This article comes from Wind Energy Update, and is authored by Kerry Chamberlain. The full piece can be read here.
New data has revealed the impact of leading-edge erosion on energy production and advanced protection packages now offer long-term performance gains and optimized maintenance windows.
As the wind-power industry matures, greater focus is being placed on Leading-edge Erosion (LEE) as technology advancements and growing data on losses point to potential performance gains.
LEE occurs when dirt, moisture, salt, or bugs create cracks or cavities on the first blade edge in contact with the air. Such defects compromise the aerodynamics of the whole blade.
Historically, many operators have not invested heavily in LEE after comparing the gains from leading-edge maintenance against the associated availability losses. Operators are now looking to maximize returns from higher-performance turbines in an increasingly competitive O&M market.
In addition, fleet owners must mitigate losses associated with aging turbines and respond to fresh environmental challenges in emerging markets. The latest test results show LEE can have a startling impact on plant profitability.
“Our testing demonstrates that even minor LEE can cause Annual Energy Production (AEP) loss of almost 2% and a potential lifetime loss of up to 7%,” Dan Molyneux, Manager of Blade Services at Vestas, told Wind Energy Update.
Initial data from the UK’s ORE Catapult Blade Leading-edge Erosion Program (BLEEP) has also indicated LEE repairs of moderate erosion can raise AEP by 1.5 to 2%. Studies by the U.S.’ Sandia National Laboratories have shown onshore AEP can drop by as much as 5% in cases of light erosion and fall up to 25% due to heavy erosion.
Wind asset owners are starting to: “Better accept the industry research showing the AEP loss due to LEE and, consequently, are giving it more attention,” Molyneux said.
Up until now, one of the biggest challenges for commissioning LEE work has been demonstrating the associated energy production loss, Molyneux noted.
Larger blades, faster tip speeds, and severe weather conditions magnify the impact of LEE and a growing bank of data is supporting action.
Higher performance blades have come at higher cost and this has increased the importance of LEE mitigation. In the onshore market, rotor diameters now surpass 100 meters with tip speeds over 200 mph.
New markets are presenting fresh environmental challenges and turbine aging is also a key factor to consider, Francisco Garcia, O&M Manager at Enel Green Power, noted.
“We are building in new locations with aggressive conditions such as India and Brazil where we don’t have as much knowledge around soil impact upon blades,” he said. Enel has a 6.8 GW global wind portfolio, including 2.4 GW in the U.S. Last month the company signed master supply agreements to build a further 3.5 GW of U.S. capacity.
For large fleet operators, performance degradation must be factored into investment decisions, Garcia said. “[Around] 50% of our fleet is more than 10 years old, so we will experience aging problems with erosion whilst rectifying the legacy of unmaintained blades.”
Changes to localized weather patterns are also impacting performance, Claus Roedsgaard, Head of Blades at Siemens, said. “The UK has experienced five years of extreme weather over the last decade, resulting in a 20% increase in rain, hail and snow. This does have an impact on the LE, which will vary from site to site.”
Read the full article here.
Filed Under: News, O&M, Projects