Talk:Intermittent power source

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Contents 1 Costs of interconnection of systems 2 HVdc 3 More HVDC 4 Decentral CHP should be added 5 Categories of problems 6 Theanphibian change 7 My rv of Engineman 8 REVERTION OF ANPHIBIANS OF ENGINEMANS EDIT 9 Reply 10 EJP tarrif - France 11 power shortages in the uk 12 British reactors 13 more on british reactors 14 intermittency 15 Rudeness 16 effects of power station outages 17 Quick add ons 18 Cost of fuel 19 back up 20 transmission costs 21 costs of keeping existing fossil power stations in reserve in a tapering period 10 - 30 years ahead 22 This article is very poor, in my humble opinion and needs to be drastically pruned 23 100% renewable electricity strategy for Europe - ie no limits to penetration 24 hvdc generation losses 25 deletions 26 Auto-archiving 27 no limit to wind power penetration in the UK - National Grid 28 Ramping Rates Nanticoke power station 29 Back up plant for nuclear power 30 Neutral point of view 31 Academic references for the Intermittency paragraph 32 Can wind give firm power? 33 Refrences to introductory paragraph 34 Some authorities think it is misleading to call renewables intermittent, whereas conventional large plant clearly are 35 Intermittency exists in conventional power grids 36 French electricity networkoperator thinks that wind can replace capacity 37 Danish Windpower experience and references

[edit] Costs of interconnection of systems

HVDC links are now relatively cheap and efficicnet - 3% losses over 1000 km, so the issue of intermittency becomes far less of an issue due to the increased diversity.

Quote from a UK power systems expert:

Cost of connecting UK to Europe

"Like most things it's dangerous to have back of the envelope numbers but the following are approximate PRIME EQUIPMENT costs for a 2000MW 500kV bipole conventional HVdc link. i.e. these costs exclude way-leaving, on-shore reinforcement works, consenting, engineering, insurance etc.

Converter stations ~£110M Subsea cable + installation ~£1M/km

So for an 8GW to the mainland in four links, you would not have much change from £750M for the installed works. you could probably add another £200-300M for the other works depending on how much additional on-shore works were required.

Regards, GB

Further info:

> > http://www.abb.com/cawp/gad02181/f665be70ddd7edb3c1256fe2002cdf0d.aspx

> > > > > > > > "The use of HVDC at 800 kV, has been found efficient, > > environmentally friendly and economically attractive for large > > point-to-point power transmissions of the order of 6400 MW and more, > > with distances of more > than > > 1,000 km. Worldwide there is an increasing interest in the > > application of HVDC at 800 kV. > > > > Paper presented at International Workshop for Ultra High Voltage > > (UHV) Transmission Systems 2006, Beijing, China, Nov. 28 - 29, 2006, > > organized by State Grid Corporation of China:"

[edit] HVdc

Roy Follow up to Dave's post. Re HVDC transmission. Planned Chinese HVDC is at http://search.abb.com/library/ABBLibrary.asp?DocumentID=9AKK101130D3877& LanguageCode=en&DocumentPartID=&Action=Launch and at http://www.abb.com/cawp/gad02181/c1256d71001e0037c12568940025fdbe.aspx Moving 6GW over ~1000+ Kilometre is well on the way.

The above link was sent to me originally by German Aerospace (Trieb) and passed to Colin Challen MP (all-party CC group Chair) at latter's request earlier this year. Trieb et al did the study for TRANS MED, which is the proposed regional EU / MENA scheme for balancing renewables electricity generation via HVDC (Gas is proposed for peak back-up and coal is to be phased out. See also TREC - Gerrry Wolfe this list - for links for info on the super-grid to include CSP Spain and then further CSP in N Africa etc).

The Norway hydro link to our huge wind reserves (a resource shared also with some of EU neighbours), is an obvious starter. Trieb et al study suggests nuclear can only get in the way of rational balanced grid-to-grid linkages of bulk power. Norway to NL bulk transfer cable is already underway as is NL to UK HVDC link, repsectively http://www.norwaypost.no/cgi-bin/norwaypost/imaker?id=75975 and http://www.nationalgrid.com/uk/Media+Centre/PressReleases/220507britned.htm. best PhilDC

[edit] More HVDC

From: energy-discussion-group@googlegroups.com [1] On Behalf Of Philip Harris Sent: 08 June 2007 14:04 To: energy-discussion-group@googlegroups.com Subject: future world HVDC re Compass AGM

Can't resist sharing. Snippet from Swedish company who will build the UK / NL HVDC link open in 2010. http://www.abb.com/cawp/seitp202/40b621aafd3db79cc1257225002fcd3d.aspx " ... China and India are set to be the main users of the new technology as [they] seek to secure reliable power supplies. India plans to build five ultra high-voltage DC lines over the next ten years, each with a capacity of 6,000 megawatts (MW); China is planning one line every year for the next decade, each with a capacity of 5,000 MW to 6,400 MW. ..."

Read these old engineers on a roll with ultra HVDC. Phil

[edit] Decentral CHP should be added

Decentral Combined Heat and Power Plants are mostly optimised on the heat part. In practise this means the Plants only produces electrity when there is a demand for heat. From the grid operator's point of view these systems are non-dispatchable and intermittent.

comment on CHP plants is obsolete nonsense.

It took us long time in Denmark to convince the public that electricity from CHP plants does not delay the climate change when there is no demand for electricity.

Now the local CHP plants in Denmark are more and more operating on market conditions, both day ahead and real time. They can react very efficiently on price signals, and they are only generating both electricity and heat when there is a demand for both products.

Paul-Frederik —Preceding unsigned comment added by Engineman (talk • contribs) 16:58, 30 October 2007 (UTC)

[edit] Categories of problems

I reinserted the deleted explanation of generic reasons for power outages, which provides value to the readership. Simply repeating them over and over again in each type of power source does not make sense. Perhaps this would be best associated with fossil fuel and nuclear power plants, as was originally assigned. My Popups are acting differently, so was not able to add to submit subject line. --Skyemoor 18:08, 11 August 2007 (UTC)

Of the possible intermittencies listed, most are generic to wind, solar, conventional and nuclear.

Planned outages

Component failures

Design flaws

Operator error (primarily in conventional and nuclear)

Grid disconnects

Natural disasters

If anything, we should expand the discussion of these in the generic section. We might also add "Terrorism". Simesa 18:15, 11 August 2007 (UTC)

Added "Terrorism" and restructured the opening line to enhance context. Thanks, --Skyemoor 18:35, 11 August 2007 (UTC)

Is terrorism really a significant cause of intermittency? I would argue that it's not. There has been ONE, count them, ONE cases in history where a nuclear power plant was actually shut down due to a terrorist act; see Brennilis Nuclear Power Plant. I really don't think it should be on this list. -Theanphibian ^{(talk • contribs)} 06:09, 15 August 2007 (UTC)

These are not solely nuclear possibilities, though terrorism is indeed a possibility at nuclear plants. --Skyemoor 01:45, 18 August 2007 (UTC)

Yes, certainly true. The amount invested in security at large plants shows that it's a threat taken very seriously. -Theanphibian ^{(talk • contribs)} 04:02, 8 November 2007 (UTC)

[edit] Theanphibian change

• "concerns about integrating wind energy into existing grids have surfaced" is passive; who has expressed this concern? Include references
• "A study during the 2006 California heat storm revealed that output from wind power significantly decreased as peak demand increased (due to greater air conditioning and other demands that stem from high temperatures)." This is one study by a nuclear engineer that covers 2 weeks in one state of one nation, which is getting a very high profile here. Is this widespread enough to warrant inclusion? If so where are the references?
• "If weather patterns can frequently cause demand to increase while at the same time decreasing output of wind farms over a large area like this in the future, it could cause high penetration by wind power to be much more uneconomical since it would require that much more replacement capacity." This is speculative in nature, which does not belong in WP. --Skyemoor 02:11, 18 August 2007 (UTC)
  • Sorry I didn't get to these comments until now. This pretty much all revolves around this source: [2]. Your first bullet and third bullet were merely things I wrote with knowledge from that article. I think you can agree that it wouldn't be accurate or truthful to write "It is believed that wind power can be used to high penetration levels with high reliability. A study through the July 2006 California Heat Storm indicated that output drastically dropped to 5% of capacity during peak demand when the grid was strained and threatened with rolling blackouts."
  • It is just one study, but the entire point of criticizing wind power on reliability is that it can crap out at high demand times. The author even calls for more studies of peak demand performance of wind power. If you can find more studies that do this, they'll be included to. The fact is that there is a valid concern that the same weather patterns that cause demand to increase may cause wind power's output to decrease. It's just a concern. Much more research is needed, and I would like to see that research as well. Rephrase things all you want, as long as issue here is addressed. -Theanphibian ^{(talk • contribs)} 03:57, 8 November 2007 (UTC)

[edit] My rv of Engineman

This was mostly because much of the data just didn't sound right. A quick check of the database shows about 80% capacity factor, which is not poor performance at all. Other things: I don't think half of the outages in the UK are unplanned. We would need to know what's meant by that as well as have a source. Also, if you're going to add stuff about deisel generators combined with nuclear plants, you need to distinguish from the onsite generators and separate power plants. Onsite generators are very common (I think all plants have them actualy) and have startup times of like 20 seconds. Gas peaking units can be really quick to start up, but they don't necessarily work in tandum with nuclear power - they work in tandum with all power sources. Furthermore, in many cases I didn't know what specifics the contributor was refering to, or if he/she knew what they were talking about at all. -Theanphibian ^{(talk • contribs)} 01:22, 2 November 2007 (UTC)

==Anbphibians edit++

Quote:

[edit] REVERTION OF ANPHIBIANS OF ENGINEMANS EDIT

I've broken Anthibians comments above up into Statments, and my responses.

