Advantages:
- Wind speeds off the coast are generally higher than on land. 1 Small improvements in wind speed result in significant gains in energy production: a turbine operating in a 15-mph wind can create twice as much energy as one operating in a 12-mph wind. Offshore, higher wind speeds mean more energy can be created.
- Offshore wind speeds are generally more consistent than on land.
- 1 A more consistent wind supply provides a more dependable source of energy.
- Many coastal places require a lot of electricity. Coastal areas are home to half of the United States’ population1, with concentrations in major coastal cities. Offshore wind turbines can assist meet these communities’ energy needs by supplying energy from neighboring sources.
- Offshore wind farms have many of the same benefits as land-based wind farms: they generate renewable electricity, do not consume water, are a domestic energy source, create jobs, and do not release pollutants or greenhouse gases.
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Disadvantages:
- Building and maintaining offshore wind farms can be costly and complicated. Specifically:
- Wind farms in water deeper than 200 feet (60 m), or more than half the length of a football field, are extremely difficult to construct. Despite the fact that coastal waters off the east coast of the United States are rather shallow, nearly all of the prospective wind energy resources off the west coast are in waters deeper than this. 3 Floating wind turbines are making progress in overcoming this obstacle.
- Wind turbines can be damaged by wave movement and even very high winds, especially during heavy storms or hurricanes.
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- It can be highly costly to manufacture and install power cables beneath the seafloor to transport electricity back to land.
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- The impact of offshore wind farms on marine creatures and birds is unknown.
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- Offshore wind farms that are built within view of the coastline (up to 26 miles offshore, depending on viewing conditions5) may be controversial with locals, affecting tourism and property prices.
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References
3 Executive Summary of Large-Scale Offshore Wind Power in the United States (2010) The National Renewable Energy Laboratory (NREL) is a non-profit
5 Visibility and Visual Impact Threshold Distances for Offshore Wind Turbines National Laboratory of Argonne
Why are wind turbines erected near the crests of hills?
“People turn to rules of thumb because tools for projecting how existing wind turbine farms will perform aren’t sufficiently developed,” said Richard Wlezien, Iowa State’s Chair of Aerospace Engineering.
However, you can’t just look at a bunch of turbines and determine whether or not this is a smart way to align them.
Because wind farm designs are still based on flat terrains, Hu argues that modeling turbines on slopes can provide a more accurate image of energy potential on hilly or mountainous terrain.
Hu’s group is investigating how a hill’s high grades affect turbine efficiency.
The findings demonstrate that turbines on steep terrain are subjected to higher wind loads than those on flat terrain.
As a result, as wind flows from turbine to turbine over hilly terrain, it recovers its power potential more quickly.
Hu claims that his findings suggest that turbine rows on hillsides might be closer together than previously anticipated.
“That implies you can install more wind turbines on the same acre of land, and hence more energy out of a given project,” Hu explained.
According to Wlezien, the traditional idea is to stagger the turbines so that one does not get caught in the wake of another.
However, Hu’s research suggests that in steep terrain, the upstream turbine’s effect may fade faster than expected.
As a result, turbine rows on slopes can be closer together.
“Putting one behind the other, especially on flat ground, may not be as horrible as it appears,” Wlezien remarked.
“It all depends on how far downstream you go.”
According to Hu’s research, when one turbine is placed downstream of another, there is enough mixing in the wake of the upstream turbine to make it attractive.
Developers may be forced to do so in order to reach the Department of Energy’s wind energy production targets of 20% of US electricity supply by 2030.
The United States would need to install more than 300 GW of wind energy capacity to reach its target. The United States would still need to deploy 150,000 more commercial wind turbines over the next two decades if each turbine had a minimum capacity of 2 MW. As a result, wind energy developers may have to examine unorthodox mountain sites to accomplish such objectives.
“There’s been a lot of misunderstanding about what constitutes a good and terrible placement for turbines,” Wlezien added.
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Higher height, on the other hand, means stronger winds.
In reality, according to Jim Manwell, Director of the University of Massachusetts at Amherst’s Wind Energy Center, the world’s first modern wind farm was built on Crotched Mountain in New Hampshire in 1981.
