[{"command":"openDialog","selector":"#drupal-modal","settings":null,"data":"\u003Cdiv id=\u0022republish_modal_form\u0022\u003E\u003Cform class=\u0022modal-form-example-modal-form ecl-form\u0022 data-drupal-selector=\u0022modal-form-example-modal-form\u0022 action=\u0022\/en\/article\/modal\/7222\u0022 method=\u0022post\u0022 id=\u0022modal-form-example-modal-form\u0022 accept-charset=\u0022UTF-8\u0022\u003E\u003Cp\u003EHorizon articles can be republished for free under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence.\u003C\/p\u003E\n \u003Cp\u003EYou must give appropriate credit. We ask you to do this by:\u003Cbr \/\u003E\n 1) Using the original journalist\u0027s byline\u003Cbr \/\u003E\n 2) Linking back to our original story\u003Cbr \/\u003E\n 3) Using the following text in the footer: This article was originally published in \u003Ca href=\u0027#\u0027\u003EHorizon, the EU Research and Innovation magazine\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003ESee our full republication guidelines \u003Ca href=\u0027\/horizon-magazine\/republish-our-stories\u0027\u003Ehere\u003C\/a\u003E\u003C\/p\u003E\n \u003Cp\u003EHTML for this article, including the attribution and page view counter, is below:\u003C\/p\u003E\u003Cdiv class=\u0022js-form-item form-item js-form-type-textarea form-item-body-content js-form-item-body-content ecl-form-group ecl-form-group--text-area form-no-label ecl-u-mv-m\u0022\u003E\n \n\u003Cdiv\u003E\n \u003Ctextarea data-drupal-selector=\u0022edit-body-content\u0022 aria-describedby=\u0022edit-body-content--description\u0022 id=\u0022edit-body-content\u0022 name=\u0022body_content\u0022 rows=\u00225\u0022 cols=\u002260\u0022 class=\u0022form-textarea ecl-text-area\u0022\u003E\u003Ch2\u003EFlying high: how drones on cables are expanding the scope of wind energy\u003C\/h2\u003E\u003Cp\u003EThe square drone shakes in the wind with the Swiss Alps in the background. At first glance, this looks like a holiday video of a drone enthusiast, except that the drone is generating energy when it flies. A cable connects it to the ground and when the wind pulls up the drone, it releases the cable through a winch, and energy is produced. This is a test of an airborne wind energy-system by the company Skypull from Switzerland, and it might be a key technology in shaping the future of renewables.\u003C\/p\u003E\u003Cp\u003EIn attempts to tackle climate change, wind energy is probably going to key. By 2027, the \u003Ca href=\u0022https:\/\/windeurope.org\/newsroom\/news\/wind-to-become-eus-largest-power-source-well-before-2030-according-to-iea-executive-director\/\u0022 target=\u0022_blank\u0022 rel=\u0022noopener noreferrer\u0022\u003EInternational Energy Agency\u003C\/a\u003E estimates that wind turbines will be the number one source of energy in the EU. Yet that also comes with a range of downsides: turbines are big, expensive and hard to build.\u003C\/p\u003E\u003Cp\u003EThat\u2019s why a range of scientists and startups are now experimenting with so-called airborne wind energy. Designs differ greatly, but generally it means using a blimp, kite or drone, which is attached to the ground with a cable, to produce energy. Airborne installations such as these can access stronger winds by flying higher than conventional wind turbines, while also, in theory, being cheaper and easier to install, compensating for some of the weaknesses of ground-based wind.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EDeployability\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003E\u2018Airborne wind will cost less compared to traditional wind energy,\u2019 said Nicola Mona, co-founder of Skypull. \u2018There\u0027s an economic driver. But there\u0027s also the deployability. Traditional wind turbines are running into space constraints, while airborne systems can work in a larger variety of places.\u2019\u003C\/p\u003E\u003Cp\u003ESkypull\u2019s design is a hybrid between a multicopter drone, and a regular fixed-wing aircraft. The craft looks like a box, with four wings attached to each other in a square and rotors on the corners. This allows it to take off in difficult spots but at higher altitudes fly like a regular glider, which generates lift through its wings. Right now the team is still testing out the concept with smaller designs of around 1.25-metre wingspan, but eventually they want to build a drone with a total 17-metre wingspan.\u003C\/p\u003E\u003Cp\u003EThe startup took off when the three founders \u2013 Mona, Marcello Corongiu and Aldo Cattano \u2013 met. \u2018When I first met Aldo, he presented the idea to me, I remember my first reaction was: \u201cThis is crazy, this will never work\u201d,\u2019 said Mona, an aerospace engineer who had been involved with several startups before. Yet, over time he became more convinced about the potential. \u2018I looked at the documents and numbers, and checked everything, which convinced me.\u2019\u003C\/p\u003E\u003Cp\u003EAfterwards, the company participated in several startup competitions, winning a slew of them. Currently the team is completing the design of their craft. \u2018We have a few working prototypes,\u2019 said Mona. \u2018They don\u0027t look like the final product, but they\u0027re good enough to prove the concept.\u2019\u003C\/p\u003E\u003Cp\u003EWhich, if it will work, could generate a sizeable amount of energy. Mona notes they are currently reaching a peak output of 3 kilowatts per metre of wingspan, while their initial commercial product planned for 2022 will reach 100 kilowatts for approximately 6 metres of wingspan. From this, a larger system will be built that generates 1 megawatt, lower than an onshore wind turbine, which averages around 2.5 to 3 megawatts, but interesting for remote locations and off-grid operations around the globe.