In 10 years, the Offshore Wind Accelerator (OWA) has run over 150 projects supporting innovations that have led to both a significant reduction in the cost of energy and risk, whilst making offshore operations safer. To mark this milestone in R&D collaboration, we have selected 10 high impact innovations to showcase the breadth and depth of the programme.
Most offshore turbines currently installed are built on large steel tubes called monopiles. These monopiles are installed using large hydraulic hammers and with some monopiles having a diameter of up to nine metres they require a great deal of energy. This brings its own challenges in terms of underwater noise, installation time and shorter fatigue life.
The Offshore Wind Accelerator decided to investigate two new types of technology to replace the hydraulic hammer.
The first technology was vibratory piling. This involves driving the pile into the seabed using vibrations that liquefy the soil, which subsequently solidifies naturally once the pile is installed. The process is much faster and quieter than the traditional hydraulic hammer method.
Tests for the vibratory piling took place in summer 2014, in similar soil to those found offshore in the North Sea. The experiment provided considerable data to better understand the technology and further development needs, so that it can be an option to the offshore wind market.
The second technology is called the BLUE Hammer – an entirely new way to secure the piles in the seabed. Rather than hammering in a traditional way, it consists of a large water tank containing an open combustion chamber. The combustion accelerates a large column of water within the tank, which pushes the pile into the seabed. Because this happens much more slowly than a blow from a hydraulic hammer, it provides a quieter, gentler but more energetic blow, more like pushing than striking.
This has several distinct advantages. It reduces underwater noise and it is likely to reduce fatigue damage of the pile during installation. This means that secondary steel can be pre-welded to the pile, potentially unlocking ‘transition piece free’ designs. It is also safer, because it reduces the amount of time and number of operations carried out offshore.
The first tests on the BLUE Hammer were carried out in August 2018, and the results are being analysed to better understand the technology.
These are perfect examples of how the OWA brings together different pieces of the complex offshore wind puzzle, to speed up the process of developing, testing, and de-risking new technologies.
This article is part of 10 years, 10 innovations: A summary of the impact of the Offshore Wind Accelerator