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Old 11-28-2019, 10:36 PM
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Wind Turbines


Some Questions: How much energy is used to manufacture ONE of those giant wind turbines? How much energy is required to produce the various parts that go into ONE of those wind turbines? How much energy is needed to transport to a suitable site and install ONE of those wind turbines? How many years of service can ONE of these wind turbines be expected to deliver? How many parts of these wind turbines can be recycled when their usable life is gone? How many of the parts just end up in a landfill? And finally, ALL things considered, do these wind turbines actually produce MORE energy then they consume over the life of the unit?
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Old 11-28-2019, 10:41 PM
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This is an older paper, but even then, the conclusion was that a turbine generates 20x of it's embodied energy over it's lifetime.
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Old 11-29-2019, 12:34 AM
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A wind turbine pays back its energy cost in 3-6 months. That includes all future maintenance and decommissioning as well.

Wind Turbines' EROI is around 20. The only better EROI is hydroelectric, at 40. But that comes with its own, IMO much larger, set of problems and challenges.

Last edited by MrDibble; 11-29-2019 at 12:35 AM.
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Old 11-29-2019, 12:53 AM
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Sorry, I should have said EROI is Energy Return On Investment.

And I was only considering renewables when saying what was better. Depending on how its calculated, nuclear is better still.
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Old 11-29-2019, 01:02 AM
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I would think the same questions could be asked of any electrical generator. And it seems that wind turbines would be much less 'overhead' than others.

How much energy is used in digging coal out of a mine & transporting railcars full of it across the country to a coal-fired generator? Or a hydroelectric plant: how much energy did it take to build the dam, and how much will it eventually cost to remove it*, plus energy to build & install the generators?

*Here in the Midwest, we are running into problems with the remains of small hydroelectric plants on minor rivers, that became not cost-effective to operate, and were abandoned. Now they often have empty, falling-down buildings there, and the dams are deteriorating without maintenance. And these were often set up a separate corporations,which are now out of business -- the main electric company survives, but disclaims all responsibility for cleaning up after that 'separate' company.
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Old 11-29-2019, 02:03 AM
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Wind is not consistent power. If you want to factor in the total cost of wind generation, you also have to factor in the cost of having a fossil fuel (usually) plant idling to pick up the generation slack when the wind dies down.

In some places, wind is used to store energy by doing things like pumping water uphill, then releasing the water into hydroelectric turbines. When these types of energy storage methods are used, then the power output is more constant and you don't need a fossil fuel plant idling. But then you also have to factor in the cost of the pumps and hydro generators.

Even factoring in all of these considerations, wind turbines produce quite a bit more power over their lifetime than they consume.

The expected lifespan of a modern wind turbine is about 20 to 25 years. The reliability and expected life have been increasing in recent years, and the costs (directly related to the energy required to produce them) has also decreased substantially.
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Old 11-29-2019, 07:47 AM
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Quote:
Originally Posted by engineer_comp_geek View Post
...The expected lifespan of a modern wind turbine is about 20 to 25 years. The reliability and expected life have been increasing in recent years, and the costs (directly related to the energy required to produce them) has also decreased substantially.
There are various numbers for annual operations and maintenance costs for each type of power plant. This recent document says nuclear, coal and wind are all about $2 per megawatt hr, and hydro is $2.50: http://www.caiso.com/Documents/Varia...-Dec212018.pdf

The largest U.S. wind farm, Alta Wind Energy Centre in Tehachapi California produced 3.37 terawatt hr in 2018. That implies the annual operations and maintenance cost is about $6.74 million, not that much considering the plant cost was $2.9 billion.

By contrast the average U.S. nuclear plant produces about 8.2 terawatt hrs per year, operations and maintenance cost apparently similar to wind in $/watt hr, but the construction cost is much higher.

It may be hard to understand why a "simple" wind turbine would have a life limit or require significant maintenance. Starting at about 10:30, this video contains a good explanation of the physics and mechanics involved: https://youtu.be/Fq3NgMqt_K0
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Old 11-29-2019, 08:08 AM
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Originally Posted by Mangosteen View Post
And finally, ALL things considered, do these wind turbines actually produce MORE energy then they consume over the life of the unit?
If they didn't then nobody would be building them because there would be zero economic point in doing so.
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Old 11-29-2019, 08:36 AM
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If they didn't then nobody would be building them because there would be zero economic point in doing so.
It would be far worse than zero. Significantly negative.

There are costs in putting up a wind turbine: Energy, materials, manufacturing, installation, etc. These costs are recovered by selling the energy produced. So all of those have to be paid back and ergo one can see that the input energy must be just a fraction of it.

Note that not all standby energy for wind is fossil fuel. On the Columbia River in the PNW there is a lot of hydro.

You don't actually have to pump water up into the dams. When not all the water is needed you just reduce the flow thru the dams and use as much wind power as you can get. When the wind dies down, put more water thru. Effectively a highly efficient energy storage system.

(When the water is high and they're running the dam turbines full out, there are times when the wind turbines above the dams on the Columbia Plateau are idle since there is no need for their energy on the grid. The Texas grid has a similar excess of wind power at times. This is unfortunate. Problems such as this can be fixed by upgrading our grids. )
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Old 11-29-2019, 08:51 AM
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Quote:
Quoth Colophon:

If they didn't then nobody would be building them because there would be zero economic point in doing so.
Would that that were true. Fuel ethanol does have a negative return on energy investment, and yet it's still profitable, due to some very ill-advised government subsidies. Renewable energy like wind also gets subsidies (in most places, at least; Ohio recently re-defined wind as not being renewable), and so it's reasonable to ask whether those subsidies are the only reason it's profitable.

Or for the more extreme answer, the total cost of most fossil fuel plants is greater than what they produce, too, except that we as a society have decided that the users of fossil fuels don't need to pay the total costs.

Happily, the answer in this case is that wind energy, even accounting for all of the costs, is still actually profitable.
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Old 11-29-2019, 01:51 PM
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... the answer in this case is that wind energy, even accounting for all of the costs, is still actually profitable.
Overall, yes. But there are more than a few locations where wind turbines are built only to "harvest the subsidy".

I live in one - central PA - where the would-be turbine builders are strongly sensitive to the cost of construction and the production tax credit they will receive. Local "green" groups fight these projects on the basis that the overall energy balance is unfavorable and the huge turbines have numerous negative effects. But the essential point is that with sufficient subsidy they can still be profitable.
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