Researchers at Universidad Carlos III de Madrid (UC3M) in Spain have developed software to help make airborne wind energy (AWE) systems more efficient and effective at generating wind energy. AWES harvest wind energy using lightweight aircraft such as kites or drones. In AWE ground generation schemes, the aircraft is tethered to an electrical generator and uses the tension of the tether to move the generator. In fly generation schemes, wind turbines on the aircraft generate electrical energy and transmit that energy to the ground through a conductive tether.
At UC3M, scientists have developed flight simulation software that help engineers better design and optimize AWE aircraft. The software was recently presented in the peer-reviewed Applied Mathematical Modelling.
“The simulator can be used to study the behavior of AWE [systems], optimize their design and find the trajectories maximizing the generation of energy,” said Ricardo Borobia Moreno, aerospace engineer from the Flight Mechanics Area at the Spanish National Institute of Aerospace Technology (INTA) and a researcher for the project.
Watch a video about the simulator here:
“The aim of this simulation system is to reproduce how these systems will behave in flight, in order to predict as accurately as possible how much energy we can generate, and its reliability and safety in flight,” Moreno said in the video. “We gauge its position, the speed of the kite and the speed of the air.”
To test and enhance the software, the team created a flight testbed for AWE systems. The testbed is made up of two kitesurf kites that are equipped with instruments that measure position and speed of the kite, attack and sideslip angles, and tether tensions of the system. The team used the testbed for multiple flights in order to gather experimental data which was then used to validate software tools for the simulator.
AWE is a new and growing field in renewable energy technology. High-altitude airborne energy generation systems, which marry aviation technology with renewable energy generation, have attracted new investments from sources ranging from the European Commission to Google over the past few years. “AWE [systems] are disruptive technologies,” said Gonzalo Sánchez Arriaga, Ramón y Cajal research fellow at the department of Bioengineering and Aerospace Engineering at the UC3M. “They combine well-known disciplines from electrical engineering and aeronautics, such as the design of electric machines, aeroelasticity and control, with novel and non-conventional disciplines related to drones and tether dynamics.”
Proponents of the technology think airborne energy generation offers plenty of benefits as modular and “deployable” renewable energy systems. AWE systems have low material and installation costs, and are mobile because they are easily transported. They also operate at altitudes above 500 meters from the ground, where the wind is generally more intense and reliable.
“We believe systems like these can be placed in a container and in the case of a catastrophe, such as an earthquake, or where energy needs to be generated in specific place, where fuel cannot be supplied, for example, these kinds of devices can be used,” Arriaga said.
But AWE technology is still in the early phases of development. A recent study published by the European Commission concluded that companies furthest along in development in AWE systems are only at a technology readiness level (TRL) of 4 or 5, as indicated by prototypes. It concludes that AWE systems have a long way to go before they are ready for commercialization. That makes UC3M’s software all that more interesting, as it can help streamline some of the technology development. The software, which is owned by UC3M, is registered and can be freely downloaded and used for research purposes by other groups.
To learn more about AWE systems, read this (free) technology review: Airborne Wind Energy Systems: A review of the technologies