Energy at great heights
Ampyx Power’s AWES (Airborne Wind Energy System) is a tethered rigid wing drone connected to a generator on the ground. The drone steers itself across the wind in a repetitive pattern at an altitude of up to 450 m. The aircraft creates a pull in the tether that causes the winch to rotate and drive the generator like a dynamo. Once the tether has been reeled out to its maximum length, the aircraft glides back towards the platform, while the tether is retrieved under low tension. Then the process is repeated.
The system accesses the higher and more powerful winds above 200 m, requiring much smaller foundations and much less material overall. It greatly increases the availability of sites for cost-effective harvesting of wind energy.
While Ampyx Power is building its pre-commercial demonstrator, the commercial version is already on the drawing board. With a subsidy from TKI Wind op Zee two research projects, AKKA and Daedalus, have started. The aim of the projects is to de-risk the development of a megawatt-scale system and allow for a cost-effective design.
After having built and tested various prototypes, Ampyx Power now flies a small prototype with a wingspan of 5 meters at its test centre in The Netherlands. The subsequent prototype with a 12-meter wing is currently being built and will be tested from next year to demonstrate autonomous operation and safety. In the meantime, Ampyx Power started the design for the commercial successor.
To be cost-efficient the commercial model needs to be scaled up to a considerable size aircraft that at the same time is very agile. Such a type of aircraft does not yet exist. Ampyx Power collaborates with NLR (Netherlands Aerospace Centre) for this special innovation. Together they look at the aircraft design, the aerodynamic properties and the software tool development.
The commercial model will be developed for the replacement market of the first-generation offshore wind turbines in Europe, when they are at the end of their lifespan. Existing foundations can be reused to place small platforms. From there, the aircraft can be launched and landed for maintenance or repair.
An essential component of the system is the cable, ‘tether’, which connects the aircraft to a winch that is located on the platform. The tether will have to wind and unwind around the sheaves of the generator hundreds of thousands of times a year. Therefore, Ampyx Power, in partnership with DSM, will work on a tether that is safe, durable, strong, and keeps maintenance and replacement costs to a minimum.
The Daedalus-project involves both developing the mathematical models needed to design and test optimized AWES tethers and building a test setup for scaling up tethers for megawatt-scale application. The tether will be designed, built and tested in a setup that mimics a realistic operational environment.
This article is part of the series Project in the Spotlight. Discover more projects here.