IET
Decrease font size
Increase font size
Topic Title: London Array
Topic Summary:
Created On: 25 June 2012 12:34 PM
Status: Read Only
Linear : Threading : Single : Branch
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 25 June 2012 12:34 PM
User is offline View Users Profile Print this message



rogerbryant

Posts: 866
Joined: 19 July 2002

There is an interesting article on offshore wind power in The Engineer.

http://www.theengineer.co.uk/s...array/1012971.article

Taking the key numbers the first phase is 175 3.6 MW turbines spread over 100 km2 at a cost of £2 Billion.

An output of 630 MW is quoted which I assume to be peak.If we give a generous duty cycle of 30% as this is offshore the average output will be 190 MW.

If we compare this to a 1 GWe thermal station the wind power solution will cost ~£10 Billion and cover an area of 500 km2 without any allowance for storage/back up for when the wind isn't blowing.

The current quotes for a 1 GWe nuclear station are in the £5-7 Billion range. I don't have any figures for a 1 GWe gas station but I guess the capital cost is rather less but the running costs will be higher.

'Big Wind' still has some way to go.

Best regards

Roger
 25 June 2012 01:27 PM
User is offline View Users Profile Print this message


Avatar for aroscoe.
aroscoe

Posts: 91
Joined: 18 October 2002

Roger,

The "target" for wind (offshore) is being set at £100/MWh I believe - at least I have seen presentations by a number of suitably infomed people recently, all of whom mention this figure. Presently onshore wind can hit this but offshore wind can't, especially the bigger more ambitious schemes which are in deep water and further from shore. This is expecially true for some of the really big "round 3" schemes off the Northeast of scotland. The big "push" is all about minimising the cost through better (quicker) installation techniques, cheaper tower/seabed construction and better reliability etc. The industry is still young compared to the nuclear and CCGT industry, and the companies who are getting involved with such schemes are pinning their business cases on being able to achieve such cost reductions in the long term. This will certainly need to be the case when the "ROC banding" of offshore wind drops away, otherwise the companies involved will start making losses!

Figures I have seen also put nuclear at ~£100/MWh (cheaper capital than wind but fuel/decommissiong etc also need to be included) and CCGT at £80/MWh.

For the scheme you mention, if you run a very basic financial analysis assuming the energy capture you mention, over 25 years, at a discount rate of 8%, produces a theoretical cost of £113/MWh which isn't actually that bad. Of course there will be ongoing OPEX expenditure which isn't included in that figure, but against that you have to also remember that the nuclear option you present will also have ongoing OPEX/ fuel and decommisioning costs to add. Also, the "hypothetical" nuclear station won't be operating at a capacity factor of unity, due to sheduling and maintenance, so to be fair you also need to include that in the comparison.

The "controllability" issue is of course real, and isn't accounted for in the simplistic £/MWh figures. There will be an (increasing) value on controllability as we go forward and this will favour things like CCGTs, although in 2020-2030 how energy storage, demand-response, and electric vehicle charging will interact with this (or not) is all as-yet unknown ...

Andrew

-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 25 June 2012 02:17 PM
User is offline View Users Profile Print this message



rogerbryant

Posts: 866
Joined: 19 July 2002

Andrew,

Thank you for the additional information. I like the use of the term 'controllability' as a euphamism for inconsistency.

This is certainly a very big issue for most of the renewables. Having enough CCGT systems to fill in the times when the wind isn't blowing or the sun isn't shining over a wide area will push up the costs considerably especially as these stations will have to recover their capital costs when only partially loaded.

Current nuclear stations are only really suitable for base load. I don't know if any of the newer generations are more 'controllable' but then comes the problem again of recovering capital costs on a partially loaded system.

Best regards

Roger
 26 June 2012 12:45 AM
User is offline View Users Profile Print this message



stableford

Posts: 64
Joined: 04 April 2006

As I've posted elsewhere, the book Sustainable Energy- without the hot air, by David MacKay has a very good section on wind.

Remember its free.

Google -without hot air.

It does not go into the price so much as good rule of thumb for capacity calcs, with back up for those assumptions.

Regards

Derrick
 26 June 2012 12:52 AM
User is offline View Users Profile Print this message



stableford

Posts: 64
Joined: 04 April 2006

The life cycle isnt discussed enough.

Windfarm - design 6mth to year, approvals 1-2 yrs. build 1-2years, decommission couple of days apiece. Land out of use to others-ready as soon as land cleared.

These are possibles.

Nuclear-2-3years, approvals 5-10 yrs. build 5-10years, decommission Who knows- no site has cleaned up yet- even Dounray, the first one to be built, and switched off.
land out of use to others- 1000+years.
And who knows what the real pounds cost is for clean up?

