Posted on October 14, 2024
OPINION | The massive scale of components and a drive into new regions of the seabed mean crucial capability gaps need to be filled if offshore wind is to meet its growth ambitions, writes Fabian Hippe
Offshore renewable energy developers are facing challenges with foundation installation due to increasing turbine sizes requiring larger foundations and higher turbine hub heights, revealing technology gaps and limitations in existing and traditional installation equipment.
Many offshore renewable development areas are emerging outside traditional oil and gas regions, which have historically been well explored and understood with established geotechnical frameworks. Unexplored regions contain natural soil deposits, presenting a challenge because understanding them takes time. New natural materials are being detected, whose reactions and interactions with operations like dynamic loading remain poorly understood. As developers venture further offshore, increasing water depth complicates matters as soil conditions change again.
Not knowing the foundation soils probably bears the largest risk overall, where the ability to adjust quickly and effectively to these conditions is crucial for economic and low-risk developments.
Lastly, the availability and reliability of suitable installation equipment remain a challenge. Technologically, some elements are at the absolute limit of current capabilities. For example, large forgings needed for some installation equipment components for pile driving and drilling has pushed the boundaries of global manufacturing capabilities.
So, how can these challenges be addressed? From understanding soil conditions, identifying sites, and conducting pre-engineering and preliminary front-end engineering design analysis, to deriving concepts and directions for wind farm development, various services and engineering practices play a crucial role in the early stages of the offshore wind farm lifecycle.
Novel concepts from the supply chain can be developed in close cooperation with developers during the engineering phases to ensure tailored foundation solutions that remain commercially and operationally viable.
To address the renewable energy industry’s need for installing the next generation of monopiles and turbines to increase gigawatt production, new technological advancements are required. The size of a pile-driving hammer used in offshore wind installations is determined by factors such as turbine size, water depth, and seabed conditions. The larger and more demanding the task, the more powerful the hammer needs to be.
Developing pile-driving technology involves balancing what needs to be installed with what will be used to install it. A small hammer cannot drive a massive pile. A large-diameter, heavy pile, which we now see more of, encompasses significant embedded surface area and may require significant energy to overcome soil resistance. However, driving becomes easier if the hammer is also heavy because kinetic energy – the movement of a mass impacting a steel surface – can be used to develop the driving and progression energy.
MENCK, an Acteon Marine Foundations brand, offers an example of how technology is responding to developers’ requirements to install larger, heavier piles. The newest and largest hammer in its MHU fleet: the MHU 6000W Wind Hammer, delivers a minimum energy of 200 kJ and a maximum of 6,250 kJ.
It features a pile sleeve anvil and anvil adapters adaptable to pile diameters up to nine metres, which can be customised to suit even larger pile diameters. It relies on known and trusted technology characteristics while extending operational and situational insights into the installation process and equipment performance.
A smaller hammer could be used to do the same job, but significant wear and tear on both the machinery and the pile would be encountered, along with installation inefficiencies. Most piles do not require the hammer’s maximum energy, but the hammer’s weight itself supports a smoother installation. This applies to both the fatigue induced into the pile during pile driving and various environmental concerns and challenges linked to the pile driving process.
Environmental concerns around pile driving have arisen over time and are now prominent. Oil and gas installations used to involve one jacket with a few piles, but now we drive hundreds of piles at once for wind farm developments, significantly impacting the region in which we operate. This is one of the main reasons for oversizing the hammer and running a heavier hammer at lower energy levels to reduce noise emissions into the water column and dynamic stresses within the pile due to the pile driving process.
Balancing power and precision are crucial for the next generation of hydraulic hammers in offshore wind installations. These tools drive monopiles into challenging seabeds, ensuring wind turbine stability. Their evolution meets the growing renewable energy demand, combining power with precision to protect marine environments. This technology accelerates project timelines and embodies the innovative spirit of the global shift towards sustainable energy.
Fabian Hippe is director of sales for Acteon Marine Foundations
