Home Ice bergs T-Omega redesigns floating offshore wind turbines for huge savings

T-Omega redesigns floating offshore wind turbines for huge savings

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All of the world’s greatest wind resources are found offshore – often far offshore, where the water is so deep that it is impossible to build typical fan-on-stick wind turbines with bases sunk deep into the seabed. Floating wind, at this point, is so expensive to build, deploy, and maintain that it ends up costing two to three times more per kilowatt-hour of energy than fixed-bottom offshore installations.

There’s a huge opportunity for technological advancement here, and companies like Norway’s World Wide Wind are coming up with some pretty radical ideas in space. Much of the cost of power comes down to the size, weight, and materials involved in the structure of the turbine, as well as the logistical issues and specialized equipment needed to build, install, and maintain things.

Boston startup T-Omega Wind says it has prototyped and tested a unique floating offshore wind turbine design that can withstand massive storms and hundred-foot waves, but at 20% the weight and about 30% the price of conventional designs – not to mention super-simple deployment and installation – unlocking an affordable way to harness the world’s best wind resources.

Because there is so little below the waterline, T-Omega’s turbines can easily be towed by a single inexpensive tug, meaning maintenance can be carried out in port, rather than at sea at using incredibly expensive and specialized ships.

T-Omega Wind

“All offshore floating turbines except ours are like icebergs,” says Jim Papadopoulos, co-founder and chief engineer of T-Omega, during a video chat. “Whatever they have above water, they have four times as much under water. If they have 1,500 tonnes above water, they have 6,000 under water. It’s a big expense. almost nothing underwater. This is one of the big differences in cost, mobility and launch.

Conventional floating turbines, Papadopoulos says, use technology that was only ever designed for land. “Right now, a Vestas or GE style turbine, they have a super rotor, with a one-sided shaft. You can design almost anything, but with a one-sided shaft, that shaft is massive and requires some special bearings.And because of the forces going through this design, there is very little room for it to change angle, so they have to keep them stationary, perfectly straight – hence the heavy and expensive base .They’re steeped in an earth-style philosophy, and it’s incredibly expensive.”

T-Omega’s approach is completely different, starting with the turbine and generator itself, which are mounted on a double-sided axle shaft that is rigidly supported at both ends. So, rather than a single heavy pole, the turbine is supported by four much slimmer legs, reaching to lightweight, widely spaced floating base platforms. It’s a bit like the way a Ferris wheel is suspended; there’s a reason they don’t build them on a single pole.

Complete 3D video of the T Omega wind turbine

Will it capsize?

“If you take a wooden door and put it in water, it’s not going to tip over,” Papadopoulos says. “It’s width versus height. So yes, we have a very wide base compared to any other floating design. To lift the floats out of the water, you’re looking for an ungodly amount of torque – that’s much more than the torque of the generator.”

The floating base is attached to the sea floor, and when the wind changes, the base spins freely around its pivot point on the sea floor, so it’s always facing into the wind – but without the need for sensors, motors and slewing mechanisms to achieve this end. The material cost savings are huge, Papadopoulos says.

“Suddenly the weight of the tower can be something like 10% of the weight of a normal tower. And instead of dealing with steel two or three inches thick – and all the equipment, the time and the logistics that entails – you’re dealing with steel half an inch or less, and anyone can cut it and weld it.”

This also continues up to the top gear. Supported from both ends, the T-Omega design does not need the same type of massive generator and axle designs that conventional turbines need, simply to cope with the enormous stress imposed by a single-sided axle. This means less metal, less weight, less specialized tooling and less cost at every stage of the process. It also means a wider range of manufacturing companies can build things.

The company built a two-meter-tall (6.5-foot) prototype – a 1:60 scale model of a commercial-size 10 MW product, and tested it for stability in a tank at waves in Glasgow.

“This is the lightest 1-60 scale floating wind model I have ever tested,” Kelvin Hydrodynamics Laboratory project leader Dr Saishuai Dai said in a press release. “The model successfully overlapped a stormy sea state with an equivalent full-scale significant wave height of 18 meters (59 ft). An equivalent full-scale maximum wave height of 30 meters (98 ft) was observed in this stormy sea state, and that was pushing the upper limit of our wave makers.”

