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Post by David B. Benson on Mar 21, 2013 13:21:51 GMT 9.5
A question came up elsewhere about load following with an NPP. I found the quite decent ansnuclearcafe.org/tag/load-following/to note that on the left sidebar there are links to several other pro-nuclear sites, including Brave New Climate. So I thought it appropriate to return the favor here. |
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Post by sod on Mar 22, 2013 3:49:47 GMT 9.5
A question came up elsewhere about load following with an NPP. I found the quite decent ansnuclearcafe.org/tag/load-following/to note that on the left sidebar there are links to several other pro-nuclear sites, including Brave New Climate. So I thought it appropriate to return the favor here. Sorry, but that article is horrible. To give a typical quote: "Westinghouse Pressurized Water Reactor: This design of nuclear plant was advertised in the 1980s as being “able to follow repetitive load changes automatically"basically it is quoting advertisements. at least the comments contain a useful link: www.oecd-nea.org/ndd/reports/2011/load-following-npp.pdf(though not from a very objective source) France has a long history of load following with reactors and we know from them, that load following capacity is connected to the position in the fuel cycle. (good with a fresh load, problematic later on) so what we want to know is the capacity of the entire fleet. (for example look at the graph on page 9 of the pdf i linked above) Nuclear power plants build today need near perfect load following capabilities. the whole fleet needs to go close to zero during high winds or summer afternoons... and this needs to be economically feasible. good luck! |
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Post by anonposter on Mar 22, 2013 10:24:30 GMT 9.5
France has a long history of load following with reactors and we know from them, that load following capacity is connected to the position in the fuel cycle. (good with a fresh load, problematic later on) To solve global warming some countries are going to need a higher percentage of their electricity generated from nuclear power than France gets currently (Australia is one of them). But not to worry, fluid fuel reactors like the LFTR are great at load following. Nuclear power plants build today need near perfect load following capabilities. Hardly, in most grids nuclear will be the baseload that stays at 100% power all the time they are running while other more expensive sources will be shut off in low demand periods. the whole fleet needs to go close to zero during high winds or summer afternoons... No, the renewable energy facilities need to lose their subsidies. and this needs to be economically feasible. good luck! Having the renewables pay for the problems their unreliability causes would be a good idea. |
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Post by edireland on Mar 23, 2013 6:32:29 GMT 9.5
The CANDU reactors are Bruce NPP were kept running at 60% reactor load for hours during a massive power cut by the simple expedient of dumping steam directly to the condensors instead of through the turbines. This tends to get expensive though as it reduces capacity factor, and since a nuclear power plants costs are basically all capital and staffing (which must retained no matter what the plant is actually doing) they do not reduce in line with produced energy output being cut. Load Following is going to be a lot less important in the future if we get intot things like Solid State Ammonia Synthesis or hydrogen production that will be able to reliably consume huge amounts of off peak electricity. Nuclear power plants build today need near perfect load following capabilities. the whole fleet needs to go close to zero during high winds or summer afternoons... and this needs to be economically feasible. good luck! Why? It would be cheaper to simply not build the wind or solar installations and keep the nuclear plants running 24/7. Once you have a staffed nuclear power plant the cost of additional generating capacity up to max capacity is ~1cent/kWh. |
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Post by anonposter on Mar 23, 2013 8:32:21 GMT 9.5
Load Following is going to be a lot less important in the future if we get intot things like Solid State Ammonia Synthesis or hydrogen production that will be able to reliably consume huge amounts of off peak electricity. Assuming such things are most economically done at night instead of all the time. Also hydrogen would probably be more efficiently produced using thermochemical means. Why? It would be cheaper to simply not build the wind or solar installations and keep the nuclear plants running 24/7. Yeah, but then sod wouldn't be able to have his fantasy world where everyone who doesn't understand basic physics felt really good about how they really care for the environment. |
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Post by David B. Benson on Mar 23, 2013 13:26:45 GMT 9.5
Assuming solar PV costs drop (far enough) it becomes sensible to consider a NPP+solarPV mix. The reserves for long cloudy times might be thermal stores on the NPPs or might be biomass fired thermal units.
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Post by anonposter on Mar 23, 2013 15:06:40 GMT 9.5
You'd still need a lot of energy storage, to use a lot of biomass (which itself has very severe problems to the point at which we should avoid it where we can) or run a nuclear reactor at half load a lot to the point at which I doubt such a thing would be economical even if solar panels were free.
