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I'm not sure I understand the numbers
When calculating the number of 5MW turbines is it really 6600 i.e. 33000/5.
Why is it you do not have to include the capacity factor and technical availability i.e. 33000/(5*.4*.95). That would mean over 17000 turbines ?
Also is it realistic to assume these are all 5MW turbines - are 5MW off-shore turbines proven yet and would all off-shore sites be suitable for these big turbines ?
The 33GW Hutton is talking about refers to name plate capacity. Sure - that needs to be multiplied by the load factor (27% for UK offshore wind in 2006) to get the actual amount of energy generated. This is no different to other ways of generating electricity. The UK nuclear fleet had an load factor of 69% in 2006, coal 66%, gas 54%... it should be noted that gas at least wasn't trying to maintain 100%, whereas the wind and nuclear would have been targeting maximum production.
But the headlines talk about wind providing "half Britain’s current electricity consumption" or 100% of household consumption.
Is this reasonable ?
Indeed not.
The confusion between name plate capacity and actual output is an issue that dogs the wind industry, becuase such inaccurate claims are made, and then used to point out that wind is not as good as it looks.
What matters is the MWh rather than the MW. On that basis, wind is expected to provide 30% or so of total electricity generation in 2020.
Is it fair to say that 50% (or more) of wind's MWh are produced at night when demand is lowest ?
I can see that some of this night-time wind power can replace gas/coal baseload generation but surely not all of it due to the technical demands on maintaining a stable 50Hz grid.
Without the pump storage capacity available in Scandanavia won't much of the night-time wind MWh simply be thrown away ?
No, actually wind production patterns quite closely follow consumption mattern, being lowest at night and highest in the afternoon. Offshore is the same, with smaller intra day variations (on average). I have a graph showing this, but not on this computer, I'll try to post it later.
Wind turbine are actually helpful to maintain voltage stability and reactive power.
No, actually wind production patterns quite closely follow consumption mattern, being lowest at night and highest in the afternoon. Offshore is the same, with smaller intra day variations (on average). I have a graph showing this, but not on this computer, I'll try to post it later.
Wind turbine are actually helpful to maintain voltage stability and reactive power.
In your story entitled: No Technical Limitation to Wind Power Penetration published on line in the European Tribune,
http://www.eurotrib.com/story/2007/1/28/183633/609
I found a link which led me to a report by the Tyndall Center for Climate Change entitled: Security assessment of future UK electricity scenarios.
http://www.tyndall.ac.uk/research/theme2/project_overviews/t2_24.shtml
In this report they modeled the effects of wind penetration into the U.K. electricity mix up to 37% of total electric energy supplies. At this level of penetration they claim that only 9.4% of conventional capacity can be retired. This claim alone would appear to imply that this model is in strong disagreement with your claim that “wind turbines are actually helpful to maintain voltage stability”. However, here is specific verbiage from the report about the need to compensate for wind variability with conventional generation:
Due to this disproportion between conventional capacity and energy substitution by the wind source, a considerable number of thermal plants will be running at low output levels over a significant proportion of their operational time in order to accommodate wind energy. Consequently these plants will have to compromise on their efficiency, resulting in increased levels of fuel consumption as well as emissions per unit of electricity produced. This will cause higher electricity production costs.
The average load factors for conventional plants, with 25GW installed wind capacity at 35% average output, will reduce to about 40% (utilization factor for UK plants in the year 2002 was 54%)[DTI04]. Nevertheless the cost recovery of those plants that might be forced to run at lower load factors will be a major challenge for future electricity systems.
Would you care to comment on the contradiction between the conclusions of this paper and your statement above?
See my comments that the UK needs a half dozen pumped storage schemes in Wales & Scotland. These could absorb the fluctuations nicely. Interconnections to hydroproducers Iceland & Norway would also be useful.
Alan
I agree that storage is needed for effective integration of wind energy into the grid. Including it will naturally increase the costs. Also if they end up pumping fresh water rather than sea water then seasonality issues and long term fluctuations in rainfall may also affect the economics. Iceland seems like it's a long way away from the U.K. Norway is already providing effective storage for Danish wind power producers. They may have excess capacity, but I doubt that they can provide storage services to all of Europe.
Roger
Pumped storage water (other than - evaporation & + rainfall) is recycled. One time allotment basically.
Pumped Storage is also requied with a high % nuke grid (France uses Swiss Hydro + German coal, Italian, Spanish, Belgium FF + Luxembourg pumped storage to balance their nukes at night). Uk does not have the interconnections to do that. A high % nuke UK would also require pumped storage. As would massive tidal powerplants.
Landsvirkjun made a study on supplying 2 GW of peak hydropower to UK a dozen + years ago. UK uninterested, plant was built instead for steady 540 MW for aluminum smelter.
UK has best wind resources in EU, so "getting your share" should mean a fair % of Norwegian (and even Swedish) hydro. Biggest threat is large Norse wind development IMO.
Best Hopes,
Alan
There is no contradiction whatsoever. You need a lot of wind MW to replace a conventional MW (roughly 4 for 1). But each MWh of wind replaces a MWh of conventional electricity.
All we care about are MWh, not MW.
I wrote:
In this report they modeled the effects of wind penetration into the U.K. electricity mix up to 37% of total electric energy supplies.
I said 'energy' and I meant 'energy'. I know the difference between MW and MWh. In this report 37% displacement of energy (MWh) supply resulted in 9.4% displacement capacity (MW). Have you actually read the report? I got the link to it from your article. You have not answered my question. You also conveniently ignored the statement by the report authors talking about the need to turn conventional generation plants up and down to compensate for wind variability which is in clear contradiction to your statement that wind capacity adds to the voltage stability of the grid.