Statement: This was mostly because much of the data just didn't sound right.

Response: That’s is not a good enough reason - just seems like opinion without any basis. I can assure you it is right a quick check of the database shows about 80% capacity factor, which is not poor performance at all.

Response I don't know what you mean here, but in any case it is irrelevant. It is well known in the uk that Sizewell b the largest nuke on the system does stop, and can therefore impose an instant unplanned outage - and this is the largest outage on the uk system. Exactly the same applies to other countries like usa.

Statement: other things: i don't think half of the outages in the uk are unplanned.

Response It was on the bbc news only a few days ago, that half of the UK nuclear outages were unplanned, the rest being planned. That is why there is concern in England about a winter power shortage and the grid issued a nims = notice of insufficient margin.

Statement: We would need to know what's meant by that as well as have a source. Also, if you're going to add stuff about diesel generators combined with nuclear plants, you need to distinguish from the onsite generators and separate power plants.

Response The stuff isn’t combined with nuclear power plants it is a separate heading, and they form a vital part of the grid operation as in France, and the UK. Small diesels are used worldwide to back up main grid power station outages by paralleling and feed in. Please read how the grid is controlled on Wikipedia.

Statement: Onsite generators are very common (i think all plants have them actually) and have startup times of like 20 seconds.

Response I’m not talking about diesels for nuclear power plant i'm talking about the thousands installed in hospitals, water works etc that also feed into the greed on demand, in uk, usa, and France which you are apparently unaware of.

Statement: Gas peaking units can be really quick to start up,

No gas turbines are quite slow to start - can be several minutes compared to 10 - 20 secs for a diesel

Statement: but they don't necessarily work in tandem with nuclear power - they work in tandem with all power sources.

I didn’t say they did - the work in tandem with frequency controlled load shedding for any large power station outage - its just that in the uk Sizewell happens to be the largest

Furthermore, in many cases i didn't know what specifics the contributor was referring to, or if he/she knew what they were talking about at all.

i do. User:theanphibian|theanphibian]] (talk • contribs) 01:22, 2 november 2007 (utc)

[edit] Reply

This is about the most extreme response I've ever seen to one of my edits :-/

You should really have a look at the entirety of Wikipedia policies. You're edits still need a LOT of work before they can be accepted into the article. -Theanphibian ^{(talk • contribs)} 19:09, 3 November 2007 (UTC)

Aplogies if I was a bit short, but I have raised these issues in the past carefully even contributing quite long articles which have been deleted and ignored. It gets a bit frustrating after a while.

FOR A FULL DISCUSSION OF ALL THE ISSUES RAISED, AND OTHERS TO DO WITH INTERMITTENCY SEE:

A confernence held at the Open University -

"Integrating renewables into the electricity system" A one day conference on Tuesday January 24th at the Open University, Milton Keynes.......http://eeru.open.ac.uk/conferences.htm - viewable on line. The resulst of this conference were published as a book:

"Renewable Electricity and the Grid - the challenge of variability" Pub Earthscan. London isbn 13:978-1-84407-418-1

Synopsis of above book: Can renewable energy provide reliable power? Will it need extensive back-up? The energy available from wind, waves, tides and the sun varies in ways that may not match variations in energy demand. Assimilating these fluctuations could affect the operation and economics of electricity networks, markets and the output of other forms of generation. Is this a significant problem, or can these new sources be integrated into the grid system without the need for extensive back-up or energy storage capacity? This book examines the significance of the issue of variability of renewable electricity supplies, and presents technical and operational solutions to the problem of reconciling the differing patterns of supply and demand. Its chapters are authored by the leading experts in the field, who aim to explain and quantify the impacts of variability in renewable energy, and in doing so, dispel many of the myths and misunderstandings surrounding the topic.

especially the chapter on diesels where you will see all the points made fully referenced. "Renewable Electricity and the Grid - the challenge of variability" Pub Earthscan. London isbn 13:978-1-84407-418-1

Power Convention 2007 10 - 11 september Imperial College, London 2007 covers these points as well.

http://en.wikipedia.org/wiki/Control_of_the_National_Grid_%28UK%29

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

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

[edit] EJP tarrif - France

http://bulletin.cern.ch/eng/articles.php?bullno=46/2005&base=gen

Quote from the CERN site bulletin:

Reduction of electricity comsumption during 'high cost' periods in winter 2005 - 2006

In previous years CERN was able to limit its electricity consumption during the winter months sufficiently to be supplied from the Swiss grid. In order to make enough power available for the LHC machine and experiments at the lowest possible cost during the coming winter 2005 / 2006 CERN is supplied from the French grid by EDF (Electricité de France). As a consequence, when the grids are at peak demand during the tariff period 'Effacement Jour de Pointe' (EJP) in France, the energy price is at least four times as high as for the usual winter period.

From 1st November until 31st March these increased prices are applicable during twenty-two 18-hour periods, each beginning at 7 a.m. and ending at 1 a.m. the following day. Notice will be given by EDF to the Technical Infrastructure Control Room (TI) at 5 p.m. the previous day. The notice period may be reduced to two hours for days following weekends and public holidays, or omitted entirely for technical reasons.

During these days of EJP CERN has a strong financial interest to reduce its power consumption as much as possible whilst minimizing disruptions for LHC machine and experiment commissioning, accelerator and experiment tests and start-up.

In order to inform staff and users EJP days will be announced via the NICE Alerter and also on the luminous panels at the entrances of the Meyrin and Prévessin sites.

HIGH ELECTRICITY PRICES Reduce Consumption

Information will also be placed on the public PS, SPS and TI video pages, as well as in several CERN NEWS groups.

In the interests of all, staff should refrain from carrying out tests or work requiring additional power during these periods.

For more details please contact:

Endquote.

For the reasons above and implied in the sources I have given, i have changed to emphasis from "load could be shed", to "it alread is being shed"- due in fact largely to nuclear unplanned outages both in France and the UK .Engineman 18:07, 3 November 2007 (UTC)

[edit] power shortages in the uk

http://www.bbc.co.uk/pressoffice/pressreleases/stories/2006/12_december/04/power.shtml

This article stated on air, that half of the outages were maintenance, the other half unplanned. —Preceding unsigned comment added by Engineman (talk • contribs) 20:19, 3 November 2007 (UTC)

No it doesn't. The closest I can find is:

British Energy says that six of their nuclear reactors are currently shut down, two each at Hinkley Point and Hartlepool in England, and two more at Hunterston in Scotland.

Which makes perfect sense since the article is from April 12, when demand is fairly low - probably around the end of outage season. -Theanphibian ^{(talk • contribs)} 20:28, 3 November 2007 (UTC)

Ah, I see. That was when they had one big problem and had to shut down 6 reactors. That means that at one time in history half of the reactors that were shut down were due to to maintenance. That's not what you were trying to claim in the article. -Theanphibian ^{(talk • contribs)} 20:31, 3 November 2007 (UTC)

[edit] British reactors

I heard the or a relevant news item on the BBC about 3 weeks ago, and it stated that of the outaged stations, half were down due to unplanned maintenence or inspection.

But in fact this is totally irrelevant to the issue of intermittency. The fact is, any large power station, nuclear of fossile can and does fail unpredictabley and it is this possbiliyt that sets the size of the reserve margin.

Such intermittency is much higher than can be generated by even 100% wind power penetration in terms of energy delivered. So please remove any reference to nuclear's load factor as they have no bearing on this. Engineman 20:50, 3 November 2007 (UTC)

No. You're view that wind power is less intermittent than others at high penetration levels is a minority opinion and already covered in the article by other editors. Load factor and percentage of unplanned outages are direct indicators of the predictability of nuclear power. Predictable is good, it allows planning. -Theanphibian ^{(talk • contribs)} 20:59, 3 November 2007 (UTC)

[edit] more on british reactors

http://www.guardian.co.uk/nuclear/article/0,,2197499,00.html

He stressed that up to four plants would be closed down at this time of year for regular maintenance and refuelling, and said the others had been shut down on decisions made by British Energy.

