For a 1 MW turbine, a typical slab foundation would be 15 meters in diameter and 1.5 to 3.5 meters deep. The foundation for turbines in the 1 to 2 MW range typically uses 130 to 240 m3 of concrete.
In a wind turbine foundation, how many yards of concrete are used?
Lafarge North America cement was used in the construction of the Blue Creek Wind Farm in Ohio, which is owned and operated by Iberdrola Renewables, earlier this year. With 152 Gamesa G90 turbines, the facility has a producing capacity of 304 MW, making it one of the world’s largest wind power stations.
Irving Concrete of Ohio built a portable ready-mix batch plant to create around 122,500 yd3 of concrete for the project, using Type I portland cement from Lafarge’s Paulding plant. 30,000 tons of cement were used to build 15 to 20 foot-deep concrete foundations to support all of the 328-foot-high towers with 2-MW turbines. Each of these below-ground support systems required 60 truckloads (750 yd3) of concrete, which was poured in two stages. Step one was to pour a 2-foot thick mud matte to form a sturdy basis, and step two was to pour an upper pedestal where the tower attaches. The massive bolts that secure the tower were embedded in the concrete’s upper part. To ensure a solid cure, quality testing was performed at 7, 14, 21, and 28 days.
Lafarge also contributed 20,000 tons of Type I cement for the soil stabilization of about 44 miles of roads, allowing access to the site despite severe soil conditions and laying the foundation for permanent roadways. The country roads were ground down, mixed with 5% cement at a 12-inch treatment depth, and allowed to harden before being coated with asphalt because they were not designed to bear the significant construction traffic loads. This provided a strong foundation that could withstand the huge truckloads of concrete and other construction equipment required to erect the wind turbines. “Because of the stronger and more durable base underneath, the restored streets will require significantly less maintenance in the future,” stated Tom Rapp, Lafarge’s Major Market Manager. “The enhanced long-lasting roadways in what is primarily maize and soybean country are in considerably better form now for vehicles delivering these agricultural products.”
The Blue Creek Wind Farm offsets carbon dioxide emissions by around 1.6 billion lb/year, which is comparable to planting an estimated 138,000 acres of trees, when compared to the rest of Ohio’s electricity generation fleet.
What is the diameter of a wind turbine’s base?
Wind energy is booming in the United States; the country’s renewable energy capacity has more than tripled in the last nine years, thanks mostly to wind and solar power. Businesses now want to harvest even more wind energy at a reduced cost, and one of the most cost-effective methods to do so is to build larger turbines. That’s why, with a height of 500 metersnearly a third of a mile and 57 meters higher than the Empire State Buildinga group of six institutions led by University of Virginia experts is designing the world’s tallest wind turbine.
Turbines are much bigger now than they were 15 or 20 years ago. Wind farm towers vary in size, but most are roughly 70 meters tall and have blades that are about 50 meters long. Their power production varies depending on size and height, but it usually falls between one and five megawattsenough to power around 1,100 households on the higher end. “The drive to go to larger wind turbines is largely economic,” says John Hall, an assistant professor of mechanical and aerospace engineering at the University of Buffalo, S.U.N.Y. Wind blows stronger and more persistently at higher elevations, which makes huge turbines more cost-effective. As a result “According to Eric Loth, project head of the enormous turbine project, which is sponsored by the US Department of Energy’s Advanced Research Projects AgencyEnergy (ARPAE), “you capture more energy” with a taller structure.
Another reason why bigger is better, according to wind experts, is that longer turbine blades capture the wind more efficiently, and taller towers allow for longer blades. The power of a turbine is proportional to its size “According to Christopher Niezrecki, a professor of mechanical engineering and head of the University of Massachusetts Lowell’s Center for Wind Energy, “swept area” refers to the circular area covered by the blades’ rotation. And, as Niezrecki shows, this relationship is not linear: if blade length doubles, a system can produce four times as much energy. He points out that larger turbines have a lower efficiency “The wind speed at which they can begin generating energy is known as the “cut-in” speed.
