<Help Prioritize the Questions for the APIThe Oil DrumDrumBeat: April 19, 2007>

81 comments on How Uranium Depletion Affects the Economics of Nuclear Power

Comments can no longer be added to this story.

crobar on April 18, 2007 - 12:14pm Permalink | Subthread | Comments top

" To name two examples: when considering a the small UK region, wind power is capable of baseload to a 20%+ degree[9]. "

Actually what this report states is that 40GW of wind capacity is necessary to displace about 8GW of conventional capacity (20%) due to the wind only blowing 20-40% of the time. Your statement is technically true, that we can replace 20% of UK capacity with wind power, but we will require 5 times the installed capacity of conventional sources.

There are further reasons based on security of supply issues why wind is not suitable for base load. The probability of any particular amount of capacity actually being available to the network at any particular moment tends to a normal distribution. For wind power this distibution is considerably wider (and its mean considerably lower per installed MW) than conventional sources. The probablility of the demand also has a normal distribution. Since prices are based on the next maginal MW, i.e. the most expensive producer, the point where these two curves overlap is the point of interest. The less predictable either of these curves are, the greater the fluctuations in price. If a hydro station has to come online to make up the shortfall, everyone has to pay their bid price, so the cost of generating the wind power has little to do with the price to customers simply because it's less predictable.

Those of you from California may have heard of a company called Enron which gamed the system (took capacity off-line for "maintenance" etc) so prices rose to the costs of the next most expensive producer. In California this resulted in prices rising tenfold and contributed to the disruptions of supply. We had sinilar problems in the UK when there were too few competitors. This could happen for less malicious reasons with unpredictable power sources such as wind making up significant amounts of the capacity.

0
Comments can no longer be added to this story.
wkwillis on April 18, 2007 - 1:41pm Permalink | Subthread | Parent | Comments top

Just to clear up a slight misunderstanding, when we have to install five times as much wind capacity because the wind isn't blowing all the time in one place, what it means is that to replace a 5 cents a kilowatt nuclear power plant, we have to build five windmills (at the current price of 1 cents a kilowatt) in five locations and hook them up to the power grid in Europe or America in order to get 5 cents a kilowatt power at any time.
If you already have installed hydro, you can use windpower to extend the hydro by using wind when the wind is blowing, and hydro when it is not, but your windpower still costs the same 5 cents a kilowatt because the wind is only blowing one fifth of the time.
I have run into people who think that since wind is only blowing one fifth of the time, that therefore you have to multiply the cost of wind capacity by five times to get the true cost.

0
Comments can no longer be added to this story.
crobar on April 18, 2007 - 2:35pm Permalink | Subthread | Parent | Comments top

You misunderstand my point, it doesn't matter how much it costs any of thoses five wind generators to produce. If the wind resources all happen not to be producing at any one time, which will happen, an expensive producer will have to take up the slack. I gave hydro as an example as hydro is what is used in the UK for peak loads as it can be brought on stream very rapidly. It is still pretty cheap but they can pretty much charge what they like as there's noone else to supply that marginal MW. Customers pay ALL the producers that expensive price, for all the MWs produced regardless of how much it costs them to produce.

Windpower is cheap to produce, but unpredictable, in fact the clearing time in the UK trading system was lowered from 3 hours before production to one hour primarily because wind producers couldn't predict accurately enough in that time frame. Compare this to conventional sources which generally trade CFD's months or years in advance of production and you begin to see the problem. Wind, wave and solar power are perfectly adequate for supplying power, but they are most certainly not suitable for a reliable base load.

0
Comments can no longer be added to this story.
Toby Kelsey on April 18, 2007 - 8:53pm Permalink | Subthread | Parent | Comments top

we will require 5 times the installed capacity

Conflating maximum output and design output (deliberately or not) does not help your credibility.

If the wind resources all happen not to be producing at any one time, which will happen, an expensive producer will have to take up the slack.

