The Making of a Wind Turbine | Exceptional Engineering | Free Documentary

[Music] [Music] [Music] turning wind into energy these high-tech high output turbines are powering the switch to green energy worldwide but building and installing these ever larger wind turbines poses an enormous challenge you can make the mob jump that makes them more efficient as the turbines grow so do the factories in which they're built state-of-the-art robot technology is used to build the enormousness cells and powerful generators the rotor blades are especially large they're more than 80 meters long and weigh 20 tons and are molded in one piece I'm one blade is larger than the wingspan of an a380 to bring the enormous components to remote locations the engineers need special ships high-low transporters and mega cranes without them the wind turbines couldn't leave the factory the crews need nerves of steel when they assemble the wind turbines on-site even a tiny error can have deadly results we don't necessarily have more problems but the more dangerous and more dentists wind turbine manufacturing is booming around the world the industry is driven by a single goal [Music] a giant wind turbine is being built a high/low transporter is delivering the first concrete parts 10 specialists will build the first of a total of 24 tower elements each weighing at least a ton at the Falcon tall wind park near Berlin 11 giant wind turbines can generate up to 530 megawatt hours a day under optimal weather conditions but that's not enough over the next week's and e82 wind turbine will be joining them here the turbines measure 138 meters from ground to hub and have a rotor diameter of 83 meters under good wind conditions they can produce up to 5,000 megawatt hours per year enough to meet the annual energy needs of some 1,200 households [Music] the first step is laying the foundation made out of 75 tons of steel and 700 cubic meters of concrete it extends four meters into the ground and weighs several thousand tons if the ground can't support such weight the foundation is further anchored with 40 concrete pillars that extend 15 meters into the ground the crew has already placed the first section of the tower onto the foundation now a special crane is hoisting the second ring onto the base three crew members push the second ring which weighs almost 120 tons into position two iron centering pins help position the second segment flush with the first the two segments must maintain tolerances of just a few millimeters [Music] [Applause] fifteen minutes later the second ring is in place and the tower has grown by four meters [Music] inside the tower the crew also moves higher they stand on a platform that has six legs which adjusts to the towers diameter every time the tower grows the crane pulls the platform up another three meters then the platform is reentered onto the interior wall outside the rest of the crew is preparing the third ring the crane suspension system uses several orange heavy load slings to hoist the tower sections the number length and strength of the slings vary according to the nature and the weight of the load the crew carries out precise calculations taking all the various factors into account to make sure that everything goes smoothly the singer makes people's lives are at stake the crane operators view might be obstructed so they guided by radio she hasn't moved onon the towers first rings are very heavy more than 100 tons so we use it floating ballast the floating ballast is the massive counterweight that stabilizes the crane and keeps it from tipping under heavy loads it allows the 565 ton crane to lift more than its own weight 600 tons the cranes boom is 126 metres long it takes three days just to set up the crane [Music] there's a wind meter at the tip of the boom according to safety regulations wind speed can't exceed 9 meters per second during this part of the operation even a tiny amount of Swing in the load could be extremely dangerous [Music] today the wind speed is 3.6 m/s so the work can proceed the crawler crane lifts the ring and the crew shifts it into position they've built dozens of wind turbines around the world and know they're on a tight schedule over the next eight days they'll add another 18 cement rings reaching a height of 83 meters right now the segments are being staffed they won't be joined together until his steel section goes from unfuck raped we used to glue the segments together now we stopped doing that years ago for reasons of cost and efficiency right now the Rings are being placed one atop the other their enormous weight makes the tower stable later the crew will mount 24 steel cables each as thick as an arm into the structure the cables will lash the tower segments tightly together now it's time to remove the work platform its legs are retracted and the crane lifts it out of the tower with the crew still on board at this stage in the construction the diameter of the top segment is still large enough to permit the control cabinets and electrical equipment to be lowered into the interior the next set of turbine parts are almost at the construction site twelve trucks are just a few hundred meters from the tower they are carrying the next four rings each of which is made up of three segments in record time the crew have attached the slings and unloaded the trucks [Music] the first of the three concrete shells are positioned on a mounting star casting the concrete into a single piece and then transporting the 100 ton Colossus would be inefficient and very expensive that's why it's assembled on site the crew unload the second shell and place it on the mounting star they use chain hoists