Harnessing the power of the sea
Experience gained within the established wind energy sector can be applied to ocean energy systems, in particular, highlighting the importance of building in reliability at a component and system level, says Phil Burge.
The goal for the maintenance of wind turbines has been to set in place a series of procedures that will increase efficiency by preventative measures. The aim of these procedures is to enable operators to minimise maintenance costs and maximise turbine availability, protect profits for operators and provide the rest of us with a supply of renewable, reliable energy. There is now great potential to apply some of this knowledge and experience to another burgeoning sector of the renewable energy industry where turbines are utilised and truly maximise the performance and reliability of ocean energy systems.
Globally, there are currently around 150 technology concepts in wave and 100 in tidal being developed; however this is still early days and only 10 to 15 of these concepts have progressed to an advanced prototype stage. The market today consists of first full-scale prototypes, with first small-scale farm installations in the planning phase. From 2020 onwards, it is expected that the industry will achieve commercialisation with arrays comprising hundreds of units deployed worldwide.
There are two main groups involved in this development; those that could be described as testing their devices in the 'bath tub' with a great need for venture capital, and the large OEMs and power companies that provide it by taking equity stakes in the companies they believe will be the future market leaders. For the manufacturers and providers of turbine components, the on-going task is to evaluate the different technologies and provide products and services that reduce the total cost of energy. The market demands that the technology performs reliably between maintenance interventions for up to five years and, even then, maintenance must be handled efficiently and with speed to keep cost at a minimum.
Development in bearing design to meet the needs of the wind industry has had to address the handling of minimal load conditions and quick acceleration and deceleration. These conditions can cause conventional bearings to suffer smearing due to high levels of wear, potentially leading to bearing failure. New high-capacity cylindrical roller bearings are therefore optimised with the addition of an inner ring cage guidance mechanism and a lower weight brass cage, for low inertia of the roller set.
Harsh environmental conditionsSKF High Endurance Slewing Bearings, with enhanced sealing capabilities and redesigned internal geometry, offer increased resistance to harsh environmental conditions in both wind and ocean energy. The SKF High Endurance Slewing Bearing was developed to meet the challenges of extreme weather, heavy loads, remote locations and increasingly powerful designs - just a few of the operational challenges affecting turbines. Featuring enhanced sealing capabilities and redesigned internal geometry, this next-generation bearing can help increase turbine reliability while reducing operating and maintenance costs.
The new internal bearing geometry in the cage and raceways reduces friction and increases turbine and pitch control performance. A new, polyurethane-based seal material can provide better resistance to ozone, UV and salt water, reducing wear and providing longer service life than traditional nitride-based sealing solutions. The seal design is less sensitive to ring deformation during operation, reducing grease leakage and water ingress to help improve robustness and lower maintenance costs.
By pooling the knowledge already gained from the marine, wind, oil and gas, and hydroelectric industries a range of wave and tidal solutions are being developed, from plain bearings to seals and condition monitoring. These solutions are already making significant improvements to the performance of ocean energy systems, protecting profits, boosting efficiency and supporting sustainability for us all.
Other News from SKF (UK) Ltd
Latest news about Rotary bearings