354 comments on Making the case for wind, again
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354 comments on Making the case for wind, again
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As jeppen noted, any complex machinery will have an expected lifespan ... in the end, entropy wins.
What is notable is how quickly within that lifespan the wind generators tend to pay back the energy invested, so that the net EROI is quite high for a well-sited wind generator.
There are power plants older than 50 years still operating, and their steam turbines experience much worse conditions than any wind turbine. You replace the parts that wear out, like bearings, and keep going. For a wind turbine, short of the foundation failing or a blade failure, I can't think of any reason the thing couldn't run forever with the correct spare parts and maintenance.
But then you are looking at the paradox of the classic car, "I've owned it for forty years, and replaced every part in it at least twice".
Whether the depreciation is made good incrementally or by taking it down and putting up the latest model, it still must be made good, and for the NEROI, it matters little whether the energy cost of that is accounted for as periodic replacement or as investment in major maintenance.
Disagree. The maintenance is always cheaper. You do not have to invest in site prep and a myriad of other things for a new unit. Again, I live twenty miles from Power Vista, which is like a 60 year old hydroelectric generating facility. Nobody talks about replacing that. You replace worn parts and keep on trucking.
Accounting for it as the wind generator lasting forever is not simply saying that the major maintenance is less expensive, its saying that the major maintenance is free.
And if the NEROI is attractive under the simpler complete replacement accounting, then it is clearly still attractive if the average life is extended with incremental rather than complete replacement. So I do not see why assuming away depreciation leads to a more robust estimate of NEROI than making a conservative lifetime assumption and assuming simple replacement at the end of the working life.
What do you mean by "maintenance is always cheaper"? At some point, you have spent as much on maintenance as you did on the original investment. Perhaps in 20-30 years.
Comparing with hydro isn't really fair - site prep and dam building represents most of the cost there. For wind, you are talking about regularly replacing the expensive parts. The logistics is harder, too.
Also, there are multiple large bearings, for instance the one that makes the tower able to face the wind. Forces are applied unevenly as the tower stops some wind at the bottom, btw.
Thanks for highlighting that ... its a critical point. And given that a new wind turbine with the same sweep can use the same site, and that building a new turbine (with the latest technology) will take place in a factory at ground level under cover at a site dedicated to producing turbines, rather than at a remote site, and either at elevation and in cramped quarters or exposed, or at ground level with much of the cost of installing a new turbine required to re-install the refitted turbine ...
... it is by no means automatic that the rebuild/refit versus replacement decision will always go to rebuild/refit.
Meanwhile, in determining the NEROI, it is possible to evaluate the current Full Energy Cost of the current technology, and estimate the expected life under the replacement scenario, and get a conservative NEROI ... the net energy savings for refit/rebuild versus replacement are more speculative, and there is no pressing need to engage in the speculation.
Actually I am questioning exactly that. The most expensive parts of the turbine installation are the foundation, the electrical, and the blades themselves. Bearings are a small part of the project. I do not see much reason why the most expensive parts have to be regularly replaced.
But the foundation won't necessarily need to be replaced with installation of a new turbine, so how does it enter into the refit versus replace decision? Unless, of course, a substantially larger turbine is being installed, and if it is, that would mean that its benefit justifies the extra expense over replacing on the same footprint, and the same benefit would translate to the refit decision.
The installation and transportation of the towers is the largest expense. The 100 m towers are too long to truck in one piece by road or rail. Large, heavy- lift cranes are required to put these and the gyres/alternators into place.
Once in place, they can stand for decades as have the wind turbines in Pasadena, California.
Ironically, wind farms could (and should) be placed in suburbia. This is where the demand is and the towers would add some soul to the otherwise 'soul destroying landscape'.
Massive wind and solar development ... is the only possible hope for the future ... for sprawl.
Given the existing technology that can carry electricity for 1,000km with substantially less than 10% line losses, the wind towers should be placed where the resource is.
Even in the updated Ohio map that showed that there was more onshore wind resource here than had previously been suspected ... most of the core resource area are rural counties. Cleveland, Columbus, Cincinnati, Akron, Canton, Dayton are all in low resource areas ... towers in some outlying suburbs of Toledo, maybe, depending on the price of electricity ... but mostly in maize and soybean farm territory.
And of course the most substantial resource is still Lake Erie.
The 2006 report to the UK government (pdf) that is cited in a discussion below gives installation costs as 1% of capital expenses for onshore wind generators. I have not seen that it breaks down the expense of the wind turbine between tower, nacelle components, and rotor components, or cost at site between manufacturing cost and transport cost, but the installation does not appear to be a massive part of the CAPEX.
This 2004 source (pdf) on the economic impact of expanded wind turbine installation in the US, gives the cost breakdown as:
So if those costs decline roughly in line over the expected life of a newly installed wind turbine, then replacement-in-place would save a little less than a quarter of the original installation costs if the tower is still sound ... given that CAPEX is such a dominant component of cost for a wind turbine, a larger sweep that requires larger towers with different spacing would have to expect a revenue gain of 36% to break even.