Regards

Derrick
 26 June 2012 01:55 PM
User is offline View Users Profile Print this message


Avatar for aroscoe.
aroscoe

Posts: 91
Joined: 18 October 2002


I wouldn't disagree with that comment. I'm not anti-nuclear, but I too get annoyed when the decommission costs and the potential shortages/costs of the nuclear fuel supply/disposal/recycling process are ignored in cost comparisons.

The last figure I heard for decommissioning in the UK was £70bn in 2006
http://news.bbc.co.uk/1/hi/business/4859980.stm

There must be a more up-to-date figure, but I don't know it. Seems to be about £3bn a year anyway ...

http://www.nda.gov.uk/document...ss-Plan-2012-2015.pdf



-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 26 June 2012 03:27 PM
User is offline View Users Profile Print this message



rogerbryant

Posts: 866
Joined: 19 July 2002

Andrew,

On another thread I think that you came up with a figure of 3.28 p/kW hour for decommisioning. I also had a go at estimating the build and decommissioning costs:

The currently quoted cost for an EPR reactor is around £7 Billion.

The currently quoted figures of ~£ 70 x 10 exp 9 for decommissioning 10 reactors (rounded and conservative) gives £ 7 x 10 exp 9 decommissioning per reactor.

If this is added to the build costs quoted above this gives £14 x 10 exp 9 for 1 Gwe for 60 years. If we assume an up time of 8000 hour per year this gives 480 x 10 exp9 kw hours for £14 x 10 exp 9 which is 2.9 pence kWh.

What are the current subsidies for renewables, 10-20 pence kwh?

If we can reduce the build costs to a more sensible £5 x 10 exp 9 and apply more realistic decommissioning costs on the basis that the new reactors are designed for decommissioning rather than to make weapons grade plutonium as quickly as possible the costs will be under 2 pence per kwh.

Derrick,

I think that your views on the decommisioning of wind farms are a little simplistic. They are certainly much easier than NPPs but there is also a lot of infrastructure spread over a wide area, Foundation slabs for the turbines, sub stations, cables and often in remote locations. It is difficult to find good figures for the size of foundation required as it is very terain dependant, but I have figures of a concrete slab ~20m x 20m x 4m for a land based 3.6 MW turbine.
The London array first phase is 175 turbines spread over 100km2. If that was land based thats quite a lot of cleaning up to do for an average output of 190 MW.

You can of course just abandon the systems as was done in the first wave in America.

http://www.americanthinker.com...energys_ghosts_1.html

Best regards

Roger
 26 June 2012 04:28 PM
User is offline View Users Profile Print this message


Avatar for aroscoe.
aroscoe

Posts: 91
Joined: 18 October 2002


Roger,

No argument with your figures as such, but somewhere there is the gap between the 2.9p/kWh (£29/MWh) and the £100/MWh which seems to be used for nuclear. I'm getting this £100/MWh figure from presentations from people who have a much better insider-industry view than me. The difference must be all the "other stuff" like fuel, OPEX etc.

The subsidy at present for onshore wind is currently ROC band 1, i.e. about £40/MWh, plus LEC at £4.7/MWh, so a total of about £45/MWh or 4.5p/kWh. For offshore wind I think the ROC band is 2, although it might fall to 1.5. This would put the subsidy at £85/MWh, 8.5p/kWh.

The ROC banding subsidy would be reduced after the costs come down, and the longterm target for the "wind people" is that magical £100/MWh to be competetive with nuclear in the absence of any subsidy, as far as I can see.

On a non-financial basis, I guess another observation would be that there seems to be no end of private companies lining up to fund/build/install windfarms, but a distinct lack of private-sector companies lining up to fund/build nuclear stations. Of course, some of this is certainly due to the "dash for wind" with the ROC/LEC subsidy, but we all know this subsidy will drop once the industry and best-practice technology is established.

That's an interesting article about the dead turbines. A lot of those machines must have had appalling reliability so it can be understood that they died in the end and it made no sense to repair them again. I'm surprised the scrappies haven't been in though. Surely there's enough scrap-metal money to be made cutting these things up that it would fund at least a first-order clean-up. Granted, taking out the concrete bases might be hard to justify, but the towers and nacelles surely?

I'm wondering why the sites haven't been re-used to site new-generation, more efficient, cost-effective machines. The article suggests that a US policy of non-subsidy means that wind power might not be installed (wasting money) in the US:
...
"But the wind-subsidy proposals being floated in Congress suggest that American political leaders have yet to understand that "green power" means generating electricity by burning dollars."
...

However, how do we reconcile that against the state of Texas which has in excess of 10GW of wind installed, without subsidy, by private companies? The wikipedia entry http://en.wikipedia.org/wiki/Wind_power_in_Texas
suggests simply that it is competetive (without subsidy?) against gas powered generation! The same web page also highlights some of the problems they have with variability etc and new transmission investment needed .... so I'll let someone else pick up on this and keep this debate going ...



