Pushing the boundaries of installation jack-ups
Photo credit: Fred. Olsen Windcarrier
The rapid development of wind turbine technology is one of the most exciting stories in renewable energy today. However, the rapid pace of change does bring with it costs as industry participants respond to the changing operational landscape. One of those costs is the development and build of the equipment that will be needed to install and maintain the new turbines, and it is no secret that many of today’s jack-ups are reaching their functional limits.
The wind turbines of the near future are going to require a new generation of larger and smarter installation jack-ups capable of handling the increasing weight and installation height of wind turbine components while delivering the economies that are needed to maintain wind power as a viable alternative to hydrocarbons. This latter requirement is best met by reducing the number of steps involved, and is best achieved by combining transport and installation in robust, purpose-built jack-ups. This both reduces downtime and increases safety.
Keeping pace with ever larger turbine sizes
“Turbine sizes are growing fast with units generating 10 to 12 megawatts expected just a few years ahead,” says Jan-Mark Meeuwisse, commercial director at GustoMSC. “However, today’s installation jack-ups are not going to be capable of installing them.” The period from 2011 to 2013 saw many new jack-ups enter the market, but since then only three new vessels have been built. This leaves a substantial gap in the market and risks slowing the roll-out of the new, more efficient turbines at a critical time for the industry.
“To address this, GustoMSC has been working in consultation with its industry partners to develop the designs that will meet this precise need,” continues Jan- Mark. “Our approach has been to combine proven jack-up designs, jacking systems and cranes with innovative incremental improvements that together deliver a unique, high performance, integrated piece of machinery to the vessel operator.”
“This can be seen in our latest range of NG wind turbine installation jack-ups. Proven jacking systems, legs and hulls deliver the reliable platforms that will be vital for safe and efficient operations. The significance of this cannot be underestimated; the installation of individual components, some of which weigh over 1,000 tonnes, at heights of 160 -170 metres has never been done before, except in the space industry.”
The innovation in the new designs is most evident in the telescopic leg cranes that will be used to lift and install every part of the wind turbine structures. Their key feature is the combination of the ability to reach the heights required for tower, nacelle, and blade installation, and heavy load capability at a lower height for foundation installation. GustoMSC developed the telescopic leg crane to combine these two extreme requirements. By introducing a telescopic boom with a very high hook when extended, as well as increased hoisting capacity and extra side lead when retracted, it is possible to break the cycle of flimsy booms.
The result is a more economic crane design and increased variable load available for operations. The compact storage of the crane boom also increases the range of sea states in which the vessels can transit by avoiding a traditional fragile boom that can sway around dangerously when sailing in heavy weather. Reducing this risk enhances seaworthiness and so increases overall uptime.
“Having a single vessel undertaking an installation process previously done by two will also improve utilisation rates,” Jan-Mark points out. “Larger turbines mean that fewer will be required to generate the same amount of electricity, so installation operators will benefit from only having to invest in one installation vessel class to deliver a full service.”
…and maximising capacity
Carrying even one extra turbine set on a jack-up has a big impact on reducing costs, and with the new extra-large turbines taking up more space and adding more weight than previously, GustoMSC’s new designs also address that issue. They feature large unobstructed deck areas and fully integrated jacking systems, providing a large deck loading capability. By carefully selecting the crane’s capacity and lifting height, and taking into account the interaction between crane and jacking system, the result is solid and stable platforms which reduce installation risks.
The range starts with the compact NG-8000X, followed by the NG-14000XL, as demonstrated by the successful Scylla which is presently the largest and most efficient jack-up in the market. At the top end is the NG-20000X design, which can be fitted with a 2,500 tonne telescopic leg crane and can elevate more weight out of the water than even the largest harsh-environment offshore drilling rigs. With demand for jack-ups of this type expected to come on-stream in 2021, the race is now on to find operators ready to meet the challenge ahead and start building.”
“While new jack-ups will be required to install tomorrow’s 10 megawatt-plus turbines, the existing fleet will continue to play a role,” says Jan-Mark. “Most likely in O&M and decommissioning activities on the legacy wind farms. New O&M jack-ups will also be needed for the next generation turbines. In order to be cost-effective these will need to be compact yet able to reach the required heights and have multi-purpose functionality.
“It is still unclear how the future will unfold, but it is clear that the offshore wind market is again at a decisive point in its development. At GustoMSC we will continue to play a leading role in the offshore wind installation sector and use our experience and expertise to provide the market with safe, solid and stable solutions for the successful development of European, US and Asian offshore wind.”