Can Underwater Turbines Solve Our Energy Problems?

This episode of real engineering is brought to you by Breed, a problem-solving website that teaches you how to think like an engineer the next time you're near the ocean. Listen carefully to the sounding waves. It's wasted

energy

. The

energy

of waves, tides and currents. Collectively known as ocean energy, it is a huge resource waiting to be harnessed. The total energy available along the US continental shelf could provide about half of the current US total energy supply, with an estimated 250 terawatt-hours per year for the West Coast, 160 for the East Coast, and 60 for the Gulf. from Mexico 620 for Alaska 80 for Hawaii and 20 for Puerto Rico harnessing all that energy while transporting ash to population centers and finding suitable locations along the coast that do not affect coastal ecosystems or property values ​​would be an difficult task If not an impossible task, but if we can find a suitable way to harness the power of the tides and waves off our coasts, it could provide the final push needed to convert our grid to a 100% renewable system.

There are many methods to obtain energy from the ocean. Ocean wave energy is created when the wind pushes the surface of the ocean. Ocean currents provide energy driven predominantly by wind and heat from the Sun. Some systems have even used salinity differences between rivers and seas to produce electricity. However, today we are going to investigate one of the most promising technologies in this sector, tidal energy. It has enormous potential in the renewable energy market thanks to its predictable and constant availability. The tides change four times a day every day. This is a result of the Earth's rotation through bulges of ocean water formed.

Due to the gravitational influence of the Sun and the Moon we experience higher tides called spring tides when the Sun is aligned with the Moon allowing the gravitational influence to combine. This corresponds to the new and full moon phases of the Moon and we experience smaller tides and smaller differences. At high and low tides during neap tides, this occurs when the moon is 1/4 of its face offset from the Sun by 90 degrees, meaning that not only are our tides smaller overall, but the changes in the tide these tidal changes are minimized while their intensity varies. they come four times a day and result in a flow of water that will look like this for a spring tide and this for an ape linked with the spring tide will not only result in a higher tide but also a faster flow of water , which means more energy is consumed. available for extraction, these patterns can be projected into the future thanks to the predictable movement of the Sun, Moon and Earth, which definitely cannot be said for the unpredictable weather here on Earth, which affects wind and solar energy despite of the constant and reliable flow of ocean water.

The power provides the smallest percentage of renewable energy with only two large-scale tidal power plants, a 240-megawatt system located in the estuary of the Rance River in northern France and a 254-megawatt system at Shi Wallach in South Korea. South, both our tidal barrier systems. which works similarly to dams by opening and closing gates to control the flow of water through its

turbines

. This is a proven technology that shows they can generate electricity and operate in seawater without corrosion being a huge problem thanks to cathodic protection. Why are there so many systems of this type in the world, the problem is twofold: first, the installation cost is incredibly high, it requires a very large structure to control the flow of water, it simply makes more sense to use other forms of renewable energies such as wind and solar, and second, a great barrier.

As this has a significant effect on the local ecosystem, a company Simek Atlantis is looking to improve both points with its

underwater

turbines

that look remarkably similar to normal wind turbines, but thanks to the higher density of water, they can be much smaller. Its first prototype system was placed. Here at the mouth of Strangford Lough in Ireland, this area benefits from one of the fastest water flows in Ireland as the tides move in and out of the Strangford Lough bottleneck. Millions of tons of water flow through the canal every day. The system consisted of two 16 meter diameter turbines with a nominal capacity of 0.6 megawatts each for reference, an equivalent wind turbine would have a diameter of around 40 meters.

These turbines reached their maximum capacity in November 2008 and were decommissioned in May 2016 if those 1.2 megawatts operated continuously at full capacity. during all that time it would result in between 77 and 79 gigawatt hours of energy; However, it only produced 11.6 gigawatt hours, enough to power about 1,000 American homes for a year, but that is only 15 percent of its total potential; That percentage is called the capacity factor and 15 percent is a very low capacity factor, as Ireland's five-year average wind power capacity factor is around 28 percent. However, this was a prototype that did not operate continuously and was routinely taken offline for inspection and research in its best month.

Jen produced 522 megawatts. hours with a 59% capacity factor and see Jen claim that that is reproducible year-round with a 59% year-round capacity factor, this would make tidal energy an incredibly reliable energy source with just a minimum storage needed to smooth out the peaks and troughs between tides with a short time between maximum power generation and minimum power generation this form of tidal energy could use cheaper short term energy storage solutions such as mechanical batteries, to create a desperately needed renewable baseload. This project was dismantled in 2016 as part of the investigation. In the process, it was vitally important to test whether these machines could be effectively removed from the environment with minimal impact.

This, of course, is a major concern for any machinery that is placed in a marine environment. Jen met this requirement and had no significant effect on the local ecosystem. They have since moved on to the next stage of their technology with major installations between the island of Stroma and the northeast coast of Scotland. Its original lease was for up to 400 megawatts, provided the initial test phase with four turbines met environmental impact requirements. The latest version of the subsea turbine now has three turbine blades, allowing for a capacity increase to 1.5 megawatts with only a slightly larger diameter turbine than the 16 meter zero point five megawatt turbines from its previous project in Ireland. .

