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Comment by krschultz | Hacker News Reader

I've never heard the argument that current wind turbine are unsustainable before. I don't see why that would be so. The base is concrete, the tower is steel, neither of which is exotic. The generator is pretty standard. All of that is industrial tech we invented a century ago, and we know how to maintain it for the long haul.

The blades themselves are composite, that may have some longevity issues (you typically need to paint carbon fiber to prevent UV degradation every view years), but I don't know, they can last for a long time. Fiberglass boats last 50+ years.

I would imagine the designed lifecycle of a wind turbine is 25+ years, and I also imagine that the bases will last long beyond that. In 50 years we may have to go around and replace the blades on these things, but that's it.

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My understanding is that, among other things, the generators come under extreme stress during exceptionally windy occasions, causing a lot of wear and tear that happens way up at the top of these giant windmills.

These require a lot of manual maintenance, which is dangerous and expensive due to the nature (and location) of the work.

Additionally (and as a demonstration of just how much stress they come under), while coming under said strain, they've been known to burst into flames https://www.youtube.com/watch?v=C_oFPF6Anwo

As for their lifespan, the government agencies that build them claim 25 years, but there's controversy about this. Searching online will find you conflicting studies, including this one http://www.ref.org.uk/publications/280-analysis-of-wind-farm..., which states

"Analysis of site-specific performance reveals that the average normalised load factor of new UK onshore wind farms at age 1 (the peak year of operation) declined significantly from 2000 to 2011" indicating that they may wear out more on the order of ten years.

Now that was a cursory search but in any case the argument that the wind farms cost so much to maintain that they're nonviable is not new.

Wind turbines aren't exotic tech, but it is a giant turbine that is placed way up on a pole, and fundamentally a turbine will need maintenance, so someone has to go up and do that maintenance, and that's expensive.

What government agencies are out there mass-building wind? In terms of America at least, that's not how our generation system is set up.

Also, the recently-published Wind Vision[1] runs with an expected 20-year lifetime, and starts digging into system reliability specifics on page 70. Wind Vision was a lengthy collaborative process with industry, the labs, and DOE HQ. Good news is that there have been significant reliability gains in the gearboxes, generators, and electrical systems.

[1] http://www.energy.gov/windvision .pdfs are on the right.

> Additionally (and as a demonstration of just how much stress they come under), while coming under said strain, they've been known to burst into flames

I thought all wind turbines were built with brakes now exactly to prevent this and other more spectacular failure modes, like the blades fragmenting. They have a defined operating range, and if the wind isn't in that range the brakes engage and the blades don't move.

Not quite, if the wind is too strong the blades feather (edge on to the wind) brakes exist but are puny and are only for maintenance use. Some blades have a tip that the rotates and causes high drag in the event of feathering failing and going into an overspeed.

Current designs are not standardized, so the worst case is fairly poor. However, economically on average wind is fairly close to Coal Power and in some cases actually cheaper even without subsidies. So, there is no way for it to be a net loss energy wise because electricity is vary cheap energy.

PS: For scale wind is on target to hit ~8% of total electricity generation in 2018.

Could you cite sources for the coal to wind economics?

The LCOE can also be regarded as the cost at which electricity must be generated in order to break-even over the lifetime of the project.

http://en.wikipedia.org/wiki/Cost_of_electricity_by_source

Note, wind has gotten much better over time so 2013 numbers look much better than 2006 numbers.

Germany levelized cost of electricity generation in 2013 (EUR/MWh)

  Onshore wind farms 45–107
  Coal-fired power plants (brown coal) 38–53
  Coal-fired power plant (hard coal) 63–80

Though I may have undersold things for new generation:

  Regional Variation in Levelized Costs of New Generation Resources
  Conventional Coal Minimum 87.0, Average 95.6, Maximum 114.4
  Wind Minimum  71.3, Average 80.3, Maximum 90.3

IMO one of the more interesting numbers was Wind, onshore Operating Cost (USD/kW) Min 10.95 Max 60.00. That's a wide gap.

PS: Granted, these don't seem to account for time value of money but that's often overstated in terms of economic impact. Basically, if you turn 1oz of gold into 2oz of gold for free it's a net gain even if it takes 50 years, time value really just means there might be better uses of your personal money not that something is a net loss.

Thank you!

I think last year I read about an experimental setup that uses lidars to measure incoming wind allowing angle to be adjusted, ideally before the gusts hit. No conclusion at that time though.