As we are comparing wind and nuclear, the assumption being made is that nuclear is reliable. In fact the BWEA gives a capacity factor of 65%-85% for nuclear power. If you think they're biased, a US industry site claims "Currently, nuclear power plant capacity factors average over 75%", while in the UK the average load factor (actual output/design output) for nuclear is 64.7% (individual plants vary from 34.1% to 83.5%, the newer AGR plants actually average 60.4%), and that is before allowing for planned maintenance downtime. Of course the industry claims future plants will be more reliable and won't suffer cost overruns of 40%.

Now consider that the next generation of nuclear plants are designed in the 1000-1600MW range, while commercial wind turbines are in the 500kW - 1MW range. What is the probability that a nuclear plant will have unplanned downtime, compared to simultaneous downtime of the 1500 substitute turbines spread around the country? Unsurprisingly an unreliable power sector that comes in bigger lumps leads to greater fluctuations in output. If the UK builds 10 next-generation plants, assuming an improved load factor of 85% then for more than 80% of the time one or more will be broken (unplanned downtime) and 45% of the time two or more will be broken. How many extra plants at what extra cost will we need to ensure, say, 95% "base load" reliability?

Wind, wave and solar power are perfectly adequate for supplying power, but they are most certainly not suitable for a reliable base load.

Although more R&D is needed, we know wave and tidal power are much less variable than wind. More independent sources of power leads to greater overall stability, but we still need to improve storage, demand management and inter-regional grid connections to reduce the amount of expensive dispatchable sources needed. With enough stability and demand management, the required dispatchable power could come from biofuels.

0
Comments can no longer be added to this story.
crobar on April 19, 2007 - 6:34am Permalink | Subthread | Parent | Comments top

Studies[1] have shown that the capacity factor of wind is around 35% at it's highest.

"The reported annual capacity factor for the UK wind power has varied from 24% to 31%, with a long-term average of around 27% (DUKES, 1998 and DUKES, 2005); these reported figures include downtime due to maintenance, and forced outages due to mechanical failure. In contrast to these reported figures, recent studies (cf. Dale et al., 2004) have tended to use a long-term annual average capacity factor of 35%; this decision is likely based on the higher wind speeds, and hence capacity factors, that are expected from offshore wind power developments, and a bias towards future onshore wind power developments in higher wind speed regions such as Scotland. A pessimistic view of UK capacity factors for wind power has also been put forward by a number of authors, suggesting capacity factor figures of 25% and below (Royal Academy of Engineering, 2003; Sharman, 2005)."

Somewhat lower than the 60% lower estimate you gave for nuclear power. In addition you claim that it is unlikely that 1500 turbines will go down at once. In an area the size of the UK it not that unlikely that an unusual large scale weather event could cause a significant portion of the wind power to go off-line. Since the UK is only connected to Europe by 2 2GW busbars (which incidentally both once went out of service despite being an event considered so unlikely no contingency plan existed, demonstrating that unlikely events do occur) it is effectively an isolated region.

The main problem with wind, however, is not it's capacity factor but the security of supply. On average the wind will supply a given amount of power to the network but this amount cannot be changed as it is dictated by the wind. For instance, there can be no spinning reserve with wind power, in the event of a frequency drop on the network due to a large plant coming off line, the first port of call for maintaining system stability is for the running plants to increase their output, they're supposed to operate slightly less than their rated capacity to do this (whether they actually do or not is another matter). Hydro which is used for peak demand cannot supply emergency power as for the first few fractions of a second of output they cause further strain on the network, which would result in a further drop in frequency and could cause the other generators to become desynchronised. Following taking up the slack by increasing power to the running generators, the spinning reserve is brought online. These are generators which are spun up but not supplying power to the network. The next step following this is to spin up off-line generators, in order to replace the reserve capacity, this can take minutes to hours depending on the type of plant. How would you suggest any of this is achieved with wind or indeed wave power when you have no clue how much wind or waves will be available at any given time? There is more to the security of the electricity network than just the installed capacity. You are correct in stating that storage could solve some of these problems, but this technology is in its early stages.

Further problems with wind are that the best resources bear no particular relation to existing load centres such as cities etc. When you consider that the transmission infrastructure necessary is at least as expensive as the installed capacity this cost can be quite significant.

