Further development on the FLAG will focus on several key areas:
- Operating Voltage
Design improvements that increase the operating voltage dramatically increase the power output of a FLAG. Prototype FLAGs have conductive circuits mounted on the outside surface of the plastic film, which is open to air. This allows parasitic conduction of electricity across the surface of the plastic, particularly at high humidity. This effect can be virtually eliminated by improving the construction of the FLAG and encasing the conductors completely within the insulating film.
The current prototypes typically operate at approximately 500 V, but by encapsulating the conductors and increasing this to 2500 V, the FLAG will be approximately matched to the available energy of the wind. As rotary type electrostatic generators routinely reach voltages in excess of 250000 V, 2500 V is an attainable development target which would make the technology well matched to wind power applications.
Power harvesting circuits already exist that are suitable for use in the FLAG, such as the simple harvesting circuit successfully used in the prototypes. Switched-Capacitor-Converter technology has also been recently developed, appropriate for transforming FLAG output to useful voltages and currents. (Switched-capacitor-convertors based on fractal design for output power management of triboelectric nanogenerator | Nature Communications). Switched-Capacitor-Converters are efficient, inexpensive, and the authors found them to be 12% the mass of a conventional transformer.
There have been recent advancements in printed electronics technology, such as printed diodes and transistors. In the future, all the electronics required for both harvesting and power conversion could exist within the flexible film.
- Airborne Applications
FLAG technology is the lightest weight power generation solution for airborne power generation research. High altitude winds are stronger, and more consistent than ground level winds, but the heavy coils, bearings, and support structures of conventional wind generators make them ill suited to airborne applications. Multilayer FLAG arrays can serve as the aerodynamic surfaces of high power generation kites, or can otherwise be suspended below high altitude balloons. The high voltage, low current output is well-matched to the lightweight conductors required in these applications.
By optimizing the aerodynamics, both the oscillating frequency and operating wind range can be increased. The oscillating frequency is directly related to the output current, and power output. On the demonstration FLAG, the frequency at 20 km/h windspeed is approximately 5 Hz, however no optimization efforts have been made to improve this.
- Improved Materials
Improved materials will improve the performance of the FLAG. Materials with high dielectric constant, dielectric strength, high resistivity, and low adsorption of humidity will have the highest performance. Special surface treatments can also reduce any buildup of charge on plastic surfaces, and further improve surface resistivity.
- Reduced Mass
The FLAG cut-in wind velocity is also related to the mass of the wind generator. It is expected that more advanced manufacturing methods and materials will achieve cut-in windspeeds below 10 km/h.
- Alternative Applications
The highly modifiable form factor and reliable oscillation mechanism of the FLAG has potential for applications in sensors, flow measurement, space, nanotechnology, environmentally friendly buildings and structures, and other applications.