(The offshore ones are huge and I guess changing the angle can't be done anywhere near fast atm.)

Thank you for your reply. I used to live in Scotland where there are a lot of wind turbines and I remember controversy in the news about the fact that while the expected lifespan of a wind turbine should be around 20 years, the actual lifespan ended up being in the region of 12 years, and the long-term maintenance costs ended up being higher than expected. There was also controversy about the environmental damage done to forests and birds, as well as noise pollution, though I guess this isn't directly related to the subject at hand.

Please don't get me wrong, I'm all in favor of clean energy, I'm genuinely trying to inform myself about the pros and cons of each solution.

Well if you are talking about damage done to forests & noise pollution, then you are trying to capture the externalities of power production into its "true cost".

I'm all for that, but if you decide to do that you also have to use the same methodology for coal, oil, nuclear, etc. Sorry birds, but I feel like the cost of every bird killed by a wind turbine pales in comparison to what a few mountain top removal coal mines do to an area.

In terms of economic ROI for the corporations owning wind turbines, I think it works out even w/o tax credits. Obviously the tax credits help, but the credits are not generous enough to justify all of this investing on their own. I believe the companies have done the analysis and believe it is profitable.

FYI: bird deaths via wind turbines are trivial.

Collisions with wind turbines account for about one-tenth of one percent of all "unnatural" bird deaths in the United States each year.

http://science.howstuffworks.com/environmental/green-science...

I was thinking about starting the anti-windows party to campaign for banning glass in architecture, just to see how dedicated people are to the premise of reducing bird deaths caused by human structures.

It's a bit odd to be attempting to inform yourself of pros and cons you don't know, but also make a very strong opening statement about wind power. I work in the energy industry and I can honestly say I've never heard someone refer to wind turbines as "effectively unsustainable." Maybe, as a joke? But certainly not in any serious way.

If you want to learn more about wind in general you can cherry pick sections from the recently released Wind Vision[1]. It should be able to answer most anything you'd wonder about.

[1] http://www.energy.gov/windvision

I honestly wasn't trying to make a strong statement, but given the reactions and the downvotes, it does seem like I didn't come across as intended, my apologies for that.

And thank you for the reference, I will make sure to read through it as soon as I get more time.

controversy in the news about the fact that while the expected lifespan of a wind turbine should be around 20 years, the actual lifespan ended up being in the region of 12 years

There certainly was controversy. An initial study did indicate the lifespan was likely to be 12 years[1], but that was immediately questioned because Scotland already had 16 yo windfarms with no maintenance issues.

That initial study led to additional research, which showed that:

the UK's earliest turbines, built in the 1990s, are still producing three-quarters of their original output after 19 years of operation, nearly twice the amount previously claimed, and will operate effectively up to 25 years. This is comparable to the performance of gas turbines used in power stations.

The study also found that more recent turbines are performing even better than the earliest models, suggesting they could have a longer lifespan.[2]

Also, there's no real controversy about "damage done to forests and birds, as well as noise pollution". There's no damage at all to forests, bird deaths are in the order of 0.1% and noise pollution is what it is: they can be noisy if they are built near you, but there is no mystical "subsonics" or something that some people claim.

[1] http://www.thecourier.co.uk/news/scotland/wind-turbines-life...

[2] http://www3.imperial.ac.uk/newsandeventspggrp/imperialcolleg...

Motor assemblies and the hub likely take the brunt of the stress and would require the most maintenance. Servicing them in the long term is a problem in that there simply not enough qualified people to do that job. Figure part electrician, part mechanic, and more, just to be able to work on one. Then throw in that candidates for this work must be very physically fit and mentally agile to be able to do the two hundred foot or more climbs.

So besides the material costs of building and maintaining we may run up against one that isn't fixable as quickly, getting the people to do the work.

The people-work relation is a whole other subject. Definitely something to look at, but one that drags in a lot of other topics.

But I would like to add this: other power plants have similar complex HR requirements (think nuclear, water).

Me neither, I'd be interested to hear more. I understand that 25 years is their lifespan. There was an interesting HN submission recently that discussed the problem of what to do with the blades once they reach EOL. Obviously they are very large and very hard to recycle due to the materials they are made from - a problem that increases with scale of course.

Like everything, I'm sure turbine blade tech will iterate. I recall hearing once that solar panels weren't viable because they didn't last long enough to recoup the energy cost it took to build them. I don't believe this is the case any more though?

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