This turbine is also completely submerged, so it is not an eyesore for local residents, as Jen previously had actuators to lift the turbine out of the water and allow maintenance to be carried out, but the new generation of turbines are designed so that The actual turbines and generators can simply be attached and removed from the substructure in approximately 30 minutes, making installation and maintenance much easier and cheaper, environmental impact has been a central focus of the project and this began with a comprehensive study of the ecosystem surrounding area, from algae and shellfish to the whales that occasionally visit the area.

Fortunately, the area is so fast-paced. moving water that the seabed was stripped of sand and silt, so the facility had little impact on the ecology of the rocky seafloor, the impact the facility could have on local marine mammals was of much greater concern, as Surveys showed a large population of ship seals and dolphins with several seal hauling areas nearby. Both mammals are sensitive to noise and will likely avoid any areas with excessive sound. The noise levels at which these turbines fail are not terribly high since they move relatively slowly through the water. 544 page A long environmental report that I read to the best of my ability during the week of research I did for this video indicates that seals will strongly avoid noise within 38 meters of structures, while mild avoidance can extend up to a hundred. and sixty-eight meters with seal howls over a kilometer away, this was considered acceptable, while dolphins are expected to avoid noise up to 100 meters and filter feeders such as whales up to 500 meters, which can eliminate a use small section of sea but does not act as a barrier to any significant feeding grounds, a significant improvement over tidal barriers, this theory is supported by studies conducted during the CJ operation which found little evidence that the two turbines had a significant effect on the number of seals and dolphins during operation, but they did. have an effect during the construction phase where the noise was much higher.

Avoiding the area would be helpful because it would prevent animals from getting too close to the turbines and being hit by them, which could injure themselves and damage the turbine once again. I got some positive data from CJ, who examined all the bodies discovered near the site and found no evidence that the deaths were caused by impacts to the turbines. This seems unlikely, but they theorized that these animals actually avoid the area while the turbine is running, not because of the sound. but because the water flows fast enough to make it too difficult to swim and catch prey, the last major concern for these types of devices is the fact that they need to use toxic antifouling coatings to prevent marine growth on the turbines; however, Meijin uses an intelligent system.

Low friction paint that self-cleans as soon as the marine growth grows enough where the resistance exceeds its ability to add ears to the slippery paint. Additionally, they tested a sonar detection system that would allow them to track and potentially stop the turbines when larger animals are occasionally present. Without a doubt, these types of turbines would pass through the area and have a smaller impact on the environment than the tidal barriers seen in France and South Korea, but only time will tell if this system in the confines of Scotland will have as much of an impact. small enough to encourage installation of systems, cost will still be a huge factor according to your company's financial reports, mage's final project generated $2.7 million in revenue for the company in 2018, i.e. 0. 67 million dollars of revenue for each turbine according to its estimated cost for a larger forty-nine turbines at five hundred and forty million dollars, we can calculate that each one would have an installation cost of around eleven million dollars, so it would be necessary sixteen point three years to recover the installation cost, which is better than the twenty years it took to recover the cost of the tidal barrier system in France and those figures are likely to continue to fall if the company manages to start manufacturing these

underwater

turbines at larger scale, it is also slow, iterating and improving designs for tidal energy is much more difficult than others.

Some forms of renewable energy testing must be conducted in coastal waters, most of which are public spaces that require extensive permitting and testing. These underwater turbines are unlikely to ever compete on cost with onshore wind or solar turbines, but thanks to tidal predictability, this form of energy could provide a reliable base load when combined with low-cost batteries, if this project is successful, it could justify large-scale manufacturing of these turbines and transform tidal energy from a small niche industry to a big player in the renewable energy industry, after all Meijin is just a small section of a larger project large ocean energy project of 1,600 megawatts destined for the Pentland Firth and Orkney with combinations of wave and tidal energy, a colossal amount of energy that could go a long way to diversifying energy use in Scotland and we will delve further into the world. of wave energy in a future video, in the meantime you can learn more about other forms of renewable energy like solar by watching some of my previous videos on the topic or taking this course on solar energy on a bright date or even better for your Christmas.

Give the gift of lifelong learning to one of your loved ones by giving them a brilliant premium subscription. If you know someone who is passionate about math and science, this is a great gift that will nurture their curiosity, build confidence, and help develop life issues. -Crucial resolution skills for school job interviews and in your professional brilliance. Thought-provoking content breaks complexities into fragmentssmall and understandable ones that will take them from curiosity to mastery. This obviously works because someone from Tesla contacted me this week and told Amin. I took this solar energy course in preparation for an interview for Solar City.

If I've inspired you, head over to the brilliant Ford Slash Real Engineering organization and get a gift subscription to help your loved one spark a lifelong love of learning, as always, thanks for watching and thank you. To all my Patreon followers, if you would like to see more from me, the links to my Instagram Twitter subreddit and Discord server are below.