Wind turbines have lately been built on mountainside ski regions in Vermont and Massachusetts, he says.
The Intermountain West, the Appalachians, and hilly portions of the Northeast have the country’s strongest winds.
Wind turbines on mountaintops appear to be a smart idea at first glance, according to Manwell.
Because mountains act as natural towers, the wind speed is higher than in the lowlands surrounding them.
“Wind flow through steep terrain may be relatively turbulent,” Manwell noted, “and may be outside the range for which commercial turbines are designed.”
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This could hasten fatigue damage and early failure, necessitating component replacement.
As a result, reputable manufacturers may be hesitant to sell turbines in such areas.
There could also be difficulties obtaining finance or insurance.
According to David Minster, Manager of the Wind Energy Technologies department at Sandia National Labs in Albuquerque, wind farms are most cost effective in plains regions and flat mesas.
That is, sites where the wind and direction of the wind are known.
Although most wind turbines are intended to change direction to face the wind, Minster believes they would have to change direction frequently in mountainous places.
Professor of mechanical engineering Darrell Pepper of the University of Nevada at Las Vegas has looked into potential mountainous wind farm sites all around the state.
“Mountainous locations in Nevada have a lot of wind potential, but they’re so remote that they’re not cost-effective,” Pepper explained.
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But it’s the lack of electrical transmission lines, each of which could cost a million dollars per mile, that will sink the project.
What would have to occur for commercial wind energy to become more frequent in mountainous or hilly areas?
“To make it profitable, the cost of power would have to rise dramatically,” Minster stated.
Wind turbine blades would have to be more reliable, and the technology would have to be less expensive.
Wind farms will certainly continue to dominate the high desert and Great Plains in the United States until then.
What is the purpose of certain wind turbines in the ocean?
The advantage of placing wind turbines offshore is that the wind is significantly stronger off the coasts, and unlike wind over land, offshore breezes can be strong in the afternoon, which coincides with peak electricity usage.
Offshore turbines can also be placed near load centers along the coasts, such as large cities, reducing the need for additional long-distance transmission lines.
Offshore installations, on the other hand, have a number of drawbacks, including higher installation costs, difficulty of access, and harsher operating conditions for the units.
Offshore wind turbines are exposed to high humidity, salt water, and salt water spray, all of which reduce service life, cause corrosion and oxidation, raise maintenance and repair costs, and make every aspect of installation and operation much more difficult, time-consuming, dangerous, and expensive than onshore sites. The sealed nacelle’s humidity and temperature are managed by air conditioning. Wear, maintenance, and repair requirements rise correspondingly with continued high-speed operation and generation.
The turbine itself accounts for only one-third to one-half of overall expenses in today’s offshore projects; the remainder is made up of infrastructure, maintenance, and oversight. When compared to onshore wind farms, foundations, installation, electrical connections, and operation and maintenance (O&M) costs account for a considerable portion of the entire cost. The cost of installation and electrical connection rises significantly as the distance from the shore and the depth of the sea rise.
Other drawbacks of offshore wind energy include the still-small number of installations. As of 2017, the offshore wind sector is still not fully industrialized, with supply bottlenecks.
Is it true that wind turbines perform better on hills?
A three-year, $300,000 grant from the National Science Foundation and a two-year, $100,000 grant from the Iowa Alliance for Wind Innovation and Novel Development are funding the engineers’ research.
Wind tunnel tests are being used by the researchers to quantify the features of surface winds over steep terrains, determine the optimal location for wind turbines on hilly terrains, and find the best design for big wind farms on difficult terrains.
The following are some examples of experiments:
- The power production is measured by small generators positioned inside the mini turbine nacelles.
- Wind loads on turbines and turbine towers are measured using sensors positioned at the base of the tiny turbines.
- To measure wind flow fields, the wind vortices created by the tips of turbine blades, and the total wind energy captured by the blades, advanced flow measurements such as particle image velocimetry (which uses a laser and camera to take nearly simultaneous images that show the movement and velocity of individual particles) are used.