to pull it into the correct position [Music] the third concrete shell completes the ring the crew begin to shift all of the parts into alignment and screw them together we want them to be plush so that the screws will fit into the holes so we have to paint this one out with hydraulic pumps and chain hoists the crew tugs the concrete shells into place centimeter by centimeter then they fix the segment's together using thirty millimeter steel screws in less than an hour the crew has assembled the fourth ring the huge crane hoists it into position where it will remain for about two decades then the wind turbine will be refurbished or replaced the minimum lifespan of 20 years is also why manufacturing and assembling the turbine is precision work this Factory in the town of banda denmark produces more than 1,000 on and offshore wind turbines a year 3000 skilled workers use high-tech robot technology to assemble the multi-ton gondola as the cover of the nacelle is called wind turbines built here are found in more than 90 countries around the world these large factory halls awareness cells used in the SW t7 wind turbines are built these wind turbines are up to 165 metres high and are intended for offshore use their rotors are 154 metres in diameter each wind turbine has a capacity rating of 7 megawatts a year more than enough to power 7,000 washing machines a crew of 65 is building the offshore Giants the 3000 square meter production line can produce 4 into cells a week demand for these turbines is rising as are the technical demands being placed on them industry is to constantly improve the technology to bring down cost the expectations from all our customers and Indian from society is that we can get wind energy to a level of what other fuels cost first of all you can make the matcha that makes them more efficient but then we also work on more advanced aerodynamics for the plates lights or structures but basically we work on everything building offshore wind turbines is a very complex process because they're much larger than their cousins on land but their enormous rotors also generate more electricity and the higher wind speeds over water are converted even more efficiently into electricity [Music] erecting wind parks on the open sea requires special ships jakab platforms and heavy-duty floating cranes to withstand years of wind waves and inclement weather offshore turbines need to be supported by a massive foundation depending on the depth of the water and the prevailing currents up to four massive steel pillars are driven up to 30 metres deep into the ocean floor this anchors the offshore turbines which weighs several hundred tonnes Germany built its first offshore wind parks in 2004 since then it's been adding about 100 offshore turbines a year unlike their Scandinavian and British counterparts German offshore wind parks are not situated near the coast instead they're located more than 12 nautical miles out at sea meaning at least 22.2 kilometres from land vinton edgiest us wind energy has become quite competitive because it's been around for 2030 in some places 40 years and we keep getting better than neutral beams and called the turbines have grown larger they started out the size as a dining room table now a single blade is larger than the wingspan of an a380 the technology keeps getting better and better and the costs keep getting lower that's why wind energy is in such demand around the world today and why it's so useful the components for a giant offshore wind turbine have just arrived at the factory this 30 tonne mainframe is the heart of the turbine the cast iron structure will join the tower to the oversize nacelle and rotor which will be able to spin the mainframe is equipped with an enormous gearbox so that the nacelle and rotors can turn as needed at the next station the crew will install 16 yogi's each of these electrical motors turns a yaw Drive that meshes with the gearbox in the nacelle Matt allows the rotor to turn and nacelle to swivel toward the wind sensors are placed at various points in Menna cell to measure vibration wind direction and wind speed the 16 electric motors turn the 80 ton nacelle as efficiently as possible toward the wind when the nacelle turns the rotors must stand still the SW t7 wind turbine can handle wind speeds between 2 and 25 m/s and convert that energy into electricity at higher wind speeds the unit shuts off for safety reasons these high-tech electronic boxes keep the nacelle properly oriented in the wind the boxes contain complex sensors and the control systems electrical panels with electronic equipment that controls the motion of the blades and does some measurement so a lot of sensors are there we measure temperatures we measure wind speed wind directions vibrations we match the pitch angle so how the blades are positioned we measure the yaw angle so a whole lot of parameters that are all fed back to our monitoring center the company has installed some 11,000 wind turbines around the world data from the turbines is transmitted through fiber optic cables to the Diagnostic Center in Denmark 85% of disruptions can be fixed remotely the data also supplies information about the wind turbines efficiency this nacelle has been equipped with all the necessary electronic sensors and control elements now the crew begins assembling the sidewalls they're made of glass fiber reinforced plastic porgy FRP this composite material which is light in weight and extremely strong is also used in airplanes older wind turbines were made of aluminum but metal is too heavy for today's massive structures [Music] then the crew fastened the sidewalls using two hundred twenty two