"This is a very high proportion - 16 nuclear power stations, seven out of action. That's almost unprecedented, and I think it is pretty worrying that they themselves have a major problem as a result of breakdowns and the need for repair and maintenance. —Preceding unsigned comment added by Engineman (talk • contribs) 20:59, 3 November 2007 (UTC)

That's three reactors shut down "on decisions made by British Energy". Three out of 16. Phrase your comment in relation to those 3, not the others that are operating as planned. -Theanphibian ^{(talk • contribs)} 21:10, 3 November 2007 (UTC)

[edit] intermittency

This article is about intermittency. the point I am making, and you are evading is that the biggest source of intermittency on any power system is the large power statons themsevles.

Suddenly losing 1.32 GW in the UK or a TMI in the US sets the reseve margin and is a far greater rate of change than a large penetration of wind farms could induce.

Average losses of capacity are irreleveant in this context.

Please go away and think about htis before making any more edits.Engineman 21:22, 3 November 2007 (UTC)

Do you see what I did with my edit? I added YOUR references. I have been working to HELP you add your material, which you can see through a host of my edits. You will get torn to shreds when other users get back to this article. Please have a look over Wikipedia policies. -Theanphibian ^{(talk • contribs)} 21:50, 3 November 2007 (UTC)

Engineman: please see WP:CIVIL. Rudeness like your comment above is simply not acceptable under any circumstance. If you want to add a bunch of information - and please do! - it will go better if you listen, pay attention to how things are done here, like how references are formatted and how articles are structured. Spelling counts! Putting in text riddled with typos makes it look like you expect someone else to clean up after you. We've been through this before: if you don't see others using ALL CAPS, it's because they don't use them (and it comes across as rude).

You have a lot to contribute but read the guidelines and try to follow them.

It would also be useful and easier for others if you used the preview button, and made fewer edits (rather than correcting multiple times). And welcome.--Gregalton 15:33, 4 November 2007 (UTC)

On intermittency. Isn't the question not so much the outage figures for individual plants, but the problem of common-cause failures? In other words, if I have three nuclear plants operating in some area, the chances of all three failing at the same time are extremely low, since their probability of failure is independent. If three plants isn't good enough, I can add 2 more, or 3 more, or whatever - and each plant I add will reduce overall failures. If I have 10 wind turbines operating in some area, then the probability of failure is a question of climatic factors (the speed of the wind). Critically, if I increase the number of wind turbines in that area (to 20, say) I have not significantly reduced my overall failure rate, since the common-cause failure (loss of wind) is the same.

So basically what makes 'baseload' baseload is the fact that failure rates for baseload sources can be calculated accurately, and that redundancy can significantly reduce the overall failure rate (i.e. blackouts).

Now undoubtedly diversity can reduce this. I imagine you can distribute wind generation across a wide area, for example. But with 'traditional' baseload, you don't even have to make these calculations. If you have the fuel, you have the plant. If the plant fails too often, build another plant, and the logic of failure independence will take care of the rest.

Right? --123.243.210.39 (talk) 14:24, 12 March 2008 (UTC)

While broadly speaking I agree with you, two quick points: i) the largest single-point failure issue is likely the grid itself, not the traditional plants; ii) it may be overly-optimistic to say that traditional plant is not subject to common-cause issues (to use your terminology) - see, for example, the issues with French nuclear plants during heat waves - they sometimes have to cut back due to lack of water for cooling. Similarly, if all gas-fired is dependent on pipelines, are they really independent? Or safety issues discovered at a number of plants of similar design at once (something that has come up with nuclear). Just askin'.

The point about failure of individual plants is that when individual plants are very large, any potential tripping/shutdown is very significant. Wind certainly has more correlation between plants (geographical diversification is by definition limited).--Gregalton (talk) 16:04, 12 March 2008 (UTC)

Well, yes :-) I suppose my main problem is that the Nuclear Power section of the main article doesn't really make that point clear. It sort of mentions the fact that a large British nuclear reactor went offline, and sort of implies that that alone means that wind (say) and nuclear are both as intermittent as each other. It doesn't make the common safety issue argument, or the French reactor shutdown argument, as strongly as it probably should. Well OK, maybe they're mentioned somewhere, but the best actual quantitive sourced data in the nuclear section is regarding the unplanned outages statistics for the US, and the Sizewell B shutdown, which I don't think is a fair comparison for the 'failure independence' reasons I gave above.

btw, on common-cause, maybe what I actually should have said there is common mode.

When you say 'when plants are very large, individual shutdown is significant', I don't think that that alone is enough information. In order to talk about the reliability of a system, you would need to know the power loss caused by a single failure (which if a big plant goes offline could be large), but you also need the total number of plants in the system. If I have 5 1GW plants, the failure of one is very significant, but if I have 10, then the failure becomes less significant. In other words, the fact that large single plant failures happen do not automatically mean that the entire system shares the same failure characteristics as wind (say); they could just as easily be used as arguments for building a few more plants for redundancy. If you assume failure independence, then just building some more is a viable strategy for increasing overall reliability. --144.53.251.2 (talk) 02:38, 13 March 2008 (UTC)

[edit] Rudeness

Ok - thanks for pointing that out, and I apologise for my rudeness to Anthibian - but I do think his attitude to my comments, came over as rude and arrogant as well.

I take your points about use of capitals, and general sloppiness, but bear in mind I have made all these points before which have been ignored - including quite a lengthy de-typoed article which has been deleted.Engineman 20:05, 6 November 2007 (UTC)

[edit] effects of power station outages

To summarize part of what I have been trying to get over is that the unavailability of large power stations - coal or nuclear - has several effects for consideration:

1. No matter how short the periods of unavailability, the grid has to estimate the worst case simultaneous unavailability and keep that amount of reserve power stations ready - these can be started up in good time as needed. This includes cold stations, or stations on hot standby. I think that in the UK the max loss envisaged by National Grid is the sudden loss of 1.2 GW closely followed by 3 more - which is what appeared to have happened this month.

2. The fact that power stations can stop suddenly and without warning, even if infrequently, means that spinning reserve and frequency sheddable loads have to be instantly available to cover the maximum size likelihood. In the UK it happens to be 1.32 GW which happens to be Sizewell.

3. Fast response plant - OCGTs and diesels have to be available to back the Frequency Response sheddable loads.

4. Some grids eg France have special tariffs that can be invoked to cover sudden losses - eg EJP in France.

So, overall, grids always have to have quite large reserves to back up power stations, BECAUSE POWER STATIONS ARE INTERMITTENT THEMSELVES (Caps only added for emphasis, not rudeness)

And of course exactly the same, already existing mechanisms can be used for wind power at large penetrations.

A final point, is that if you were to have 50,000 wind turbines in the UK to run the whole grid...just imagine it, no fossil or nuclear plant on the grid, apart from spinning reserve, and some on warming, then they cannot all a) simultaneously fail, or b) nor can the wind simultaneously die away to nothing instantly over all turbines.

To that extent, the large the penetration of Windpower the less intermittent the mix of plant becomes, although of course it becomes more variable.

The rate at which the wind could, over a large area die away to nothing is quite within the ability of fossil plant, already in existence in the UK and on warming, to be started, particularly with current weather forecasting techniques.

Always remembering that 90% of the cost of running a power station is the fuel, so keeping already paid for plant idle is not particularly high.

[edit] Quick add ons

A diesel plant's cost is generally around 90% fuel I hear. However, coal is significantly less, and nuclear is even lower (both in exchange for higher capital). Nuclear Fuel Cycle Costs (FCC) is typically about 42$ million per year for a single large reactor, which makes up around 30% of the total cost I believe. Anyway, I (and many others) already wrote much of this in various articles.

Wind is similar to nuclear - fuel costs are exchanged for capital costs.

Point taken that Sizewell is the largest plant on the British grid. Still, it's not even that big compared to many being built today. Whenever I get into skirmishes with newcomers I always wind up directing them to the Kashiwazaki-Kariwa Nuclear Power Plant article, and they invariably make it a cornerstone of their argument. You think a 1.32 GW disconnect would be a problem? Try 5 GW gone offline in a fraction of a second.

What matters is the grid size, like you were saying before, the backup power is shared among all the plants. Developed economies have large electric grids, that's a fact of life. Wind power is often cited as a "distributed" power source, but I've yet to be convinced that this will help reliability and decrease grid demands, in fact... it should increase them.