I have written it three times: wind power replaces few conventional MWs. Yes, that's true. It does not matter. What causes global warming is conventional MWh, not conventional MW. So yes, wind power development requires that conventional capacity be kept in place - but used much less than now. I fail to see how this is a problem. It's not like you need to build new gas-fired plants, they are already there.
As to stability, I'm not sure what you mean. How are starts and stops of gas-fired plants detrimental to voltage stability?
I do not dispute that wind generation displaces some amount of CO2 emissions. I am not arguing that wind power is a useless technology, but we need to be realistic about its economic potential. The fact that with 37% energy displacement over 90% of conventional generation remains in place means that the capital cost of a wind/conventional generation system is much higher than conventional generation alone. And as the authors of the study quoted above point out the displacement of emissions is far less than 37% since spinning reserve and peaking reserve emit much more CO2 per kHw produced, and in addition this excess fuel use means excess costs.
Also natural gas, and after it coal, are going to decline in supply. If we have only displaced 9.4% of conventional capacity at 37% energy penetration then how are we going to produce a stable grid voltage in a post-fossil fuel world? My feeling is that in the long term effective integration of wind capacity will require energy storage which will add substantially to the costs.
I am convinced that wind energy will play an important role in humanity's future, but the claim that wind is already cheaper than natural gas and that there are no economic limits to obtaining arbitrarily large amounts of grid electricity from this source is incorrect.
The fundamental realization that the developed world needs to come to is that our levels of economic production are already too high and that reduction of consumption should be a primary goal. Encouraging people to believe that wind can easily substitute for fossil fuel and thus maintain our high consumption lifestyles without guilt about CO2 emission is dangerous.
Not if there are enough PHEV's and EV's. And with the V2G discussion, it's frequently mentioned that people don't want to see the Grid's unimaginable Demands leaning on their expensive batteries and their morning available-commute-miles, but this is a good reminder that if there are intermittent sources more heavily in the mix, that there will be times that there is 'Surplus to sell' too, and if V2G happens, isn't it reasonable to expect that people with such a 'Portable Smart-Grid Intertie' will pretty much set up their buy pricing scheme, their SELL price-scheme, and their 'Lowest Discharge Before Cutoff' or some such thing, so that on a Dark and Stormy Night when it's howling out there, you might get yourself a fine deal purchasing, and if the next calm morning, demand is high and your car is selling at a profit, you opt to jump on the bus or the bike. (I think it would actually be your car AND house that would be in automated Buy/Sell negotiations with the grid, not just the car.. ?)
By the way, who knows whether there is a functioning Flywheel System in standard use out there? I never hear any updates at TOD for the current state of that storage medium.
Bob
"I'm going off the rails on a crazy train!.."
- Ozzy
V2G is surely the way to go.
Or any other storage in that sense.
The danish wind industry has made an ambitious plan named "windforce 50" that outlines a plan to make wind contribute to 50% of our electricity use.
This envisions a major change in how we use electricity and which windturbines to build. Today we (danes) get 20% from 5.200 WT but with modern larger WT we could get 50% from 1.700 WT
The biggest issues are to get people to change when they use electricity and to what.
We need to get EV's or PHEV and use electricity to heating as well as transport.
The industry is already cooling freezers below -18 at times of cheap electricity to enable idling of cooling when electricity is expensive. The same idea applies to heating where the use of district heating is widespread and using electricity to heat water is a great way to store energy.
Cooling ice or heating water is just one way to even out consumption. In some areas they have installed meters that charge users by the hour on spotprice to encourage people to start there driers at night etc. We have 2 hours with very high electricity use, and it is easy to imagine that these hours could be covered by reduced use or V2G.
Soon the EV's will have >200 miles capacity and with most people traveling less than 30 miles a day, there is good storagecapacity available here.
Being close to Norway makes it a lot easier as their hydroplants give us the flexibility needed, but as soon as V2G is widespread the need for external storage is reduced.
Rune
Confident that most of our energy use can be replaced by efficiency and alternate generation.
use the electricity to make NH3, you can sell it at $500/t if you don't need it.
Here's the breakdown from 2004 (sorry no time to draw a new a new chart):
Click to enlarge
According to George Monbiot in his book Heat on p. 101, the UK uses about 400 TWh/year, an average power supply then of about 46 GW. Half of that is 23 GW so the required capacity factor on 33 GW nameplate is 70%. It is quite windy off shore of the UK, but I kind of think that there must be some anticipation of reduced consumption. California has shown that a 20% per capita reduction in consumption is good for the economy. Doing that gives a 55% capacity factor which sounds about right for offshore wind. Interestingly, Monbiot points out that the material requirements for offshore wind are lower than for onshore wind because the wind blows harder offshore. He cites the Performance and Innovation Unit, 10 Downing Street, as finding on shore wind reducing in price by factor of 1.4 between now and 2020 and offshore wind reducing in price by a factor of 2.75 by 2020 to the current onshore price. Both are expected to be less expensive than nuclear power in 2020 by factors of 2.5 and 1.75 respectively. See tables on pp. 111 and 95.
Chris
27% load factr sounds strangely low. The projects I have financed are close to 40% (and that's with pretty conservative estimates for the banking case).
Maybe this is the overall rate for all of wind in the UK?
The load factors for UK wind (offshore and onshore) as published by the Department for Business, Enterprise & Regulatory Reform (stupid, stupid name) are here (Excel):
http://stats.berr.gov.uk/energystats/dukes7_4.xls