Can Drivetrain Design Updates Improve Wind Turbine Efficiency?

Old-fashioned drivetrain technology is one reason behind cost frustrations and inefficiencies in offshore wind turbines. A recent study by the U.S. Department of Energy’s National Renewable Energy Laboratory and General Electric Research analyzed new drivetrain designs for improvements. The results could catapult wind turbines into an era of cost-effectiveness and productivity and boost their potential as offshore power generators.

 

Wind turbine drivetrain. Image used courtesy of NREL

 

What Does the Study Reveal?

A drivetrain is responsible for electricity production in a world that needs more energy daily. According to the study, the gearboxes and generators in drivetrains for wind turbines need updating. Over the years, turbines have become taller and more powerful, yet these crucial components received little attention as wind power expanded. How can antiquated resources supply the nation’s goal of 30 gigawatts by 2030?

The NREL study showed conceptual designs for drivetrains the modern age requires for terrestrial and floating wind turbines. Geared drivetrains have extensive maintenance requirements because of the turbine's pressure on numerous moving parts. Sometimes, these components jam or fail, compromising the rest of the unit. Magnet-powered direct-drive drivetrains are not ideal because the immense magnets need large quantities of mined rare metals. However, they run at lower speeds while producing competitive amounts of electricity.

The study posed alternatives based on levelized energy cost, determining a turbine’s life against its generation potential. For example, superconducting magnets that are easier and less intensive to source may replace traditional models. Additionally, permanent-magnet synchronous generators reduce offshore turbines’ costs by around 7%. 

 

Parts of a turbine drivetrain. Image used courtesy of DOE

The success of these designs to reduce costs and improve output relies on numerous other factors, including:

• Amount of maintenance gearboxes require
• Investments in digital or live testing
• Gearbox speed
• How well materials work in water over time
• Weight of the floating turbine, primarily at the top where drivetrains are located

 

Why Consider Drivetrains Now?

Renewable energy adoption is hastening at a surprising pace in the eyes of regulators. Around 75% of new energy-generating capacity in the U.S. in 2022 came from renewable sources. 

Renewable energy engineers have relied on the same technologies to drive progress for decades because they have satisfied grid needs. However, the old tech responsible for stabilizing wind adoption will not suffice anymore. Initiatives like the Inflation Reduction Act increase funding and urgency for renewable projects. In 2021, for example, the Department of Energy gave $500,000 for innovative projects to test scaling offshore turbines to 10 megawatts.

The most successful trial of wind power was General Electric Research in Niskayuna, New York. It leveraged the superconducting generators based on MRI technologies. The final prototype has the potential to be 50% lighter and 10% cheaper. The lightweight design is crucial because offshore turbines must become taller to reach ocean floors.

Offshore turbines are more reliable because of the ocean’s consistent tides and currents, and implementing new generators and gearboxes increases their attractiveness for regulatory and citizen buy-in.

 

What Advancements Make New Drivetrains a Reality?

The drivetrains are one part of the cost- and resource-saving equation. Engineers must consider how additional performance-enhancing and monitoring technologies need compatibility with drivetrains. For example, remote visual inspections employing aerial drones eliminate hundreds of accidents for commercial climbers. Remote operational controls for reviews and audits help compliance, data mining, and worker safety.

 

Drone inspection of a wind turbine. Image used courtesy of UT Dallas

 

Offshore wind power also needs more collaborative enhancements. Initiatives like the Drivetrain Reliability Collaborative demonstrate the necessity of communication and data-driven standardization for scaling offshore wind. The cooperative undergoes research using a medley of mediums, including:

• Physical and digital modeling
• Field failure data
• Field characterization
• Operational and maintenance statistics
• Dynamometers