Minesto's Dragon 12 behaves remarkably like a kite underwater - using lift generated by tidal flows to fly patterns faster than the currents, thereby harvesting renewable energy.
Solar energy is one of the key components of most renewable energy grids - but lunar energy is even more predictable, and a number of different companies are working to generate energy from the regular inflows and outflows of the tides.
Minesto's Dragon device is anchored to the sea bed, and flies around like kites, treating the currents like wind. Just as land-based wind energy kites fly in figure 8 patterns to accelerate themselves faster than the wind, so does the Dragon underwater. This, says Minesto, lets the Dragon pull more energy from a given tidal current than other designs - and it also changes the commercial calcultations for relevant sites, even making slower tidal flows worth exploiting.
The Dragon has 12m (39ft) wingspan, and weighs 28 tons. But compared to other offshore power options like wind turbines, it's an absolute minnow, and extremely easy to install using a single smallish boat and a sea bed tether.
The Dragon 12, like other tidal devices, will be more effective in some places than others - and Denmark's Faroe Islands, an archipelago in the chilly North Atlantic between Scotland and Iceland, provides ideal conditions - because the Faroe Islands funnel tidal currents through a number of slim channels. This accelerates the water significantly, and thus increases the energy that devices like the Dragon can harvest.
Thanks to these ideal conditions, the first Dragon was deployed here last week and has already begun delivering cost-effective, predictable energy to the grid.