Mega Dams – Hydroelectric Evolution – Big Bigger Biggest

From the waters of the Yangtze River in China rises the largest concrete structure on the planet, the Three Gorges Dam, it is more than two kilometers long and 60 stories high. It took forty thousand workers 17 years to build it. When fully operational, this dam will produce over twenty thousand

mega

watts of power, twice as much as all of Britain's nuclear power stations combined, it is the pinnacle of dam engineering. The beautiful dam owes its success to five iconic

dams

, at the heart of each of them lies a major technological innovation that allowed engineers to build larger and larger

dams

, one by one, traveling up the scale, we will reveal the incredible stories behind these structures and the inventions that allowed them to produce more and more energy.

Six ingenious leaps forward from big to

bigger

to the world's largest foreign economies on Earth. Due to the need of its ever-accelerating industry, the nation needs more foreign energy, much of this will be provided by a massive dam spanning the mighty Yangtze River in central China, called the Three Gorges Dam. Our cameras have had privileged access to capture this amazing feat of engineering in its full overseas glory. Before they could begin building the three beautiful dams, the Chinese first had to divert the Yangtze River, which is almost two kilometers wide. and move more than a million people from the area on the verge of flooding, and when they filled the reservoir behind the dam. a huge mass of water actually slowed down the Earth's rotation speed by a fraction, well that's three damn beautiful ones, it's the largest

hydroelectric

project in the world.

Its stem used 28 million cubic meters of concrete. solid concrete pipe one meter in diameter around the world, that's a lot of concrete. Chinese authorities believe it is worth the effort, as the Three Gorges Dam will provide cheap, clean electricity to millions of people abroad. To understand how the Three Gorges Dam can produce so much energy we need to travel back in time to 19th century Britain and a modest stream in Northumberland the power behind the world's first

hydroelectric

dam in the 19th century, when Great Britain was at the heart of the Industrial R

evolution

this house was the last word in modern life it belonged to Lord Armstrong, an obsessive businessman and inventor, he equipped his house with cutting-edge technology, including central heating and mechanical devices that powered lifts, washing machines and grills, but there was one place in the house where modern technology was sadly lacking.

As historian Anthony Burton explains, this was Armstrong's true pride and joy, the picture gallery full of wonderful Victorian paintings was a little gloomy even in daylight, but what he really wanted to do was bring his guests here for the night, but by candlelight nothing worked. What Armstrong needed were electric lights and a way to power them. How is electricity generated well? That's something that was known for 50 years because Michael Faraday had given the secret: you move a magnet relative to a coil of wire with a little configuration here, so how could it work now here we are here we have two magnets at the end of this disk and right here is a coil of wire now if I rotate this relative to that we should generate electricity and yes, we are getting a Reading on the ammeter, we are definitely generating electricity every time the magnets in the disk pass the coil , they generate a small electrical pulse in the copper wire, so to generate a lot of electricity you need a much larger kit and this is what Armstrong bought, the Thompson Vortex. turbine a large piece of equipment the Thompson turbine needed a large volume of fast-flowing water to drive the rotor all Lord Armstrong had available was a small stream running through his property what he needed was a voter from a small stream he built a Armstrong Dam built an earthen wall almost 10 meters high that turned its stream into a deep lake.

The mass of water from it was pushed down with pressure to lower depths. Armstrong channeled this high-pressure water through a pipe to the bottom of his dam. Here he injected it into a The Thompson turbine where the torrent turned the rotor, which in turn turned a shaft connected to a generator, producing 4000 watts of electricity for Armstrong. This was just the first step towards enlightenment, then he needed to get electricity from the turbine house at the bottom of the dam. All the way to his picture gallery, more than a kilometer away, Armstrong connected two strands of thick copper wire to the generator to bring electricity to his mansion.

In total, he used five tons of copper to power a single light bulb, but he created a world. First, a house illuminated by the power of water on the other side of the planet, in central China. The three precious dams can light two and a half billion light bulbs abroad. The Three Gorges Dam is China's largest construction project that British engineer Robin Charlwood has been working on. on it since 2003 and I am still impressed by its scale we are in one of the three large power stations of the Three Gorges project in this 700 meter long rum here you can see 14 of the large turbine generators and beyond this, about a kilometer away is the second power station and then beyond that there is another power station that will be underground in the rock on the other side of the river.