For what it's worth I don't have anything against wind and wave power, I'm just skeptical that they can supply a secure base supply. In fact, as I'm hoping to start a PhD based on optimising various types of marine energy machines next year, I actually have a distinct bias towards this resource! Therefore, as someone who is going to be doing a little bit of the R&D you mention I feel compelled to warn you that we will be stuck with conventional sources for a while to come.

You also state the required dispatchable power could come from biofuels. There is considerable debate on this board about the viability of biofuels, I personally don't know enough to comment.

[1] Graham Sinden, Characteristics of the UK wind resource: Long-term patterns and relationship to electricity demand, Energy Policy, Volume 35, Issue 1, January 2007, Pages 112-127

EDIT FOR TYPOS

0
Comments can no longer be added to this story.
Toby Kelsey on April 19, 2007 - 10:26am Permalink | Subthread | Parent | Comments top

Somewhat lower than the 60% lower estimate you gave for nuclear power

Note that wind capacity factor relates average power output to maximum output, while nuclear load factor relates actual power output to design output. No-one (except you?) claims wind turbines are expected to produce maximum power continuously, but that is exactly what design output is meant to be.

A better comparison is between nuclear load factor and wind variability. In Alberta (pdf) they calculate they need an excess capacity of 2-7% to cope with variability at moderate (20%) wind penetration. "The emerging consensus in America – from a review of several utility and other studies by the National renewable Energy Laboratory - is that the variability of wind adds very little cost.".

In Denmark the standard deviation of wind variability one hour ahead is 3% (the UK will be significantly smaller). The standard deviation of the error in predicting demand in the UK is about 1.3%, so variability over that timescale is comparable to unpredictable demand fluctuations and poses no new problem.

there can be no spinning reserve with wind power

Using wind instead of nuclear does not require increasing spinning reserves. Nuclear power certainly cannot provide spinning reserve - start-up times are I believe several hours. It is because of large lumpy unreliable power sources like nuclear that we need spinning reserve in the first place - the spinning reserve is sized to cope with losing the largest lump. As we move away from those sources the need will in fact decrease, not increase.

they're supposed to operate slightly less than their rated capacity to do this [...] How would you suggest any of this is achieved with wind or indeed wave power

Whenever wind power output exceeds momentary demand, some of the turbines will be feathered or load will be shedded in other ways. These can quickly be brought back on-line if demand increases. Contrary to your claim, there is no reason wind or wave cannot be operated at reduced power levels providing a reserve. Combining wind power with energy storage is sensible and provides additional reserve. I agree more research is needed here.

All power sources have varying availability and we need additional installed capacity for reserves. Diversity of supply is good and combining wind, wave, tidal, biomass CHP and other sources, pumped and other storage, regional grids and demand management we can create a reliable system.

Further problems with wind are that the best resources bear no particular relation to existing load centres such as cities etc

While nuclear plants are in/near them? The distributed nature of wind and small CHP can actually better match power supply to demand in some regions, but often people don't live in windy places. Offshore wind and wave requires upgrading and extending the electricity grid, this needs investment but is a small proportion of the total energy costs. TREC style electricity interconnects would require upgrading the grid anyway.

0
Comments can no longer be added to this story.
crobar on April 19, 2007 - 3:27pm Permalink | Subthread | Parent | Comments top

First of all, I do not recall mentioning nuclear anywhere until you mentioned it. My assertion was simply that wind is not suitable for base load. At all times I have referred to alternatives as conventional sources.

You state:

"Note that wind capacity factor relates average power output to maximum output, while nuclear load factor relates actual power output to design output. No-one (except you?) claims wind turbines are expected to produce maximum power continuously, but that is exactly what design output is meant to be."

So to clarify, a wind capacity factor of 35% means that if you install 100 MW of wind capacity, you will expect to produce, on average 35 MW of power averaged over the period on which the figure is measured. If we scale up the wind farms and spread them out so we have say, 25GW of capacity, we should expect to get a pretty constant 35% into the network from all sources averaged out geographically, i.e. 8.75 GW for 25 GW installed maximum possible capacity, i.e. the possible capacity if the wind was blowing really strong everywhere.

