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Should Nuclear and Renewable Energy Supporters Stop Fighting?
Lasrick writes "A debate is happening in the pages of the Bulletin of the Atomic Scientists that started with their publication of 'Nuclear vs. Renewables: Divided They Fall,' an article by Dawn Stover that chides nuclear energy advocates and advocates of renewable energy for bickering over the deck chairs while climate change sinks the ship, and while the fossil fuel industry reaps the rewards of the clean energy camp's refusal to work together. Many of the clean energy folks took umbrage at the description of nuclear power as 'clean energy,' so the Civil Society Institute has responded with a detailed look at exactly why they believe nuclear power will not be needed as the world transitions to clean energy."
France uses their nuclear plants for load-following: they can ramp up/down their nuclear plants at about 5% per minute. That means that you only need to back your wind/solar with a few minutes worth of battery capacity to work in tandem with the nuclear plants.
A lot of this talk about nuclear power plants or even coal powered power plants being inflexible is nonsense. They are run continuously because this is more energy efficient. However there is nothing stopping you from burning less coal. In France it is common to partially off nuclear power plants during the night:
In France, however, nuclear power plants use load following. French PWRs use "grey" control rods, in order to replace chemical shim, without introducing a large perturbation of the power distribution. These plants have the capability to make power changes between 30% and 100% of rated power, with a slope of 5% of rated power per minute. Their licensing permits them to respond very quickly to the grid requirements.
Not the orignal poster,but IMO...
Thorium salt reactors are still "up-and-coming" techniques. Although there have been a small smattering of experiments over time, the only significant testing of the idea was back in the '60s (the Molten Salt Reactor Experiment at Oak Ridge Nation Labs). Although most of the technical hurdles appear to be known, I don't think there is doubt that more work needs to be done to make this production worthy. Some of the biggest issues (e.g, metalugical radiation brittling and salt reprocessing efficiency), are hard to do small scale experiments with so the only real course is to build more experimental reactors to help understand this. Experiments like this are really expensive. The FUJI project (one recent attempt considered to be a leading effort) failed to raise $300M required to build their experimental miniFUJI reactor back in 2011.
There are also secondary effects that are unknown. Uranium mining of past decades created some pretty bad ecological damage and it is unclear that Thorium minining would be any better (or be similarly econonmical with lower impact mining techniques). There is also the issue with decommissioning (even with existing Light-water reactors, this is an ongoing cost concern). At Thorium Salt Reactor have greater fuel efficiency...
One of the continuous knocks against Thorium Salt Reactors has also been nuclear proliferation security issues with reprocessing (since the most efficient configuration for Thorium Salt Reactors is a breeder configuration), but although there are some known safeguards available for denaturing to make bomb-capable material difficult to extract, terrorist level dirty-bomb material is always available in large quantities (a different threat model than in the 60's)...
According to the wiki on Pumped-storage hydroelectricity (PSH), 'PSH accounts for more than 99% of bulk storage capacity worldwide: around 127,000MW, according to the Electric Power Research Institute (EPRI), the research arm of America's power utilities.' Since in pumping the size of the reservoir is not the limiting factor, but rather the throughput of the pumps, this means that PSH can be used to store the daily output of 127GW worth of power plants. Britain's consumption is 35.8GW on average, and 57.490GW at peak (http://en.wikipedia.org/wiki/Energy_in_the_United_Kingdom), so the global installed PSH's could easily absorb the UK's production.
In the UK, however, there seems to be only one plant (http://en.wikipedia.org/wiki/Dinorwig_Power_Station), costing 425M GBP in 1974 capable of absorbing around 1GW worth of power, so nowhere near 50% of base load, so it seems that PSH costs around 425M/1G = 0.5 pounds per watt capacity. Apparently, a new nuclear plant costs about US$ 5,339/kW., or 4 pounds per watt capacity, while windmills cost around 1-2 pounds per watt. So, assuming enough sites for PSH can be found, the costs for power storage capacity seems to be 5-25% of the cost for generation capacity.
According to the wiki, "The stalling of the UK nuclear power programme in the late 1980s and the coincident "dash for gas" increased the network's ability to respond to changes in demand, making the use of pumped storage for day/night load balancing less attractive. As a result, a similar facility planned for Exmoor was never built.[2]"; so it seems that at the time the demand is what limited PSH construction, not cost or environmental factors.
http://www.world-nuclear.org/i...
http://www.windustry.org/resou...
A lot of this talk about nuclear power plants or even coal powered power plants being inflexible is nonsense. They are run continuously because this is more energy efficient. However there is nothing stopping you from burning less coal. In France it is common to partially off nuclear power plants during the night:
Nuclear plants do suffer from issues with throttled usage due to the nature of the fuel cycle. It's not that you can't throttle them, it's that as you get later in the fuel cycle it becomes harder and harder to throttle them quickly and keep them from being Xenon poisoned. Add to that the fact that our currently operating nuclear plants where not designed to throttle and you can understand why it's not a good idea. There is also the efficiency issue you cite, and with nuclear power plants running on thin margins to start, this can push them over the edge.
The primary thing to note is that it's basically hard to throttle most industrial sized power generators. Nuclear plants have longer lead times because changing power output of the nuclear core requires more engineering effort than a fossil fueled burner does which needs more effort than your hydro-electric plant. But it is *extremely* difficult to plan electrical power requirements far enough in advance to use our current 30 year old nuclear power plants which where designed to run for decades at static power outputs.
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
Current power storage that is working at Andasol solar array is Molten salt.
http://en.wikipedia.org/wiki/A...
They recently added enough storage to make power 24 hours a day.
Another power storage scheme is water reservoir pumping, its done
by several US dams already.
google "32 trillion offshore needs IRS attention"
Actually that is not true either. The plants were in fact originally designed to load follow and were only later adapted to constant full power operation based on economic factors. It is not hard at all to engineer the plants to load follow. And xenon poisoning has nothing to do with it, the primary challenge is in axial offset control which becomes more difficult later in the cycle, but only because the cycles are optimized to run at constant full power with maximum fuel loading. It would only require modest adjustments typical of cycle-to-cycle operational changes to design to load follow. IAANE.
That is actually done to a very large extent now. Foundries running electric arc furnaces or induction furnaces only run in the off-peak period, currently at night. This artificially increases base loads.
The problem with trying to match generation with demand is that you still have a transmission/distribution problem. Distributed generation is the only way to really solve that, and again economics make it difficult to distribute power generation to the point where local demand is matched to local production in both capacity and timing.
People are trying to get closer to this-- automated demand response can help a little bit.
The California ISO is pretty open with information. They track daily anticipated demand, actual demand, and available capacity. Some actually predict that solar energy that is not time-shifted will become nearly worthless in five years.
Actually, most are Gen II (if I recall correctly, Gen I was just research reactors). China has some Gen II+. There are also a bunch of Gen III+ reactors out there (I believe Gen III were also only research reactors and production moved to Gen III+). The US is just starting to build Gen III+, partially due to the regulatory snarl in getting them approved.
I'm fairly certain all Gen IV designs require passive safety, but the US abandoned development of these in the 1990s led by John Kerry, largely citing data that applied only to Gen II reactors and proliferation concerns (which is ludicrous - if you're that concerned about proliferation due to continuous reprocessing, make it closed loop and get roughly 80% efficiency of fuel instead of 99.5 and burn up the nations nuclear waste stockpile in the meantime - exactly what Russia is doing) . I'm sure we will be buying these from Russia in a few years, as they are the only country to have them approaching production (well, India is isn't terribly far behind, but the only other one I know of is Japan, and they've not been doing much in the nuclear space recently).