Each of these generators cost around $50 million, which gives you an idea of ​​the scale of this Debden Dam project. a generator The Three Gorges have 32. Together they produce 5 million times more energy than the debt. To power them, the Chinese have harnessed the power of the mighty Yangtze River in the reservoir behind the dam, the river now rising up to 60 stories above the riverbed. It is channeled through gigantic concrete tubes to the generators. Here the torrent of water hits the turbines and makes them spin. This motion in turn is transferred to the generator's rotor, which is equipped with huge magnets that move across copper coils in the casing to generate electricity.

Just one of these machines produces as much electricity as a small nuclear power plant. The 32 generators together produce enough power for 60 million Chinese. This project is setting a new benchmark in the international hydropower industry. It is almost twice the size of the next largest project, the UIP. in Brazil because it is only the first of a whole series of

mega

dams that are being built here in China back in 1878. The Debden Dam showed that even the smallest current can be harnessed to produce electricity, but to generate energy on a larger scale. Engineers had to battle with larger rivers to build a dam that could produce 128 megawatts French engineers had to persuade the mighty River Dordoin to follow a new course 1914 France the outbreak of World War I plunged the country into a deep crisis The Germans and the French were forced to import coal from abroad to fuel their power plants and keep the country running, so after the war they decided to increase the country's energy supply with electricity from a hydroelectric dam, but building a concrete dam on the fast-moving Dordoing River. presented quite a challenge and this is our door to Mighty River here on the beach.

Now you can't just pour concrete in the middle of a river. They wanted their dam here, but to get one dam they had to build three, first one. A temporary dam comes in here, what's called a box dam that stops the flow of the river, you can't just stop it, it will go over the top unless you do something different, which is build a diversion channel right there and then to avoid let him go back. Again, you put a second cofferdam here and you have a gap between which you can drain and that's where you can build your main dam.

Abroad, engineers blew two tunnels through the rock to carry the diverted river, dumped steel. cages containing rocks in the river to make their temporary chest then they reinforced it with concrete now the river behind the dam started to rise could drain through the tunnels to prevent the water from backing up the engineers built a second chest dam once that the water had drained from the river bed between the dams, left a perfect dry place to build the main dam, fortunately for the engineer they discovered when they emptied the central part that in reality the river bed was Solid Rock, they were able to build directly on top of it By layer the giant concrete structure rose 30 stories from the river bank, the engineers then closed the diversion tunnels and allowed the reservoir to fill and submerge the cofferdams, their work was done, they were finally able to open the turbine gates and begin producing electricity when the Mirage Dam was completed.

It produced 128 megawatts, enough to help power a train line to Olio and supply electricity to the city of Paris, 400 kilometers away. The Yangtze River is more than 6,000 kilometers long and in places several kilometers wide, the largest river in China. It presents enormous logistical challenges for Dam engineers, as the Yangtze rises behind the Three Gorges Dam, it will flood more than one hundred and fifty thousand acres of land along its banks, requiring the Chinese to relocate. more than a million people from the land behind the dam and thousands of new houses will have to be built. built for the displaced citizens to live in then the engineers can start cursing the river the engineers begin work on a series of stone dams to block part of the shaft while leaving a channel open for the rest of the river to flow through they build the first two sections of the main dam on the dry bank of the river, then they throw tons of earth into the river and on top of that they build another cofferdan, this time made of concrete, with the controlled river behind it, finally they can build the last section of the dam , then they must remove the cofferdam so that water can flow through the main dam's turbines.

Having built such substantial trust structures, it is a big challenge how to remove these things in the earlier stages where they were built with very large pieces. Rocks like this back then could be handled with relatively conventional large excavator equipment, but in the final stage where they had a solid concrete wall to remove this required major innovation, unlike the coffee dam at Mirage, the Chinese version It's too tall to just leave it there. place so the Chinese engineers build it leaving holes for the explosive charges on June 6, 2006 they filled them with 190 tons of dynamite and hold their breath it is tomorrow what has taken months to build takes only a few seconds to destroy the cofferdam crumbles free stored water Behind it lies the final test for the three magnificent dams and in 1935 the Marriage Dam demonstrated that engineers could divert rivers to build powerful dams, but to surpass the 1000 megawatts of Mark, the American engineers who built the Hoover Dam had to take their construction material.

