David Foxwell reflects on the potential – and potential for cost reduction – of airborne wind energy generators such as Alphabet’s Makani and others now under development.
Earlier this month OWJ featured Makani, the company that is now an independent business within Google parent company Alphabet, that is to demonstrate its energy kite from a floating foundation offshore Norway.
After five years of development, Makani is partnering with Shell to bring energy kites to the offshore environment. The company has been working on kites that harness energy from the wind for several years and has teamed with Shell to take the concept offshore.
This is not the only time OWJ has looked at the potential of airborne systems. In 2018, German utilities EnBW and EWE OSS and Leibniz University teamed up with SkySails Power to develop an airborne offshore wind energy system.
Together the companies plan to develop and test a fully automated airborne wind energy system based on using kites that can take advantage of greater wind speeds and higher levels of energy than a bottom-fixed offshore wind turbine.
At the 2018 OWJ conference, Mike Blanch, an associate director at BVG Associates, told delegates that he believed airborne offshore wind energy systems were a potentially disruptive technology that could have a major role as the offshore wind energy industry continues to evolve. Citing a number of potential technologies that could play a role in the long term, Mr Blanch highlighted work under way at Kite Power Systems in the UK. You can see a video in which he discussed kites and other technology here.
Kites such as these or ‘airborne wind energy generators’ as they should correctly be called, capture wind energy by flying a tethered device across the wind to produce lift and drag. Energy is passed down the tether electrically or mechanically – some systems, such as Makani, use onboard generation, and others use ground-based generation.
Wherever the electricity is generated, one of the key advantages of airborne wind energy generators is that they do not need to be supported by large platforms and are, potentially, less expensive in the long run than large offshore wind turbines.
Experts at the Offshore Renewable Energy (ORE) Catapult have also been looking at airborne wind energy generation, and believe it has the potential to compete cost-effectively in the market.
ORE Catapult innovation manager Stephanie Mann analysed the potential of the technology and compared its levelised cost of energy (LCoE) with conventional offshore wind, the LCoE of which has fallen from £142/MWh (US$185/MWh) in 2010/11 to nearly £50/MWh (US$65/MWh), largely as a result of factors such as larger turbines reducing the cost per megawatt installed, and more efficient operating costs.
Airborne wind is currently an emerging technology, and at smaller scales costs are higher than market value at over £100/MWh (US$130/MWh), but I expect that to change.
In what she said was a conservative calculation, Ms Mann found that a hypothetical 6-MW offshore airborne wind turbine could achieve an LCoE of £30/MWh (US$39/MWh), largely due to the reduced weight and lower materials costs of the generator, and an increased capacity factor from steadier, higher wind speeds.
Airborne wind still faces many challenges, with the earliest estimates of market entry around 2030, but if the reduction in costs Ms Mann highlights are possible then I believe there’s every incentive to continue to pursue development of the technology.
As I’ve remarked on many occasions with regard to new technology for offshore wind, the opportunity to test it in a realistic environment is essential, so I’m pleased to hear that the ORE Catapult is designing testing strategies for UK-based airborne wind developers and working with AWEurope, the association of the European airborne wind energy industry, to provide input from the offshore industry as dialogue with developers of airborne wind energy generators develops.