A conventional wind turbine is, in engineering terms, an expensive solution to a specific constraint: the need to hold a generator and rotor assembly at a fixed height above the ground while it captures wind energy. The tower — which typically accounts for 20 to 30 percent of a turbine’s total cost — exists entirely to solve that positional problem. The blades and nacelle are the active energy-capturing components; everything below them is support infrastructure.
Now consider an alternative framing: what if the generator didn’t need to be held at height by a fixed structure? What if a tethered flying device could reach the same altitude — or higher — using far less material, capture wind energy through its aerodynamic motion, and transmit that energy to the ground through a tether or conductive line? This is the premise of airborne wind energy, a field that has attracted significant research investment, produced genuine technical demonstrations, experienced a high-profile failure, and is now rebuilding toward commercial viability with a more realistic understanding of what the technology requires.
The Physics Case
Wind power increases with the cube of wind speed — doubling wind speed yields eight times the power. Winds at altitudes of 200 to 500 meters are substantially stronger and more consistent than at the 80 to 150 meter hub heights of today’s largest conventional turbines. The International Energy Agency has estimated that high-altitude wind resources are technically enormous — far exceeding current global electricity demand — but conventional towers cannot economically access them.
The material efficiency argument for airborne systems is compelling. A tethered kite or drone flying in crosswind patterns generates tension in the tether proportional to the apparent wind speed — which, for a kite flying figure-8 patterns across the wind at typical speeds, can be five to ten times higher than the ambient wind speed. This aerodynamic amplification means that a relatively small, lightweight flying device can generate significant tether tension, which drives a ground-based generator. The ratio of power output to material mass can, in principle, be far higher than for a conventional turbine — Kitepower’s cofounder Roland Schmehl has estimated 90 percent less material for comparable power output.
A 2024 paper in Wind Energy Science by Joshi and colleagues provided a rigorous analytical model for estimating the net power output of fixed-wing ground-generation airborne wind energy systems, documenting that current prototypes range from small research platforms to 600 kW demonstrators and validating the theoretical power curve models against field data.
The Makani Story: A Necessary Detour
Any honest account of airborne wind energy must acknowledge Makani Technologies. Founded in 2006 by kiteboarding enthusiasts with a bold hypothesis, acquired by Google X in 2013, and shut down in 2020 after 13 years and hundreds of millions of dollars of investment, Makani’s trajectory is the most important data point in the field — both for what it proved and for what it failed to achieve.
Makani’s M600 was a 26-meter wingspan carbon composite aircraft with eight onboard wind turbines, capable of automated takeoff, transition to crosswind flight at approximately 300 meters altitude, and controlled landing — all without human intervention. It demonstrated sustained crosswind flight generating power, flew successfully in the North Sea off the coast of Norway in a floating offshore configuration, and validated the core technical concept. What it could not demonstrate was an economically competitive path to commercialization. The structural complexity of the onboard turbines, the reliability challenges of operating sophisticated autonomous aircraft in harsh marine environments continuously, and the difficulty of scaling to cost-competitive power output proved longer and harder than the team had hoped. Alphabet shut the project down in 2020 and released all of Makani’s technical work, patents, and flight logs as open-source material for the broader airborne wind community.
The Makani closure was not a verdict on airborne wind energy as a concept. It was a verdict on one specific design approach — onboard turbines on a large, complex aircraft — under the economic conditions of 2020. The field has learned from it.
The Current Landscape
The companies continuing airborne wind energy development have taken different paths from Makani’s approach, most notably by keeping the generator on the ground rather than on the aircraft.
Kitepower, a TU Delft spinoff, uses a flexible membrane kite — simpler and less expensive than a rigid aircraft — connected to a ground station by a single tether. The kite flies in figure-8 patterns during a power stroke, pulling the tether and driving a generator, then reels back in during a recovery stroke using a fraction of the energy produced. Kitepower’s 30-kW Hawk system produces enough power for approximately 50 homes and fits in a standard shipping container — a form factor explicitly designed for remote and off-grid applications where the logistical complexity and cost of conventional turbine installation is prohibitive. The company is developing a 100-kW Falcon system targeted for market in 2025 or 2026, with a 500-kW system envisioned beyond that.
SkySails Power uses a large soft kite to propel a drum generator, focusing on remote island and off-grid markets. Ampyx Power’s AP-3 rigid-wing glider tugs a tether connected to a ground generator. The diversity of approaches reflects a field still searching for the optimal technical configuration — and that search is proceeding with the benefit of Makani’s open-sourced technical heritage.