Abroad, in the 1930s, the United States decided to address one of its great economic problems. Cities in the western United States couldn't grow because they lacked water and power, so to break the deadlock, engineers began work on the world's largest dam. It contains more concrete than any other construction project before it was strange, but as the concrete sets, a chemical reaction causes it to heat up, this created a problem for Hoover Dam engineers. If the Hoover Dam concrete was poured all at once, the concrete on the outside would have cooled and hardened first, while in the core of the dam the concrete would have stayed hot and tried to expand, this could stress the concrete and cause it to crack strangely, so engineers molded the concrete for the Hoover Dam into small individual blocks as the concrete in each block cooled it shrank but did not crack the shrinkage left small spaces between the blocks that engineers filled with cement but this clever design didn't solve all the problems is huge, I mean, there are six million tons of concrete in the Hoover Dam and If we could concentrate all the heat generated by the cured concrete in a single oven, we could cook half million loaves of bread every day for three years.

If this structure was left alone, they realize it would take 125 years for it to finish shrinking and cooling basically and that's not fast enough now the guy in charge is a guy named Frank Crow andThey call him hurry up Crow because he's a man in a hurry and he says this isn't good enough. I can't be 125 years old, what I'm going to do is use the Colorado River to cool my dam. Crow embedded more than 950 kilometers of steel water pipes into the concrete of the Hoover Dam. He built a huge water cooling system. At the factory here, he lowered the river water to four degrees and then shot it through the pipes into the hot concrete.

Yes, this shortened the cooldown time from 125 years to just 22 months. Now it works like a charm. All I have to do is finish the cement grout on the dam. In reality, it took 5,000 men in just 21 months to build this structure, not only did they finish two years ahead of schedule and they finished ahead of budget. The Hoover Dam stored 35 billion cubic meters of water and at that time generated more energy than any other dam in the world with this magnificent dam behind them, cities in the American West could finally begin to prosper the three beautiful dams contain more concrete than any other structure on Earth.

Imagine the thickness of the concrete at the base of the dam, its height is 180 meters and then it is two kilometers long, so it is a colossal amount of concrete with that much concrete on your hands. The Chinese engineers had to do everything possible to hold their dam. they chilled and basically used everything that's in the book, they chilled the aggregates and the materials, the sands, before they put them in the mix, they added ice, they did everything they could to get the temperature down as much as possible before it started to heat up. on its own and here because of the problem that some of the summer weather is especially hot in July and August, they even went so far as to use a fog spray system to blow, effectively, a blanket of fog over the top of the dam in order to to prevent solar radiation from accumulating in the concrete and increasing the heat that was being generated inside with all the cooling measures implemented that Chinese engineers do not have. worry about cracks in your dam 36 the Hoover Dam showed that engineers could build incredibly large concrete dams, but as the dams grew they held back more and more water and with it tremendous destructive power to build the Grand Coulee Dam Engineers Americans had to protect it from the catastrophic effects of the Johnstown Pennsylvania overflow on May 30, 1889.

The city is hit by the heaviest rains in its history. The tranquility of a dam. The reservoir was about to break. It rained for 24 hours and the water reached the top of the dam soon. There was nowhere to go, but above it the dam failed and 20 million tons of water emptied in 45 minutes. An 60-foot-high wall of water crashed into the valley and hit Johnstown. Total destruction occurred. More than 2,200 lives were lost in the flood, the worst disaster in the U.S. Having ever seen why dams burst when they overflow, engineer Ed McCann explains that a particular problem now is when water flows over and weakens the entire ground, the ground in front, here they are very vulnerable to something called scour of the feet and us.

Let's try modeling to see if we can see what happens with the toe undercut. This is our flood that comes in our river and fills up behind the dam. We're right at the top here now and water soon. start pushing on the top and go down and it will fall down this face and clear underneath and you can see the dam start to move as the ground in front of it is lost, the dam loses its base and starts to spin on it. It won't be long before everything comes together and explodes, which is a reasonably satisfying result.