screws on each one the finish nacelle weighs as much as four school buses but before it goes to the clients it gets a thorough checkup this crucial that quality is in order because even the a minor mistake can cause they will turbine to shut down we need to make sure that turbine is running motors are in the ocean then you need to are it's quite expensive to to have it around a lot running the nacelle is now ready to head to Germany we return to the Falcon tal wind park over the last six days the wind turbines tower has grown to 22 rings totaling 80 metres and all today the crew will mount the final two segments three crew members board a work platform that's quite a bit smaller than the one used to mount the bottom rings the tower is now aware at the top then at the bottom the opening at the top is just under two and a half metres across after nearly 10 minutes they reach the 80 meter mark the crew remains in radio contact with the crane operator as they shift the cockpit into place then they give the order to lower the platform and anchor it to the tower it's routine work but they remain alert this far above the ground a single mistake can spell disaster things don't go wrong more often but when they do it's more dangerous more death 100 metres above ground anything that falls can do a lot more damage than when you're on the ground the crews get medical check-ups to confirm that they're fit to work in these Heights tall Pisan during training the crews also receive instruction on how to safely carry out a rescue operation in the event of an accident or fall every six months they also receive a medical exam to ensure they're capable of working at great heights the crew attaches the safety cable and removes the cables from the crane 20 minutes after leaving the ground they're 80 meters up and ready to work they'll be on the small platform for three or four hours there's no toilet no heat in the winter and no shade in the summer just cleaning the stop of the uppermost ring is hard work the ground crew has an easier time of it they're preparing the next concrete element for installation the underside of the ring has to be cleaned and - centering pins are released into position [Music] the crawler crane hoists the concrete ring to the top this one is 42 tons a light weight compared to those at the bottom but that also has a disadvantage the lighter the load the more likely it is to swing when raised the crane operator has to be extremely skilled and relies on precise instructions from the platform crew the crew begins to carefully maneuver the segment into place [Music] 20 minutes later the concrete ring is in place at the top of the tower [Music] the crew are now 83 meters above ground they begin opening the contact channels two dozen shafts extend down the outer wall from the top to the basement they use a pendulum to make sure that each shaft is clear if it's blocked at any point the steel cable won't descend [Music] while the crew mount four threaded bolts the next segment is waiting on the ground it's solid iron not concrete like a kind of cork at the top it will be attached to the 24 steel cables that will extend all the way to the ground squeezing the segments together once the screws are in place it's time for a lunch break but first they have to climb down the ladder they attach their harness into the ladders fall arrest system then they detach the second lifeline from the work platform 80 meters and almost three hundred rungs descending the ladder requires strength and stamina the tower grows wider toward the bottom so the descent is also at an angle the crew members body weight pulls them away from the ladder six minutes later all three are safe on the ground while the platform crew takes a break the others unwrap an enormous reel holding the wound steel cables each reel holds 485 meter cables each made of nine individual strands of steel they'll eventually extend from the top to the bottom of the tower right now the crew attached the cables at the foundation then they'll be pulled up through the shafts another special component is on its way this is the motorized unreeling device that will unwind the cables on the reels so that they can be extended through the channels the cables are so heavy that they can't be unwound by hand the crew board a platform basket which is raised to the top of the tower climbing the ladder would be too strenuous and time-consuming but the way up still takes nerves of steel [Music] the fall protection cables are detached and the crew returns to the platform [Music] the five-ton cable reel now attached to the motorized unreeling device is raised to the top of the tower two crew members begin unraveling the first steel cable [Music] [Applause] one level below the third crewmember feeds it into the channel then the rest is unraveled [Applause] it extends down through the wall of the tower all the way to the basement then the mounting bracket on top of the cable is fastened with six screws by the end of the day 24 steel cables extend from the top of the tower down to the basement later the crew will use a special procedure to tighten the cables that will ensure that the final structure is stable the facility in banda denmark doesn't only build missiles for offshore wind turbines every week 18 high techni cells for onshore wind turbines are also made here [Music] s.w.t three wind turbines are up to 142 meters tall and have a rotor diameter of about 100 meters with a maximum speed of 19 revolutions a minute it has a capacity rating of 3.2 megawatts the crew works at a set pace every 4 hours and 20 minutes the assembly line moves forward one station [Music] we have a whole