Think of ‘wind energy’ and it’s likely your mind will conjure up a field (or sea) of wind turbines. But there are a great number of other potential ways to harness the enormous power of the wind, with as much as 95 terawatts (TW) remaining to be developed onshore, and offshore having ‘an even larger resource potential’ according to IRENA (the International Renewable Energy Agency). One such example involves that favourite wind-powered toy which has entertained generation after generation, the kite.
‘The idea first surfaced in 1975, but the material technology for the kites and the tethers was insufficient, and the microprocessors required to control the system were in their infancy,’ explains David Ainsworth, spokesperson for Kite Power Solutions (KPS). Today, however, the idea of using kites to generate renewable energy from the wind is taking off, albeit slowly, with the recent granting of consent for a KPS kite power technology test and development site in West Freugh, Scotland, described as ‘the preferred location’ by Ainsworth. ‘We believe that our project in West Freugh is the first environmentally permitted permanent site in Europe, if not the world,’ he adds.
Founded in 2011 in Burnham-on-Crouch, Essex, KPS aspires to ‘develop a low-cost solution to harness energy from the wind using kites’. Such technology works by flying twin kites, attached to a generator, in strong winds as high as 450m above the ground. Specially designed to fly in a circular looping path, the kites can reach over 100mph in 20mph winds, generating strong aerodynamic lifting forces. At full-scale, the 40m kites have a two to three megawatt capacity, about the same as a 100m-tall conventional turbine.
With the highly fertile ground available for the development of wind energy, and KPS the only UK-based enterprise out of the handful of global players exploring the opportunities presented by kites, the opportunities potentially available from this technology seem significant. ‘We plan to deploy these in arrays, just like conventional wind turbines,’ explains Ainsworth, adding that the ideal base for where this technology could be located is ‘very much the same as for conventional horizontal axis wind turbines for resource, topography and footprint.’
One extra advantage kites have over permanent wind turbines is their small scale and portability, which, like solar technology, allows for temporary and/or localised community-ownership schemes. ‘We can pack a 500kW system into a single 40ft ISO container,’ says Ainsworth. ‘The target is to have the system deployed and operational – as long as there is an electrical connection – in less than a day. We can thus use single systems in isolated, off-grid communities.’
As could be imagined with anything flying as high as 450m, KPS has required constant consultation with the Civil Aviation Authority (CAA) regarding research at its current test site in Bradwell-on-Sea, Essex, which is on the approach path to Stanstead, Luton, London City, Heathrow and Gatwick airports. ‘The latest drafts of drone legislation from the European Aviation Safety Agency (EASA) enables a process by which tethered kites can be approved for operation,’ says Ainsworth.
The first kite system flying at West Freugh is expected in April 2017. Whether the flying of such kites to generate clean energy ever ends up provoking the same levels of anger directed towards traditional onshore wind turbines remains to be seen.