When the dam fails, a tremendous wall of water appears down the valley, and if you're down there, you're probably already dead. Well, you can do it. seeing your toes spook at this type of dam is a huge potential problem, it's something that absolutely needs to be fixed in 1933. American engineers began work on the Grand Coulee Dam across the Columbia River in northwest USA. It would require three times as much concrete as the Hoover Dam and span three times the distance. When engineers completed the Grand Coulee Dam, they had to make sure that what happened at Johnstown didn't happen here, the water rushing over the dam could have quickly eroded the river bed and caused a disaster, so engineers formed the bottom of the dam into a concrete ramp.

The water shot down the spillway, forming a vortex that dissipated its energy as the water cascaded down the spillway. ramp, lost much of its destructive power with the ramp in place Engineers were able to safely operate the largest hydroelectric dam in the U.S., a title the Grand Coulee Dam retained to this day, the builders of The Three Gorges Dam face a similar problem, they must also ensure that their dam is not damaged by the flood water passing through it, basically the dam retains a large volume. of the water during the flood period here can hold around 22 billion cubic meters of water and then it is released in a controlled manner through this system of 46 spillway gates and these conduits, as you can see below me here the design of a spillway like This has to deal with the force of the water as it falls more than 100 meters in this case and then reaches a high speed at the bottom of the dam to deflect the force of the crashing water.

The Chinese use technology similar to the Grand Coulee as The water levels rise. Engineers open a series of gates to drain flood water from the reservoir, but if the water fell directly it could undermine the dam's foundation, so engineers equipped the spillway with concrete spouts, unlike the Grand Ramp. Coulee that is underwater. The Three Gorges shots launch water into the air, once in the air, the water splits into small droplets and loses much of its destructive energy, landing more than a hundred meters downstream, where it cannot cause any damage, so now, when they open the spillway gates, the Chinese have nothing to worry about, thanks back in 1942, the Grand Coulee showed how dams could cope with the abrasive power of flood water, but to build a dam at across the mighty Yenessy River in Russia, engineers had to find a way to stop the water while keeping ships moving In the 1960s, the Soviet Union wanted to increase its industrial power, so they planned a series of gigantic dams. .

One of the first. The dam would extend for a kilometer along the Yennessy River and generate 6,000 megawatts of power, but this river was also the main shipping route to Siberia and would be blocked by the dam to keep ships moving. The engineers came up with an ingenious plan: they decided to build a steel trough large enough to carry a ship and then planned to push the trough and ship it to the top. of the dam here they would spin the entire Contraption and lower it back into the river on the other side to move the seven thousand ton load they would use hydraulic pumps engineer Ed McCann uses a hot water bottle to demonstrate the principle behind hydraulic power Lo which is a water bottle is a pipe that goes to this piece of garden hose and is connected to this little water tank here, so let's see what happens.

I'm going to lift it about three feet, so I lifted it up. went up a meter now the pressure in this system has increased but it hasn't increased enough to lift this yet so there is no movement the hot water bottle is still crushed now I'm going to stay back here because I don't want a load of blocks on my head, so I'm lifting them up, now it's about three meters and you can see that the concrete blocks are moving very fast. Now I'm going to take them to the top, which is about four meters, and there they go.

You can see that there is amazing power and strength you can get from water under pressure and that's what we use to lift big, heavy things. Russian engineers used liquid under pressure to lift their ship. On the walls of the chamber there were powerful bombs that pressed. Hydraulic fluid under immense pressure in a set of motors mounted beneath these drove enormous steel gears that propelled the channel along a guide ramp. The engines generated so much traction that they raised the chamber from the river to the reservoir in just 90 minutes when the ship's elevator opened the Citizens of Krusnayask flocked to the foreigners.

Marvel was the crowning glory of the world's largest dam in China's three beautiful dams. Engineers also face a major traffic problem. Its dam is located on one of the busiest rivers in Asia. The Yangtze is a really important river. Waterway for shipping traffic in China running from the coast of Shanghai to Yi Chang and on to Chongqing. It has been transporting around 18 million tons of cargo per year and transporting around 170 ships per day through a dam more than 100 meters high. a difficult task for engineers worthy of the largest dam on Earth, the Chinese solve it by building the largest lock on Earth, ships enter the lock at the bottom of the dam, the gates close, the water floods and lift the boats to the next lock. pass through five levels of locks to reach the top, which can take up to four hours, a penalty for cargo ships, but for the many passenger ships operating on the Yangtze it is too slow to provide a further transit opportunity. efficient for the passenger traffic they have built.