line here and for each station we have four hours and 20 minutes to do the assembly process that we need to do in this station if the tact is not working then we will need to look into what is the problem it could be a quality issue from missing parts when that happens we need to contact our support functions to get them to help us and make a decision on what to do then losing tack will also mean that we will lose our money it means that we laid on need to do overtime to catch up and probably reschedule some of the deliveries that we have this compact nacelle has been in series production since 2010 one of its selling points is that it's assembled here in the factory and not at the construction site there are currently two ways to generate electricity out of wind in the first option the rotors rotation is passed on through a series of gears to a small generator and the other the rotor directly powers a large generator wind turbines that use gears have a longer nacelle which holds the gears [Music] a direct-drive wind turbine has a comparatively shorter nacelle the branda factory specializes in direct-drive wind turbines their generators operate much like an oversized bottle dynamo on a bicycle an enormous copper coil is located inside the generator [Music] when wind turns the rotor magnets are spinned around the copper coil which generates electricity we introduced the technology in 2007 by on the first test machines but it's only in the recent five years that we have really reached high volume in this technology macapa ring is built out of six massive parts copper is a metal with very high electrical conductivity the coiled copper increases inductance copper is also a soft metal that is easy to work with the crew is now fitting the so called stator in a special housing the generator housing is then inserted into this machine inside the machine for robot arms installed magnets into the drum surrounding the copper coil we receive the magnets we call them cold so they are not magnetized the robot takes a cold magnet magnetizes it and puts it into the finished generator the magnetic strength in this cell here is very very high so no humans can infer there once they are in the generator they are not dangerous anymore the cold magnets are coated in a special alloy that helps protect them from wear and tear the high-tech robots install a total of 648 magnets in the generator [Music] [Applause] [Music] then the generators placed on a platform truck which transports the three million watt generator to the next factory hall this is where the generator will be installed in the nacelle [Music] first the crew attaches a large transport frame to the ceiling crane a custom-built prong device makes it possible to move the generators safely [Music] here in this 3000 square meter Factory Hall on a cell for an SWT three wind turbine is assembled every four hours [Music] when the direct drive generator is docked and screwed into place the entire nacelle weighs 73 tonnes this factory belongs to one of the world's largest wind turbine manufacturers it costs almost three million euros to build one of these turbines three different types of the cells are built here a heavy truck brings it to the harbour in the Danish city of SP ugh from there the units are shipped all around the world the freighter also transports the enormousness cells to Germany [Music] at the Falcon tal wind park near Berlin preparations for the arrival of the nacelle are underway but before the nacelle can be raised to the top of the eet two wind turbine the crew has to install the last two steel sections two cranes are needed to lift the steel sections that allows the crew to lift the pipe while making sure that the delicate ends of the section don't hit the ground the fog and approaching dusk make the work more difficult winds could also pose a problem at wind speeds of more than eight meters a second this stage of the work would have to be postponed the nakhon decide if the crane tried to lift 58 tons at a wind speed of 10 or 12 m/s the steel section would start to swing crane could even tip over that we'd be risking the workers lives if I there's no way to know where the crane would land if it fell within it despite the less than optimal conditions the steel section is raised without a hitch the crane hoists the section to the top of the 83 meter tower the tower is another 25 meters taller the war continues without a break the next steel section is raised its 28 meters long and weighs 42 tons after its imposition the wind turbines tower is finished [Music] the 136 meter tower is made up of 24 separate elements [Music] the crew is now preparing the high-tech nacelle for the last stage in the process this type of nacelle weighs 19 tons the crew have to work quickly it's getting dark and it's getting foggy err [Music] the operation gets underway under optimal conditions it takes a month for a new wind turbine to be ready to go online the crew are working under difficult conditions today but time is still money they've already spent ten days building the tower in the last few hours they installed the final two steel sections now they've attached the nacelle onto the tower 136 metres above ground they'll have only one day to install the enormous rotor another Factory in the Danish city of olive oil makes rotor blades for wind turbines 1,300 workers produce about 2,000 blades here a year a number of different factors play a role in their construction including their lifespan their noise emissions and especially their performance and planned all what we're doing both onshore and offshore blades and it's integral blades that means is actually one-piece