Putting Your Wind Farm on the Ocean

I was taken a train to taitong and I saw some wind turbines outside wind farms aren't uncommon in Taiwan I walked right up to a bunch of turbines on atariyan beach but there was something different about these turbines they were standing on the ocean perched on top of Offshore platforms in recent years Taiwan has been working to build out this renewable energy source in this video I want to take a look at the growing offshore wind industry but first let me talk about the Asian Armature patreon Early Access members get to see new videos and selected references for those videos before the release to the public it helps support the videos and appreciate every pledge thanks and all with the show so why put a wind turbine offshore first some of the world's windiest places are coastal the wind speeds there are on average higher and with less turbulence second you have much more space offshore wind farms were first developed in Europe those European countries are quite population dense and space is at a premium as a result they found it harder to find suitable onshore locations for wind farms especially ones large enough to offer economies of scale offshore locations also let you have wider turbine blades much like a semiconductor Fab bigger turbines have scale advantages though with the downside of increased probability for failure third local neighbors of onshore wind farms complain about their look and sound spoiling their formerly pristine environments whatever that might mean such opposition tends to end up in court moving those Farms offshore helps with the issue though not entirely the concept of offshore wind farms date back to the 1930s but ideas are cheap real substantial Research into offshore wind technology first began with the work of Dr William heronimus a naval architect and professor at the University of Massachusetts Amherst Dr hironimus was a significant contributor to the modern wind power industry in 1972 he first proposed the concept of a floating wind turbine for producing either electricity or hydrogen subsequent government studies initially discarded the idea citing its challenges it took until 1991 to see the first onshore wind farm out in Denmark the Danish have been using wind energy for centuries but up through the 1960s the country was 90 reliant on fossil fuels imported from the Middle East this became a very slight problem when the energy crisis of the 1970s struck the region in response the Danish government began supporting the development of a modern wind energy industry first with the use of feed and tariffs in 1976 and later subsidies for r d into better wind Technologies over time the environmental and space advantages of offshore wind farms became more compelling but there were many technical issues to resolve thus in June 1989 the lcraft power company decided to produce a small offshore wind farm with just 11 turbines as a demonstration project we should take a pause that discussed the technological fundamentals of wind turbines the wind turbines design has a few goals first it has to capture as much of the wind's energy as possible and convert that energy into electricity second it has to protect itself from the damage inflicted by its surrounding conditions namely violent winds and other such extreme conditions imagine a turbine sitting in a steady Airstream the amount of power intercepted by that turbine is proportional to the Air's density the area of the blade swept over by the wind and most crucially the cube of the wind speed so all things being equal are turbine receiving cold air intercepts more power than if it were receiving hot air because cold air is denser than hot air remember hot air rises and this is also why bigger blades have scaling advantages you intercept more power by having the larger area swept over by the wind anyway so if the wind speed doubles then all things being equal the turbines intercepted power increases by eight times this cubic relationship is the single most important equation in wind turbine design stronger winds can lead to Dangerous Power surges in addition to physical damage inflicted by The Winds of extreme events as a result the generators in a turbine are designed with cut out limits that kick in whenever the winds reach a certain wind speed ensuring these safety systems are reliable is critical one last thing note how I have consistently used the phrase intercepted rather than generated there is a difference the turbine is fundamentally limited on how much electricity it can generate from the amount of power it intercepts there are a variety of Blade configurations but most modern wind farms use a large horizontal axis wind turbine or hot with three blades horizontal axis meaning that the blades are mounted horizontally parallel to the ground these are in contrast to the vertical axis or vot why Hots and not votes Lots do offer a few significant advantages they are always pointing towards the wind and you can also put the gearbox and the electrical generator beneath the rotor closer to the ground but the problem with the VOD is that you cannot turn it away