“These waves are the equivalent of 100 feet high,” Papadopoulos said. “That thing was rocking like a fairground ride. No problem.”

Testing the T-Omega Wind Strathclyde Tank

Since the design doesn’t extend very far underwater, deployment is an absolute breeze. You can assemble these items on a dock, float them directly in the water, then tow them to the site. The upkeep is much the same; Unhook the wind turbine, tow it to shore, perform any necessary maintenance, then put it back into the live wind farm rotation when you’re done. No need for jack-up vessels or floating cranes, just tow the turbines to the port where everything is easy.

“We’re going for the cheap, the cheap, the cheap,” Papadopoulos says. “And part of our game is that we’re not going to aim for 25 years without maintenance. We’ll replace parts in three years if they crack, because we’ve made it easy. Conventional turbines are incredibly expensive to maintain. – you have to hire a turret ship for two or three million pounds a week, and even then it is only possible in good weather They wait until two or three have failed to justify the cost of this ship – and to avoid That’s one of the reasons they’re so expensive. They want perfection in their design. We don’t. Cost works out much better.

While nearly every other offshore wind design seeks to continually evolve with ever-larger turbines, T-Omega says its economic sweet spot will be about half the size of today’s largest turbines. “Everybody seems to like the idea of ​​getting bigger,” says Papadopoulos, “but we hate the idea of ​​massive size because it means you need bigger ports, bigger ships, everything. bigger.”

And, he says, T-Omega’s proposition is fundamentally different.

“Why are they getting so big? ” he asks. “What happens is that the installation and maintenance costs are so crazy for these turbines, that you’d rather install and maintain one giant than two medium ones. But those costs don’t apply to us. And there’s something called the square-cubic law; when you double the size of a turbine design, you increase the swept area of ​​the rotor by four – but the weight increases by eight times, because you double the height, width and length of each three-dimensional part. So it’s actually a losing proposition to go too big for us. We’ll probably find our sweet spot with the lowest cost at around 7-8 megawatts.

Supporting the turbine at both ends means T-Omega can get away with much simpler, cheaper and lighter generators and support structures
Supporting the turbine at both ends means T-Omega can get away with much simpler, cheaper and lighter generators and support structures

T-Omega Wind

The company projects a levelized cost of energy (LCoE) of around $50 per megawatt-hour in internal calculations. It works for this figure to be rerun by an independent third party.

“Based on our numbers,” Papadopoulos says, “we’re in the range of the best fixed-bottom offshore wind turbines available today.”

At this point, T-Omega is a small group of people working without pay and funding prototypes through grants and accelerator funds.

“We’re just starting to seriously look for investment,” says Papadopoulos, “We think this could be the most versatile, easiest to build, and cheapest floating wind turbine on offer. So why isn’t anyone wouldn’t he want it? Maybe it’s naive!

Indeed, there are other massive market forces in the way.

“We went to show it to a company that makes some of the biggest turbines in the world,” Papadopoulos says. “We spoke to a former CEO, a guy who really knows the business. We showed him our design. He said in awe, ‘It’s a really good design. Everyone needs it. This will make maintenance easier. That’ll make it easier to build.” and install it easier. That’s a good thing. I’m not giving you any chance of success. And we looked at him all crestfallen and asked him why. And he said, “Hey. good because just before I left, we just invested three or four billion in making things the old fashioned way. Do you think we want to throw this factory away? So the big turbine manufacturers aren’t interested, they want to keep selling what they’re making now.”

The challenge for T-Omega is therefore to find manufacturers that are not locked into legacy technology. Papadopoulos says the company has a few lines in the water with investors, but has yet to strike a deal that could fund the next step: a 100-foot-tall design that could end up being a product. for small coastal settlements and islands.

“We are only at the beginning of our efforts to prove that the ideas are good and doable,” he says. “With more evidence, you get more investment, until it’s a real product.”

Floating offshore wind turbines will play a vital role in the transition to clean energy, but their contribution will be limited by their cost. It’s an industry ripe for technological disruption, and T-Omega’s refreshingly simple approach seems to have a lot to offer. We wish the team the best of luck moving the project forward and we look forward to seeing how it progresses.

Check out an animation detailing the process of building, installing and maintaining T-Omega’s turbine design in the video below.

TOW_001_ExplainerAnimations_v0.6_SB

Source: T-Omega