Note that the transmission system to achieve this will have to be rated to the maximum capacity otherwise the averaging geographically will not work as congestion will prevent power going where it's needed.

With nuclear capacity averaging 64.7% nationwide from your figures, if there were 25 GW of installed nuclear capacity we ought to expect to get, on average, a pretty reliable 16.175 GW of actual input to the grid.

I fail to see how these two figures cannot be compared directly. For a given installed productive capacity a certain average power output is achieved. In addition, a wind turbine has a lifetime of approximately half that of a nuclear installation.

You also state:
"While nuclear plants are in/near them?"

They may not be right next door, but they're certainly not up to three kilometres off-shore (for near shore) or ten kilometers or more (off-shore) or in hilly or mountainous regions on ridgelines in order to exploit the topographic acceleration where the hill or ridge causes the wind to accelerate as it is forced over it.

As for the reserve provided by wind farms.

You are correct that a nuclear plant may require up to a day and a half to come on line in some cases, this is not spinning reserve. Spinning reserve are synchronous machines which have been spun up in advance to the synchronous speed of the the grid, but not bearing any actual load. You will find in the document you referred to definitions of the three types of reserve.

Wind farms may be able to operate a form a spinning reserve, the amount of which available in any location will be unpredictable more than an hour in advance, but this is not the same as operating under the rated capacity for a conventional plant. In the event of a frequency drop due to a plant outage, I explained the response is to increase the output at generators already connected to the grid and supplying power. This is achieved by increasing the fuel supply to the generator. Since no wind plant can know more that one hour in advance what it's fuel supply will be, how can it provide for this? Nuclear plants most certainly can, and indeed, are obliged to operate less than their rated capacity to allow for this fast-frequency response as it is known.

I reiterate my actual point, wind power is fine, but not suitable for base load.

edited for many typos! There's probably still plenty there too.

0
Comments can no longer be added to this story.
crobar on April 19, 2007 - 3:56pm Permalink | Subthread | Parent | Comments top

And another thing, you also state it is because of large lumpy power stations that we require reserve. As I have already pointed out, one of the worst losses in the UK was the grid interconnect with france, not the loss of a power station. Power losses are more frequently the result of transmission failures as this infrastructure is much more vulnerable to weather, trees falling over etc. The loss of the grid interconnect to a 1500MW wind farm will appear identical to the rest of the grid as the loss of a nuclear power station.

0
Comments can no longer be added to this story.
crobar on April 19, 2007 - 5:36pm Permalink | Subthread | Parent | Comments top

Sorry about this, but there is one more thing I noticed when reviewing the paper you cited.

The following maximum errors were recorded in predicting wind speed nationwide:
UK: not quoted
Denmark: 18%
Germany: 20%

The following are the expected errors in the outputs compared to that predicted for given time periods before production. This means this is actually the error in what was produced compared to what was predicted to be produced.

1hr___________
UK: 3.1%
Denmark: 3%

2 hrs_________
Denmark: 5.6%

3.5 hrs_______
UK: 6%

4 hrs_________
Denmark: 10%

So 4 hrs before they had to supply electricity the Danish producers would have been wrong about what they could produce by 10% etc.

0
Comments can no longer be added to this story.
Squalish on April 18, 2007 - 5:24pm Permalink | Subthread | Parent | Comments top

The problem isn't that you have to build 5 windmills to get 1 nameplate capacity, it's that the production of all 5 will closely correspond. That's what limits penetration, and prevents wind from producing all the power of a grid.

To create a reliable wind-only power supply without significant energy storage, you need massive amounts of cross-country infrastructure. Most likely, based on superconducting 'trunk' lines or an expansion of HVDC lines that would give Alcoa wet dreams.

0
Comments can no longer be added to this story.
rainsong on April 18, 2007 - 1:43pm Permalink | Subthread | Parent | Comments top

The world's largest known uranium deposit was at Olympic Lake in Australia. BHP had plans to produce the deposit over a 60 year mine life.

