https://www.windtech-international.com/editorial-features/airborne-wind-energy-the-game-changer
By Kristian Petrick, Secretary General, Airborne Wind Europe, Belgium
1 Like
Can you paste the text here or link to a different source so we don’t need to make an account on that website to read it?
The text below is from the same website. It was accessible to me by updating my account.
Europe and other areas of the world need to harness all those renewable resources that can be sustainably and viably accessed. Airborne wind energy, alongside established wind technology, should be considered as one of the key solutions to the world’s energy decarbonisation challenge.
By Kristian Petrick, Secretary General, Airborne Wind Europe, Belgium
Airborne wind energy (AWE) is wind 2.0 – a game-changing solution accessing the large untapped wind resource potential at altitudes which cannot be reached by established wind technology. It enables more energy to be extracted at lower carbon intensity and eventually also at lower cost. Airborne wind devices convert energy from the wind without needing a tower and a large foundation.
The association Airborne Wind Europe was founded in 2018 by AWE technology developers and universities active in this field. The main objectives are to raise awareness of this new technology and to join forces as a sector in order to get AWE recognised in policy, regulation, industry and society.
How Does it Work?
A control system steers the kite or glider so that it flies stably on a cross-wind trajectory, which results in a high pulling force on the tether. The tether is connected to a base station on the ground or to a fixed or floating platform in the case of offshore applications. There are three main AWE concepts:****
Ground-gen: A tether is wound around a winch connected to a generator located in a containerised ground station. There are two phases in a cycle. Electric power is generated in the traction phase, in which the kite flies out in figures of eight or circles, pulling the tether which is reeled out, turning the winch and with the electric machine acting as a generator producing electricity. In the retraction phase the electric machine is used as a motor to reel in the kite before it flies out again, starting the next cycle. The energy used for the retraction is less than 20% of the energy generated in the traction phase.
Fly-gen: The kite is rigid and hosts on-board turbines with generators and power electronics. The kite is reeled out and flies cross-wind figures of eight, and the on-board turbines convert the wind energy into electricity, which is transferred down through the cable to the ground station.
Rotary: Rotary AWE systems consist of a stationary soft kite that keeps a structure of tethers and airfoils airborne. The airfoils rotate around a common axis. On the ground, the tethers are linked to a generator and make it rotate, thus producing power through torque.
Benefits
AWE offers a multitude of benefits:
- Opening new areas for energy from wind. AWE allows access to a large wind resource potential at heights above established wind turbines. Flying up to a height of 600 metres allows access to higher wind speeds, which has a significant impact on energy production due to higher capacity factors.
- Delivering more energy per square kilometre. AWE has a higher power density than established wind technology on the same site with the same nominal capacity, potentially reaching up to 60% more power on sites with good wind resources.
- Providing energy at lower cost. By also harvesting the larger wind resource potential at higher altitudes, AWE will be viable on sites which are not viable or accessible for established wind technology. AWE will be able to directly compete with onshore wind in the mid-2030s.
- Lower environmental impact. AWE has a roughly 40% lower carbon intensity than established wind technology, fundamentally because it uses much less material – some concepts achieve a reduction of up to 90% of mass. This results in higher security of the supply chain and also benefits in terms of logistics as port and road infrastructure requirements are much lower – AWE systems can be shipped in regular 40ft containers. First studies show that the impact on birds and bats is reduced as AWE systems fly higher than most species. If there is no wind, the kites will land, thus reducing visual impact.
The Sector
At the moment, Airborne Wind Europe has 15 members, including 10 technology developers from Germany, Italy, the Netherlands, Norway, Switzerland, the UK and the USA.Airborne Wind Europe is a member of WindEurope, the voice of the European wind industry. There are still many people – even in the wind industry – that have not heard about AWE and the opportunities it brings for the whole energy sector.
Since the end of 2021, Airborne Wind Europe has been an Operating Agent of the new AWE Task 48 of the International Energy Agency Wind Technology Collaboration Programme, supported by 11 countries. The aim of this platform is to build a strong community that works together to identify and overcome the barriers to deployment of AWE systems. Airborne Wind Europe provides a structured forum for international collaboration among researchers, policymakers, regulators, suppliers and users to exchange needs, ideas and experience.
Airborne Wind Europe and its members are involved in a number of projects co-funded by Interreg North-West Europe and Horizon Europe: MegaAWE is preparing the ground for a joint test site in Ireland and for upscaling AWE systems; MERIDIONAL will do multi-scale modelling for wind farm design, performance assessment and loading, including data and cases from AWE sites; and JustWind4All is focusing on social acceptance, a topic that the sector takes very seriously and where solid research is needed to understand how locals and other stakeholders perceive this new technology.