Loth’s team hopes to create a 50-megawatt system with blades that are 200 meters long, which is substantially larger than current wind turbines. The researchers predict that if they succeed, the turbine will be ten times more powerful than current equipment. However, the researchers are not simply enlarging existing designs; they are radically altering the turbine construction. The ultralarge machine will have two blades rather than the typical three, reducing the structure’s weight and slashing costs. Although lowering the number of blades would normally make a turbine less efficient, Loth claims that his team’s sophisticated aerodynamic design compensates for those losses.
According to Loth, the team also envisions these massive structures standing at least 80 kilometers offshore, where winds are greater and people on land cannot see or hear them. But when powerful storms hit such locationsfor example, off the east coast of the United States in the Atlantic Oceanteam Loth’s was faced with the challenge of designing something large while remaining relatively lightweight and sturdy in the face of hurricanes. The researchers used one of nature’s own design ideas to solve the problem: palm plants. “Palm trees are very tall, but physically they are very light, and the trunk can bow if the wind blows hard,” Loth notes. “We’re attempting to use the same notion by designing our wind turbines to be flexible, bending and adapting to the flow.”
The two blades are situated downwind of the turbine’s tower in the team’s design, rather than upwind as they are on standard turbines. Like a palm tree, the blades change shape in response to the direction of the wind. “You don’t need to construct the blades as heavy or sturdy when they bend back at a downwind angle, so you can use less material,” Loth explains. This design also reduces the risk of a spinning blade being bent toward its tower by heavy winds, potentially bringing the entire structure down. “At high speeds, the blades will adjust and begin to fold in, reducing the dynamic stresses on them,” Loth explains. “In non-operational conditions, we’d like our turbines to be able to handle winds of more than 253 kilometers per hour.” The system would shut down at 80 to 95 kilometers per hour, and the blades would bend away from the wind to survive powerful gusts, according to Loth.
The 500-meter turbine still confronts difficulties, and there are valid reasons why no one has attempted to build one of this size: “How do you produce blades that are 200 meters long? What’s the best way to put them together? How do you build such a tall structure? Cranes can only reach a certain height. “There are additional challenges with offshore wind,” Niezrecki adds. The team’s idea features a segmented blade that could be constructed on-site from sections, but Niezrecki points out that the wind industry has yet to find out how to segment blades. “He says, “There are a lot of research questions that need to be answered.” “It carries a significant risk, but it also has the potential for a great payout. Those issues, in my opinion, are not insurmountable.” Hall also wonders if such a huge turbine is the best size. “We’ve discovered that bigger is better. The question is, how much larger will it be? He continues, “We need to find that sweet spot.” “This project will teach us a great deal.”
Loth and his team have yet to test a prototype; they are now designing the turbine’s structure and control system, and this summer they will build a model that is about two meters in diameter, much smaller than the actual thing. They intend to build a larger version with two 20-meter-long blades that will generate less than a kilowatt of power and will be tested in Colorado next summer. Loth himself is unsure whether his team’s massive turbine will become a reality, but he believes it is worth a shot. “There are no promises that this will succeed because it is a fairly novel concept,” he explains. “But if it succeeds, offshore wind energy will be transformed.”
What is the weight of a wind turbine base?
A 1.5-megawatt (MW) wind turbine with a tower 80 meters (260 feet) tall is common in the United States. The total weight of the rotor assembly (blades and hub) is 22,000 kg (48,000 lb). The generator is housed in a nacelle that weighs 52,000 kilos (115,000 lb). The tower’s concrete base is made up of 190 cubic meters (250 cu yd) of concrete and weighs 26,000 kilograms (58,000 lb) of reinforcing steel. The base has a diameter of 15 meters (50 feet) and is 2.4 meters (8 feet) thick at the middle.
What is a wind turbine’s foundation?
Towers of wind turbines Gravity and monopile foundations are widely employed in shallow waters. Rather as gravity type foundation, monopile type foundation is most usually employed. In sea depths more than 10 meters, constructing a gravity type foundation is prohibitively expensive.
What is the steel content of a wind turbine foundation?
For a 5-megawatt turbine, the steel alone averages 150 metric tons for the reinforced concrete foundations, 250 metric tons for the rotor hubs and nacelles (which house the gearbox and generator), and 500 metric tons for the towers.