Output of each unit is not decoupled from the rest - one windmill will not back up another one in the event of low winds unless it is very very far away. Wind power in Spain has changed from making up less than 10% of the nation's electricity production on some days to 27% other days (I'm not even exaggerating). Note: this is a bigger reserve problem that what you get when an act of God hit the monster nuclear plant in Japan - and it happens all the time. Large use of wind power creates HUGE distribution problems. And yet, we have armies of people coming on here trying to enlighten us to the truth that wind power CAN be used at high penetration levels with negligible modification costs to the infrastructure because they just know it deep to their bone that it would work. I seriously don't understand how they keep coming.

Well, this discussion isn't serving the article anymore, so I'll try to stop. -Theanphibian ^{(talk • contribs)} 23:40, 6 November 2007 (UTC)

Once again Theanthibian - you are putting words into wind power proponents and no doubt myself which we have not said. quote: " we have armies of people coming on here trying to enlighten us to the truth that wind power CAN be used at high penetration levels with negligible modification costs to the infrastructure " Serious people have never said that but we / they / I have studied in detail the likely costs and they are not overwhelming. For a start, the point you refuse to grasp is that all grids already have massive investments in coping with the intermittency of the existing power stations - such as existing load shedding arrangements, diesels, the very transmission system itself and inter system interconnections. Yet these capital costs are quite low compared to the fuel costs of the systems. Engineman (talk) 14:56, 17 November 2007 (UTC)

By the way, have you looked at the lists of planned HVDC interconnections ? there are huge plans, nothing to do particularly with wind, it just helps the grid security by sharing reserve capacity and reducing spinning reserves. It so happens that this inevitable helps wind power because over large distance wind power output does become decoupled.

The other point you need to get into your mind, is that in for example the UK, but equally any where else, the costs need to maintain the existing fossil power stations idle, and then to ramp them up in a timely fashion is quite low. In other words the back up has already been built. Various studies have shown that the timescales to ramp them up are well within the range of existing weather forecasting techniques.

[edit] Cost of fuel

Dear Anthibian, what I said was, that the cost of running a typical UK coal station, last time I looked, 90% was the cost of the fuel, ie coal not diesel, so leaving them idle as back up to wind isn't very expensive. I was not talking about diesel costs which are higher.

No, you heard wrong. Coal costs are commonly placed at around 30 - 60 % of total generation costs, ballpark. nucleartourist, in its comparison for instance, cites coal fuel costs at 11.0 out of a total 29.1 $/MWh. This varies a great deal, and not many coal plants are run at near 100% capacity all of the time like nuclear plants, causing more variation, but if they DID run at full capacity all the time, the fuel costs would still be around 60%, no where NEAR 90%.

Honestly, where do you get your information? These numbers are given in academic sources all over the place. I know the ballpark figure just in the course of getting a simple undergrad degree. The Uranium information centre reports about the same thing - 13.1 out of 44.3 (38.1 without the emissions trade). It is not 90%.

Stuff like this is why we require references to add things in an article. -Theanphibian ^{(talk • contribs)} 01:48, 8 November 2007 (UTC)

Well, I did say "the cost of running a typical UK coal station" what I meant was the non capital costs ie fuel and maintenance. I worked this out by looking up the cost of coal at the time, and selling price of power into the UK system - and you quickly realise that yes, the cost of running a power station is in fact largely the fuel - this is obvious - what else could it be?

My point is, that the profit the guys make on these stations is quite low... I worked it out at about 0.7p from memory.... so my point is, if you wanted to ensure the coal and gas guys made the same sort of profit, you would only need to pay them something like 0.7p/kWh for all the kWh generated by a 100% wind scenario, just to sit there and they would be no worse off economically speaking. so the cost of back up is as I said, very low comparatively speaking.

This point is referenced in the paper given at the Open University conference which is viewable on the web. Happy to see anyone else's figures but remember it is the marginal cost we are talking about not capital and that is nearly all fuel.

http://eeru.open.ac.uk/conferences.htm#jan06

The 0.7p/kWh is out of what total cost? If something quotes 2 cents/kWh for capital costs, that is still a cost you have to pay off. Whoever runs the coal plant has to use some percentage (usually about half as I was saying above) of the cents/kWh price to pay off the debt they incurred through the construction of the plant. Even if you don't run the plant, the ratepayers will still have to pay for this cost one way or the other (unless you just pass a law allowing you to screw the utility). It's not profit you have to pay them in this situation, you have to pay them back the construction costs at a decent rate of return (well, that includes profit in a sense).

What I'm saying is that if total generation costs at a coal plant are 2.5 p/kWh, the share for capital costs is 1.5 p/kWh, fuel costs are 0.9 p/kWh, and O&M costs are 0.1 p/kWh, then simply keeping the plant on reserve all of the time will cost 1.5+0.1 = 1.6 p/kWh. Even if you bulldozed the plant right then and there, you would still have to pay (some sort of equivalent to) 1.5 p/kWh for the next 20 years or so. -Theanphibian ^{(talk • contribs)} 19:33, 17 November 2007 (UTC)

[edit] back up

The point I have been perhaps labouring, is that existing grids need back up as much as very large penetrations of wind.

Geographically separated wind farms - say over the whole of Europe, linked by hvdc cables, will provide an only gradually varying output, meaning that conventional plant can be run up and down as required and will not cause insurmountable control problems. Check with the article from Graham Sinden.

Thus the "distributed" power source will increase transmission costs, not decrease them. I've read plenty about the HVDC cables, and yes, this could be a leap forward and allow for greater ease in using renewables. But it will yet again increase the costs of already non-competitive wind power. -Theanphibian ^{(talk • contribs)} 01:57, 8 November 2007 (UTC)

[edit] transmission costs

Dear Anthibian - you seem to have a habit of putting words into my mouth and then "disproving" them. I have not said that distributed power will decrease transmission costs so why have you said "not decrease them"?

In any case, what counts is how great the cost increase is compared to cost savings elsewhere in the system.... and it doesn't take much math to show that the costs are sufficiently low to justify them.

Why do you think that HVDC lines were laid in the 90s to connect England to France? (using expensive old tech HVDC) The reason was that the Frenchies couldn't turn their nukes off so it made sense to flog the occasional surplus to us Brits. Are you saying that that made the already uneconomic French stations less economic?

Also you have to consider that again, the Frenchies can only operated their system by exporting at night and keeping the lights on in Belgium and Italy - another cost to nuclear being the added transmission to these countries.... they also need the EJP tariff which pays for 5000 MW of Caterpillar diesels.

If nuclear is so economic, why is wind power experiencing an annual growth rate of about 40%, but nuclear is a few percent?

The reason is that there are huge hidden costs with nuclear - the cost of waste disposal, decommissioning, terrorist threats and insurance which governments have to pick up.Engineman (talk) 13:11, 17 November 2007 (UTC)

By the way, Theanthibian - why do you think the UK went from 400 small isolated power stations prior to WW2 with no National Grid, to maybe 50 stations now linked by HV AC lines? Obviously this increases the costs of transmission, but overall, it was much cheaper to do it that way.

HVDC linking Europe and indeed continents is merely an extension of this process. Check out the HVDC page on Wikipedia to see some of the massive investments in this tech. The longest so far is as I recall 500 MW over 1500 km in Africa....Engineman (talk) 13:15, 17 November 2007 (UTC)

[edit] costs of keeping existing fossil power stations in reserve in a tapering period 10 - 30 years ahead

Quote from Theanphibian,

"The 0.7p/kWh is out of what total cost? If something quotes 2 cents/kWh for capital costs, that is still a cost you have to pay off. Whoever runs the coal plant has to use some percentage (usually about half as I was saying above) of the cents/kWh price to pay off the debt they incurred through the construction of the plant. Even if you don't run the plant, the ratepayers will still have to pay for this cost one way or the other (unless you just pass a law allowing you to screw the utility). It's not profit you have to pay them in this situation, you have to pay them back the construction costs at a decent rate of return (well, that includes profit in a sense). What I'm saying is that if total generation costs at a coal plant are 2.5 p/kWh, the share for capital costs is 1.5 p/kWh, fuel costs are 0.9 p/kWh, and O&M costs are 0.1 p/kWh, then simply keeping the plant on reserve all of the time will cost 1.5+0.1 = 1.6 p/kWh. Even if you bulldozed the plant right then and there, you would still have to pay (some sort of equivalent to) 1.5 p/kWh for the next 20 years or so. -Theanphibian (talk • contribs) 19:33, 17 November 2007 (UTC) "

Theanphibian,

Your points above are well made, but in the UK and most of the world we are talking about existing power stations which have already been built and operated for many years. In the UK you can look up the Spark / Dark Spread which shows roughly the difference between the cost of fuel, gas/coal and the value of power when sold, ie it gives you an idea of the profit albeit there will be particular circumstances for each station. It turns out the last time I looked which was some time ago, the spark spread was a mere £7/MWh, ie 0.7p/kWh. This gives a guide to the kind of profit per kWh the stations are getting for the hours they are running, and the stations are bought and sold with this kind of return factored in by the analyst who act for the owners / purchasers. (It is reckoned by experts that the market needs about £13 / MWh spark spread to build new gas.) Since the Spreads have to include O and M then the actual profit to the owner will be less than the spread.

