Pros and Cons of Wind Turbines, Does it Worth It?
Author: Mark Gavalda
In short: resounding yes. Many are against wind turbines and wind farm building, and I have to admit they have a few good reasons other than the stupid „I don’t like the look of wind mills in the countryside”. Well, I don’t like that the Arctic is getting smaller and smaller every day, and the fact that maybe my children won’t be able to experience the world as it is today. Letting go of the untouched view is a small sacrifice in exchange for nothing less than the whole future of Earth.
Wind turbines do not produce constantly. Their performance varies based on the actual power of the wind. This can be from zero to storm force!
Efficiency is not the best available: a modern turbine running at its normal pace can deliver power to 500 households. Count quickly how many would be needed for a city with 20 million habitants?
It is not true that wind turbines are 100% environment friendly, because when factories produce them, they do emit pollution into the air. But that is a onetime pollution against the constant negative effects of regular ways.
They are noisy creatures. One turbine can produce the same level of noise as a car travelling at 60mph on the highway! You certainly don’t want that under your window constantly.
BUT almost all of these are against the industrial versions, not the ones built for home usage.
The wind is free, and it can be captured with good efficiency nowadays compared to the results some decades ago.
They do not take large portion of lands like solar farms do! The land around these small towers can be cultivated or used in a different way without any problem!
The other half of people thinks they add to the view of the landscape!
If you live on the top of the hill or miles away from any civilization you can still generate your own power with smaller wind turbines!
And the last and best one: you can build one yourself! It’s an easy process and nowadays there are complete guides available. You can view a few of these on the link found at the end of this article!
Article Source: http://www.articlesbase.com/moving-and-relocating-articles/pros-and-cons-of-wind-turbines-does-it-worth-it-553101.html
About the Author
Mark Gavalda is an environment enthusiast, author of several articles in the Green and Eco industry. You can find more interesting news, articles, how-to guides at his online magazine: http://www.EcoTaz.com click on the link to visit!
How efficient are small wind turbines for homes (not wind farms) in percent efficiency? Which small is a buy?
Germany has a program (“A Million Points of Light”) to install wind turbines in homes. Finland has small vertical axis wind turbines going up in cottages, on chimneys.
Which is the best design for a home-power installation? What are the efficiencies of the different blade designs?
Anybody know anything about the ‘bent-prop’ design, like this one?
http://wind-farm.blogspot.com/
Does the chimney need to be reinforced?
How high does the wind turbine have to be, over the tallest house in the neighborhood?
What is the formula of the efficiency of gaz turbines?
what is the maximum possible efficiency of these turbines?
A typical nuclear power plant delivers heat from the reactor to the turbines at a temperature of 460°C. If the turbines release heat at a temperature of 260°C, what is the maximum possible efficiency of these turbines?
Why the difference in behavior of compressor and turbine efficiency?
Hi,
I have been trying to understand how compressor efficiency and turbine efficiency affects the outlet temperatures of compressor and turbines.
What I read in books is the following:
“Since efficiency is never 100%, the temperature rise during compression process (in compressor) is actually HIGHER than what would have been in ideal isentropic process. The temperature fall during expansion process(in turbine) is actually LESSER than the ideal isentropic expansion process.”
Can anybody explain why this happens in the two cases.? I have been trying to understand if this is indeed intuitive.
Thanks!
what level of efficiency does 2 MW wind turbines run at?
I need to know what level of efficiency a 2 MW wind turbine runs at? So does it only run at 50% efficiency, making it only produce 1 MW an hour?
Thanks everyone!
According to Carnot’s theorem maximum efficiency of a heat engine is related to the absolute temperature ratio of cold and hot reservoir as:
η_max = 1 – Tc/Th
for
Tc = 260°C = 533K
Th = 460°C = 733K
η_max = 1 – 533/733 = 0.273 = 27.3%
For the efficiency calculation the formula
Power in wind = (density of air ) x (turbine blade diameter)2 x( velocity of wind)3 x (a constant)
Power in wind = d x D2 x v3 x c
Notice that the power in the wind depends on the density of the air, the diameter of the turbine blades squared (D times D), and the velocity of the wind to the third power (V times V times V). There is also a constant in there which I’ll discuss in the very next paragraph.