-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 26 June 2012 04:47 PM
User is offline View Users Profile Print this message


Avatar for aroscoe.
aroscoe

Posts: 91
Joined: 18 October 2002


I'm finding this quite an interesting trail of background information ...

Some of the "dead" windfarms referred to in the article Roger referred to aren't actually so "dead" it would seem. The Tehachapi site has now been developed into the world's largest windfarm (at 2012), 1020MW. I don't know if this means that the old turbines have been removed or not now, but you would assume there would be cash for that and that cleanup would be part of the deal, or that the original site would be wanted for some of the new turbines anyway?
http://en.wikipedia.org/wiki/Alta_Wind_Energy_Center

The Altamont site (I remember driving through this a few years ago) had a lot of small, old turbines and it seems these have picked up a reputation for bird-kill. However, it would appear that a lot of these are planned to be replaced with newer turbines which are more "bird friendly". I'm not a bird-kill turbine expert, but I guess the new machines with bigger rotor diameters and slower revolutions are easier for birds to see/avoid.
http://en.wikipedia.org/wiki/Altamont_Pass_Wind_Farm

Given that there is ?no subsidy for wind in the US? its interesting that these massive farms are being financed privately. Does anyone know if there is a subsidy in the US? Or, is the onshore wind literally competitive there without subsidy?


-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 26 June 2012 05:33 PM
User is offline View Users Profile Print this message



Ipayyoursalary

Posts: 265
Joined: 21 November 2009

Originally posted by: aroscoe
The subsidy at present for onshore wind is currently ROC band 1, i.e. about £40/MWh, plus LEC at £4.7/MWh, so a total of about £45/MWh or 4.5p/kWh. For offshore wind I think the ROC band is 2, although it might fall to 1.5. This would put the subsidy at £85/MWh, 8.5p/kWh.


But what about the additional hidden subsidies? An estimated £8.8 Billion for hundreds of miles of ugly new pylons needed to connect windfarms located in remote areas to the cities where the power is needed.

How about the hidden cost of incorporating the erratic unpredictable output of windfarms into the grid? The additional costs of providing 100% conventional backup stations. The additional fuel and depreciation costs from the continual ramping up and down of backup stations to smooth the erratic wind output?

The fact that energy suppliers are legally obliged to pay for every MW of wind output - even if they cannot make use of it due to low demand (eg. if a storm blows up in the night when demand is low). Again - another form of hidden subsidy.

I think these costs should be factored in to give a true like-for-like comparison.

Colin Gibson, former power network director at National Grid, said: "I estimate the extra costs of having wind are coming out at £80 per megawatt-hour of electricity generated. Even if the capital cost of building a wind farm was zero, it would still be more expensive than a conventional power station because of the costs of integrating it into the grid."

Regards

Edited: 26 June 2012 at 05:43 PM by Ipayyoursalary
 26 June 2012 07:06 PM
User is offline View Users Profile Print this message



ADJONES

Posts: 31
Joined: 15 November 2002

Originally posted by: aroscoe I guess another observation would be that there seems to be no end of private companies lining up to fund/build/install windfarms, but a distinct lack of private-sector companies lining up to fund/build nuclear stations. Of course, some of this is certainly due to the "dash for wind" with the ROC/LEC subsidy, but we all know this subsidy will drop once the industry and best-practice technology is established.
The subsidies won't drop for existing windfarms, any reduction in ROC subsidy only applies to new developments. For nuclear there is no functioning subsidy system in place. Regarding the position on ROC entitlements, to quote the DECC website:
In addition the Government remains committed to the principle of grandfathering - the position of those who have made significant investments should be protected in terms of the number of ROCs they receive.
 28 June 2012 02:57 PM
User is offline View Users Profile Print this message



stableford

Posts: 64
Joined: 04 April 2006

The wind farms in sw Alberta, Pincher Creek, are not subsidized, it can blow hard enough to blow trains off the tracks. Trucks are banned from the area, when the Chinook wind blows. I lost my winter shelter for my car, due to a 150km blow.
 28 June 2012 04:29 PM
User is offline View Users Profile Print this message



jcm256

Posts: 1866
Joined: 01 April 2006

Keeping my eye on the latest folly on the once perfect hilly landscape, it seems to be true that wind turbines use power when the wind is not blowing and the sun shines, you can sometimes see them turning ever so slowly must be to keep the blades from twisting like a plank of wood does in warm sunshine. Instead of importing power, would PV on the top of the nautical work to reduce the burden on the grid. Well maybe on second thought that would not boil a kettle and in this northern hemisphere-cooling period, would use up all the combined PV output just to keep these things cooled in summer, to warm in winter nights would just use grid power anyhow.
Engineers are not getting this right, nor is no one taking any heed of engineers.

