But what challenges does a project of this scale present for electrical infrastructure? Here, Mike Torbitt, managing director of resistor manufacturer Cressall, discusses how resistors can help stabilise the grid and extend component lifespan to ensure the long-term success of tidal projects.
Managing Grid Reliability in Tidal Power Generation
The Mersey Tidal Power project is one of the UK’s most ambitious renewable energy projects to date. Inspired by successful tidal range developments such as La Rance in France and Sihwa Lake in South Korea, it aims to replicate the long-term viability of tidal power on an even larger scale. Using a barrage-style turbine array to harness the immense power of the river Mersey’s tides, the development could generate up to one gigawatt (GW) of clean energy. However, despite its promise, the scale and ambition of the project raises several challenges that require careful consideration.
Tidal Power Generation and Electrical Infrastructure Demands
Unlike other renewable sources, tidal power generation follows a predictable pattern, being governed by the lunar cycle. However, tidal energy still experiences variations in output due to the changing intensity of tidal flows. Managing these fluctuations, particularly at such a scale, requires highly efficient electrical infrastructure.
Any variation in energy production needs to be carefully managed to prevent fluctuations from causing inefficiencies or disruptions in power transmission. Without this precise control, power surges or dips could destabilise the grid, undermining the reliability of the entire energy network.
The Mersey Tidal Power project’s sheer scale also introduces technical demands beyond standard renewable installations. With an expected operational lifespan of over 120 years, all components — especially electrical systems — must be designed to withstand extreme marine conditions. Saltwater corrosion and high mechanical stresses from strong tidal currents place exceptional demands on electrical equipment. Ensuring system longevity requires components that are not only resilient but also capable of maintaining performance over decades of operation.
How Resistors Improve Grid Stability and Equipment Longevity
The success of large-scale tidal energy projects depends on a responsive and reliable electrical system. Dynamic braking resistors (DBRs) play a key role by absorbing excess energy during peak tidal flow. When tidal currents are at their strongest, turbines can generate more electricity than the grid can immediately use. DBRs convert this surplus electrical energy into heat, safely dissipating it to prevent voltage spikes or overloading transformers. By smoothing out power delivery, they help maintain a consistent and reliable supply of electricity, ensuring that tidal energy can integrate seamlessly with the wider grid.
Beyond grid stability, resistors also protect the physical infrastructure of the turbines. Rapid changes in water flow, such as shifts between ebb and flood tides, can create sudden torque variations on turbine blades and drive systems. DBRs help regulate these mechanical stresses by slowing the turbine’s rotational speed in a controlled manner, reducing wear on bearings, shafts and other moving parts.
Marine-Grade Resistor Design for Harsh Environments
Given the vital role that resistors play in tidal power generation, their durability in harsh seawater is essential. Cressall designs and manufactures marine braking resistors that are engineered to withstand the extreme conditions of tidal power systems, including corrosion, heat and mechanical wear. Using high-quality materials like sheathed mineral-insulated elements protects against physical damage and environmental degradation, while marine-grade stainless steel ensures that all metal components resist saltwater exposure. These durable materials allow the resistors to maintain peak performance for decades, even in the demanding conditions of tidal power projects.
Tidal Projects and the Future of the Clean Energy Transition
While the scale of the Mersey Tidal Power project raises technical challenges, the proposed development is a bold testament to the UK’s commitment to clean energy transition. As the government increasingly supports tidal power as part of its long-term energy strategy, this project could pave the way for widespread adoption of tidal infrastructure. Throughout this transition, durable resistor solutions will play a vital role in ensuring the stability of the grid and the longevity of power generation systems — contributing directly to the UK’s clean energy transition.
