www.hpmag.co.uk HYDRAULICS & PNEUMATICS October 2025 43 Keeping the blades turning When most people think about wind power, they picture the vast white turbines turning steadily offshore or across open hillsides. What’s less visible are the complex systems inside those towers, the components quietly making sure those blades turn safely, efficiently and exactly as they should. At the heart of much of that work are hydraulic and actuation systems. H&P reports. Hydraulics might not get the headlines that blades, cables or generators do, but they’re essential. In every modern wind turbine, particularly those operating offshore, hydraulic power is used to pitch the blades, control yaw movement, apply brakes, and support a range of auxiliary functions. These systems are the muscle of the turbine - converting electrical power into precise mechanical movement that can respond instantly to changing wind conditions. As the UK pushes to expand its offshore capacity, with targets for 50 GW of offshore wind by 2030, the demand for reliable, efficient and maintainable hydraulic systems is growing rapidly. The challenge is not simply producing more turbines, but making sure each one performs consistently in harsh conditions, often hundreds of miles from shore. That’s where hydraulics come into focus. Offshore wind farms are unforgiving places for machinery. Saltwater, constant vibration, temperature swings and limited access for maintenance all add up to a tough working environment. Components that perform flawlessly in a factory or onshore setting can degrade quickly at sea. Hydraulic systems, with their seals, fluids and moving parts, need to be designed for resilience. Corrosion-resistant materials, robust filtration and carefully chosen fluids all make a difference to long-term reliability. One of the recurring issues for operators has been maintenance. Accessing a turbine offshore can be difficult, especially during winter. Any failure that requires a technician to go out by boat or helicopter adds significant cost and downtime. For that reason, there’s been a strong move towards designing hydraulic systems that are not just durable, but also easier to monitor and maintain remotely. Condition monitoring is becoming standard. Sensors that track pressure, temperature, and fluid cleanliness can send live data back to shore-based teams. With predictive analytics, operators can identify small issues before they turn into breakdowns. It’s not glamorous work, but it’s the kind of detail that keeps wind farms running smoothly. Some turbine manufacturers are now experimenting with semi-closed or fully closed hydraulic circuits to minimise the risk of leaks and contamination. These systems maintain fluid purity and reduce the need for regular maintenance visits. Others are using modular actuation systems that can be swapped out quickly when required, rather than serviced in place. The goal is the same: maximise uptime and reduce costly interventions offshore. The conversation about hydraulics in renewables also ties into a wider effort to make wind turbines more efficient and sustainable. Hydraulic systems have traditionally been viewed as less energyefficient than purely electric alternatives, mainly due to losses in fluid compression and throttling. However, advances in design are closing that gap. Variablespeed pumps, proportional control valves, and better system architecture are helping to reduce energy losses significantly. In some cases, hybrid electro-hydraulic solutions are being introduced - combining the fine control of hydraulics with the efficiency of electric drives. Reliability and efficiency Reliability and efficiency are two sides of the same coin in this context. Every hour of downtime on a large offshore turbine can mean thousands of pounds in lost generation. With arrays stretching into the hundreds of machines, even small improvements in reliability can have a noticeable impact on overall performance. It’s why the supply chain around hydraulic components, from seals and hoses to accumulators and servo valves, is now seen as a strategic priority. The UK’s growing offshore sector provides a real opportunity for the domestic fluid power industry. British companies already have deep expertise in hydraulics through industrial, aerospace and marine engineering. Translating that experience into renewable applications is a logical next step. There’s scope to supply systems for new builds, but also to support maintenance, upgrades and retrofits on the growing number of operational turbines. Localising more of the supply chain Hydraulic pitch control assembly inside an offshore wind turbine nacelle
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