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

So my argument is the owners will be indifferent to running or not so long as in some tax / levy / legislative / rate fixing / type way they are paid the part of the spread they are getting now as profit.

If you imagine a scenario in which sufficient wind had been built to provide 95% of total electricity supplied by a power system in a year, (That would be 55,000 5 MW turbines in the UK) then to arrive at the real cost of wind, you would have to add to the cost of EACH wind kWh, (350 TWh/y for the UK) generated a levy to go to the fossil people to which as a total cash sum per year would equal the total cash sum they are getting now for all the hours they now run.

Since a coal station presently only runs about half the time (very roughly), and we approximate that say in the UK power comes from power stations all on average operating half the time, the levy per kWh wind generated would be less than about half of the 0.7p/kWh Dark Spread (or whatever) they presently get for half the year (or whatever), but paid for every wind kWh generated so in effect the fossil people would end up with the same amount of cash annually as now, and the fossil people would be happy. More than happy because they would not be wearing their station out. In effect this means that the fee that every wind kWh would have to pay would be about 0.35p/kWh (adjusted by a more detailed analysis of all spreads and load factors) if all the coal and gas were kept idle except when there were no wind.

This is only a crude working of the figures but it seems to me pretty clear that keeping existing fossil stations idle for occasional back up is not expensive, if spread over 99% wind kWh because you have taken out the biggest costs which is the fuel.

Your argument about costs having to include capital would be quite right if we were building more, but we aren't - they have all already been built.

In a truly competitive market, as more and more wind is built, it automatically goes to the top of the merit order since, like nuclear it has very low operating costs, and will, if the market is constructed correctly gradually and inevitably force high running costs stations (ie fossil) down the merit order, and over time, as these stations change hands, the analysts will gradually sell them and buy them for less and less, because they will calculate the returns will get less and less.

To take the argument to an unrealistic but instructive extreme, if, overnight 55,000 x 5 MW turbines were constructed, then over night, all the fossil stations would become bankrupt, the banks would foreclose, the investors would lose their money, and the banks would then sell them for what they were worth. Being in a then competitive market, the new owners would calculate how much the could get from running only those hours when there was no or low wind. Since there would be an over supply of capacity, they would be forced to offer the lowest prices consistent with earning a return, which would basically be the fuel, plus O and M plus some profit plus whatever they decided to pay the liquidator. The lost Capex wouldn't come into it.

Don't forget that to build an entirely wind scenario in the UK, which is quite possible logistically would take 10 - 30 years depending at what point we suddenly realise we have a disaster staring us in the face and the world economy goes onto effectively a war footing to combat both climate change and peak oil / coal / gas.

Over time old fossil will also be competing with a whole raft of increasing other cheaper back up systems, already widely in use - such as inter-connectors, load shedding, diesels, etc.

During that 30 year timescale, electric vehicles and charging stations will become widespread and these will have the ability to feed power into the grid during idle off road charging time (vehicles on run about 8 - 10% of the time). In the UK there are 2000 GW of existing vehicle engine capacity compared to only 70 GW of power station, and this will all have to be replaced with probably battery power from the grid.

So you would by means need to retains the entire portfolio of existing stations.

[edit] This article is very poor, in my humble opinion and needs to be drastically pruned

In my humble opinion, this article is very long and confusing. Presumably the humble reader want to get a concise over view of the situation and a conclusion.

It is clear at least to me, having studied the issue in some detail, that the intermittency of renewables is an exaggerated problem, as all the methods to deal with it are already in existence to a greater or lesser degree. Why then does this article need to ramble on for so long about this, and that and maybe and on the other hand. Why is it quoting some guy from Green Peace who is mi-stating Greenpeace's and other renewables proponent's position? and in any case is factually wrong, and is as far as I know an astronomer?

Why are we quoting an unnamed official of Xcel who is clearly voicing an opinion - where are the references to back it up?

Here is a reference quote from a reliable source:

"a detailed study for the UK National Grid states "We have estimated that for the case with 8000MW of wind needed to meet the 10% renewables target for 2010, balancing costs can be expected to increase by around £2 per MWh of wind production. This would represent an additional £40million per Annam, just over 10% of existing annual balancing costs."

This is a paltry £0.11/MWh of if you divide total power produced in the UK into the extra balancing costs.

source: http://www.eurotrib.com/story/2007/1/28/183633/609

[edit] 100% renewable electricity strategy for Europe - ie no limits to penetration

6. One paper, which is a detailed study of a Europe wide renewable energy strategy, indicates that 100% penetration of renewables could be achieved at a modest cost - e.g 3% extra total annual expenditure for say Germany.http://www.iset.uni-kassel.de/abt/w3-w/projekte/Eur-TranseurElSup.pdf. this implies there is no limit for penetration.

Engineman (talk) 11:56, 13 December 2007 (UTC)

[edit] hvdc generation losses

Quote from ABB http://www.abb.com/cawp/gad02181/c0d40da9112e6856c12573b0004490f7.aspx best Phil ---------

" ... The Xiangjiaba - Shanghai transmission link represents a major breakthrough in the technology of electric power transmission in many aspects:

The new system voltage ±800 kV is 33% higher than the voltage used for the Itaipu ±600 kV transmission in Brazil, until now the world’s highest HVDC transmission voltage rating. The power rating, 6,400 MW, is more than double the power rating of the most powerful transmission in operation today. The overhead line length, 2,071 km, will be the longest overhead transmission in the world, compared with 1,700 km for the Inga-Shaba HVDC transmission in Kongo-Kinshasa, until now the world’s longest transmission line. The losses for this long line will be reduced to 7% compared with 10% if the line had been build with conventional 500 kV DC transmissions. ... "

Using long HVDC to interconnect grids reduces impact of intermittency.Engineman (talk) 20:15, 18 December 2007 (UTC)

[edit] deletions

Of great concern is the performance of wind power during heat waves, because that is typically the yearly peak electricity demand for most temperate to hot climates. A study during the 2006 California heat storm revealed that output from wind power in California significantly decreased to less than 5% during peak demand. ^[1] A similar result was seen during the 2003 European heat wave, when the output of wind power in Germany fell to 10% during peak demand times, resulting in importing a peak of around 2,000 MW of electricity.^[2]

It has been said that, "the development and expansion of well-functioning day-ahead and real time markets will provide an effective means of dealing with the variability of wind generation." ^[3] However, the experience of Denmark, which has one of the greatest percentages of wind power utilisation in the world, would suggest otherwise. The ICE report on the Danish experience stated that wind power was so variable that Denmark exported most of its wind power, rather than use it itself. In addition, in 2002 the entire system had a total of 54 days without usable power generation. The report concluded that it would be very difficult for countries like Britain to use a large percentage of wind power. [3] A similar report by the Renewable Energy Foundation confirms the problems experienced in Denmark and goes on to indicate that the UK may experience a rise in CO2 emissions through using wind power:

Denmark achieves little or no direct reduction of emissions, because its CO2-free wind power is working alongside CO2-free hydro-power ... operating fossil capacity in (standby) mode generates more CO2 per kWh generated than if operating normally. [4]

I have deleted the above quotes because they are basically tosh. Wind power proponents never claim that wind capacity is firm - that fact that it is unavailable at peak is irrelevant - there are plenty of other techniques to get around that difficulty.

The ICE quote is also tosh and has been superseded by the much more comprehensive UKERC study. Ultimately even if wind power is exported it will be displacing coal at the margin. [5]

Please don't put up any more misleading statements that have been discredited by serous researchers and put up or imply false claims made and then appear to demolish them.

I don't know what tosh is, but the material you deleted is referenced and the fact that wind's intermittency is greatest during heightened summer peak demand is 100% relevant to the topic Intermittent power source. The fact that methods to mitigate the problem exist doesn't allow for censoring text that describes the problem. The statements were added in WP:Good faith, discuss findings of real studies, and were not intended to be misleading. Adding back. -Theanphibian ^{(talk • contribs)} 17:46, 30 December 2007 (UTC)

Proponenst of wind power do not claim it offers firm capacity. It is a fuel saver - that is where the economics come from, and the carbon benefits.

