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Leeward leans into repowering wind project

Leeward Renewable Energy has successfully completed the repowering of its existing Aragonne Repower wind projects in New Mexico, with 100 percent of the blades from the decommissioned turbines being recycled or reused.

By Robin Brunet

Like death and taxes, infrastructure aging is inevitable. And in the renewable energy realm where technology improves in a relatively short period of time, aging can happen quicker compared to other types of infrastructure. Fortunately, companies such as Leeward Renewable Energy (LRE) are focusing on re-commissioning certain installations, and its recently completed Aragonne Repower and Aragonne Mesa projects are noteworthy examples on several levels.

Dallas-based LRE is an early mover in the repower industry, with its first project undertaken in 2017. The company owns and operates 22 renewable energy facilities across nine U.S. states totalling 2,000 megawatts of generating capacity. It also actively develops and contracts to build new wind, solar, and energy storage projects across the U.S., with 1.9 gigawatts contracted and 17 gigawatts under development.

Repowering has become an important facet of LRE's operations, and Vice President of Development John Wycherley explains why: "Tying into the grid with a new project can easily take up to seven years, whereas repowering an existing facility is much faster," he says.

"Other benefits include the fact that the community has already embraced the facility, so regulatory hurdles are less onerous. There is also great potential for components to be recycled, including wind turbine blades—and all of this was very much the case when the opportunity to repower Aragonne was brought to our attention in 2020."

Located in Guadalupe County, New Mexico, the Aragonne projects will provide 200 megawatts (MW) of wind power generation over a 20-year period to Arizona Public Service Company (APS) under a previously announced agreement, with the capacity to generate up to 235 MW of renewable energy. This agreement builds on LRE's long-term operating success with APS and further supports the clean energy goals of APS.

The new projects consist of 86 advanced GE wind turbines capable of generating over three times the power produced by the legacy Aragonne Wind project, while using 60 percent less land. Additionally, as part of LRE's commitment to environmental stewardship, 100 percent of the blades from the decommissioned Aragonne Wind turbines were recycled or reused, as were a majority of the other materials removed from service.

Aragonne began life in 2005 as a medium-sized 90 MW installation about 100 miles east of Albuquerque, on a high mesa ridge. "For us it was an important flagship project in a high wind resource zone," Wycherley says. "And because we view all of our projects with an eye towards what will happen towards the end of their productive life, we were well acquainted with Aragonne's extended life potential as well as elements such as site conditions and local government."

Although 2020 was deemed a good time to launch the repower project, LRE faced several hurdles, not the least of which was a compressed design/construction timeline. "After assessing all the elements of the project, we realized we had about 24 months to do the work, so Aragonne became very much an exercise in taking all the traditional steps of repowering, only on steroids," Wycherley says.

Located in Guadalupe County, New Mexico, the Aragonne projects will provide 200 megawatts of wind power generation over a 20-year period to Arizona Public Service Company under a previously announced agreement, with the capacity to generate up to 235 MW of renewable energy. 

The high mesa location was a major challenge, especially considering that LRE's goal was to minimize the project's footprint. "It was very complex terrain with lots of gorges and steep edges, as well as elevation drops of 400 feet within a span of several hundred feet: in short, this wasn't exactly a cornfield in Iowa," Wycherley explains. "It's a very sensitive area with subsurface constraints, and this obliged us to consider many design iterations before settling on a definitive one."

While the distance between turbines is typically about 350 metres, the unidirectional wind on the mesa combined with the rugged topography obliged LRE to space its turbines closer together in some instances and as far apart as 500 metres in others. "We also designed the arrangement to be accessible to as many existing roads as possible, but nonetheless some road expansion was required, especially to accommodate heavier trucks," Wycherley says.

As for the new equipment that would give Aragonne another 30 years of energy production, Wycherley says, "We decided to use the same platform as that of our Mountain Breeze Wind Farm in Weld County, Colorado," a recently completed project made up of 62 GE Renewable Energy wind turbines with a total capacity of 171 MW—and which was also completed within a compressed time frame. "We have a long standing history of using GE turbines. Quite simply, they are well-tested technology, very efficient and reliable.

