Innovative materials + design: The equation for efficient, cost-effective wind power
While wind energy offers significant advantages as a clean energy source, broader adoption of this clean energy faces challenges related to cost and developing new approaches for higher energy output. We’re pushing boundaries with advances in polyurethane materials that enable better blade design and higher energy output. With our aim to make the world a brighter place, we’re eager to put our materials to work and demonstrate that wind energy can be a more competitive energy source.
Propelling wind energy forward with collaboration
Collaboration is needed along the entire wind energy industry value chain to make wind energy more cost competitive with more traditional energy sources. Covestro joined forces with WINDnovation, a leading designer of rotor blades for multi-megawatt wind turbines, to evaluate the potential benefits of using polyurethane as a laminate matrix in wind turbine blades. Together, our organizations conducted a study that assessed these materials in applications that required greater blade speed and higher output to help solve industry challenges.
The study focused on two key areas:
- Lighter-weight blades, which require less raw materials and lead to better product performance
- Faster production, which depends on shorter infusion and curing times, leading to reduced energy usage
These advancements can lead to a lower levelized cost of energy (LOCE), a measurement of a power source that allows the comparison of different methods of energy generation on a consistent basis. If the production cost for blades is 10 to 15 percent less, along with lower weight, and consistent performance is combined with increased blade length, LOCE could be further reduced.
Advanced materials for next-gen wind blades
The wind industry is moving toward longer blades, leading to advances in materials to support new blade design requirements, including an innovative polyurethane infusion resin from Covestro that offers several advantages over traditional glass/epoxy laminates.
This new polyurethane resin offers fast infusion and fast curing performance in production of the very large fiber composites used to form the blades. The initial viscosity of polyurethane resin is significantly lower than epoxy resin, which allows the advantage of fast infusion during wind blade production. The lower viscosity also enables better flow characteristics than epoxy, which can result in greater infusion speed.
The curing behavior of polyurethane resin offers additional advantages, allowing for almost complete curing in less than four hours. Pre-curing time can be even shorter, potentially saving valuable processing time and increasing manufacturing capacity utilization.
Wind offers a viable alternative to traditional fossil fuels, but there are still greater efficiencies that must be achieved to boost its cost competitiveness. Working alongside industry experts like WINDnovation, we’re showing that it’s possible to overcome these hurdles with a fast, cost- efficient production process that results in lighter, longer blades with a higher wind energy output. This new spin on wind power is an important step forward in broadening adoption of this more sustainable energy source.
Polyurethane resin makes a powerful difference
Several blade properties were evaluated as part of a benchmark study conducted by WINDnovation to analyze the use of polyurethane resin and explore how blade design can be enhanced by maximizing the characteristics of polyurethanes. The study was based on two blade scenarios:
- A one-to-one replacement of the epoxy resin with polyurethane resin without any form of optimization
- A polyurethane-optimized design to capitalize on the mechanical property advantages associated with the use of polyurethane
Calculations showed direct resin substitution of polyurethane for epoxy in a 1:1 scenario decreased blade weight slightly by 1.1 percent. As a result, interfiber failure, a critical measurement of failure in rotor blade design, and deflection safety margins improved considerably.
A polyurethane-optimized design adjusted the blade structure according to the new strength properties of the material. For this design, the number of layers was reduced in the spar cap area of the blade and the number of layers at the root of the blade was adjusted. The reduction of layers enables a faster and easier infusion process.
A polyurethane-optimized blade design also resulted in a lighter blade with blade weight reduced considerably by 5 percent. This mass reduction leads to a reduction in fatigue loads, particularly for large wind turbines. This enables WINDnovation and other rotor blade designers to not only further reduce the blade mass, but also the mass of other wind turbine components (especially the hub) in proportion.
- PU resin enhances wind blade production with faster infusion and curing speeds
- Faster, more efficient production lowers production costs
- PU resin results in lighter, longer and stronger blades with higher energy output