REgarding Patrick Moore..... last involvement with Greenpeace was in Canada, and was some 23 years ago. That he currently heads something called the Clean & Safe Energy Coalition, which is wholly funded by the US Nuclear Energy Institute. That he wrote last year (e.g.2005) to the Royal Society arguing there was no scientific proof that mankind was causing global warming

[edit] Auto-archiving

I am being bold and establishing an auto-archiver, as this talk page is very long. I will set it to 200 days or so. Any complaints, post here.--Gregalton (talk) 13:24, 5 March 2008 (UTC)

[edit] no limit to wind power penetration in the UK - National Grid

I offer the following personal communication as a reference. David Mill is an ex CEGB engineer and has contributed many learned papers on the subject of wind power:

" ________________________________________ From: claverton@yahoogroups.co.uk [mailto: claverton@yahoogroups.co.uk] On Behalf Of David Mill

Sent: 26 June 2007 08:58

To: claverton@yahoogroups.co.uk

Subject: Re: THE LIMITS TO WIND PENETRATION IN THE UK Andrew R.B. Ferguson Dave, (Andrews)

I would simply observe:-

NGC are on record to a Select Committee saying that they see no technical limit to wind energy penetration. I am sure Lewis Dale would not have put his name to the paper in Power UK and Energy Policy (Dale, Milborrow, Slark and Strbac) that looked at the implications of 20% UK wind if NGC thought it was that tricky The Danish SO has now published a paper at three conferences that looks at the implications of 70% wind in west DK - ignoring the links with DE, SW and NO.

Best regards,

David Mill (Ex UK Central Electricity Generating Board)"

Personal communications of any kind are unsuitable for use as references. — BillC ^talk 23:26, 4 April 2008 (UTC)

[edit] Ramping Rates Nanticoke power station

It can ramp up its output by 11,000 kilowatts a minute – almost 15 times the electricity generated by the CNE wind turbine. In four hours, it can go from idle to full throttle. http://www.thestar.com/SpecialSections/EarthHour/article/299725

[edit] Back up plant for nuclear power

http://www.thestar.com/SpecialSections/EarthHour/article/299725

Nuclear power is intermittent - more so than wind - you don;t get windless periods for months on end, but you do get nuclear shut downs lasting months.

"Last summer, when OPG had to unexpectedly shut down two nuclear reactors for several months, the province leaned on Nanticoke.

"Nanticoke has fulfilled its duty in Ontario when demand was high, when things went wrong, when the nuclear plants weren't working, and when the ice storm hit," says Amir Shalaby, vice-president of system planning at the Ontario Power Authority. "

You're confusing unplanned shutdowns with intermittent operation. They aren't the same thing. All power plants experience shutdowns, both planned and unplanned, and all plants require some degree of backup, but only some power plants can be characterized as intermittent. If its output is not unpredictable over short time periods -- hours, minutes, even seconds -- then it isn't intermittent (or at least it isn't considered intermittent by utility operators, regardless of what you yourself might call it). The way utilities plan for shutdowns is very different from the way they plan for intermittency.--Squirmymcphee (talk) 03:54, 30 March 2008 (UTC)

Fine - can you explain how the utility planned for the unexpected shutdowns of two nuclear reactors?Engineman (talk) 08:47, 3 April 2008 (UTC)

Temporarily picking up the slack for two nuclear reactors is not difficult, particularly for a very large utility. The details vary with time of year, utility, etc., but OPG (the one in the article) happens to have a gigantic coal plant that no longer runs near full capacity most of the time and is slated for decomissioning. That's what they relied upon, and the article suggests that it is an important part of OPG's current backup strategy. Most other utilities would have bumped up production from other baseload generators, possibly even delaying scheduled shutdowns to keep them available. They might have resorted to using peaking plants like natural gas turbines if (though this is generally the most expensive option). They might also have purchased power from another utility. Losing two large generators unexpectedly isn't an everyday occurrence, but it's hardly unusual.

Note that I'm not arguing against wind here -- I'm very supportive of it. I'm only saying there's a difference between intermittent operation an unplanned shutdowns and that utilities have to deal with each of them differently.--Squirmymcphee (talk) 23:12, 7 April 2008 (UTC)

yes but essentially you do the same thing if a nuclear shuts down unexpectedly or a wind farm shuts down due to low or high wind - you start up the spare plant - which you have to have in both cases. The details might differ, but the effect and plans are broadly the same.Engineman (talk) 13:16, 11 April 2008 (UTC)

You're mixing up intermittence with shutting down/throttling back again. The output from a wind farm tends not to vary smoothly over time, but to be rather "noisy" with spikes and dropouts, often over periods of seconds. The wind can start and stop much more suddenly -- even over a relatively large area -- than a conventional power plant can (if I recall correctly, such a thing caused an issue somewhere in Spain a year or two ago, so it isn't just something that can happen in theory). When a major baseload plant goes down it almost always happens in a deliberate and organized fashion, even in emergencies, as suddenly disconnecting a very large turbine from the grid tends to be a physically destructive event that will keep the plant offline for a very long time. In those cases, a backup plant that takes 10-20 minutes to start up is often perfectly acceptable. Variations in wind speed are sudden and unpredictable, though, so backing them up might not be a matter of starting up a spare plant so much as it is having a spare plant already started and able to dump power into the grid on a few seconds notice. I suppose you can call these "broadly the same," but if you need natural gas turbines running on standby 24/7 to back up your wind turbines then there's going to be a fuel cost associated with wind that otherwise wouldn't.--Squirmymcphee (talk) 17:25, 11 April 2008 (UTC)

You would have GTs running 24/7. you would have a few large coal plant running at low load, but with the steam drum full, plus a much larger tranche of frequency disconnectable / connect able load. plus a large tranche of rapid start diesels, plus greater interconnection with neighbouring grids - which is what happens at the moment.

Okay, sure. Regardless of exactly how you do it, the point remains the same -- whatever backup power you need has to be ready to go on a moment's notice, then has to be ready to disconnect at a moment's notice. From an engineering and economic perspective it's a far different scenario than backing up a plant that goes down unexpectedly.--Squirmymcphee (talk) 21:24, 15 April 2008 (UTC)

I agree it is different, but not that much different. The point is that is often overlooked is that these mechanisms are there and paid for already. It is no doubt that conventional plant failure is fairly rare, but the reserve has to be there all the time, regardless of how unlikely it is.

In the UK, the frequency disconnectable loads, and the mirror image diesels are started about once a month, meaning that at least one 660 ME set is unexpectedly and unforeseeably lost per month.Engineman (talk) 22:33, 15 April 2008 (UTC)

Thus the extra capital investment, and fuel costs are unlikely to be overwhelmingly much higher than the present situation.

Any way - do you have any problem with the introductory paragraph as it now stands?

I still disagree with the notion that plant failures and shutdowns can be characterized as intermittently, primarily because that is simply not what is meant when people talk about intermittent power sources. I'm not going to argue the point any further, though. I'd also like to see a reference for the statement that begins, "Many commentators argue...." (There's a reference a little ways after it, but it isn't clear that the reference covers this statement.) The language and formatting need some cleanup too, which I simply don't have time to do at the moment.--Squirmymcphee (talk) 19:58, 16 April 2008 (UTC)

Well - I have defined for the purposes of the paragraph the way I am using the worlds intermittency and it is pretty clear what is being talked about. It is undeniably that whatever you choose to call it, ordinary power stations need technology to cover their non performance - exactly the same technology and procedures that lots of wind needs - I take it you agree with that?

Also, it occurs to me that the paragraph is written a bit defensively for an encyclopedia entry. It should simply explain what the issues are, what solutions have been offered, and what the criticisms of those solutions are. As written, I wouldn't be surprised if its neutrality is challenged by somebody at some point.--Squirmymcphee (talk) 18:01, 17 April 2008 (UTC)

Well ok - you may be right, but bear in mind that Paul Bach who used to actually run the Western Denmark power grid, complete with masses of wind turbines, and ordinary power stations, and has chaired a group writing an application to look at plus 50% wind electricity, and is therefore a world expert, thinks it is a fair paragraph, so i would be surprised if any one has any sustainable problems with it. After all we are trying to write a short introductory paragraph which fairly summarises the issues and both he, and David Millborrow ex CEGB, so another world expert think it is ok. There is masses of stuff later on for people to go into greater detail.Engineman (talk) 16:45, 18 April 2008 (UTC)

Intermittency is not characterized by planned or exceptional phenomena but rather by random behavior. To introduce readers at the beginning of this article to a non-traditional definition of intermittency is doubly wrong. It defies convention on the one hand and indicates the wrong path toward grid development on the other. The grid can be built around intermittency but it should be clear that a grid built to accomodate unplanned shutdowns at baseload plants is a qualitatively different sort of grid from one build around intermittent power sources. A grid built around itermittency isn't simply a bigger version of what we've got - It's a smarter and more flexible version. The page should emphasize that intermittent power sources require creative grid development.