What is the depth of wind turbines in the ground?
The steel tower is supported by a platform that is 30 to 50 feet across and 6 to 30 feet deep, and weighs over a thousand tons of concrete and steel rebar. To assist anchor it, shafts are sometimes driven down further. To produce a flat area of at least 3 acres, mountain tops must be blasted. The platform is essential for supporting the turbine assembly’s massive weight.
On an acre of land, how many wind turbines can be installed?
While there is no definite answer to the question of “how many acres do I need for a wind farm?” there are certain guidelines to keep in mind. Wind leases, for example, typically demand a lot more land than solar leases. Because wind turbines take up a lot of room and wind farms need to be spaced far apart to allow for turbulence, developers are frequently looking to lease thousands of acres. On an acre of land, how many wind turbines can be installed? Each wind turbine can take up to 80 acres of land to install, and each turbine produces roughly 2.5 megawatts. Surface activities such as farming can still take place on much of the land because wind turbines are placed so widely apart.
What is the blade thickness of a wind turbine?
On TSR 0.3, the turbine with blade thicknesses of 2.6 mm and 10 mm has the maximum Cp value. The turbines with blade thicknesses of 15 mm and 20 mm, on the other hand, have the highest Cp on TSR 0.2. Overall, the turbine with a blade thickness of 20 mm has the highest Cp value of 0.499.
How big are the feet of a wind turbine?
In any case, the goal is to keep making turbines bigger and bigger. When it comes to land-based (onshore) turbines, the process runs into a number of non-technical roadblocks, including transportation and infrastructure bottlenecks, land-use considerations, concerns about views, huge birds, and shadows, among other things.
However, wind power is increasingly moving out to sea, particularly in Europe. And out in the middle of the ocean, where land is barely visible, the only restriction to size is engineering. As a result, offshore turbines are now growing at a higher rate than onshore turbines over the last decade.
In March of this year, a clear example of this pattern emerged (when I first published this story). GE Renewable Energy said that it will invest $400 million in the development of a new monster turbine called the Haliade-X, which will be the world’s biggest, tallest, and most powerful turbine (at least until the next big announcement).
It’s a remarkable engineering achievement, but the significance of increasing turbine size goes far beyond that. Turbines that are larger gather more energy and do so more consistently; the larger they are, the less variable and predictable they become, and the easier they are to integrate into the grid. On wholesale energy markets, wind is already outcompeting traditional sources. It won’t even be a competition after a few more generations of expansion.
What wind turbines are getting up to
Let’s start with some comparisons to get a sense of the size of this new GE turbine.
To gather the most up-to-date information on wind turbine sizes, I called Ben Hoen, a research scientist at Lawrence Berkeley National Laboratory. (He emphasizes that these are early data; LBNL will release a report on this in a few months, but he does not expect the figures to change significantly, if at all.)
In 2017, the average overall height (from base to tip) of an onshore US turbine was 142 meters, according to Hoen (466 feet). The median turbine height was at 152 meters (499 feet). In fact, according to Hoen, the median is getting close to the maximum. In other words, onshore wind turbines in the United States appear to be gradually approaching that height. Why? Because if you build higher than 499 feet, the FAA demands certain more steps in their clearance process, which most developers don’t seem to think is worth the trouble.
The Hancock Wind project in Hancock County, Maine, houses the world’s tallest onshore wind turbines. Those are around 574 feet tall Vestas V117-3.3s, if you must know.
So that’s all for the onshore. What about a trip to the islands? So far, the US has only one operational offshore wind farm, the Block Island Wind Farm off the coast of Rhode Island. Its turbines reach a height of about 590 feet.
How does the Haliade-X stack up against all of that? It will be 853 feet tall, according to GE.
That would be the world’s tallest wind turbine, as far as I’m aware. The previous record holder, as far as I can gather from searching (as I said, these things change frequently), is an 809-foot onshore turbine in Germany.
Bigger turbines mean more power, more often
However, height isn’t the only factor to consider. There are a few other accolades for the Haliade-X.
The whole sweep of the turbine’s blades is measured by the rotor diameter (the diameter of the circle they define). When all other factors are equal, a larger rotor diameter means the turbine can capture more wind.