What about that constant, C? It’s there because what we are really interested in is the Area swept by the blades of diameter, D. The area is calculated by multiplying the number Pi (approximately 3.14159) times the diameter squared divided by 4. So part of the constant, C, is just the constant number Pi divided by 4 pulled out to show us that the important variable in the area formula is D. The other part of the constant, C, can be whatever unit conversion numbers are needed to make sure the numbers come out right. For now, we won’t go further into that. The point is that the variables that determine the wind power blowing into a wind turbine are air density, blade diameter (resulting in a certain swept area), and wind velocity.
You have probably noted that power (not energy) is dependent on the velocity times itself 3 times (V x V x V). Whoa! In other words, if the wind speed doubles, the power available from the wind increases by a factor of eight. The diameter is significant too. Doubling that increases the power by 4 times. Faster is better, and bigger is better (if you can afford it and can build it strong enough).
Of course, the wind doesn’t blow all the time in most places and when it blows too hard the turbine blades can break or spin so fast they break off (not good when each blade can weigh several tons). In that case, the blades are usually “feathered” to reduce stresses on them and to slow them down. This means we can’t take advantage of really high wind speeds.
Turbine Efficiency
If the turbine could convert all the wind’s power to mechanical power we would say it was 100% efficient. But as you probably know, the real world is never so generous. To even achieve 50% is unlikely, and would be a very efficient machine. A 50% efficient turbine would convert half of the power in the wind to mechanical power.
Hope this will solve your problem
Regards
For other references
Efficiency Varies with Wind Speed
A given wind turbine has a “design point” that generally defines its peak efficiency at the wind speed for which the system is designed. At wind speeds above and below the design speed the efficiency is the same or less – maybe much less. If a turbine’s best efficiency is 40% at a wind velocity of 9 meters per second (about 20 mph), it will be 40% only at that wind speed. At all other wind speeds it will be something worse. That wind turbine will generally operate at lower than its best efficiency, because wind speeds are never constant or average.
The electric power actually produced will be still lower because the generator efficiencies are also less than 100% (generally in the mid- or low-90′s at best), and there are further losses in the conversion electronics and lines. But this is true of all power technologies. When all these losses are figured in, you might, if you are lucky, be getting 35% or so of the wind’s energy actually delivered as useful electrical energy to the end user in the very best conditions. The average might only be in the twenties.
In the formula above, then, we have to add one more number that I don’t show. That number is an efficiency number that would have to supplied by the manufacturer of the wind turbine, or experimentally determined by you if you make it yourself. It will not be one number, but a variable that is a function of wind speed.
Conservation of energy.
Suppose you have a 100% efficient turbine with a fixed mass flow and a fixed inlet temp and pressure. You take the maximum possible amout of work out of the gas stream (given the gas laws and the laws of thermodynamics) and you end up with some outlet temp and pressure values.
Now suppose the turbine is less than 100% efficient but the pressure ratio and mass flow are the same. You are taking less energy out of the gas (because the efficiency is less than 100%) so there is more energy left in the gas. That means the outlet temperature must be higher. (NB the book says the temperature FALL is less, not that the output temperature is lower)
The compressor is the reverse. If the efficiency is less than 100% you are doing more mechanical work to get the same compression ratio, so the “wasted” energy makes the outlet gas temperature higher.
The simplest formula for efficiency of a thermodynamic system is this:
Work Done by System / Work (Energy) input into System.
From that you have to go through and figure out which devices in the system are adding energy to the system and which are expending the energy. In this case, the turbine:
Energy out/Energy in X 100% = % efficiency.
Wind is free so it does not make sense to talk about efficiency.
robert h mentioned NOISE, that should be your primary concern.
Remember wind does not blow all the time, so, you will need a battery bank, and an inverter, to turn it into AC power. This is all rather complicated to run, if you do not have a technical bend.
Lookup some suppliers and ask them to explain it to you.