More and more energy is required each year to meet the growing demands of technology in modern-day society. While fossil fuels are still the dominant energy source, more focus is being placed on renewable energy harvesting technologies to try and combat climate change and global warming.

It’s taken a while, but many renewable energy sources are out there, some of which are more effective than others.

Nanomaterials have been enhancing different renewable energy technologies, from different energy storage devices all the way through to energy harvesting methods. They will be key for ensuring that the world gets enough energy should the switch towards a predominantly renewable energy society manifest.

Nanotechnology is also helping to bring about new energy harvesting architectures—such as wearable energy harvesters—that wouldn’t otherwise be possible with other materials.

Nanomaterials are bringing a number of benefits and innovations to the renewable energy space, but many still think the switch to nano-energy will not be cost-effective enough for large-scale commercialisation.

However, this is not true. It’s often the case that only a small amount of nanomaterial is needed to bring about performance benefits. While nanomaterials can sometimes be more expensive, the small amount required in each device or material system offsets the higher cost.

So, in the long run, there’s the potential to not only harvest more energy to meet the world's growing demands, but it could also be more cost-effective.

If renewable energy can become efficient enough to supply most of the world’s energy, then the world will have a much more cost-effective means of energy (so long as we can store it all—which nanotechnology is also helping within the creation of more efficient energy storage devices) that will not be reliant on maintaining large plants and paying for the mining and moving of fossil fuels.

Naturally, there will be other maintenance costs associated with maintaining renewable energy technologies, as well as the cost to source and main new materials for energy storage systems, but nanotechnology could help to bring a cleaner and cost-effective future—and it is doing that today.

Here, we look at two of the key renewable areas commonplace in society today—solar energy and wind energy—and how nanotechnology provides a platform to improve the status quo of these established technologies.

Nanotechnology's Pivotal Role in Advancing Solar Cell Efficiency and Innovation 

Solar cells are one of the biggest renewable energy areas where nanotechnology has made an impact.

Nanomaterials are being used to improve the absorption characteristics, charge separation, electron transport and power conversion efficiencies (PCEs) of solar cells. Nanomaterials have also been used as coatings to protect different solar modules from gathering dust and debris on the sun-facing surface.

The excellent electronic and charge carrier properties of a number of nanomaterials have been used to enhance the semiconducting photovoltaic junctions of solar cells. Likewise, despite their size, many nanomaterials (especially inorganic ones) are heavily resistant to thermal, photo, and chemical degradation, so they make excellent barrier coatings to protect solar cells from the elements.

Nanomaterials have also been behind many of the thin film solar cells that have emerged in recent years, including printable, rollable, and flexible solar cells. Nanomaterials (and nanoscale versions of bulk materials) are the only class of materials that are strong enough to be added into flexible polymers and bent while still possessing electronic properties that are good enough for the devices to function.

There are many areas where nanotechnology is innovating solar cells, and not just at the academic level. The number of types used grows yearly in terms of the materials used. It includes quantum dots, nanowires, nanostructured surfaces on bulkier materials, graphene and 2D materials, and more recently, thin-film perovskite materials (following on from the success of bulk perovskite materials).

Some examples of commercial innovation towards using nanomaterials in the solar cell space have come from Nanoco, Nanosolar, Great Cell Solar Italy, and Oxford PV.

There have also been a number of solar cells that have come out using graphene specifically because of the electronic and optical absorption properties that graphene possesses. There’s more expected to come out commercially in the coming years, but current manufacturers of commercial modules include ZN Shine, Freevolt and Grafmarine. There are also trials going on in Greece into graphene-perovskite solar cells (GRAPE) where a 40-module solar farm has been built.

The Nanotechnology Boost in Turbine Design and Efficiency 

Another big area of renewable energy is wind energy—as it is another elemental factor (alongside sunlight) that is abundant around the world.

Nanomaterials are highly beneficial for composite applications. You don’t need much material to bring about material performance and mechanical strength benefits and the finished composite is usually lighter than the composites created with other additive materials.

Nanomaterials are used for wind turbines to make light and strong composites for the turbine blades. Integrating nanomaterials into turbine composites is helping to improve the strength, stiffness, fatigue resistance, and durability of the turbine blades, which results in less wear and tear and downtime—due to a reduced need for maintenance.
The integration of nanomaterials into the turbine composites also dampens the vibrations, reducing noise and improving the stability of the turbine composites. This is something that is also seen when nanomaterials are used in aerospace composites.

But it’s not all about nanomaterials themselves. Nanofabrication and nanopatterning methods are helping to improve the aerodynamics of wind turbines by creating nanostructured surfaces that reduce the drag and turbulence of turbine blades.

The production of lighter composites with less drag also means that the turbine blades can move through the air more easily (and start moving quicker because they’re lighter), increasing energy production and energy efficiency compared to heavier and less streamlined turbine blades.

Another aspect of where nanotechnology is innovating the wind energy sector is through advanced barrier coatings that protect the turbine blades from the environment. Nanomaterials are inherently resistant to a lot of environmental stimuli, so they make excellent protective coatings.

A lot of the advancements in turbine design are still mostly confined to academia and trials. Advancements in the area have largely been kept behind closed doors, although a study was done about 10 years ago by AlphaSTAR in conjunction with the Office of Scientific and Technical Information in the US, which showed a lot of promise for nanomaterials in wind turbine blades.

The most commercial activity has come from wind turbine coatings. A couple of anti-ice nanocoatings have been developed over the years, including from Windgo and from a European Regional Development Fund (ERDF) collaboration that involved AIMPLAS and Siemens Gamesa Renewable Energies.

Conclusion

Nanotechnology allows innovations and advancements to occur in different clean energy technologies—including energy storage systems that can store the energy generated. More and more developments are emerging that are geared towards sustainable ways of harnessing and storing energy, and advanced materials are at the heart of it.

Not all advanced materials—such as bulk perovskites—are nanomaterials driving this innovation, but there are a lot of nanomaterials and nanofabrication technologies being utilised in the next generation of energy technologies because they’re offering ways to make devices more efficient with little material input.

Image

Author:

Liam Critchley

Specialist Freelance Chemistry and Nanotechnology Writer