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Post by quokka on Mar 23, 2013 16:20:16 GMT 9.5
Nuclear power plants build today need near perfect load following capabilities. the whole fleet needs to go close to zero during high winds or summer afternoons... and this needs to be economically feasible. good luck! Or you could do the "unthinkable" and spill some wind output. There is no first principles reason not to. The whole point of all this should be to get to a low emission electricity supply as soon as possible not to provide special privileges to technologies with a lousy capacity factor. You are going to get to that point soon enough anyway in a country like Germany where wind capacity factor is only around a miserable 18% and solar about 11%. Before you reach the point of 30% of electricity from wind+solar you will have hit that point - possibly quite a bit before 30% when transmission and distribution issues enter into it. Then there is the issue of much awaited non-hydro storage. When and if that happens, it would favour nuclear because of its dependable generation characteristics. In the real world, sooner or later, intermittent technologies will have to pay for the problems they cause. |
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Post by quokka on Mar 23, 2013 16:48:00 GMT 9.5
In the IEA's 2010 Projected Costs of Electricity Generation, which unfortunately is no long available free on-line, there is a sensitivity analysis of the economics of various technologies operating at less than their maximum load factor. Renewables came out worst and nuclear was somewhat less sensitive.
Pretending that this issue is unique to nuclear is disingenuous.
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Post by quokka on Mar 23, 2013 17:12:11 GMT 9.5
The report: ANALYSING TECHNICAL CONSTRAINTS ON RENEWABLE GENERATION TO 2050 prepared by the consultancy POYRY for the UK Climate Change Committee examines and models various deployments of renewables and nuclear in the UK archive.theccc.org.uk/aws/Renewables%20Review/232_Report_Analysing%20the%20technical%20constraints%20on%20renewable%20generation_v8_0.pdfIn their 2030 high renewables scenario, nuclear produces 145 TWh of a total electricity production of about 450 TWh. Modeled nuclear load factor is about 87%. In the 2050 high renewables scenario, nuclear produces 195 TWh of a total electricity production of about 600 TWh with a nuclear load factor of about 75%. In this scenario, off shore wind dominates renewable production. Which seems to indicate that load factor for nuclear, even with lots of renewables, may not be the economic issue that some would like it to be. |
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Post by sod on Mar 23, 2013 18:54:30 GMT 9.5
Very interesting link.
I think that 12% difference is very big.
And this is not weighted by power prices. (nuclear will still provide a lot of night time power. (nearly 50% of the load?)
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Post by quokka on Mar 24, 2013 16:23:45 GMT 9.5
Very interesting link. I think that 12% difference is very big. And this is not weighted by power prices. (nuclear will still provide a lot of night time power. (nearly 50% of the load?) The French nuclear fleet runs at a load factor of about 77%, though the availability factor is quite a bit higher. There seems no technical barrier to running at load factors in the mid 70s. It might add 10% to the LOCE of nuclear electricity, but LCOE is far from the whole cost story. |
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Post by sod on Mar 24, 2013 19:23:33 GMT 9.5
Very interesting link. I think that 12% difference is very big. And this is not weighted by power prices. (nuclear will still provide a lot of night time power. (nearly 50% of the load?) The French nuclear fleet runs at a load factor of about 77%, though the availability factor is quite a bit higher. There seems no technical barrier to running at load factors in the mid 70s. It might add 10% to the LOCE of nuclear electricity, but LCOE is far from the whole cost story. Yes, but the french are running a system of old, paid off reactors. These only have to cover their running costs, everything else is free money. And the other problem is, that in a high solar grid, nuclear power will not earn money during the former high price afternoon peak hours. so that capacity factor might stay the same (solar does not provide night time power), but money earned might drop sharply. |
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Post by anonposter on Mar 25, 2013 2:00:39 GMT 9.5
Yes, but the french are running a system of old, paid off reactors. These only have to cover their running costs, everything else is free money. Which certainly helps, but they had to get to that point somehow. And the other problem is, that in a high solar grid, nuclear power will not earn money during the former high price afternoon peak hours. so that capacity factor might stay the same (solar does not provide night time power), but money earned might drop sharply. Don't have a high solar grid then (or at least don't subsidise solar panels). |
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Post by David B. Benson on Apr 4, 2013 12:33:21 GMT 9.5
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