plate we're doing in the lengths between 53 meters up to 81 meters and we do in the round of 32 40 blades a week here in this factory each blade starts out in a huge mold much like this one that's also true for the largest blades built here in Denmark at 81 meters it's one of the longest rotor blades in the world this fiberglass matting is the raw material that's what the Packers has the crew at this station are called used to pack the giant mold it's easy to handle and they and very easy to form in our in our molds so I don't have any issues by laying them down or straighten them out that's the fiberglass strips have a special woven structure which makes for an exceptionally sturdy blade the matting must be laid out with no wrinkles or air pockets which would have a negative impact on the material structural properties [Music] if you pull it it's it's very stiff and just with a little bit of wrinkle you can pull it over not much strength the packers lay 500 strips of fiberglass matting into the mold they need to overlap in a specific pattern and be placed at set distances from each other then the finished blade can withstand all sorts of loads and weather conditions the interior of each blade also contains a connecting beam as tall as a man which provides additional stability to install the beam an overhead crane moves an enormous steel frame over the mold the frame holds the wooden core for safety reasons the Packers have to wait until the frame is stationary then they can remove the beam and fasten it into place wind turbine rotors are growing ever larger longer blades can generate more electricity which reduces the number of wind turbines needed to meet demand this blade will be even longer than the wingspan of an Airbus a380 next the crew install a lightning rod then a foam core is placed in the mold it will be topped with another 500 strips of fiberglass matting to form the top of the blade the foam will then be removed leaving a hollow and lighter weight blade this makes it possible to form the blade as a single part after the Packers have covered the phone core with a layer of wood they can begin laying the fiberglass panels that will form the top of the blade now all of the parts of the blade are in place the overhead crane moves a massive steel shell in position and closes the mold the inside of the shell is fitted with a system of pipes all the air inside the blade will be sucked out through the pipes and then the structure will be filled with a two-component resin a special pump and mixing unit injects 8300 kilos of resin and the hardener into the mold the resin and hardener flow through these tubes into this mixer which mixes the two components at a specific ratio that's how the EPOC see resin is made and it continues over here whatever you have lemon so where are you silent the mixed resin flows through these tubes welcome back Hume sucks the epoxy resin into the mold the form is also heated at the same time its temperature increases slowly about 0.2 degrees per minute until it reaches 92 degrees Celsius that takes about seven and a half hours then the blade is left to harden another two hours at 85 degrees the rest of the air is removed through these hoses the resulting vacuum causes the rest of the epoxy resin to move into every nook and cranny of the mold that way no air pockets can form inside the blade which helps ensure maximal stability 9 containers of epoxy resin flow into the blade once the entire mold is filled it's heated the mixture of synthetic resin and hardener binds to the fiberglass mats then the blade is left to harden the end result is one of the largest rotor blades in the world [Music] the blades used in the e82 wind turbine in falcon tile are some 38 meters long they're brought to the construction site on three special trailer trucks two cranes are used to unload the rotor blades that way the eight-ton blades can be lifted from both sides which prevents accidents and damage the blades are first set on the ground modern wind turbine blades have a sawtooth edge along a portion of the blade it makes the blades quieter and more aerodynamic which boosts efficiency the design was inspired by nature the trailing edge of the wing of an owl which allows it to swoop quickly and silently on its prey [Music] next the three blades are attached to the rotors hub when the unit is running this is what will transfer the power from the blades to the generator a hook is attached to the blades center of gravity that makes it possible for a single crane to lift the blade while keeping it parallel to the ground the blades are attached to the rotor hub at an angle of 120 degrees the hub has been carefully positioned when the blades are attached the crane will be able to lift it and turn it to the vertical position in a single motion so that it can be lifted to the top it takes about five hours for the crew to attach the blades to the hub then the 56 tonne rotor star is ready to go but first we return to the factory in Aalborg a new blade has just been made the Packers laid out 500 strips of fiberglass matting in an enormous steel mold the strips were laid out in a special overlapping pattern to ensure that each finished play would be strong enough to withstand heavy wind then a massive ceiling crane placed a connecting beam on the inside of the blade to help stabilize it a temporary foam core filled the inside of the blade that was topped with a wood panel and finally with another 500 fiberglass strips then the top of the steel mold was placed over the structure air was pumped out of the structure to generate a vacuum the mold was filled with a mixture of resin and a hardener the mold