Repowering Project Renews Company’s Commitment to Sustainability

Shell Energy upgraded a Texas wind farm to produce more power with fewer turbines, a project that showcased repurposing of old materials with new technology to enhance efficiency, reliability, and safety.

Texas leads the U.S. in overall production of renewable energy, so perhaps it’s no surprise the state also provides ample opportunities for repowering projects to extend the life of clean energy installations. Repowering is the practice of upgrading or replacing key components of an aging renewable or thermal power plant with new equipment or technologies. A solar farm might be upgraded with new inverters, racks, and/or panels and modules. A thermal plant could be switched from burning coal to using natural gas, with new turbines to produce more electricity and run more efficiently.

Wind farm repowering projects typically involve new, more efficient turbines, often taller models that capture a larger amount of wind energy. Energy analysts who have talked with POWER note that onshore wind farms present an attractive case for repowering, since many of the first U.S. wind farms were built 20 to 25 years ago, and the typical lifespan of wind power installations is 20 to 30 years. In addition, repowering projects today can take advantage of tax credits thanks to the 2022 Inflation Reduction Act.

1. Shell Energy hosted a site re-opening ceremony and ribbon-cutting for the Brazos Wind Farm on April 4, 2024. Participants, from left to right, included: Matt Solnick and Annika Venning of InfraRed Capital Partners; and Ed Rivera, Carina Lopez, Brian Kwan, Dana Herrera, Jarrette Lewis Sr., Jolanda Koot, Tony Rodriguez, and Gokhan Tekiner, all of Shell Energy. Courtesy: Shell Energy

Making an older wind farm new again provides other benefits, including efficiency and reliability gains, along with improvements to remote monitoring, a safer working environment, and the opportunity to make a site more sustainable. Such is the case with the Brazos Wind Farm in Texas, a Shell Energy project that spans about 10,000 acres across Borden and Scurry counties in Fluvanna, Texas, about 250 miles west of Fort Worth. Construction of the repowering project began in the second quarter of 2022, and was completed during the final months of 2023. Shell Energy hosted a site re-opening ceremony and ribbon-cutting (Figure 1) for the Brazos Wind Farm on April 4 of this year.

“As a group, we recognize that renewable power is critical for helping our commercial customers meet their corporate sustainability goals. This is another example of Shell’s commitment to providing the energy our customers need,” said Dana Herrera, general manager of Onshore Power Asset Management for Shell Energy.

Herrera told POWER: “Repowering involved replacing our smaller turbines with larger, more powerful ones. This transition required a thorough reassessment of site suitability, including wind conditions, ground stability, and spatial constraints. Additionally, the increased power output of the new turbines necessitated upgrades to the grid infrastructure to handle the additional load. Ensuring compatibility between new equipment and existing infrastructure—such as electrical systems—was also a critical challenge. Moreover, safety was always our number one priority; the logistics of safely transporting and installing larger turbines was complex and required specialized labor and equipment.”

The improvements at the Brazos site make it a model for a repowering project, supporting its selection as a POWER Top Plant for renewable energy.

Cost Savings Through Repowering

There has a been an uptick in repowering projects as developers recognize financial gains from upgrading existing facilities, rather than spending capital on new-build installations. Wood Mackenzie, in a research report done in partnership with the American Clean Power Association, in October 2023, wrote, “Repowering has experienced significant success under the previous PTC [production tax credit] regime, but a new wave of wind projects are now eligible for repowering and are expected to take advantage of this incentive. Repowering is expected to be performed on over 30 GW, or 20%, of the existing U.S. onshore wind energy fleet by the end of 2028.”

The U.S. Department of Energy has said, “Wind repowering enables owners to retrofit power plants on existing sites with new and/or refurbished technology, including erecting taller, more efficient wind turbines to increase productivity. Repowered projects can often gain further cost-saving advantages, relative to new greenfield [or vacant-lot] developments, by using existing grid connections and infrastructure.”

