Energy

28-ton, 1.2-megawatt tidal kite is now exporting power to the grid

28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
The 39-foot wingspan of the Dragon 12, being towed out for sub-surface deployment
The 39-foot wingspan of the Dragon 12, being towed out for sub-surface deployment
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The 39-foot wingspan of the Dragon 12, being towed out for sub-surface deployment
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The 39-foot wingspan of the Dragon 12, being towed out for sub-surface deployment
The Minesto team poses with the 1.2 megawatt Dragon 12
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The Minesto team poses with the 1.2 megawatt Dragon 12
The narrow channels between the Faroe Islands accelerate tidal flows, creating an ideal location for tidal energy projects
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The narrow channels between the Faroe Islands accelerate tidal flows, creating an ideal location for tidal energy projects
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Minesto's fully operational Dragon 12 looks like some sort of futuristic military drone – but it behaves remarkably like a kite underwater. It uses lift generated by tidal flows to fly patterns faster than the currents, harvesting renewable energy.

Solar energy is the bedrock of most renewable energy grid plans – but lunar energy is even more predictable, and a number of different companies are working to commercialize energy generated from the regular inflows and outflows of the tides.

One we've completely missed is Minesto, which is taking a very different and remarkably dynamic approach compared to most. Where devices like Orbital's O2 tidal turbine more or less just sit there in the water harvesting energy from tidal currents, Minesto's Dragon series are anchored to the sea bed, and fly around like kites, treating the currents like wind.

Minesto's Deep Green technology – Unlocking renewable baseload power

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 economic equations for relevant sites, making slower tidal flows worth exploiting.

These are by no means small kites – the Dragon 12 needs to be disassembled to fit in a shipping container. It rocks a monster 12-meter (39-ft) wingspan, and weighs no less than 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.

As with any renewable energy project, the key figure here is LCoE (levelized cost of energy) – so what's it gonna cost? Well, back in 2017, Minesto projected about US$108/MWh once its first hundred megawatts of capacity are installed – with costs falling thereafter as low as $54/MWh.

The Minesto team poses with the 1.2 megawatt Dragon 12
The Minesto team poses with the 1.2 megawatt Dragon 12

For an unfair comparison, Orbital has claimed it's hoping for an LCoE less than $253/MWh for its very first O2 tidal turbine, a figure that'll drop with scale, and fixed-bottom offshore wind projects in 2022 had an estimated average LCoE around $89/MWh in 2022, according to the US DoE.

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, offer ideal conditions. Home to about 55,000 people and more than a million puffins, 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 12 can harvest.

The narrow channels between the Faroe Islands accelerate tidal flows, creating an ideal location for tidal energy projects
The narrow channels between the Faroe Islands accelerate tidal flows, creating an ideal location for tidal energy projects

That's where the first Dragon has been deployed, and on Friday, it was connected to the local power grid to begin delivering energy.

"This is a big day for Minesto," said Dr Martin Edlund, CEO of Minesto, in a press release. "We have reached the most significant milestone in the history of the company by producing electricity to the grid with our mega-watt scale powerplant. We are both proud and happy and more than ever look forward to the journey ahead ... The competitiveness of the Dragon 12 is straight to the point; it's powerful, cost-effective and feeds predictable electricity to the grid."

Check out a video below.

Minesto reaches historic milestone – first electricity to grid with tidal powerplant Dragon 12

Source: Minesto

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14 comments
14 comments
Rustgecko
There must be many excellent sites for this in the UK, notably around the Scottish island and the Menai Strait in Wales.
Nick Jacob
Minesto were working with SEACAMS (University of Bangor) looking at areas around Anglesey to deploy the tidal kites from about 2011
CDE
Would any efficiencies be gained by using a toroidal propeller to turn the generator?
rgbatduke
A narrow tidal channel is super -- there are several of them within 20 miles of our house at the coast (the Beaufort inlet, Cape Lookout, several breaks in Core banks). BUT those same channels maintain their depth by sweeping out migrating sand in the very strong tidal flow through the bottlenecks that this is supposed to harvest. If you put a fleet of these into the channel, you will slow the flow and reduce the effectiveness of the broom. Which will, in turn, cause the channels to close up. As it is, the channels used for shipping have to periodically be dredged because the coast is actually dynamic while humans like to pretend that it is not so that they can build ports and things like that that will last hundreds of years.

The second thing I would worry about is that the channels are almost invariably THE roadways for traffic ranging from small fishing boats up to giant freighters. The latter require a lot of draft, especially when loaded, hence the need to occasionally dredge (50' of depth all the way out to the ocean proper is usually a requirement). Fishing boats don't draw as much, but pull nets and lures through precisely this same zone as it is usually rich with fish, ditto shrimpers. The fish, of course, are often heading inshore from offshore so that they can -- y'know -- breed. Placing what amounts to an array of propellers in giant kite-like structures at mid-depth seems more than a bit likely to affect these migratory patterns, interfere with the fishing, obstruct any shipping in the same channel, and act as a serious hazard in places (like North Carolina) subject to occasional major hurricanes. If a half-dozen of these behemoths tore loose from the bottom and floated in with the storm surge, they would literally scythe there way through anything they encountered.

Last I would be curious to know what their running maintenance costs are. Anything left in the water where I live starts to foul within 48 hours unless it is coated with toxic paint. In a single year, smooth surfaces are literally covered with barnacles, oysters, a variety of seaweed-y growths. I grow oysters and have to regularly service their cages or they turn into floating upside down reefs. Do they plan to haul them inshore 2-4 times a year to give them a muriatic acid bath, or use hypertoxic paint, or only deploy them in waters so cold that barnacles aren't an issue (if there are any such in the world)?
Grunchy
We've had windmills and dams and other power sources for centuries, really it amounts to putting a harness onto the wild beast. There's no way to do that without harming the wild beast. Even something as passive as solar collectors, which seem inert in the environment: they deprive the ground beneath of solar irradiance, while creating shady patches that encourage rattlers to congregate.
Kpar
I have long been a skeptic of "renewables" as they have been too expensive, complicated, erratic, and environmentally damaging.

This is one of the first designs I could get behind. I am looking forward to the testing, performance and longevity of this device.
Adrian Akau
It appears to be a very useful technology and might be used wherever steady currents abound. For example, the currents off the south eastern side of the Big Island flow continually at about 2-3 mph along the coastline.
Catweazle
But still stochastic...
Jim
I cannot find any description of how the energy is transported to land.... please post if you found this info. thanks
Pupp1
This is one of the few renewables that is 100% predictable. You won't have days when there is no tide. People think batteries can solve the intermittent nature of wind or solar. But, in reality, you can't afford batteries to back-up power for a week.

But another reality may doom this tidal turbine. As was mentioned earlier, the sea is VERY hostile to technology. Perhaps the ease of deployment and retrieval will make this one easy to service. Enough, that it proves to actually be practical.
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