Growing Role of Polymers and Plastics Used in Renewable Energy Sector

TAGS:  New Energy Solutions      Thermoplastic Composites      Cost Efficiency    

Renewable energy is at the forefront of the energy policy of all major economies. It not only helps to reduce the dependence on fossil fuel but also helps to reduce the negative impact on the environment and economy.

A major portion of greenhouse gas is carbon dioxide, pumped into the environment by industries, specifically the power sector. Major sources of carbon dioxide gas are the burning of fossil fuels in the production of electricity and heat in various industries.

Wind and Solar energy are key sources that can play a pivotal role in:

• Tackling global warming and
• Reducing reliance on fossil fuel for electricity production

According to International Energy Agency (IEA), solar PV and wind energy account for 86% of renewable energy installations in 2019.

In the wind energy sector, the length of the blade is crucial to improve the efficiency of the wind turbine. Larger the blade higher the power production capacity.

• In the last decade, wind turbine blade length has seen an increase from 60 meters in 2010 to 107-meter length (LM wind) in 2020. 
• The weight of the blade also increases with an increasing blade length and that can reduce the optimal efficiency of the turbine.

Here, polymer composite material plays a key role in reducing the weight and increasing the strength and efficiency of the turbine.

The use of polymer composites in renewable energy has played a crucial role in the development of the wind energy sector. It is widely used in structural components of the wind turbine. Composite materials offer various advantages, such as:

• Reduced weight compared to metallic structures
• Lower transportation and erection costs, and
• Lower maintenance costs over the lifespan of the structure

Let’s find out the growing role of polymer composites in wind and solar energy applications.

Polymer Composites in Wind Energy Applications

The wind energy sector is the major consumer of composite materials among renewable energy sources. The wind energy sector accounts for over 5% of electricity production globally. In 2019, the global new wind energy installations were 60,351 MW, which is 19.1% higher than the installations in 2018.

The wind energy is the second-largest consumer of polymer composite materials in 2019. The global polymer composites demand from the wind energy industry stand at 1,502.4 Kiloton in 2019. The polymer composites demand in the wind energy industry is expected to be 9.2% between 2020 and 2025. The composites are used in:

• Wind turbine blades
• Nacelles
• Towers, and
• Hubs

APAC is leading the race of the new installation of the wind turbine on the back of high installation in China and India. This is also reflected in the composite consumption which makes APAC the largest wind turbine composites market in 2019. China emerged as the world leader in wind energy installations, accounting for over 40% wind turbine installations in 2019.

Types of Composites in Wind Blade Manufacturing

The various types of composites used in manufacturing wind blades include:

• Glass fiber
• Carbon fiber, and
• Aramid fiber

The glass fiber composites hold the largest share in the composite's demand for the wind energy industry. Largely combination of E-glass or boron-free E-CR glass and liquid epoxy is used to manufacture wind turbine blade.

Currently, carbon fiber composites are mainly used in the spar or structural element of wind blades longer than 45m/148 ft. The manufactures have started increasing the use of carbon fiber composites as it gives higher stiffness and lower density than glass fiber composites. This allows a thinner blade profile while producing stiffer, lighter blades.

A 100m blade made entirely out of glass fiber composites can weigh up to 50 tons. Companies can achieve a 20 to 30% weight saving by using carbon fiber composites, which results in overall weight savings up to 15 metric tons.

For instance, Vestas has used carbon fiber in its composite wind blade manufacturing, which initially resulted in addition of 5m/16 ft in blade length without any additional weight gain. The increasing offshore wind energy installations are the key factor that will drive the demand for carbon fiber composites in the wind energy industry.

The high cost of carbon fibers has led to the use of hybrid fibers in wind turbine manufacturing. The demand for hybrid fibers is expected to grow rapidly as it provides cost competitiveness and improves mechanical property in large wind blades. Such hybrid fibers include:

• E-glass/carbon
• E-glass/aramid fibers

Basalt fiber, in combination with carbon fiber, is also emerging as one of the interesting hybrid fiber combination for wind blade manufacturing.

Key wind turbine blade manufacturers have been increasingly focusing on R&D to increasing blade length without increasing blade weight and costs. These manufacturers include:

• Vestas (Denmark)
• Goldwind (China)
• Seimens Gamesha (Spain)
• GE Renewable Energy (the US)
• Enercon (Germany), and
• Envision (China)

There are some challenges as well in replacing glass fiber composites with carbon fiber composites in the wind turbine blade. Carbon fiber composites have a relatively low damage tolerance, and its compressive strength is greatly affected by fiber alignment.

Further, molders encounter greater difficulty in achieving fiber wet-out during vacuum infusion; given this, wind blade manufacturers have tended to use more expensive pre-preg products.

Impact of Resin Systems on Composite Components

The adhesion of resin systems is important as it defines the mechanical properties of composites components. The major polymer resins used in the wind energy industry for manufacturing composite components are:

• Epoxy
• Polyester, and
• Vinyl Ester

The key factors driving the demand of epoxy resins versus other resins include:

• Epoxy resins have high strength to weight ratio, dimensional stability, high adhesion properties compared to polyester and vinyl ester resins.
• The shelf-life of epoxy resins is several years as compared while the shelf-life of polyester resins is six months only.
• Epoxy resins offer excellent moisture resistance properties when reinforced with fiber.

