Nanotechnology-enabled
wind turbines offer a chance for improved wind generation efficiency and
subsequent drops in cost and emissions. Wind energy companies Siemens Gamesa
and Orsted have been collaborating with academic researchers at UK universities
Sheffield, Durham, and Hull for R&D. The goal is to make wind turbines more
reliable, more efficient, lighter, and cheaper. There is also potential to extend
turbine life and reduce maintenance needs. Nanotechnology includes the development
of nanomaterials, manufacturing techniques, and new designs.
Improved Direct-Drive Generators (Gearless Turbines)
Of particular
note is a new design for the direct-drive generator, first introduced in
1991, which eliminates the need for a gear box. Gear boxes are often the most
vulnerable part of a wind turbine, requiring expensive maintenance and repairs.
As a result, a direct-drive generator eliminates 50% of the components of a
wind turbine. Further improvements in materials and manufacturing can make
turbines more efficient and lighter. In addition to those improvements there
are also new methods to better predict and monitor the health of turbine
components. These improved monitoring techniques involve data analytics and
physics.
Also known as
gearless turbines, direct-drive turbines eliminate the gear box and its components.
Direct-drive turbines have been around for a decade or more and are especially
used in offshore wind deployments. However,
there are some disadvantages. One is that they require magnets made from rare
earth elements derived mainly from China which has a monopoly on mining, and
processing of REEs as well as on manufacture of the neodymium magnets. According
to Net Zero Drive:
“In a conventional, gear-driven turbine, the rotor
blades spin a shaft which drives gears that drive a generator. In a direct
drive design, the drive shaft spins the generator directly, causing it to spin
at the same speed as the turbine blades.”
“With a
conventional generator, the gearbox dramatically increases the speed at which
the generator spins so as to generate high amounts of power. With a direct
drive turbine, a larger generator is used to generate the same power from a
slower rotation speed.”
Direct-drive
systems use permanent magnet generators (PMGs) while gear box driven turbines use
electrically excited synchronous generators (EESGs). PMGs are often used for
small power turbines. For larger power turbines greater than 7MW output there
is a need for an additional gear box which makes power losses higher and
efficiency lower. Thus, direct-drive is the choice for these turbines. The direct-drive
generator must be larger and heavier in these higher output turbines due to
higher torque requirements. PM generators work better with partial loads which is
common since wind is a variable resource.
One advantage
of direct-drive over convention gear box turbines is that kinetic energy that
is lost in the gear box is retained in the direct-drive design, leading to
greater efficiency. Another advantage is that the direct-drive design uses
permanent magnets rather than electromagnets and this along with the elimination
of the heavy gear box reduces weight. This is especially important in offshore
wind farms where the turbines are supported on a floating buoy. Direct-drive is
simpler to maintain, reducing costs. This simplicity in maintenance
requirements is especially important for offshore wind since these turbines are
more difficult to access. The EU has been developing a direct-drive system that
utilizes super conductor technology. The newest high output (over 10MW but up
to 15MW with boost) turbines developed by Siemens Gamesa and GE are using
direct-drive and the industry as a whole is moving to direct-drive. The DOE has
been involved in improved direct-drive design as well.
According to the article in Engineering.com:
1. “The costs for the offshore support structure for
direct-drive wind turbines is lower due to its lighter weight.”
2. “Direct-drive has more potential for further
improvement. Experts argue the gearbox wind turbine is almost at its maximum
efficiency point, while the direct-drive turbines have more possibilities for
improvement.”
3. “Direct drive is more efficient for future higher
power rating wind because the gearbox wind turbines require extra stages of
gears, leading to more gearbox losses.”
Nano Treatments and Nano Sensors
Newly developed
nano-coatings can improve aerodynamics, reduce drag, and increase energy
capture according to Nano Magazine. Nano sensors enable real-time monitoring.
They note that further advancements in nanomaterials, nanocoatings, and
nanosensors are expected. According to Chapter 43 of the 2017 book Nanotechnology
for Energy Sustainability entitled Techno-Commercial Opportunities of
Nanotechnology in Wind Energy:
“The wind turbine
blades cycle lifetime can be increased by using nanocoatings and nanopaints;
weight can be reduced by using nano-based prepregs; efficiency can be increased
by the use of nanolubricants, nanofluids, nano-enabled wires and cables; and
nanosensors can be used for nondestructive testing of composites. The
commercial success of nano-enabled products for structural and functional
applications parts in the wind energy sector has been slow and currently being
used mainly as the structural nanocomposites in rotor blades.”
According to a December
2020 paper in the International Journal of Energy Applications and
Technologies: An overview on the use of nanotechnology in the renewable
energy field, lightweight nanomaterials can increase wind turbine
efficiency. Carbon nanotubes used in wind turbine construction are both lighter
and more durable. The lifetime of the turbines can be increased with these nanomaterials.
Indeed, nanotechnology is used in many forms of energy, particularly renewable
energy: hydrogen, fuel cells, tidal energy, geothermal drilling applications,
solar applications, and much more. Future improvements and new applications
are likely.
References:
Unleashing
the Potential of Next-Generation Wind Turbines for a Sustainable Future through
Nanotechnology. Nano Magazine. June 20, 2023. Unleashing the Potential of
Next-Generation Wind Turbines for a Sustainable Future through Nanotechnology —
Nano Magazine - Latest Nanotechnology News (nano-magazine.com)
Universities
develop ways for wind turbines to generate more energy, Sean Barton. University
of Sheffield. March 22, 2023. Universities
develop ways for wind turbines to generate more energy | News | The University
of Sheffield
Techno-Commercial
Opportunities of Nanotechnology in Wind Energy. Abstract. Chapter 43 of
Nanotechnology for Energy Sustainability. Edited by Prof. Baldev Raj, Prof. Marcel Van de
Voorde, Yashwant Mahajan Dr., February 1, 2017. Wiley‐VCH Verlag GmbH & Co. KGaA.
Techno‐Commercial
Opportunities of Nanotechnology in Wind Energy - Nanotechnology for Energy
Sustainability - Wiley Online Library
An
overview on the use of nanotechnology in the renewable energy field. Kazım
Kumaş and Ali Akyüz. International Journal of Energy Applications and
Technologies 7(4) [2020] 143-148. Anoverviewontheuseofnanotechnologyintherenewableenergyfield764240-1187965.pdf
Development
effort focuses on two types of wind turbines, is there a dominant choice? Edis
Osmanbasic. Engineering.com. April 7, 2020. The
Future of Wind Turbines: Comparing Direct Drive and Gearbox | Engineering.com
The
Power of Nanotechnology. Pradeep Haldar. Power Engineering. July 1, 2007. The Power of Nanotechnology (power-eng.com)
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