The Niche Market Hypothesis
The most credible near-term commercial path for airborne wind energy is not direct competition with utility-scale conventional wind in favorable wind sites — where the economics of large conventional turbines are well established and hard to beat. It is accessing locations where conventional turbines cannot operate: deep offshore waters where floating platforms are too expensive, mountainous terrain where installation is impractical, remote communities where the logistics of transporting and erecting large tower sections are prohibitive, and locations with regulatory restrictions on tower height.
As Roland Schmehl noted in a 2024 IEEE Spectrum profile: “The power of airborne wind is that you have a much lower material footprint than a wind turbine or solar PV. This means a lower environmental footprint, which also means that you could go to areas which are more sensitive.” Two-thirds of coastal waters globally are too deep for fixed-bottom offshore wind and economically challenging for floating platforms. Islands and remote Arctic communities pay extraordinarily high prices for diesel generation. These are the markets where airborne wind energy’s combination of mobility, lower material requirements, and altitude access could be genuinely competitive.
What Remains Challenging
The reliability requirements for commercial wind power are demanding: systems are expected to operate for 20 to 25 years with high availability, in all weather conditions including storms, ice, lightning, and extreme temperatures. A tethered kite or aircraft must either survive these conditions aloft or have reliable, rapid automated landing and relaunch capabilities — both of which add engineering complexity and cost. The airspace regulatory environment for autonomous flying devices operating continuously in one location is not yet well defined in most jurisdictions. Grid integration for systems with variable output profiles requires careful power electronics design. Public acceptance of flying devices in persistent operation over residential or natural areas involves considerations beyond the purely technical.
The fundamental economic challenge remains: the cost per kilowatt-hour from airborne wind systems must compete with rapidly falling costs from conventional wind and solar. For utility-scale applications in good wind sites, that competition is difficult. For niche applications in challenging locations, the calculation is more favorable, and that is where the near-term commercial case is being built.
Why It Matters
The energy transition requires renewable generation to reach locations and contexts that today’s technology cannot serve economically. Remote communities dependent on diesel, island nations exposed to energy price volatility, deep offshore sites with exceptional wind resources, and regions with regulatory or terrain constraints on conventional turbines all represent unserved markets where reliable, low-carbon generation would have significant impact. Airborne wind energy, if it reaches commercial viability in these niches, does not need to compete with utility-scale wind to matter. It needs to provide an economically viable alternative where no good alternative currently exists — and that is a more achievable target than displacing the conventional wind industry.
Closing Human Dimension
The kitesurfers who founded Makani in 2006 were working from a genuine intuition: that the dynamics of a kite flying in powerful winds contained enormous energy potential that conventional engineering was not capturing. They were right about the physics and wrong about the timeline and cost structure. The field they helped create is now advancing more carefully, with a clearer view of which markets the technology can serve and which it cannot. That is not failure — it is the normal trajectory of a technology working through the gap between a compelling physical principle and a commercially viable product.
Sources
1. Joshi, R., Schmehl, R., and Kruijff, M. (2024). “Power curve modelling and scaling of fixed-wing ground-generation airborne wind energy systems.” Wind Energy Science 9, 2195–2215. https://wes.copernicus.org/articles/9/2195/2024/
2. IEEE Spectrum. “Kitepower’s Wind Energy System Fits in a Shipping Container.” (January 2024). https://spectrum.ieee.org/micro-wind-power-kitepower
3. IEEE Spectrum. “Alphabet’s Wind Energy Kites to Fly Offshore.” https://spectrum.ieee.org/alphabets-moonshot-wind-kites-to-fly-offshore
4. Makani / X Development. “Makani: A Google X Moonshot.” Project archive and documentation. https://x.company/projects/makani/
5. Yale Environment 360. “After a Shaky Start, Airborne Wind Energy Is Slowly Taking Off.” (February 2022). https://e360.yale.edu/features/after-a-shaky-start-airborne-wind-energy-is-slowly-taking-off
6. AWESCO. “Airborne Wind Energy Explained.” Technical overview including prototype specifications. https://awesco.eu/awe-explained/
7. Energies Media. “Flying kites are no longer science fiction: Norway tests a 600-kW prototype to power 300 homes.” (January 2026). https://energiesmedia.com/flying-kites-are-no-longer-science-fiction-600kw/
Idea generated by Grok. Article expanded with Grok, substantially rewritten with Claude Sonnet 4.6. Published at artificialideas.org.
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