Contractors and developers face multiple challenges in keeping up with the pace of demand for larger turbines – new approaches are needed, writes Alex Fyfe.
The offshore windfarm market has witnessed stellar growth as demand for clean energy has increased and this growth is set to accelerate. The global demand for energy derived from windfarms will see total windfarm deployments grow to reach 320GW in 2030 and 1800GW by 2050.
First and second generation windfarms were constructed with the available technology rather than dedicated assets which have the ability to scale. As the size of turbines grows from 12mw through 15MW and towards 20-25MW, existing or mass produced lifting equipment and existing logistics processes will not be big enough to handle the components.
Contractors and developers will need much more lifting and marshalling capacity, as well as cargo vessels and other support equipment to meet projected windfarm demand. They will also need to consider new approaches to the supply chain and how to plan for handling of higher volumes of larger components.
A Market in Shortage
Using data produced for HLP by Maritime Strategies International, forecasting the total number of offshore wind projects to be installed, per year, for both fixed and floating foundation windfarms, HLP believes project developers will struggle to meet demand based on current logistics practices and equipment provision.
In 2030, when 54.9GW of windfarm capacity is expected to be installed, HLP estimates that the market will require 28 ring cranes with the capacity great enough to handle these larger units. In 2050 when 87.1 GW of windfarm capacity is expected to be installed, HLP estimates that the market will require 43 ring cranes.
Jacket and monopile windfarm projects, with either floating or fixed foundation usually require two ring cranes – one at each fabrication and marshalling/loading-unloading installation location or a minimum of one located at one location.
Only where there is very shallow water depth, or where small, low capacity monopiles are to be used are they not required. All floating foundations require a ring crane during the turbine installation stage at quayside.
HLP’s estimate of the demand for lifting capacity large enough to handle the next generation of windfarm logistics make no allowances for any growth in demand from the oil and gas, nuclear or construction sectors.
Nor does it include additional commitment for offshore wind projects, other than that already forecast. Critically, no allowances are made for any ring crane requirement for fixed turbine tower pre-assembly, foundation handling or foundation fabrication.
Pre-assembly of 10MW wind turbines in marshalling ports regularly involves handling complete towers weighing 350-400t and 100m high using crawler cranes. The larger components expected in future for 15MW and 20MW wind turbines will have sections that will weigh 1,000 tonnes and be 135m high.
There is a baseline assumption that crawler cranes will be able to handle these installs but preliminary investigation shows they will not be capable of handling sections with these higher weights safely. In addition, most port areas do not have the ground bearing capacity which can exceed forces of 130 tonnes per sq m. Instead, for turbines of 15MW and upwards, ring cranes will be required for marshalling and pre-assembly.
Fabricators will also need to think creatively about improving efficiency, especially if developed economies are going to be able to fabricate competitively in future. We believe the process can be more efficient otherwise the industry will not be able to keep up with the volume or schedule of larger turbine installation plans. Without bigger thinking, current plans could remain just that.
A Sustainable Solution
With demand for lifting and logistics support set to dwarf the capacity of existing or mass produced cranes – even the largest crawler cranes – it’s clear the market needs a new solution.
Windfarm component manufacturers don’t propose the use of ring cranes for the practical reason that the few that might be available are too expensive to deploy. There are currently nine such ring cranes in operation, all built for nuclear power and the oil and gas industries. The downturn in conventional energy prior to the invasion of Ukraine means around three are currently employed on offshore wind projects.
HLP’s concept advocates for a circular arrangement of towers, using a new ring crane design to lift and connect the towers together for a single lift onto the transporter vessel. Applying innovation to crane design and operations enables HLP to provide very high capacity lifting with shorter mobilisation/demobilisation timelines. This reduces quay rental costs and provides flexibility for developers or contractors.
HLP believes windfarm developers don’t need to change their construction programmes, just use a partner that can creatively support their project. Using a ring crane will mean simplified mobilisation and assembly of greater numbers of higher capacity turbines while avoiding double handling or tandem lifting.
Safer and Smarter
The growth in size of turbines has obvious safety implications too. As component sizes increase, developers and OEMs need a safer, more efficient methodology to scale up marshalling and handling of turbines. Safety is at the centre of HLP’s approach to windfarm logistics, whether for components, equipment or people, we think risks should be reduced as far as possible.
By reducing the dock space, working time and equipment required for crane mobilisation, component assembly and deployment, we can help developers align their HSQE strategies with project deadlines while managing the increase in demand.
Until now, the windfarm industry has managed by transferring legacy knowledge, technology and processes from construction and oil and gas into this new sector. Going forward, windfarm construction will demand specialised logistics and handling for component shipping, assembly and load out.
This change is coming but the industry discussion is only just beginning to happen. We’re keen to start before the industry reaches a log jam in deployment and installation. Alternatives to current practice are available but there is a need for fresh perspectives, bigger thinking and new methodologies in this sector.