Enverus Intelligence Research (EIR) earlier this year wrote that wind developers plan to add between 6.5 GW and 7.5 GW of additional power generation capacity to the power grid through repowering projects in 2024, the most since 2019. “In this environment of rising costs, a wind repower has significant upside over a new build and developers are starting to take notice,” said Scott Wilmot, vice president at EIR. The group has noted that a repowering could cost 50% to 80% less than a new-build wind farm project, as infrastructure such a grid connections and roads are already in place.

“More developers are opting to repower instead of building new wind plants in an effort to reduce capex [capital expenditure], and operations and maintenance costs, and boost power production,” said Wilmot. “Repowering can often be done under existing premium-priced power purchase agreements [PPAs] that have remaining term. Given the status of the aging wind fleet and the turbine efficiency gains that have been achieved, we expect repowering momentum to continue in the U.S. going forward.”

Wilmot continued: “Depending on PPA price, repower economics can be preferable to a new build if a 5% capacity factor gain can be realized. This is a low benchmark to clear given the turbine efficiency gains and degradation we have observed. Projects older than 12 years [pre-2012 vintage] can realize capacity factor gains of 10% –20% through a repower—this makes repowering an easy economic decision.”

The Brazos site previously had 160 1-MW turbines, model MWT62/1.0 (MWT-1000A) manufactured by Mitsubishi. The original wind farm, for a time known as the Green Mountain Energy Wind Farm at Brazos, was commissioned in December 2003. Today the Brazos Wind Farm has 38 next-generation Nordex 4.8-MW turbines, with the 182 MW of generation representing about a 14% increase in electricity generation capacity.

Herrera said the repowering of Brazos “was a complex but necessary step to enhance the efficiency and longevity of our wind facility. By addressing the technical, financial, regulatory, environmental, social, and operational challenges, the wind energy industry can continue to thrive and contribute to a sustainable energy future.”

Herrera, referring to the decision to sell a 60% stake in the project to InfraRed Capital Investments (InfraRed) in February of this year, said, “This transaction aligns with our strategy to deliver more value with less emissions through a diligent focus on performance, discipline, and simplification. Shell continuously evaluates external opportunities that can help meet our customers’ needs while maximizing long-term shareholder value.” The February transaction also involved Shell Energy selling a 50% stake in the Madison Fields solar power development in Ohio to InfraRed.

Replacing the original 160 turbines with 38 larger, more advanced models provides a blueprint for a wind repowering project. “The Nordex turbines allow for improved remote monitoring and data generation used for advanced analytics, enhancing overall reliability and safety,” said Herrera. “We can deploy fewer and larger turbines to generate more energy for customers. These new turbines also offer several ergonomic and quality-of-life improvements over older turbines, such as service lifts, providing a safer, more comfortable work environment for the technicians maintaining them.”

Herrera said Shell Energy made it a priority to repurpose the decommissioned turbine equipment. Shell Energy contracted the removal and repurposing of 2,100 tons of fiberglass from the 160 decommissioned turbine blades. The material will be repurposed to support the creation of products for concrete, asphalt, composites, and/or bulk molding applications.

“We contracted a repurposing company local to the Lubbock area to continue our investment in local resources,” said Herrera, who noted the repowering project made sense for several reasons, including as a way to continue Shell’s commitment to the region.

“We already owned and operated the asset and have fantastic relationships spanning over two decades within the community,” said Herrera. “Repowering the site allows us to continue our involvement with residents in Borden and Scurry counties while increasing energy generation capacity by approximately 14%, generating 182 MW of electricity with 122 fewer turbines onsite.

“We are proud of our decision to repurpose and recycle old turbine components. Shell is committed to reducing emissions, protecting the environment, and respecting nature,” said Herrera. “This project aligns with Shell’s ambitions to provide more, cleaner energy options for our customers.”

—Darrell Proctor is senior editor for POWER.