Milestones
Currently, the main focus of the industry is on developing and improving onshore devices. For AWE, a big milestone was achieved in 2021 when SkySails sold the first commercial 150kW system to Mauritius. In 2023, it is planned to carry out the first flights at the Bangor Erris test site in Ireland.This is just the beginning because kites are expected to grow into the megawatt range in the years to come. For the future, offshore applications are being considered by many developers, especially mounting devices on vessels or floating platforms.
However, Airborne Wind Europe has learned the lesson that scaling too quickly is risky; therefore, all its member companies are developing systems in the 100 to 200kW range as the first commercial products, which can be combined in wind farms of a few megawatts.
****
Looking Ahead
In a recent white paper [1], BVG Associates has calculated that if AWE follows the same growth curve as established wind energy, the sector could reach up to 177GW by 2050 and in a more ambitious scenario even as high as 271GW. Regarding the public funding needed to reach these goals, BVG estimates that over the next 15 years, € 5 billion of public support will be needed to realise the net benefits of AWE, comprising € 4 billion for project electricity price support and € 1 billion for industry development support. The extra price support would see AWE break even with established wind technology by the mid-2030s. The technology is already at a cost level of about 20€ct/kWh, making it competitive with diesel-generated electricity (like on islands or remote areas). But it is crucial to give AWE the same opportunity to get connected to the European electricity grid as has been given to other renewable technologies.Conclusions
The AWE industry is at the brink of commercialising the technology and getting it onto the deployment curve. That is why Airborne Wind Europe is very active in trying to get AWE included in European and national policies and regulation as well as in energy strategies. Airborne Wind Europe is also actively looking for joint test and demonstration sites in Europe where its members can fly 24/7, generating high numbers of operational hours to further improve the systems and make them ready for global markets: onshore grid-connected, remote on- and off-grid, nearshore and offshore-floating. AWE is poised to become one of the pillars of the future energy system.
- Further Reading
https://airbornewindeurope.org/wp-content/uploads/2022/10/BVGA-Getting-Airborne-White-Paper-220929.pdfBiography of the Author
Kristian Petrick has been Secretary General of Airborne Wind Europe since 2022. He started as an industrial engineer at Siemens Power Generation before becoming a consultant for renewable energy focusing on policies and regulation. Kristian has been active in the AWE sector for the last six years. He recently started kitesurfing to experience the power of kites first hand.Tags: * Airborne Wind Europe
1 Like
From the article:
It is interesting to note that the author considers the scalability of kites based on their size rather than the use of networked kites.
The description begins by a “stationary soft kite” then continues with a “structure of tethers and airfoils airborne”. Although in a different sense from the previous example if networked kites were applied, such a structure could be called “networked kites”. The difference _ whose border is not watertight _ is that in the case of the “rotary” structure, the airfoils are somewhat like the blades of a conventional wind turbine and are appreciated as a whole, whereas in the previous example, the terms “networked kites” refer to a set of kites, each unit of which could operate on its own, while the “rotary” structure forms an assembly called a rotor.
This is not a criticism of the article, but rather an attempt to see how things are seen for autonomous units capable of forming a whole (example crosswind networked kites), and for a set of multiple elements (example a rotor). Probably the author is showing some realism.
I think the better definition would be power per ground station. Or maybe also extended in some way to designs using «earth as a spar, EaaS»
The text is a good example of trying to organize actual implementations of AWE by how they are built. This will eventually fail. The better way is to organize them by principle. Bounding for systems that are producing then reel in with less tether tension, hovering for those with more or less fixed tether length.
—
Bounding: A tether is wound around a winch connected to a generator located in a containerised ground station. There are two phases in a cycle. Electric power is generated in the traction phase, in which the kite flies out in figures of eight or circles, pulling the tether which is reeled out, turning the winch and with the electric machine acting as a generator producing electricity. In the retraction phase the electric machine is used as a motor to reel in the kite before it flies out again, starting the next cycle. The energy used for the retraction is less than 20% of the energy generated in the traction phase.
Hovering: The tether length is fixed during production. The kite or a network of kites flies in a pattern mostly perpendicular to the wind. The first typical design has the power extracted by placing wind turbines on the wing and then transferred to the ground using conducting tethers. The kite is rigid and hosts on-board power electronics. The other typical design would have multiple kites in a network and then transfer the power using rotation applied though a soft shaft, and with the power generation equipment placed on the ground.