Flying kites deliver container-sized power generation
Kite-based wind generators that reel large kites in and out from a containerized ground station are being explored as an alternative to conventional wind turbines, especially for remote or off‑grid sites now reliant on diesel. Commenters dissect how these systems work—using controlled flight patterns to generate high tension on the outbound reel and much lower tension on the return—and weigh potential advantages such as access to stronger high‑altitude winds and lower material use against serious challenges in control algorithms, durability, maintenance, safety, and aviation constraints. Many see the physics as sound but remain skeptical that the engineering complexity, wear on kites and tethers, and land/airspace requirements can compete with mature, mass‑produced tower turbines except in narrow niches.
Principle of operation & physics
- Core mechanism: kite flies crosswind in figure‑8s while tether reels out, driving a ground-based generator; then kite is depowered and reeled back in using less energy.
- Several commenters note this feels “perpetual motion–ish” at first, but others explain it’s analogous to sailing, kitesurfing, or stern sculling: you can generate strong pull in one phase and much less in the return phase.
- Control of angle of attack and depowering (via brake/control lines) is key to reducing force during reel‑in so net energy is positive.
Comparison to other wind approaches
- Compared to Google’s Makani: this system is simpler—no airborne generators, just a flexible kite, ground generator, and reel-in/out cycle producing pulsed power (smoothed via batteries).
- Traditional turbines: critics say kites add complexity and maintenance to save some materials; proponents reply that they serve different niches (remote/off‑grid, hard-to-access sites, higher-altitude winds).
- Several ask why not put turbines on the kite; replies cite extra mass, cost, complex power cabling, crash risk, and unclear efficiency gains.
Use cases & economics
- Suggested niches: replacing diesel generators on islands and remote sites, disaster relief, temporary deployments, military field use.
- Some argue that where kites can work, standard horizontal‑axis turbines likely offer better long‑term cost and land use; others note lower structural mass and containerized deployment as economic advantages.
- Consensus: viability hinges on lifecycle cost, durability, and reliability, not on raw physics.
Engineering & control complexity
- Operating in all weather with autonomous launch/recovery and continuous figure‑8 control is described as very hard.
- Control may be amenable to reinforcement learning, but requires large datasets and robust models; reel motors must react quickly to gusts and direction changes.
Durability & maintenance
- Major concern: long-term UV, fatigue, and load cycles on kite fabric and Dyneema tethers; frequent replacement may be needed.
- Some hobby and sailing experience suggests modern nylon/Kevlar kites and ropes can last years with maintenance, but continuous, high‑duty operation is unproven.
Safety, land use, and aviation
- Large exclusion/flight zones mean people can’t be within a substantial downwind sector; land-use efficiency per kW may be worse than fixed turbines.
- Aviation concerns: tethers up to ~300+ m pose hazards to VFR traffic; mitigation might rely on operating in low‑altitude airspace and radio comms.
- Wildlife: potential for bird attacks on kites is raised; impact on birds and bats versus turbines remains unclear.