According to Hoen, the average rotor diameter of US wind turbines was 367 feet in 2017. The rotor diameter of the Haliade-X will be 722 feet, which is almost double the average. The blades will be massive, measuring 351 feet in length each, longer than a football field and longer than any other offshore blade to date, according to GE.
The Haliade-X will have a very high capacity factor because to its huge rotor diameter, steady offshore wind, and 12MW turbine (onshore averages approximately 3MW; offshore around 6MW).
The following excerpt from the 2016 Wind Technologies Market Report by the Department of Energy illustrates how wind capacity factors have changed over time: “The average 2016 capacity factor for projects completed in 2014 and 2015 was 42.5 percent, compared to 32.1 percent for projects completed between 2004 and 2011, and just 25.4 percent for projects completed between 1998 and 2001.”
In 2016, the nuclear fleet in the United States had an average capacity factor of roughly 92 percent. (Nuclear is only economically viable in today’s markets when it is used as a baseload generator.) Coal and natural gas accounted for 55 and 56 percent of the total. (Natural gas is so cheap because it is routinely ramped up and down to match demand swings.) Coal used to be close to 80 percent, but it is becoming increasingly uneconomic to operate coal plants.)
So, in the United States today, wind energy accounts for 42.5 percent of total energy consumption, whereas natural gas accounts for 56 percent. According to GE, the Haliade-X would have a capacity factor of 63 percent. Though it wouldn’t be the highest in the world, the floating offshore turbines in the Hywind Scotland project just surpassed 65 percent.
When you add it all together, each Haliade-X will produce roughly 67GWh annually at a “typical German North Sea location,” according to GE, “enough clean power for up to 16,000 people per turbine, and up to 1 million European households in a 750 MW windfarm configuration.” (It goes without saying that the number would be lower for energy-sipping American households.) That’s it “It generates 45 percent more electricity than any other offshore wind turbine on the market today,” the business claims.
In Rotterdam, the Netherlands, the first Haliade-X is now being built. In April, GE said that it would start producing electricity later this year.
Bigger turbines that run more often are going to crush all competitors
This 2015 piece by energy researcher Ramez Naam on the ultimate potential of wind power is one of my favorites. “Even at today’s price per kwh, wind at 60% capacity factor would be considerably more useful than it is currently, with fewer constraints to how much of it we might utilize,” he wrote.
- The more volatile a source is, the more backup is required to solidify and ensure its reliability. (At the moment, backup is mostly provided by natural gas plants, however batteries are becoming more common.) Higher capacity factors lower backup costs by making wind less variable and more reliable.
- Renewable energy that is variable (sun and wind) has a tendency to “eat its own lunch.” The next increment of capacity added lowers the clearing price for all the other increments since it all produces energy at the same time (when the sun shines or the wind blows). The lower the price, the more energy comes online at once. A turbine with a 60 percent capacity factor blunts and reduces this price-suppressing effect by spreading its energy out over a longer period about twice the 32 percent of 2011-vintage turbines.
Although a capacity factor of 60% or above isn’t precisely “baseload,” it does appear to be less variable. Even if the price of wind energy remained constant, turbines like the Haliade-X would be more valuable.
It won’t stay the same, though; it’s down 65 percent since 2009. According to a recent NREL analysis, advancements in wind power technology (including larger turbines) could reduce it by another 50% by 2030. (University of Virginia researchers are working on a design for an offshore turbine that will be 1,640 feet taller than the Empire State Building.)
Assume that by 2025, new wind turbines in the United States have an average hub height of 460 feet, which is substantially in line with current forecasts. According to NREL research, such turbines may have capacity factors of 60 percent or higher across more than 750,000 square miles of US land and 50 percent or higher across 1.16 million square miles.
With expected developments in wind technology, that much wind, at that capacity factor, will create power cheap enough to demolish all competitors. And the year 2025 isn’t all that far away.
What is the depth of foundations for offshore wind turbines?
Offshore wind turbines, which are anchored to the seabed with monopile or jacket foundations, can only operate in waters less than 50 meters deep. This eliminates sites with the greatest winds and, in many cases, easy access to large markets.