"Also, thanks to the constant improvement of turbine technology, we were able to achieve a 300 percent increase in power generation with only 86 turbines on a site that had to be expanded by only 20 to 25 percent."

One of the more intriguing aspects of Aragonne was the dismantling and recycling of the existing infrastructure. "We're very proud of our ability to send turbine blades and other components to facilities that transform them into other products," Wycherley says. "Yes, it takes time, money and effort, but it's worth it.

"In the past year we've taken down 370 blades in different states, and a licensed company transports them off site for processing."

Indeed, LRE is tackling a challenge that will assume major proportions for the renewable energy sector in coming years. According to WindEurope, the first wind turbines installed in the 1990s are reaching the end of their 25-year lifespan, and it estimates that 25,000 metric tons of wind turbine blades by 2025 will annually reach the end of their operational life.

 Dallas-based Leeward Renewable Energy is an early mover in the repower industry, with its first project undertaken in 2017. The company owns and operates 22 renewable energy facilities across nine U.S. states totaling 2,000 megawatts of generating capacity

Currently, up to 90 percent of a wind turbine can be recycled through established metals processing, but the fiber composites of the blades are difficult to process because the resins that bond the glass fiber together can't be broken down through mechanical recycling, and thermal recycling is not yet economically feasible.

Mechanical recycling does, however, shred wind turbine blades into granules versatile enough to be used in the manufacture of skis, furniture, and other products. Also, many turbine blades have found a second life by being reinstalled in less advanced economies or repurposed for use in cement processing.

Meanwhile, early stage ventures are researching ways to use heat and nanoparticles to improve the economics of recycling fibers. For example, Carbon Rivers of Tennessee extracts the glass fiber from blades in a process whereby material is heated to very high temperatures in the absence of oxygen, to thermally decompose the chemical compounds. Additionally, the University of California at Berkeley is conducting early-stage research into thermoset resins for new blades with triggered degradability, and producers Arkema and Aditya have developed resins that can be chemically recycled to produce plastics of different forms (there is even research being conducted in Scotland that focuses on producing new materials for blades from sustainable sources like wood pulp and recycled plastic).

When construction began on the Aragonne project, LRE achieved efficiencies by using the same crews and resources for both wind sites. Also, "RES Electrical Engineers out of Colorado fulfilled the electrical portion of the project as they did for Mountain Breeze, and IEA Inc. performed the civil work," Wycherley says.

This was in addition to regulatory efficiencies already achieved. "We were an established presence in this region, so the bureaucracy was kept to a minimum," Wycherley says. "Plus, with Aragonne having proved itself when it first began producing power in 2005, the 35 landowners who originally signed off on the project were amenable to re-signing our new contract."

Unsurprisingly, high winds proved to be a construction challenge and required scrupulous scheduling of crane use, but this did not prevent LRE from fulfilling its goal of having the turbines erected by November 2021.

Given the tight timelines, critical infrastructure to increase the project from 90 to 235 MW was constructed concurrently with the turbine installations. "The network upgrades along with stacking up other tasks in order for us to meet our deadlines certainly kept us up at night, but in the end we learned a lot from this project that will be useful in future re-powering projects," Wycherley says.

However, while LRE repowering work will likely expand in the foreseeable future, Wycherley points out that such projects must be assessed on a case-by-case basis. "No two wind farms are alike, and not all of them lend themselves economically to being repowered," he says.

Still, Aragonne remains a prime example of what one company can achieve in the name of sustainability. Earlier this year upon completion of the project, LRE stated: "This is an important milestone for LRE as it showcases our ability to deliver high value renewable energy facilities through innovation, long-term trusted relationships, and by positively impacting the communities we serve. We are pleased to be extending our long-standing partnership with APS and the trusted relationships we have built with Guadalupe County community for another 20 years."

Q3 2022