Here's an interesting article wrtten by Gipe. http://www.wind-works.org/articles/Archer80Meter.html

There's frequently a big difference between expert opinion and neutral point of view, and I think somebody who wants to challenge the neutrality of the opening paragraph will be able to produce other expert opinions that run counter to your experts. Not to mention that if the personal communications that you have posted below are all you have to back up your experts' opinions then they aren't up to Wikipedia reference standards anyway. I'm not saying they're wrong and I'm not trying to argue against them, I'm just saying that expertise does not make them neutral (and in fact it might bias them quite strongly).

(And just to be clear, the unsigned response above including the Gipe article is not mine. Not that I necessarily disagree with it, but credit where credit is due and all that.)--Squirmymcphee (talk) 23:08, 21 April 2008 (UTC)

[edit] Neutral point of view

Dear Squirmypcphee - I don't see how the guy who ran the power grid, with the largest penetration of wind power on a percentage basis in the world, ie Western Denmark, and who has a hand in and is intimate with his succesors plans to go well over 50% wind cannot be consider a neutral point of view. We are not talking about amateurs giving their opinions (like me) but experts who run power systems. Please explain.

 Engineman (talk) 20:10, 22 April 2008 (UTC)

It's simple: Expert opinion is not neutral by definition. It can be neutral, but it is not necessarily so. Experts can, and often do, disagree.

In other words, just because you find experts who say one thing does not mean there aren't experts just as qualified as yours that say something different. (See the grid operator E.ON's opinions on wind energy, for example -- this is not my area of expertise, but my impression is that they see a great need for backup.)

At any rate, you asked my opinion on the opening paragraph and I gave it to you: I said I think somebody might one day challenge its neutrality. I'm not in a position to challenge its neutrality myself or to rebut your arguments in support of what it says, I simply think it reads in an un-encyclopedic, agenda-pushing manner, and I think this is likely to get it challenged as lacking NPOV someday. Whether expert opinion supports the statements in question is immaterial -- it is about how they are presented, not what they present. There's a big difference between NPOV and verifiability; citations and expert opinion speak to the latter, but not to the former.--Squirmymcphee ([[User

talk:Squirmymcphee|talk]]) 23:11, 22 April 2008 (UTC)

Well if that's how you think it reads, ie NPOV, then I guess I have to accept that. but can you not then rewrite it into a non agenda pushing manner?

The facts cited speak for themselves - intermittency is not in fact viewed as the insurmountable barrier it is often claimed to be. That conclusion is backed by academics who have studied it, and people who run power grids with large amounts of wind power and who are planning to increase the amount.Engineman (talk) 07:14, 23 April 2008 (UTC)

While I broadly agree with the conclusions mentioned above (manageable) based on the sources in the text and here, I don't think the opening is as neutral as it should be. My main point, however, is that most of this text should be later in the article, not in the lead, which should be a simple summary of the issue, not a detailed argument of pros/cons.--Gregalton (talk) 07:27, 23 April 2008 (UTC)

Gregalton - I think you have put a nice measured polish on it now. Reads very well .Engineman (talk) 20:55, 23 April 2008 (UTC)

[edit] Academic references for the Intermittency paragraph

(since these are all proper academics then presumably they are by definition NPOV)

- can someone put them into the article please - i don't have the time.Engineman (talk) 20:14, 22 April 2008 (UTC)

References for Wikipedia intermittency entry:

Dale, L; Milborrow, D; Slark, R; & Strbac, G, 2003, A shift to wind is not unfeasible (Total Cost Estimates for Large-scale Wind Scenarios in UK), Power UK, no. 109, pp. 17-25.

Farmer, E; Newman, V; & Ashmole, P, Economic and operational implications of a complex of wind-driven power generators on a power system, IEE Proceedings A, 5 edn. vol. 127.

Gross, R; Heptonstall, P; Anderson, D; Green, T; Leach, M; & Skea, J, 2006, The Costs and Impacts of Intermittency. UK Energy Research Centre, London, available from http://www.ukerc.ac.uk/Downloads/PDF/06/0604Intermittency/0604IntermittencyReport.pdf

Gross, R; Heptonstall, P; Leach, M; Anderson, D; Green, T; & Skea, J, 2007, Renewables and the grid: understanding intermittency, Proceedings of ICE, Energy, vol. 160, no. 1, pp. 31-41.

Grubb, M, 1991, The integration of renewable electricity sources, Energy Policy, vol. 19, no. 7, pp. 670-688.

Halliday, J; Lipman, N; Bossanyi, E; & Musgrove, P, 1983, Studies of wind energy integration for the UK national electricity grid, American Wind Energy Association Wind Worksop VI, Minneapolis.

Holttinen, H, 2005, Impact of hourly wind power variations on the system operation in the Nordic countries, Wind energy, vol. 8, no. 2, pp. 197-218.

Ilex & Strbac, G, 2002, Quantifying The System Costs Of Additional Renewables in 2020, DTI, urn 02/1620, available from http://www.berr.gov.uk/files/file21352.pdf

Milligan, M, 2001, A Chronological Reliability Model to Assess Operating Reserve Allocation to Wind Power Plants, National Renewable Energy Laboratory, The 2001 European Wind Energy Conference, available from http://www.nrel.gov/docs/fy01osti/30490.pdf

Skea, J; Anderson, D; Green, T; Gross, R; Heptonstall, P; & Leach, M, 2008, Intermittent renewable generation and maintaining power system reliability, Generation, Transmission & Distribution, IET, vol. 2, no. 1, pp. 82-89.

Academic articles are definitely not "by definition NPOV" -- in fact, they sometimes express a particular point of view quite explicitly. As for somebody inserting these references into the article for you, only somebody who has read them should do that. After all, without having read them it's impossible for an editor to know which statements in the article they support.--Squirmymcphee (talk) 04:55, 23 April 2008 (UTC)

Please review WP:Source to settle any issue on academic articles. Professional/scientific journals are an excellent source of reference material. 198.151.13.8 (talk) 14:52, 7 May 2008 (UTC)

That's an entirely different issue. I never said they aren't an acceptable source of reference material, only that they are not necessarily written with a neutral point of view. The distinction is important.--Squirmymcphee (talk) 14:42, 9 May 2008 (UTC)

I thought the point was that an acedemic source is more credible becasue the give references and reasons for their opinions, and they are generally published under some sort of peer reveiw. They are not just peoples personal opinions. They can surely be quoted to back up an assertion based on some sort of fact?Engineman (talk) 06:06, 15 May 2008 (UTC)

[edit] Can wind give firm power?

Apparently yes:

"26 GW of wind provides 6 GW of firm power - Comes from a detailed statistical analysis by UK National Grid Transco - NGT - I think its 5 GW of gas plant, actually. A bit more background in: "A shift to wind is not unfeasible" by Dale, Mil borrow, Slark and Strbac, Power UK 109 "- Source - David Millborrow - ex CEGB (UK Central Electricity Generating Board)

[edit] Refrences to introductory paragraph

Personal communication: 17. april 2008 10:55

"Dear Dave A, (Claverton Energy Group)

I find the text (the 11th April version) on intermittent power sources quite fair. The parallel with nuclear power may be subtle to some people. Maybe it could help understanding the point to explain that intermittent power sources and constant power sources both have poor load-following capabilities and therefore may lead to the same problems in high penetrations.

Regards,

(Paul-Frederik Bach" (Until 2005 deputy director at Eltra, which was the independent system operator (ISO) for western Denmark). Particular responsibility was system planning, which gave him a central role in most transition processes.

Paul-Frederik Bach is now a consultant. His business card says “Consultant in Power System Development”. At Energinet’s English website (http://www.energinet.dk/en/menu/R+and+D/EcoGrid/EcoGrid.dk.htm) it says: “Paul-Frederik Bach, extern evaluator for Energinet.dk”. (I guess this is poor English) In the planning phase he was chairman of the Energinnet editing group writing the Energinet application. Energinet is a project by the Danish power grid to plan for in excess of 50% wind energy)

.............................................

To: Dave Andrews (Claverton Energy Group)

Regarding the current version of the Wikipedia article (16h April) on Intermittency, that looks OK to me.

You asked for my technical background.

In my CEGB (The UK Central Electricity Generating Board) days I was:

Principal Engineer – CEGB Renewable Energy Branch Responsible for technical issues and policy development, including a major study of integration of wind energy into a utility network. (Holt, J S, Milborrow, D J and Thorpe, A, 1990 Assessment of the impact of wind energy on the CEGB system. CEC Brussels)(Sorry - we only

"The study looked at wind up to the 15% level (energy basis)and used wind data from 12 coastal and upland sites - mostly close to locations where wind farms have subsequently been built - in Cornwall, mid-Wales, the Pennines, East Anglia and elsewhere - to obtain a time series of "wind farm" power outputs - for onshore and offshore locations - at hourly intervals over a year. Using similar time series for the system demand, and plant characteristics for the nuclear, coal and other units, the "system" was operated with increasing amounts of wind, up to 16 GW. The simulation showed assimilation of wind energy could easily be managed and that the additional costs were modest"

The study conclusions have stood the test of time. It is still referenced and requested.

