate up to 6-7 MW, compared to the 1 MW output of older models, effectively tripling energy production while reducing the number of turbines by a quarter.

Repowering a wind farm can offer significant benefits to justify the investment and effort, but ultimately, the decision on whether to repower depends on key techno-economic considerations, considering the site’s unique and specific attributes.

Refurbishment versus repowering

Refurbishment is another option for extending the life of wind turbines and farms, which involves replacing like-for-like. With high capital costs, it offers limited generational gains and can have potential issues with sourcing compatible parts. The upside is that the development could be undertaken within existing regulatory parameters and permits, negating the need for lengthy approvals process.

Repowering, on the other hand, involves decommissioning the existing wind farm and rebuilding turbines, foundations and ancillary infrastructure. While some aspects, such as roads, switch rooms and other facilities can be repurposed, repowering is essentially developing a new wind farm on an existing site, leveraging modern technology to significantly boost output and efficiency.

Environmental and social considerations

Repowering can take advantage of the favourable wind conditions, established community acceptance, robust data sets and existing transmission infrastructure of older wind farm sites. In most cases where there is an existing wind farm, the community has already been consulted on its development, and it has become a part of their regional economy.

While not dismissing the need for further community consultation to repower the wind farm, an established site provides a more solid platform for gaining community acceptance and social licence. Newer and more modern turbines are quieter and more efficient, meaning repowered sites can have lower noise profiles and be less visually busy than the previous wind farm.

Repowering means that there is an overall reduction of turbines, due to the greater energy output of modern engines, reduces the need to clear land for roads and foundations while allowing for the rehabilitation of legacy infrastructure. While the larger rotor-swept areas of modern turbines do present new challenges, the ability to integrate modern curtailment technologies can help mitigate environmental impacts such as bird strikes.

While robust data sets may seem trivial, operational monitoring of existing wind farms for more than a decade has yielded vast amounts of data on birds, bats and collisions. Unlike data collected from greenfield sites, even after two years of monitoring, data from existing sites can be used to develop an accurate and robust collision risk model for repowering projects.

Transmission is one of the biggest constraints to the development of Renewable Energy Zones around Australia. Existing wind farms already have established connections to the grid. From a repowering perspective, proponents need to consider if the transmission capacity has been reached or if there’s additional capacity to harness.

Commercial and regulatory considerations

To date, assessments of wind farms in Australia have been based on greenfield sites with minimal existing impacts. Early discussions with federal and state approval bodies on how assessments are approached for repowering existing sites have highlighted that approvals will need to address repowering projects holistically, focusing on the change from the existing to the proposed wind farm.

Early planning is crucial, with decommissioning strategies and repowering preparations ideally starting as early as a decade into a wind farm’s operational life. Forecasting the point where operations become uneconomical will give you a hard deadline that sets the agenda for developing end-of-life and decommissioning strategies and a timeline for repowering.

Repowering isn’t just about replacing old turbines with new ones – it’s about harnessing the full potential of existing sites to drive the energy transition and meet our net zero goals. In Europe, repowering alone is projected to meet a quarter of the 2030 wind energy targets.

Australia’s problem with ageing wind farms is not going away and will only become more pronounced over time. While many in the wind energy space are at the other end of the development spectrum right now, collaboration with existing wind farm owners and operators whose assets are at or near their end of life could unlock a whirlwind of opportunities.

The future of wind energy is not only in new developments; it’s about breathing new life into our pioneering wind farms. Repowering offers an opportunity to turn a potential liability into a valuable asset, leveraging existing infrastructure and social licence to operate to support a sustainable energy future.