\u003C\/p\u003E\u003Cp\u003E\u003Cblockquote class=\u0022tw-text-center tw-text-blue tw-font-bold tw-text-2xl lg:tw-w-1\/2 tw-border-2 tw-border-blue tw-p-12 tw-my-8 lg:tw-m-12 lg:tw--ml-16 tw-float-left\u0022\u003E\n \u003Cspan class=\u0022tw-text-5xl tw-rotate-180\u0022\u003E\u201c\u003C\/span\u003E\n \u003Cp class=\u0022tw-font-serif tw-italic\u0022\u003E\u2018Our system begins where wind turbines end.\u2019\u003C\/p\u003E\n \u003Cfooter\u003E\n \u003Ccite class=\u0022tw-not-italic tw-font-normal tw-text-sm tw-text-black\u0022\u003EPim Breukelman, commercial director of Ampyx Power\u003C\/cite\u003E\n \u003C\/footer\u003E\n\u003C\/blockquote\u003E\n\u003C\/p\u003E\u003Cp\u003EAnother team betting on airborne wind is Ampyx Power from the Netherlands. They employ around 50 people to get their design in the air. Just like Skypull they are producing a fixed-wing, drone-like design. But Ampyx Power\u2019s craft takes off with a catapult from the ground, and looks more like an aircraft. Their pre-commercial demonstrator AP3 has a wingspan of 12 metres, with two fuselages attached to it, rear rudders and a stabiliser. This test craft could generate 150 kilowatts of power.\u003C\/p\u003E\u003Cp\u003E\u2018This is a whole new generation of wind-energy technology,\u2019 said Pim Breukelman, commercial director of Ampyx Power. \u2018We fly an aerodynamic wing connected to a cable, that in turn is connected to a generator on the ground. We fly at an altitude between 200 and 450 metres, where we find constant and powerful winds.\u2019\u003C\/p\u003E\u003Cp\u003EThe designs of Ampyx Power and Skypull might look wildly different, but both work according to similar principles. They take off in a mechanised way, climbing using engines, until they reach a certain altitude, generally around 200 meters. There they use the lift-capacity of their wings to act more like a kite or glider, getting pulled up by the wind. The cable holding the aircraft is attached to a winch, which gets pulled out when the wind pulls up the drone. This generates rotation, and thus energy. When the winch is stretched to its limit, the drone automatically steers itself down to start the process again.\u003C\/p\u003E\u003Cp\u003EAmpyx Power will test their ninth prototype at the end of the year in Spain, which will be followed by tests in Ireland. They are also working on a 2 to 3 megawatt commercial product, for onshore, offshore and eventually floating generation of energy.\u003C\/p\u003E\u003Cp\u003E\u2018These aircraft can (eventually) be flown from floating platforms, and are suited for places at sea where current wind technology isn\u2019t profitable or technically feasible,\u2019 said Breukelman. \u2018In a few years this system is supposed to be operational.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EComplementary\u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003EYet for all the advantages of the airborne version, Skypull and Ampyx Power don\u2019t want to replace regular wind energy. \u2018Our system begins where wind turbines end,\u2019 said Breukelman, noting that their aircraft flies at higher altitudes than turbines can reach, and are complementary to them. He also says that airborne wind might be useful to extend the life of wind turbines at sea, whose foundations might serve as starting pads for airborne wind drones.\u003C\/p\u003E\u003Cp\u003ENicola Mona agrees. \u2018We will always need a mix of energy sources,\u2019 he said. \u2018There will never be one single renewable source replacing everything. We need a combination of hydro, traditional wind, airborne wind, solar and geothermal.\u2019\u003C\/p\u003E\u003Cp\u003EIn the meantime, airborne wind technology is also evolving. Until a few years ago, kite-like designs predominated, similar to large versions of the kites flown by children at the beach. But today, the fixed-wing designs, that look more like drones, are on the rise.\u003C\/p\u003E\u003Cp\u003E\u2018Airborne wind started out by adapting what was already flying,\u2019 said Mona. \u2018So it\u2019s logical kites came first. But in the end fixed-wing designs offer better aerodynamics and energy potential.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ESafety \u003C\/strong\u003E\u003C\/p\u003E\u003Cp\u003ESafety is, however, something that airborne wind companies are still struggling with. If airborne wind wants to generate energy at scale they will need to let their designs fly autonomously in the wind for days or even weeks. Software systems will need to control these craft during these periods, and make them operate under changing weather conditions. And all of that without them crashing down.\u003C\/p\u003E\u003Cp\u003E\u2018Software is our biggest challenge right now,\u2019 said Mona. \u2018You want these systems to be fully autonomous, which isn\u2019t easy.\u2019\u003C\/p\u003E\u003Cp\u003EAnd then there\u2019s also the regulation. Regulation for unmanned aircraft is still lagging behind in many countries, also affecting airborne wind companies.\u003C\/p\u003E\u003Cp\u003EAnd finally there\u2019s the question of PR. \u2018Over time we saw that people don\u0027t like wind turbines,\u2019 said Mona, referring to how in countries like Germany or the Netherlands wind turbines aren\u0027t being built because of local opposition.\u003C\/p\u003E\u003Cp\u003E\u2018They\u0027re big, cumbersome and have a visual impact. And airborne wind also runs the risk of a public backlash, because they fly over people\u0027s heads. So we will need good storytelling, and an emphasis on safety, to prevent the same reaction we saw against wind turbines.\u2019\u003C\/p\u003E\u003Cp\u003E\u003Cem\u003EThe research in this article was funded by the EU. 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