According to preliminary findings, wind turbines on steep terrain are subjected to significantly higher wind loads than turbines on level territory. In comparison to turbines on level ground, wind flowing over hilly terrain recovers its power potential more quickly as it moves from turbine to turbine, according to the research.
According to wind tunnel data, a turbine on level ground following another turbine at a distance of six times the diameter of the turbines loses 13% of its power generation. On hilly ground, a turbine in the wake of another with the same downstream distance loses 3% of its power generation.
What effect does a hill have on wind?
Within a boundary layer, wind flows. When a slope is encountered, the wind is pushed to flow faster across a limited area. That’s why, near the top of a hill, the wind is usually stronger.
Why is offshore wind preferable to onshore wind?
Offshore wind farms harness the power of the wind as it blows across the water. Because of the higher wind speeds, greater consistency, and lack of physical interference from the land or human-made things, they are regarded more efficient than onshore wind farms.
What is the mechanism through which windmills pump water?
- The windmill wheel’s blades, also known as sails, capture the wind and turn the rotor.
- Long arms connect the wheel assembly to the hub assembly.
- The hub assembly is connected to a geared mechanism that translates rotary motion into up-and-down motion.
- A lengthy sucker rod, also known as a pump rod, is driven up and down within a pipe in the well by this up-and-down motion.
- A cylinder with a sealed plunger running up and down inside is attached to the pipe’s end, forcing the water up the pipe.
- Water is drawn into the cylinder with each upstroke.
- Because a check valve in the bottom of the pipe prevents the water from being pushed out on the downstroke, the water is driven up the pipe on the following upstroke.
Why should Windmill’s location be appropriate?
Prior to the introduction of the USGS Windfarm Mapper, which was replaced by the U.S. Wind Turbine Database (USWTDB) in 2018, there was no publicly available, national database of wind turbines.
Knowing the exact position of individual turbines, as well as their technical details, opens up new avenues for research and better siting, as well as providing valuable information for land and resource management. Large turbines can also interfere with weather and air traffic radar. Knowing where and how tall the turbines are helps to better understand radar-wind difficulties and improves the efficiency of designing new radar and wind turbine placements.
What constitutes a good wind farm location?
There are five essential qualities of a good wind power site:
- Winds with a high average speed. The location is usually on top of a hill or in a large open space with no local barriers. See if you can find out how windy it needs to be.
- Separation from noise-sensitive neighbors is sufficient. Even though modern wind turbines are incredibly quiet, there are very strict maximum noise limits that must be met in order to gain planning approval. The minimum separation varies depending on the size of the turbine, however as a general rule, the following should prevent any problems:
- Connection to the grid is excellent. All of the wind turbines we sell need to be connected to a three-phase electrical source. As a rough estimate, you’ll need an 11 kV transformer or substation with nearly double the rated power output of the wind turbine you’re contemplating, or an 11 kV three-phase power line nearby that can be linked to a new transformer / substation.
Larger multi-MW turbines could connect to 33 kV power lines, although connecting at such a high voltage is often too expensive for smaller wind turbine projects.
- Access to the location is excellent. Because wind turbines are enormous and heavy, the site’s access roads and tracks must be capable of carrying oversize weights, with no weak bridges, overly tight turns, or high hills. As the projected turbine grows in size, the size of the constituent pieces that must be delivered grows in size, and the access requirements become more demanding. The Endurance 55 kW turbine is supplied on conventional articulated lorries, whereas the other turbines are delivered on special oversize trailers.
- There are no official designations for the environment or the landscape. Even though many of the older objections against wind turbines based on bird attacks have been proven to be false, it is still a prudent practice to avoid installing a wind turbine(s) in an area with particular bird designations. Wind turbines are often prohibited in peat bogs.
Wind turbines are very visible within the landscape, so sites with landscape designations such as National Parks or Areas of Outstanding Natural Beauty (AONB) will have more difficulty obtaining planning consent, though it is still possible to get planning consent in AONBs.
If your site fulfills these basic conditions, please contact us and we’ll conduct a preliminary (free) desktop evaluation, after which we’ll offer our wind feasibility study package if it still looks acceptable.