If uranium will reach 500 dollars a pound, someone will invest in a geigercounter and trek across some wilderness area in search of uranium mineralization.

0
Comments can no longer be added to this story.
Boof on April 18, 2007 - 5:54pm Permalink | Subthread | Parent | Comments top

Olympic Dam is to get a major expansion to become the world's largest mine of any kind if can it get more water and electrical power. A nuclear power station and desal plant at the coast 300km away would solve this but whaddaya know the nimbies don't like it. That whole geological province has other uranium and thorium reserves and guess who has snapped them up? ..the Chinese.

A side effect of this geology is that hot granite at depth could be used to generate steam albeit with minor radon gas. As with potentially dangerous molten salt reservoirs for solar thermal it seems nukular-lite is OK but traditional nuclear isn't.

0
Comments can no longer be added to this story.
ExPatch on April 21, 2007 - 9:43am Permalink | Subthread | Parent | Comments top

The so called "nimbies" have a particularly strong argument...

The desal plant is situated at the head of a gulf (Spencer Gulf) which is recognised as an important aquatic nursery for this whole gulf.

There has been limited info on where the desal plant will discharge brine and the obvious is at the top of the gulf; a region which is naturally saltier due to limited mixing this far inland and the shallow nature of said body of water. The trial plant will be watched intensely...

0
Comments can no longer be added to this story.
Miquel Torres on April 18, 2007 - 3:38pm Permalink | Subthread | Parent | Comments top

Mmm. I think you misunderstand the concepts baseload and capacity credit.

At lower levels of wind penetrations the capacity credit of wind generation is found to be about the same as the
average load factor of wind.

That means that you can actually decommission a conventional plant of the same capacity as the energy produced by the wind mills (20-30% of nominal capacity). That also means no extra costs, intermittency is not an issue.

However, as the level of wind penetration rises, the capacity credit begins to tail off. That is why in order to maintain the same level of system security a significant capacity of conventional plant will still be required.

So when wind produces a big percentage of a country's electricity, say 20%, the capacity credit it gets is smaller than the energy it produces. That means extra costs arise because backup power plants will have to be kept ready. So at some penetration point it will be uneconomical to continue to expand wind because you would have to keep an entire power plant fleet ready to cover calm periods. The discussion is where that point lies. A worst-case coal backup power plant (capital costs low) that is on standby most of the time and only burns fuel (the expensive and dirty part) on rare occasions is not that bad (most of the time hydro could be enough).

0
Comments can no longer be added to this story.
NZSanctuary on April 19, 2007 - 1:11am Permalink | Subthread | Parent | Comments top

"That means extra costs arise because backup power plants will have to be kept ready."

Nuclear faces the same issue. Nuclear plants do not run non-stop and at full capacity for their entire life - nothing near it. Toby looked at some of the numbers above.

"You can never solve a problem on the level on which it was created."
Albert Einstein

0
Comments can no longer be added to this story.
Squalish on April 19, 2007 - 4:44pm Permalink | Subthread | Parent | Comments top

But Plant Maintenance doesn't take every nuclear plant on the eastern seaboard off at the same time for a scheduled quarterly inspection.

Whereas a weeklong weather pattern just might.

No, not all of the turbines will stop blowing completely... but with the new high efficiency turbines, they produce nearly all their power in a specified range. If a lack of weather events conspire to bring the average windspeed down from 21 mph to 13 mph over a large area... while some mills will keep blowing, you're likely to go from 15-25% of your power generated by wind to 1% of your power generated by wind overnight.

The larger and more interconnected your grid, and the more on-demand generation you have, the better prepared for such a weather pattern you are.

0
Comments can no longer be added to this story.
crobar on April 19, 2007 - 6:50am Permalink | Subthread | Parent | Comments top

You are right, I was confusing this with net capacity factor

Capacity factor (net)
The ratio of the net electricity generated, for the time considered, to the energy that could have been generated at continuous full-power operation during the same period.

0
Comments can no longer be added to this story.