Best regards,

David Millborrow (Claverton Energy Group) 17 April 2008 14:40

These are nice references, but personal communications do not meet the test;this has nothing to do with the people but the publication. Quote from their published works and/or presentations that are available on the web.--Gregalton (talk) 14:10, 17 April 2008 (UTC)

Sent: 26 June 2007 08:58

To: claverton@yahoogroups.co.uk

Subject: Re: THE LIMITS TO WIND PENETRATION IN THE UK Andrew R.B. Ferguson Dave, (Andrews)

I would simply observe:-

NGC are on record to a Select Committee saying that they see no technical limit to wind energy penetration. I am sure Lewis Dale would not have put his name to the paper in Power UK and Energy Policy (Dale, Milborrow, Slark and Strbac) that looked at the implications of 20% UK wind if NGC thought it was that tricky The Danish SO has now published a paper at three conferences that looks at the implications of 70% wind in west DK - ignoring the links with DE, SW and NO.

Best regards,

David Mill (Ex UK Central Electricity Generating Board)"

...................................................... From POWER UK / ISSUE 109 / MARCH 2003 "A shift to wind is not unfeasible"

Lewis Dale*, David Milborrow**, Richard Slark*** and Goran Strbac****

Conclusions

This paper has estimated the additional costs that would arise if 20% of electricity requirements were produced from wind power. Using conservative assumptions, the total additional cost is estimated to be around 0.3p/kWh

......................................... What NGT (National Grid Co said was: --

"In the longer term, we do not think it is likely that there will be a technical limit on the amount of wind that may be accommodated as a result of short-term balancing issues but economic and market factors will become increasingly important." House of Lords, Science and Technology Committee, 2004. Renewable Energy: Practicalities. HL Paper 126-II++

[edit] Some authorities think it is misleading to call renewables intermittent, whereas conventional large plant clearly are

(What they mean is, that whereas large plant like Sizewell can and do fail suddenly, the equivalent sized wind farm simply cannot suddenly fail simultaneously whereas, its power might fade away over some hours.)

To: Dave T,

Well said. Which is why I have been arguing for some time that wind, wave, tidal and solar should be described as "variable", rather than "intermittent". Nuclear, coal and gas are intermittent: when Sizewell trips out, 1200 MW are lost rather quickly!

Best regards

David Mil (Ex UK Central Electricity Generating Board and co author of many of the papers listed in the main article under further reading)

David Toke <tokedy at adf.bham.ac.uk> wrote: Dear All, Some of you may have noticed yesterdays news story about how ‘hundreds of thousands’ suffered power blackouts after the sudden (unplanned) failure of over 3GWe of nuclear and coal power station failure (‘within a few minutes’). See http://news.bbc.co.uk/1/hi/uk/7422817.stm I do find it very irritating that this is turned around and put down as something to do with a lack of power stations.

What, at the end of May!

It was nothing of the sort. It is a clear case of how the traditional power station set-up is just as vulnerable to mass blackouts as intermittent sources (while we’re in a tizzy over the possible impact of large volumes of wind power). Now, granted, we do need research into how intermittent generation sources are going to affect things, and we need to build up the ability of the system to respond quickly to unplanned changes in supply side availability, but let’s pour cold water on this notion that wind systems are inherently more vulnerable to blackouts from unplanned outages than traditional power systems. We’ve seen the data on how storms in Denmark cause wind farms to go offline. But does it, or is it going to, happen with windfarms at the rate of 3GWe in ten minutes? The records of hurricanes in Denmark that I have at my disposal suggests that this rate of loss occurs over hours, not a few minutes. What I do find interesting is the lack of discussion by major power companies on the dangers posed by real unplanned outages by conventional power stations compared to the siren alarm calls over the problems that are going to be caused by windfarms.

Yes, we urgently need a lot more demand response methods (and also an increase in standby generation response rates using existing plant), but this is required just as much for the sake of the problems caused by the great lumbering conventional coal and nuclear dinosaurs as much as an anything else! Best Wishes, Dr Dave Toke

[edit] Intermittency exists in conventional power grids

From BBC UK power supply back to normal Wed - National Grid Wed May 28, 2008 5:07am EDT Email | Print | Share| Reprints | Single Page| Recommend (-) [-] Text [+] LONDON, May 28 (Reuters) - Britain's power supplies returned to normal on Wednesday after a series of unexpected plant shutdowns briefly cut off hundreds of thousands of people on Tuesday, network operator National Grid (NG.L: Quote, Profile, Research) said.

The almost simultaneous shutdowns of British Energy's (BGY.L: Quote, Profile, Research) Sizewell B nuclear power station and Scottish Power's (IBE.MC: Quote, Profile, Research) Longannet 1 coal-fired power plant caused local network trips, which left parts of the country without power.

Although the blackouts were resolved quickly, more unexpected plant shutdowns later in the day saw National Grid warn about possible volatage reductions and plead for more units to be made available.

But supplies were comfortable again by Wednesday morning, with Longannet restarting overnight and other generating units responding to the calls for more power.

"Some of the power stations that went off yesterday have come back and other generation has become available so it's back to business as usual," a spokesman for the grid operator said on Wednesday.

British Energy (BGY.L: Quote, Profile, Research) chief executive Bill Coley said on Wednesday that the company expected to restart the 1,180-megawatt Sizewell B power station within days.

"It appears to be an instrument problem. There is no issue with the plant and it should return (to operation) very quickly," he told reporters. (Reporting by Daniel Fineren)

[edit] French electricity networkoperator thinks that wind can replace capacity

If I may quote the 2007 RTE report (French electricity network operator, big PDF, in French), p.49

The second point is about wind's contribution to peak demand: despite wind's intermittency, wind farms reduce the need in thermal power plants to ensure the requisite level of supply security. One can speak of substituted capacity.

The capacity substitution rate (ratio of thermal capacity replaced to installed wind capacity) is close to the average capacity factor of wind farms in winter (around 30%) for a small proportion of wind in the system (a few GW). It goes down as that proportion increases, but remains above 20% with around 15GW of wind power.

RTE was really wary of wind, and has turned around quite spectacularly. Their report takes pain to explain how France benefits from some special factors (the total decorelation of wind regimes between the Mediteranean, Brittany and Northern regions, and the fact that most of its thermal capacity is already available for peak capacity), but the fact remains: a wind MWh fully replaces a thermal MWh, and creates no additional requirement for thermal reserves.

Jérôme

[edit] Danish Windpower experience and references

Dave,

Energinet.dk: Environmental Report 2008, table 1:

Key figures 2007

DK East
DK West
DK total

Wind share of net generation in the area

11,8 %
23,8 %
19,4 %

Wind share of consumption in the area

11,3 %
26,3 %
20,3 %

RE share of net generation in the area

22,2 %
31,5 %
28,1 %

Electricity accounts for the grid 2007

GWh
GWh
GWh

Electricity generation ex plant (gross incl. own consumption)

14.622
24.749
39.371

Electricity generation ex plant (net excl. own consumption)

13.653
23.371
37.024

Import, gross

4.053
6.266
10.319

Export, gross

3.233
8.041
11.274

Transmission grid losses

252
488
740

Sales to distribution

14.221
21.108
35.329

Specification of electricity generation

GWh
GWh
GWh

Electricity from wind

1.609
5.562
7.171

Electricity from hydro power and photovoltaic

0,09
30
30

Electricity from thermal production based on VE fuels

1.428
1.764
3.192

Electricity from thermal production based on non-VE fuels

10.616
16.016
26.631

So far the report is available in Danish only. Translations are from Environmental Report 2007,

http://www.energinet.dk/NR/rdonlyres/20F79A25-71A2-4B69-9F2E-125B6703F345/0/EnvironmentalReport2007.pdf

Reference to the 2025 target:

http://www.ens.dk/graphics/Publikationer/Energipolitik_UK/Engelsk_endelig_udgave_visionaer_energipolitikA4.pdf

I shall look for German figures.

Regards,

Paul-Frederik

............. Dave A,

According to the German Wind Energy Association............

19,460 wind turbines with a total capacity of 22,247 MW were installed in Germany altogether by the end of 2007. 39.5 TWh of wind electricity were generated during this year. These are over 7 % of Germany’s electricity consumption.

I defer to Paul for DK.

Best regards

David Mil