This boat lift system here will allow boats to pass through in approximately 36 minutes. Unlike the abandoned ship in Krusnayask, the Three Gorges will lift ships upward like an elevator and the secret of its success will be hidden in its concrete walls. Engineers will place a series of huge counterweights that will do most of the lifting. Sixteen thousand-ton concrete blocks will be connected by cables to the steel trough that will transport the ship and the water in which it floats. As the counterweights fall, they will lift the trough upward. and lift the ship to the top um, this chip elevator here is 113 meters high and can handle ships up to 3000 tons.

It will make it the largest in the world and double the size of the one that crushed Meowsk, no doubt when you look at the structure now it has a ways to go in terms of construction it won't be finished until 2015 but it is clearly huge it is another very impressive achievement underway here foreign dams have produced more and more energy the day there is hardly a form of energy that is as clean as hydroelectric power, but as the dams grow, so does their impact on the environment by design of the three beautiful dams. Chinese engineers must ensure that their structure does not completely block the way nature feeds the land with the Three Gorges Dam.

It produces more energy than any other, but that's not the main reason it was built. The Yangtze River is known for its really severe flooding over the past two thousand years. There has been about one major flood every 10 years in 1931. There was one really serious death. 135,000 people destroyed almost 2 million homes and this is the main reason they built the Three Gorges Dam: to control this terrible flooding problem. The dam blocks the path of destructive flood water. Water is stored in its reservoir and then released in a controlled manner and flood water management can also have serious environmental side effects, as recent history has shown.

In 1970, Egyptian engineers built the US-1 High Dam across the Nile River to control foreign floods, but soon Downstream farmers noticed that their crops were beginning. When it failed, its soil became so barren that farmers needed millions of tons of fertilizer each year to nourish their crops. Their land had suffered because it had been deprived of flood water, which carries with it the vital components of life, as demonstrated by chemist Dr. Andrew Shidlow. here we have our clean rainwater that has been falling, we are adding some good quality topsoil to it, then we add some animal droppings, we have some snail shells essentially made of calcium carbonate, then we have some dry leaves, vegetation vegetable here and, of course, fish.

As the storm progresses and the water begins to flow rapidly, all of these ingredients mix together in the enormously violent storm waters that are produced, so here we have a true cocktail of Mother Nature's most important plant nutrients, nitrogen, phosphorus, calcium, magnesium and potassium, but if the water is flooded the water stops flowing these nutritious silt particles will begin to settle.It is a big problem, especially in the largest dam in the world, the flow of the precious Yangtsy silt is blocked by the dam and trapped in the slowly moving water of the reservoir, it quickly sinks to the bottom, where it accumulates.

The consulting problem in the Yangtze is a huge problem. The total amount that falls is about 500 million tons per year, which is equivalent to approximately one cubic kilometer, enough to fill large sports stadiums hundreds of times over. It's a huge amount of sediment. If this sediment remains trapped behind the dam, it would mean that farmers, fishermen and wildlife would be deprived of nutrients in the water for hundreds of miles downstream and tons of sediment or settled sediment could accumulate in the reservoir and threaten the dam itself, basically sediment. falling into the reservoir here would reduce the capacity of the reservoir and eventually perhaps interfere with the ability to run the turbines if it got that high.

Chinese engineers cleverly exploited the power of flood water to remove sediment from the reservoir and send it downstream abroad, installing gates deep in the dam. Each gate weighs as much as a bus and requires a powerful hydraulic piston to lift it when operators open the gates. The floodwater runs over the trapped sediment and sweeps it across the dam. Just as Chinese authorities expect it to be at least another 100 years before sediment buildup affects energy production as the Three Gorges project nears completion, its scale is impressive even with some of its turbines yet to be turned on.

It produces more energy than any other dam in the world, built on the shoulders of historic engineering giants. The Three Gorges are really the ultimate hydroelectric dam until someone builds an even

bigger

one abroad.