Apologies for not coming back to you earlier - I did not have time to re-check my sources.
The figure you give for the estimate for off-shore wind of 35% is correct on page 32.
It should be noted though that these are early estimates only, and I have also linked to more recent plans to move off-shore turbines closer in to reduce costs, so it is a bit early to work out how all the different factors will play out.
This is the reason I also gave the link to 'The Times' article, which although it does not give a detailed breakdown, is based on estimates from EON, one of the major suppliers.
Other estimates are readily available by googling which are in the same ball-park.
This link from a specific site in New Zealand may also be of interest to you, as it is both more specific and more current:
http://www.contactenergy.co.nz/web/pdf/our_projects/waikatowindfarm/june....
One element which I noted was the high estimates of transmission losses, going up to as much as 15% in the case of transmission between the two islands. (p21)
Of course, both costs and geography are far more favourable in NZ than the UK, with hydroelectricity and geothermal to back it up, plentiful land and high average wind speeds.
Yes, there is a trade-off between HVAC transmission and HVDC transmission, with HVAC transmission having much higher line losses per 100km, and HVDC having a high fixed cost component in the conversion to AC at the grid feed-in end of the trunk (both ends for a cross-haul trunk). New Zealand is a nation with a relatively small population ... under half the population of my state of Ohio ... with somewhere around 1m in the South Island. At the scale of a continental scale interconnection grid in the EU or North America or even Oz (which for Oz might well be just one or two trunks), NZ would be one grid in the network.
New Zealand is an excellent test site to assess running most of a grid on renewables.
With the very small population it would not be suitable for nuclear reactors - if one went down it would take out too much of the grid, although the small floating Russian reactors or the Pebble bed reactor might do.
Back up for wind seems to be the chief difficulty, when hydroelectric power is low due to drought.
I have a lot less difficulty in imagining NZ or Iceland being all renewable than Britain or Germany though, and for the more extreme advocates of renewables only it should be noted that neither are anywhere near being able to run everything on them.
Hopefully that will change in the next few years, and we can use the experience gained to increase the percentage elsewhere.
It's a darn sight easier to run on renewables with a population of 4 million, closer to the equator and with good wind and geothermal resources then in cold and crowded Britain - the land area is about equal.
David,
New Zealand is, wisely, a nuclear free zone. http://en.wikipedia.org/wiki/Nuclear-free_zone#New_Zealand
Chris
Somewhere in one of these comment threads I make reference to the biocapacity estimates of the Global Footprint Network ... the US biocapacity is estimated at 4.7 hectares/capita (against a footprint of 9.6 ha/capita), and the EU biocapacity is estimated at 2.2 ha/capita (against a footprint of 4.8 ha/capita). Taking that as a rough guide, the same intensity of harvest of sustainable renewable resources that would cover 100% of US electricity supply would cover somewhere shy of 50% of EU electricity supply. Now, that is the roughest of BOTE calculations, given different resource mixes, different electricity share in total energy use, etc. ...
... but it does, I think, give a reasonable ballpark idea of the difference in situation ... the EU has a larger population on a smaller natural resource base.
The "biocapacity rich" countries include many of the ones we would expect ... listing biocapacity first, Australia at 12.4 vs 6.6 ha/capita, Canada at 14.5 vs 7.6 ha/capita, Brazil at 9.9 vs 2.1 ha/capita.
Bruce, just as an update and to show the extreme difficulty of getting accurate figures for wind because costs are changing so rapidly, here are current figures according to 'The Times' -
http://business.timesonline.co.uk/tol/business/industry_sectors/natural_...
This puts the on-shore costs up to something similar to the 2006 estimates for off-shore, so the costs for off-shore would fall into line with EON's estimates of £80 billion for 33 GW nameplate quite easily.
It is also doubtful if these figures include the latest fall of the pound sterling, but recent falls in commodity prices would go in the other direction.
The cost of other energy sources will also rise, but there are very serious questions as to how much off-shore will be affordable, even using ODE's estimate of a 35% capacity factor.
BTW, I believe the figure I was using of 30% was from the BERR estimates, but I did the investigation some time ago when the plans for 33GW of off-shore was first announced, and so now can't be sure.
The assumptions behind various estimates is often critical, and since the latest plan is to move them closer in-shore to minimise cost it seems possible that a lower capacity factor than ODE's estimates might be more appropriate.
Overall though, unless we can access up to date figures for specific installations, the estimates are a pretty rough guide.
Dear DaveMart,
my apologies if I use this thread that is a bit off-topic but the more on-topic posts are closed already.
I've just noticed that you are a huge fan of KiteGen: perhaps you are the biggest fan of KiteGen on the whole OildDrum! :-)
Once you wrote that financing it is an issue and yes, it is but you might be pleased to know that now there is a small holding trying to finance it... allowing small/medium investors to take part in this project.
I don't want to bother the other readers so feel free to write me if you want to.
Your profile does not give a contact address, so please feel free to contact me at brittanicone2007 at yahoo dot co dot uk