Fast curing leading edge protection at low temperatures
Driven by the need to reduce global warming and contamination of the air and water, power companies around the world are shifting from fossil fuels to renewable sources of energy
This shift is also reflected in the trends of investments where, according to a UN report, the global expenditure on renewable energy infrastructures hit $272.9 billion in 2018, far outstripping investments in new fossil fuel generation.
To earn a return on investment, it is important to ensure that the infrastructures are maintained and that any issues affecting their operation are promptly managed. While the growing use of renewable energies is great for the environment, replacing the assets of a facility can incur in high costs.
The maintenance issues of the wind power industry
Wind power is one of the growing forms of renewable energy and by its very nature, the process of capturing and generating power involves exposure to the elements.
The blade tips of a turbine can revolve at up to 190mph (300km/h) in widely fluctuating temperatures.
When encountering external agents such as intense sunlight, rain, snow, hail, dust, and dirt, the leading edge of the turbine blade can get severely damaged. The erosion and impact damage of the leading edge create uneven surfaces on the blades which subsequently decrease the wind turbines’ energy output in the long run.
Evidence suggests that the damage to the leading edges of a turbine blade can lower the annual energy production (AEP) of the wind power site, with energy losses ranging between 4% to 20% when the damage is acute. Replacing the blades is not the most cost-efficient option as a new set of blades can cost the equal of 20–25% of the original price of the wind turbine. This, when combined with the downtime costs during the replacement process, can result in excessive costs.
Damaged wind turbine blade
As an alternative, repairing and protecting the blades instead of replacement, is a much more economical option, due to a minor blade repair costing only 10% of a replacement blade’s expense.
Finding cost-effective solutions to apply in-situ, are easy to apply and are fast curing at low temperature whilst ensuring a long-term erosion and corrosion protection is not always an easy task.
Newly developed system
Belzona has recently formulated a new system specifically formulated for LEP which holds the main features mentioned above. Belzona 5721 is a two-component coating, suited for in-field applications due to its fast cure time and ability to be brush-applied in a single coat. The system also offers excellent adhesion to Glass Reinforced Plastic (GRP) and protection from UV degradation.
This solution has been recently applied to protect eroded leading-edge blades at a wind power site in Minnesota, US.
Case study – LEP application in Minnesota, US
In September 2019, a blade maintenance company located in Minnesota, US, reached out to Belzona to enquire about a solution which would not require long curing times and would perform well in cold weather.
The client needed a solution which would repair the eroded leading edges of the turbine blades and was negatively impacting the overall energy production of the facility.
Minnesota typically has a continental climate with cold and windy winters and the client was looking for a solution which could be applied under those conditions. In fact, most leading-edge protection solutions need higher temperatures to be applied and fully cure. As the temperatures dropped down to 40° F (4.4°c) there were no products in the market which could solve the problem.
The application procedure
Belzona had the appropriate solution which could be easily applied on-site without using specialist tools and could cure in cold and humid temperatures. The leading edges of 30 different turbines were to be coated at two of the client’s windfarms and 180kgs of Belzona 5721 were purchased to protect all the 90 blades.
The weather conditions during the application were 50°F (10°C) with 71 per cent humidity. After preparing the surface using a mechanical orbital sander, the pitting and loss of surface on the leading edge was resurfaced with a filler and rebuilt to its original dimensions.
Once the reconstructed surface was smooth and even, a coat of Belzona 5721 was then applied using a brush.
Application of Belzona 5721
The substance cured in only six hours and permitted the turbines to go back in service immediately after. The fast cure of Belzona 5721 and in-situ application allowed the client to significantly lower downtime costs. Furthermore, the one-coat system and no need of specialist tools ensured that costs associated with labour were also minimised.
In conclusion, Belzona 5721 left the client very satisfied as it allowed to repair and protect the blades rapidly even in low temperature condition without waiting for a warmer weather window. This allowed the site to resume the normal operation of assets and save time and money.
Turbine leading edge protected with Belzona 5721