containing the fiberglass an epoxy resin mixture was heated for 10 hours and allowed to harden the end result was an 81 meter long blade made out of glass fiber reinforced plastic or GF RP the material is robust and light in weight but it also has some disadvantages even small air pockets or indentations can weaken the blade that's why the crew is now making sure that the material is perfectly solid and smooth any flaws are removed with a grinder and the resulting holes are refilled with new GFR P until the blade is solid and smooth next the rotor blades go to the painting line they first get a primer coat which is then topped with a special protective coating the polyurethane varnish creates a hard-wearing surface that can withstand immense mechanical stress [Music] this mechanical stress increases proportionally to the length of the blade so it goes towards longer bigger and then you need to think about the nature loss how you bring it around in the production how you manufacture it but also how you bring it from the plants actually out to the sides either on ships or lorries and how do you actually bring it on the site and install it you need also big cranes installation ships so there is a lot of parameters that you need to be thinking about and thinking new ways to be able actually to fulfill and and meet these new challenges next the blades are subjected to various fatigue tests which can take up to 12 weeks the engineers subject the blades to extreme bending and torsional moments over long periods in the simulations the blades must withstand the same force that it will be exposed to over its entire lifespan not every blade is tested in this way but a random sample of blades receive rigorous testing as do prototypes and new designs are tested for some loads equal 25 years of light of lifetime it can also be 20 years but mostly 25 years we can also to extend the tests programs for we test a place to another lifetime so it can be put long time but a complete this program for a blade can be up to one year the blade is attached to a special test tower in the middle of the blade a multi-ton weight causes the blade to oscillate depending on the size of the blade up to 400 sensors measure various parameters 25 times per second around the clock almost 70 years I think I've seen only two blades failing and a fatigue test it's it's so real that the blades come down because we monitor all the data so closely that we will find the errors before they actually develop to something serious damage the enormous blades from Aalborg are amongst the largest in the world at 81 meters in length they have a surface area of 20,000 square meters blades of this size produce offshore wind turbines with a capacity rating of seven to eight megawatts at the Falcon tailwind park the rotors star has been assembled the next step will be a complicated one the crane will lift the rotor from the ground and then turn it upright in the air just a few metres away from the waiting tower for safety reasons the maximum wind speed during this maneuver is 6 meters per second DD's always mom you can see the size of it now the diameter is 83 meters the crew have to stand nearby because we need to tip the star we lift the star and then the star is tipped up right and let's so that it can be raised and then gonna hold me pop the crane slowly lifts the rotor star about 56 tonne rotor the size of half a soccer field will now be moved to a vertical position the rotors hanging on a special hook called a banana it's curved shape allows the entire rotor star to hang in perfect balance only a small amount of force is needed to tip it while the crane lifts the star two crew members pull it toward the tower [Music] the enormous rotors star slowly moves from a horizontal to a vertical position [Music] meter 4 meter the wind turbines propeller is slowly raised to the top 2 long cables are attached to the blades which the crew use to maintain an even keel [Music] an hour later the enormous rotors star has arrived at the nacelle 138 meters above ground the crew then attaches it to the generator with screws after four weeks of work the new EAD two wind turbine is finally in position over the next few days the wind turbine will go online when the wind reaches a speed of two meters a second the turbine will start automatically and generate green energy we have an immense and growing need for electricity due to a rising global population the expansion of the grid and electric vehicles cheap renewable energy from wind power is ideal the first wind turbine was built almost 130 years ago since then people have been harnessing the power of the wind as a cheap powerful and unlimited source of energy today wind turbines are high-tech industrial installations their enormousness cells contain giant copper coils state-of-the-art robots install enormous magnets in them nowadays wind turbines are made on the assembly line the rotor blades are made with the help of enormous steel molds and special robust materials thousands of production steps are needed to bring a new wind turbine online once it's finally in operation nature and Technology work hand in hand to generate energy out of wind

Channel: Free Documentary

Views: 2,243,007

Rating: 4.784349 out of 5

Keywords: Free Documentary, Documentaries, Full documentary, HD documentary, documentary - topic, documentary (tv genre), engineering, exceptional engineering, german engineering, german engineering documentary, engineering documentary, Wind Turbine, building a wind turbine, high tech documentary, green energy, green energy documentary

Id: 8NXLKRW1IEU

Length: 49min 42sec (2982 seconds)

Published: Fri Feb 28 2020