Turbine Blade Habitat, according to the UK-based manufacturer, GEV Group, can cut costs and improve blade upkeep, particularly offshore.
GEV Group already serves the oil and gas energy sector with activities such as industrial coatings and subsea equipment maintenance, and also provides specialist wind-turbine blade maintenance services.
Blade inspection and repair activities are commonly conducted either using rope access or a mobile platform. An inherent problem with these options, says GEV Wind Power projects director Alastair Gadney, is the inadequate protection for worker and blade against weather-related hazards including snow, rain, moist saline air, and low temperatures.
Yet, temperature and humidity are the two single most critical parameters when processing and curing composite materials during structural blade repairs and surface-related repairs including repainting, he explains. Direct exposure to weather and hard-to-control working conditions could delay essential repairs, but if these repairs are undertaken in sub optimal conditions long-term issues could manifest.
Leading-edge erosion is a major problem that will not go away easily, according to Gadney - especially offshore, where blade surfaces are subject to continuous bombardment by wave-swept water droplets. Repairs can quickly become costly, requiring service and/or transport vessels plus extra downtime hours when blades have to be removed, as Dong Energy recently announced it is doing for 91 of its 2.3MW Horns Rev 2 turbines. Any offshore-turbine blade damage, including any resulting from lightning strikes, must be properly addressed well before it develops into a major issue.
GEV Wind Power has become the first approved installation company trained in chemical giant BASF's new leading-edge protection system, called BASF Relest. This is a specific application that requires a processing range of 15-35 degrees Celsius, Gadney explains, which is where GEV's Turbine Blade Habitat can make a huge difference.
The Habitat is in essence a field-deployed structure that is loosely wrapped around a small section of the blade like a coat, sealed-off on top with the bottom section open. This provides a protective environment and sufficient manoeuvring room for service technicians, with all required tools and equipment attached inside the top section. The full device can be tailored for any blade access platform. When in position, it takes less than five minutes to inflate and secure around the blade.
Apart from the ability to control temperature, humidity and mitigate rain, Habitat ensures that any blade work is undertaken in optimum conditions. "This is currently the only way of guaranteeing that scheduled or reactive maintenance work can be completed without incurring unnecessary lost time due to inclement conditions," says Gadney. "Our O&M experience highlights that about 40% of planned maintenance days are cancelled due to bad weather and, of those 50% was for humidity or precipitation, which can now be mitigated completely."
Based on in-field data, he suggests that a minimum of five extra production days per year per turbine could be gained by using the Habitat device and when taking into account average O&M requirements.
"Habitat's material is lightweight, waterproof and robust, which enhances the flexibility of a matching blade access platform without constraining controlled working capability," Gadney says. "The platforms are deployable in around the same time it takes to set-up a rope access system and they offer considerably more flexibility than a crane or ground based mechanised platform system."
The product is awaiting patent approval and the intellectual property incorporates a "unique" top seal providing watertight interface between the blade and the Habitat. The seal is connected to the Habitat via waterproof extensions.
One key added benefit of the product is that it enables the entire length of a blade to remain shielded from the weather during an extensive repair action for curing and within a predetermined period.
"The Habitat structure is largely similar to what emergency aid organisations fly-in following human disasters," he adds. The company already uses similar structures in offshore oil & gas, where maintenance activities face the harshest of all environments irrespective of weather conditions. It was a natural progression to adapt this technology for offshore wind where conditions are largely similar, he concludes.