The challenges of lifting in the wind power sector
Ross Moloney, CEO of the Lifting Equipment Engineers Association (LEEA) CEO, raises awareness of some of the lifting issues involved in the wind power sector
Given the option, it’s likely that most lifting equipment engineers wouldn’t choose to ply their trade several hundred feet up a swaying pole, above a bleak moorland or raging sea, in a location expressly chosen for its high winds. But with wind power increasingly seen as an answer to both energy security and climate change, it is a growing requirement.
Training standards for offshore turbine work are set by the Global Wind Organisation, which is a non-profit body set up by the leading turbine manufacturers and operators. Mandatory training covers Sea Survival and Boat Transfer, Manual Handling, Fire Awareness, Working at Height, and First Aid.
It takes around five days, costs approximately €1,700 and is to be renewed every two years. Specific training requirements may also be imposed. This all adds up to a significant sum, so it is important that the right people are selected.
Inspections – the work involved
Two service engineers for each turbine can, in good conditions, inspect one or two turbines a day. The duration of each inspection can vary considerably depending not only on weather conditions, but also on the condition of the assets and their age.
Newer turbines have more equipment to inspect but on the other hand tend to have modern lifts to make access to the top of the turbine easier. Items to be inspected include service lifts, ladders, lifelines, hoists, davits, jib cranes and a whole range of lifting and man-riding anchor points.
Requests may also be made for Inspection of fire and auxiliary equipment, First Aid supplies, accumulator/pressure systems and so on. The largest, more modern turbines may have 140 assets to inspect – there might be 72 fall arrest anchor points alone. On smaller, older turbines will perhaps have 40 or 50 assets.
Stripping, inspecting, measuring and reassembling a lift can take three hours – with another hour to inspect up to 80 metres of latchway ladder. After inspection there may well be follow-up actions required – the client needs to know, and agree a course of action, straight away.
Lifting equipment challenges
Wind turbines are composed of a nacelle, a hub, carrying typically three blades, and a tower – onshore the latter is usually of concrete but offshore the tower or monopile, whether floating or fixed to the seabed, is generally of steel. These items are seriously big – a current offshore turbine may have a hub height of over 300 feet, and in future could be approaching 500 ft.
Blades can be over 60m long, and a blade/hub assembly is around 22,000 kg while a complete nacelle with generator may weigh 52 tonnes.
The industry has specific lifting and lashing equipment requirements in tower production, load securing during transport, tower installation, maintenance, and regeneration.
A wide variety of chains, shackles, slings, clamps, lifting and anchoring points are used, specified especially for offshore to cope with an aggressive environment. Installation, in particular, is a highly specialised business.
Components tend to be not only large but unwieldy so, for example, in the production of hubs and nacelles there are requirements for shackles and slings to present components at an angle during production processes while monopile production requires clamping systems to manipulate big steel plates and assemblies in confined spaces by only one operator.
Installation requires a variety of lifting frames and spreader beams, often of (relatively) lightweight lattice construction. As may be imagined, load monitoring by load links or load pin shackles is of critical importance. Maintenance requires the provision of very many anchorage points, usually in stainless steel for longevity, as well as appropriate PPE for staff.
At LEEA, we want to remind end users how important it is to use high quality suppliers who utilise experience and high-quality training, and who routinely develop innovative solutions. Look for the LEEA logo, because it offers operations in this sector assurance of safe and expert practice when it comes to procuring lifting equipment and services such as maintenance and inspection.
A LEEA member will be recognised globally as ‘competent’ having undergone a rigorous auditing process tailored to the circumstances of different industries – to uphold LEEA’s ‘gold standard’ and provide customers with the assurance of excellence.
Lifting Equipment Engineers Association (LEEA)