from the wind to keep it from sustaining damage or producing power surges furthermore the Watts blade creates downward turbulence that can interfere with its neighbors as for the blade number you can be like Gillette and try adding more blades but the industry has largely adopted the three blade configuration as having the right balance between cost performance and long-term reliability and also aesthetically people seem to like the three blade Arrangement more than the two blade setup such a thing matters installing a wind turbine offshore presents a multitude of new technical challenges there is no such thing as a standard offshore wind turbine installation unique factors like the water depth rotor size and the foundation all affect the process the biggest issue to consider is the foundation onshore wind turbines are secure with reinforced concrete slabs drilled into the ground with metal rods easy money but for offshore installations we have three generally accepted options we can first try sticking them right into the ground like a chopstick the monopile approach these three to eight meter wide monopiles work best in water depths of 20 to 40 meters with hard to semi-hard seabed conditions or you can have a big heavy concrete thingy holding the thing down using their sheer weight the gravity-based approach these are appropriate for shallow Waters about less than 10 meters with clay and sandy soil seabeds or you can set up a frame of hollow steel tubes the jacket or tripod offshore Foundation these are most suited for medium depth Waters of about 50 to 70 meters but also presents substantial logistical issues let us pick up the Danish story again the location chosen for this first offshore Wind Farm named vinda B was a bit of shallow sea about 1.5 to 3 kilometers off the northwest coast of the Danish island of La Land lawland don't laugh the name means lowland and it seems like the Island used to be actually called La Land the waters are super deep ranging from three to five meters despite being so far out from the shore this shallowness was originally thought to be an advantage but later during construction it was discovered that the waters were actually too shallow for floating ships while also being too deep for ordinary construction Machinery worst of Both Worlds the seabed was a 10 meter deep layer of clay topped with a thin layer of sand so the committee decided to go with a gravity-based foundation heavy concrete caissons 14 meters wide and with walls 60 centimeters thick each kaisan weighs about 710 to 1105 tons the equivalent of about 320 female elephants they were all built to stand about 2.5 meters above the water line regardless of the water's depths installing an offshore wind turbine is the process of dragging the turbines different parts out to the site assembling them and connecting the whole thing to the grid for vinda B the caissons were floated out to the site and installed using a custom-built catamaran-like pontoon guided Along by tugboats then you use a jack up barge to lift and place the pre-assembled turbine pieces onto their foundations a jack up is like a boat with vertical legs it floats along to where it needs to go then puts its legs down and literally stands up out of the water these Jack of barges were first used by the oil industry for the installation of offshore oil platforms I kind of like the relation as offshore wind turbines have gotten larger over time for scaling purposes they have needed bigger boats so nowadays you can commission custom-built Jack UPS there are over 100 meters long and can carry multiple turbines in a single day but with the downside of costing a lot more the insulation procedures depend on the foundation offering their own unique challenges for monopile and jacket foundations you literally Hammer the thing into the ground like a nail which trigger noise concerns for a gravity Foundation you have to first clean the seabed of soft soils that can't handle the huge weight this is what the vinda B people did digging a one meter deep hole into the seabed and adding a 40 centimeter thin layer of crushed stones after that is done you lay down a cable to connect the whole thing to the grid if the farm is particularly distant the installers might use a high voltage DC cable despite the added costs of a power converter due to cheaper cables and lower transmission losses it is estimated that the installation process covers just about six percent of a wind Farm's total lifetime capital expenditure despite this it is a hugely important part of the overall design the vinda B Installation crew encountered relatively little trouble and actually came in 3 million Danish kroner under budget the most significant issue was a limited time afforded by the weather recommending that Crews start work between 2 to 4 a.m in the morning when the waters are the columnist the ocean is an unforgiving place with violent squalls and corrosive salt water thusly the single biggest concern associated with offshore wind turbines is that of reliability and maintenance turbines have to survive these conditions for some 25 years with as little maintenance