window.dotcom = window.dotcom || { cmd: [] }; window.dotcom.ads = window.dotcom.ads || { resolves: {enabled: [], getAdTag: []}, enabled: () => new Promise(r => window.dotcom.ads.resolves.enabled.push(r)), getAdTag: () => new Promise(r => window.dotcom.ads.resolves.getAdTag.push(r)) }; setTimeout(() => { if(window.dotcom.ads.resolves){ window.dotcom.ads.resolves.enabled.forEach(r => r(false)); window.dotcom.ads.resolves.getAdTag.forEach(r => r("")); window.dotcom.ads.enabled = () => new Promise(r => r(false)); window.dotcom.ads.getAdTag = () => new Promise(r => r("")); console.error("NGAS load timeout"); } }, 5000)

Tidal kites: New technology harnessing ocean energy

Winged machines are 'flying' - or at least swimming - beneath the waters of the Faroe Islands in the North Atlantic. Known as 'sea dragons' or 'tidal kites', they look like aircraft, but are in fact high-tech tidal turbines, generating electricity from the power of the ocean. So, how does the technology work?

This video is from BBC Click, the BBC’s flagship technology programme.