All these factors are driving the demand of epoxy resins over polyester and vinyl ester resins in wind energy applications. Though Epoxy will remain a key resin, polyurethane is expected to make rapid progress in the next 5 years as compared to epoxy resin due to its:

• Better mechanical properties
• Faster infusion speed, and
• Cost competitiveness

Moving towards this in August 2020, Covestro has announced to develop a 64.2-meter-long wind turbine blade made completely of polyurethane.


Wind Turbine Blade Made of Polyurethane Developed by Covestro

Using gel coats in a wind turbine blade is gaining momentum in the wind energy industry. The use of in-mold gelcoat not only reduces labor costs significantly but also provides better protection to trailing edges. The commonly employed material for spinners, nacelle covers, and nose cones is polyester or glass with a polyester resin-based gelcoat. Epoxy and polyurethane resin-based gelcoats can also be employed due to their superior mechanical properties.

The core material is another area where the polymer has made significant in roads over last decades. PVC foam and PET foam are rapidly replacing Balsa wood in the manufacturing of wind turbine blades. PET Foam is the fastest growing core material in the wind energy industry as it is a low cost and lightweight material than Balsa wood.

Various companies are focusing on the development of PET foam as it gives environment friendly alternative as it can be made with recyclable PET bottles. The major manufactures of PET foam for wind energy applications are:

• 3A Composites (Switzerland)
• Aramcell International SA (Luxembourg), and
• Gurit Gmbh (Switzerland)

Are Thermoplastic Composite Blades the Future of Wind Energy Industry?

The disposition of decommissioned wind turbine blades is a key issue before the wind energy industry. Recycling existing commonly used thermoset composites materials in wind blades is a major challenge.

Research activities are going on to achieve new recyclable lightweight thermoplastic composite materials to replace thermoset composites. These key benefits of thermoplastics include:

• Recyclable at the end of a blade's life.
• They are less expensive to manufacture.
• They enable thermal joining and shaping, which is a lighter and potentially more reliable manufacturing process.

The leading research laboratory, associations and government agencies are working together to achieve these benefits. For instance, National Renewable Energy Laboratory (NREL) is a national laboratory of the U.S. Department of Energy that shows achievements in energy savings by recycling retired materials and using thermal welding practices. The repairability, reduced space and manufacturing time requirements of thermoplastic blades make them cost-effective compared to thermosetting composites. The NREL had shown technoeconomic impacts¹ of thermoplastic blades which is going to change the wind blade material world in the coming years.

Leading thermoplastic resin manufacturers, such as Arkema, demonstrated the recyclability of small Elium parts on a laboratory scale, focusing on a new phase that is inline aiming to demonstrate the recyclability at a lower cost of increased blade length of Elium composites.

During the initial research, a 60-65m thermoplastic blade costs around 4%-5% less than an equivalent epoxy blade. Even though the thermoplastic resins are more expensive than epoxy, but cost effectiveness is due to:

• Decreased capital costs
• Low cycle times
• Reduced energy requirements, and
• Labor costs

NREL Produces Wind Turbine Blade Components Using Arkema’s Thermoplastic Resin

With increasing focus on developing a high-performance thermoplastic wind blade, the next decade could be a turning point for the wind energy industry.

Polymer Materials in Solar Energy Industry

As per IEA, 114.9 GW of new solar power installations happened globally in 2019. The year 2019 shows a 12% growth over 2018 in terms of new installations. The solar energy constitutes around 3% of global electricity demand in 2019.

According to IEA, the new solar installations are expected to decline by 12% in 2020 as compared to 2019 installations, due to the Covid-19 pandemic. The solar installations are estimated to rebound as majority of the projects in pipeline are financed and can start construction as the pandemic situation gets normal.

As PV, Solar Thermoelectric Generators (STEG), PV/T, and concentrated or conventional PV systems integrated with STEG, STC, and energy storage can lead to an increase in the electrical and thermal energy generated and in system lifetime. Hence PV-based configurations and hybrid systems demand increased.

Due to the new advancements, solar technology is set to become lighter, more flexible, and applicable everywhere. These advances include:

• Floating solar farms
• BIPV solar technology
• Solar skins
• Solar fabric, and
• Photovoltaic solar noise barriers (PVNB)

In 2020, innovative residential solar technologies are in development stage, such as perovskite solar cells, which could soon be used to create solar paint.



Polymer materials have made significant progress in the solar PV Cells market. Polymer material are used in various applications in solar energy sector, such as:

• PV cells are encapsulated with polymer materials
• Solar panels are coated with UV coatings, and
• Anti-reflective coatings among other application

List of Polymers that Play an Important Role in the PV Cells Encapsulation

Ethylene vinyl acetate (EVA) Polyvinyl butyral (PVB) Polydimethylsiloxane (PDMS) Ionomer Thermoplastic polyurethane (TPU), and Polyolefin

This polymeric encapsulation holds the solar cells together and provides protection against humidity, dust, corrosion. The ethylene vinyl acetate (EVA) polymer material holds the largest share in PV cell encapsulation.

PV panels are coated with anti-reflective coatings, which help to increase the light absorbed into the PV cell. The mostly used materials for antireflective coatings are:

• Silicon nitride, and
• Titanium oxide

The anti-reflective coated PV panels is expected to grow at faster rate than the non-coated PV panels in the coming years.

Conductive polymer such as poly (3, 4-ethylenedioxythiophene) or PEDOT is also expected grow faster in the solar energy industry in the coming years due to its high stability and optical transparency in its conducting state.

Check Out the Polymers Used in Renewable Energy Industry