as possible you can't exactly drive out there in your truck and if a turbine goes down at the wrong time it can take an awful long time to get back online due to high wind speeds and strong waves so companies need to send maintenance teams over to the site at regular intervals but as a result maintenance costs for offshore wind farms can cost up to two to three times more than their onshore equivalents and in case you are wondering like I was the turbines most frequently broken down part is the gearbox the gearbox raises the speed of the blaze relatively slow spin into something more suitable for generating power so the gearbox is highly mechanical and subjected to some torturous physical conditions worse yet it is difficult to replace when it breaks down if the tower has to go down then all the expensive jack up barges and whatnot have to come out when it comes to Offshore wind technology the leaders are in Europe countries like the United Kingdom Denmark and such have leveraged their North Sea oil experience to help produce a multitude of offshore wind farms but Taiwan is looking to build these two in recent years Taiwan has wanted to diversify away from fossil fuels in 2020 60 percent of taiwan's total power was generated using coal and natural gas some of the world's dirtiest power plants are in Taiwan for instance the Tai Zhong power plant is the world's fourth largest coal-fired power plant by generation capacity such things of course lead to air pollution and climate change concerns considering the controversy over its nuclear power plants taiwan's third largest power source and the lack of buildable space the government has sought to build out offshore wind energy as it turns out the Taiwan Strait has some of the world's best sights for offshore wind farms data over the past nine years have found some of the highest wind speeds of the region taiwan's first offshore Wind Farm to come online was the Formosa one offshore Wind Farm an 11 square kilometer Farm located six kilometers off the meowli county Coast the Taiwanese government has a three-phase plan for developing wind energy the first phase would be to build two demo units by 2020 after which the goal would be to have 5.7 gigawatts of capacity by 2025. Formosa one was the first demo Farm but the second in Zhang Hua the ones I saw on the way to Taichung remain unfinished due to red tape environmental concerns and local opposition we shall see how it turns out the original concept forwarded by Dr hironimus envisioned a floating turbine I should briefly talk about these before we close floating wind farms are a compelling idea for deep water sites because of their portability you can pre-assemble it on land drag it out to sea and just leave it there after 25 years at the end of its useful life you go and drag it back home the downside of course is that since it floats it is not entirely stable pitching and rocking from the waves can cause unpredictable outcomes for the turbine including significant effects on its power generating efficiency floating wind turbines remain a developing technology and not yet quite reached the production stage but there are a few competing ideas on how to achieve them one is The Spar buoy a closed cylinder that floats upright just under the sea surface and is tied to the seat bed you can add more cylinders for more stability and resilience against waves The Spar was first installed in 2009 with the high wind demo in Norway the concept was later expanded to 2017's high wind Scotland Wind Farm the First floating wind farm the second idea is to submerge tension-legged platform this is where you have a floating platform just under the surface anchored to the seabed using slim tension legs sometimes called tendons this idea is derived again from the petroleum industry their offshore oil rigs very widely proposed it has not yet caught fire though a few demos do exist in 2017 after 25 years of hard work the vinda B offshore Wind Farm the world's first ever offshore wind farm was retired in 1995 Denmark built their second wind farm tuno knob today they have 15 offshore wind farms with many more planned other countries have gotten into the mix the Netherlands Sweden and the United Kingdom are today some of the leading countries in offshore wind projects there remain substantial questions however about how competitive offshore wind is compared to other sources of energy like solar the amount of subsidies implies that it right now is not but as Builders have gotten more experienced these projects have gotten better using bigger turbines in an attempt to reach economies of scale the massive horn sea wind farm for instance and certain European countries there are hints that offshore wind is already competitive without subsidy it's an exciting hint at a young but rapidly moving technology keep your eyes on this one all right everyone that's it for tonight thanks for watching subscribe to the Channel Sign up for the newsletter and I'll see you guys next time

Channel: Asianometry

Views: 72,437

Keywords: asianometry

Id: jMciEIbvCko

Length: 15min 52sec (952 seconds)

Published: Thu Jun 01 2023