The wind engineer leading an international project to develop recommended practice for tackling leading edge erosion of wind turbine blades said offshore windfarms in Taiwan could be an especially good testing environment.
DNV GL senior wind engineer Amilcar Quispitupa, who leads the COmprehensive methodology for Blade Rain erosion Analysis (COBRA) project – a project that also includes 10 commercial partners, Vestas, Siemens Gamesa Renewable Energy, LM Wind Power, Ørsted, Mankeweicz, Akzonobel, Aerox-CEU, Polytech, Hempel and PPG – told OWJ that blades on offshore wind turbines in Taiwan may experience a particularly testing combination of high rainfall levels and other environmental conditions such as UV exposure, temperature, humidity and salt spray that may act as ageing factors of leading edge protection systems.
“Edge erosion isn’t only limited to the North Sea,” he said. “We are seeing erosion of leading edges in Asia, the US, Europe, Australia and other countries, on land and at sea.
“The level of erosion depends on several factors, including rain, material technology, application processes and the quality of those processes. Combined with larger rotors and higher tip speeds, this means that impact loads imparted to the leading edge of a turbine are often very high and, over time, lead to erosion.
“Rainfall levels and intensity also vary over time and according to the season, which affects the size of raindrops and their distribution. That is an important part of estimating potential damage,” Mr Quispitupa said.
“In the COBRA project we are looking at a generic approach to tackle erosion from the design point of view, taking into consideration material systems, rain loads, design and manufacturing practices. We are planning to complete the project this year and release recommended practice by July 2020.”
Mr Quispitupa said a range of solutions to leading edge erosion are being developed. These include materials developed by coating suppliers that can reduce the rate of rain erosion.
“There is currently very little experience with these new materials but so far from what I have seen the results are promising,” Mr Quispitupa concluded.