Repowering old wind farms could treble capacity, using a lot less turbines

About 1,700 megawatts (MW) of aging wind generation in Australia could be repowered to deliver 6000 MW, using just a third of the turbines, according to an industry specialist.

The so-far untested strategy in Australia is moving on from being a theory, as when Renew Economy reported on it last year, to being a viable option that companies are now investigating, as they have done in Europe, says Simon Lukies, an approvals specialist with GHD. 

But amongst the hurdles is one big sticking point: neither state nor federal regulators are ready to be the first to state what the approvals process should look like, even though they understand the need for change.

Approval processes are set up to measure the impact of a new wind farm against what was there before – no wind farm. These rigid pathways now need to be changed to measure the impact of a repowered project against an old one. 

“From a logical sense you would say absolutely [just use the 20-30 years of data collected from the operating wind farm]. And from a proponent perspective you would want to assess the project along the lines of what’s there now,” Lukies says.

“But when you’re working with approvals bodies they’re not overly comfortable with that approach because it hasn’t really been done before in Australia.”

Instead of a baseline of no development plus two years of environmental data, regulators will need to look at each repowering project separately. 

They will need to measure the impact of older towers, which are smaller, noisier and more numerous, against much larger machines which have a bigger visual impact, although but fewer are needed to deliver the same or more power, and come with sophisticated software, for example around bird monitoring. 

A spokesperson from the NSW Department of Planning, Housing and Infrastructure says technically repowering is already allowed, but within the confines of the existing consent. This means any new machines must be, for example, the same height and no louder than the old ones.

“The approvals for NSW wind farms specifically state that wind turbines can be replaced or upgraded for the life of the project if they are within the approved disturbance area and they still meet the limits of the approval,” he said.

Australia could replace 900 turbines today

Lukies wouldn’t name which wind farms are likely the first to be repowered – he’s working with clients now on this topic – but did describe the most likely to go first. 

“The prime candidates are a wind farm that is 25 years old. The prime candidates at the moment are those sites with really early turbine models that were either installed as prototype systems or machines installed in low production volumes,” he says. 

That works out to be about 900 turbines with capacities of just over 1 MW each, with early Vestas and Suzlon models among those that are now impossible to get replacement parts for. 

Modern turbines are delivering 6 MW each, with new projects looking to install turbines rated at 7 MW to 8 MW.

“As [new wind farms] get more difficult to develop it’s going to require a much more lateral view on how we meet our [renewable energy] target. And when you have 1700 MW of sites around the country that you could potentially push to 6,000MW, because you get that [minimum] six to one gain, there’s a huge opportunity that’s untapped.”

Keeping the grid connection, great site benefits

Repowering a wind farm involves completely decommissioning the existing site – nothing can be reused except perhaps the connection to the grid. 

Bigger turbines require a new layout, as fewer machines can fit on a site and must be spaced further away. Community engagement must be repeated. 

And to top it off, in Australia those approvals pathways must be altered to allow this to happen – a daunting task given how challenging it is to get new farms through turgid regulatory systems. 

The 1500 MW Yanco Delta wind farm was the first in three years to win approval from New South Wales (NSW) when it finally got through the planning process in December last year, and commitments to big wind projects are collapsing. 

So why bother with repowering, if it will cost more (as decommissioning is added to the project) and be harder to get through planning? 

Lukies says it’s all about the rising shortage of suitable new sites and the value of connections to the grid.  

“Wind farms are hard to get approved. The only thing I’ve worked on that is harder to get approved are transmission lines. Connection is king,” he says.

The connection “is worth its weight in gold” because if it has extra capacity that means more generation can be loaded onto a site. And if it’s at capacity, that means fewer machines and lower operational and maintenance costs. 

“The other advantages are from an approvals perspective – noting that the early days of working out approvals pathways is going to be an effort – as state and commonwealth regulators are much more comfortable with existing sites because they have an abundance of data.”

Furthermore, social licence might be slightly easier to win – even factoring in turbines that are six to eight times larger dominating skylines. 

“One of the theories around repowering an existing site is that generally you have a community that has lived with the site for 20, 30 years and that site has probably become an important part of the community. So you’re probably starting from a higher footing than a place with a greenfields site,” Lukies says.

“How far that goes remains to be seen.”

Stricter rules and expectations around community engagement as well as more generous schemes such as Engie’s $1000 energy rebate to distant neighbours or Squadron Energy’s offer to let locals buy in to some of its developments, are leaps ahead from the attitudes 30 years ago towards communities.

Lessons on timing and decommissioning costs

Europe is the prime example for repowering, although it too is struggling with regulations. 

WindEurope data last year indicated that some 13 gigawatts (GW) of wind farms will be decommissioned between 2024 and 2030 but only repowered with 9 GW, due to few incentives to reuse sites. 

Europe has also reached a stage where it can recycle 85-90 per cent of turbines with the most difficult parts – the blades – being used as cement additives. 

But Lukies says the real lessons to be learned from mature repowering locations is in timing and decommissioning.

“The key one is early planning. Not waiting until things are falling apart to start getting this process underway. Because by the time you’ve gone through your business cases and your approvals you’ve probably gone six-plus years before you can start pulling down your turbines,” he says. 

And understanding who will pay for decommissioning early is critical: is this cost the operator’s problem, the new developer’s, or someone else’s? 

For many wind farms, a number was “pulled from the sky in 2000 and not looked at again”, which in the 2020s is proving to be wholly inadequate. Operators need to put a number on a balance sheet and regularly update it.

“In general the whole industry around the decommissioning and refurbishment of wind farms is developing very quickly because no one thought of it for 20 years and all of a sudden it’s a problem,” Lukies says.