http://www.aweo.org/windconsumption.html

jcm I Eng MIET MIIE
 29 June 2012 10:10 AM
User is offline View Users Profile Print this message


Avatar for aroscoe.
aroscoe

Posts: 91
Joined: 18 October 2002


jcm

This (and the referenced webpage) are a false argument because it is simply referring to ancilliary power systems. If you go to any coal, gas, or nuclear power station you find hundreds of such systems. Coolers, fans, pumps, generator excitation systems, instrumentation, SCADA systems, lighting/heating/cooling in office-space for employees, workshop facilities, loading bays etc. There are also "standing" losses in all these facilities (and wind turbines) due to the magnetisation losses (hysteresis and eddy currents) in the transformers.

I never actually heard of a wind turbine using power to turn itself to avoid bowing/warping in the sunshine, but then where I live such hot/sunny/windless weather at the top of hills is extremely rare. When the wind drops to really zero they genuinely stop (I've seen this), but they'll turn slowly with just a few mph of wind which is barely perceptable to a human even at the top of the hill. I'll ask around and see if its a known piece of the control algorithm.

But, even this can't really be used as a real argument because in steam turbines (coal/nuclear) the hogging/sagging problem is much more severe - on my old steam turbine frigate we used to have to turn the props all the time in port that the steam was "on" since the turbine metal can plastically deform at the operating temperatures. When the steam is off, its not so much of a problem. Within coal/nuclear/gas stations this is much more of an issue than wind parks. Indeed, when scheduling the operation of such thermal stations you have to allow adequate times for the stations to reach operating temperature and cool down before/after operation. This time is several hours for a coal/nuclear station, and the plant is essentially wasting energy (from fuel) without producing any electrical output.

So all these systems, wind/coal/gas/nuclear have ancialliary system losses. The only difference is that for a coal/gas/nuclear station, you have to burn more fuel to cover the losses (it gets less efficient), whereas with a wind system you simply reduce the amount of electrical power/energy you can export given a certain amount of wind and a given turbine size (it gets less effective).

Having said that, the webpage referenced by jcm256 refers to another page

http://windfarmrealities.org/?p=1594

which is quite interesting. Now, of course this is a sample size of 1 done by a single University, but the 50kW peak consumption of a 1.65MW turbine is shown in this dataset, which is interesting. This corresponds to a 3% loss at full power, although of course the more concerning thing is whether this 50kW loss is going on all the time, adding up to a significant drop in net capacity factor. This can't be discerened from the dataset, and one argument would be "do you care" during the times when you are still geting in excess of 1MW power output from the wind. But you would, since minimising any losses means more revenue.

The V82 is an "old-tech" turbine with a directly coupled induction generator, and it would be interesting to see the data from a much more modern turbine, with a wider sample size, with a greater fidelity.

One thing that crosses my mind, is that in that sample size of 1, the measured 50kW loss might be deceptive. We're talking about measuring a power flow at 3% of the "nominal", so the sensors and instrumentation will be right at the bottom of their dynamic range and subject to noise/EMC issues (you're trying to measure low-level 50Hz signals and its very hard to eliminate 50Hz ripple due to EMC/hum etc). Its quite possible that there is a large error margin on that 50kW. Maybe it is really 10kW or 100kW. It would be very interesting to see a wider study of the losses and know exactly how the measurements were taken. Another possibility is that actually some of the 50kW consumption is reactive (The V82 has a directly coupled induction generator). A larger reactive inmport/export of the induction generator and/or SVC unit and/or transformer might be incorrectly perceived as a smaller (50kW) active power if the current/voltage sensors used to instrument the turbine have any imperfectly calibrated phase shift. I'm not saying this is the case in that V82 data, just offering it as a possibility. No instrumentation is ever perfect, especially at the bottom of its measurement range!

Andrew



-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 29 June 2012 10:24 AM
User is offline View Users Profile Print this message


Avatar for aroscoe.
aroscoe

Posts: 91
Joined: 18 October 2002


As an example ...

We have an undergraduate transformer loss experiment where they have to measure the standing power losses (magnetisation, eddy current) of an energised transformer. Most of the current flowing is reactive (i.e. corresponds to no actual energy loss through heat dissipation), and there is also harmonic content in the current waveform.

I noticed last year that all the students using the brand-new digital measurement equipment were getting values which seemed too high - measuring randomly within the range of 25-50W loss range. But, when we instead measured the same transformer on either an old analogue powermeter, or, a LEM power quality analyser, we ALWAYS measured 9W+-1W, reliably (the correct result). The problem is mostly down to inadequate measurement (signal processing) algorithms in the brand-new kit.

Never trust a measurement 100%!

-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
IET » Energy » London Array

Topic Tools Topic Tools
Statistics

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2014 FuseTalk Inc. All rights reserved.