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Post by Barry Brook on Jul 16, 2013 15:28:14 GMT 9.5
A post has been published on BraveNewClimate. Link here: bravenewclimate.com/new-critique-aemo-100pc-renewTed Trainer writes: "The AEMO report concludes that 100% of Australian electricity demand could be met by renewable energy sources. The claim is far from established and highly challengeable because some of the assumptions etc. are implausible and not likely to be borne out, and some crucial factors haven’t been taken into account. Intermittency has not been dealt with at all satisfactorily, embodied energy costs seem not to have been considered, and it is admitted that some major costs have not been included. It is clear that a thorough study would have arrived at an annual capital cost in the early years of construction that was several times the sum claimed. The main issue with renewables is not whether it is technically possible for them to meet total demand – it is whether the large amount of redundant plant needed to deal with intermittency could be afforded." This BNC Discussion Forum thread is for the comments related to this BNC post.
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Post by Frank Eggers on Jul 16, 2013 16:04:59 GMT 9.5
To help determine whether renewables would actually do the job, sensors could be installed at every location where it would be reasonable to instal solar or wind power generation stations. The sensors could be connected (perhaps by radio) to a central site where the information would be recorded and analyzed. The results, collected over a long enough period (at least several years) would indicate just how practical renewable systems would be.
Obviously such a study would be exceedingly expensive. However, it would be less expensive than spending $billions on an energy system then finding out that it will not do the job unless the invested amount is increased by a factor of three or more.
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Post by Asteroid Miner on Jul 16, 2013 16:20:31 GMT 9.5
Thank you Dr. Trainer. That's what I thought. Only nuclear can shut down coal.
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Post by geoffrussell on Jul 16, 2013 19:44:13 GMT 9.5
Yes, indeed, thanks. I was suspicious of the "factor 2" overbuild but didn't look in depth at what was behind it. I think you've shown its way too optimistic. But I disagree on one point; it's not ONLY the cost that is the problem with renewables, its the roll out speed. Have a look at the US process for building the Ivanpah solar plant (400 MW) ... www.energy.ca.gov/sitingcases/ivanpah/documents/There's 13,000 pages of documents beginning in 2007 and its still not up and running ... that's a 6 year build/approval time (after the company had done its planning) and you need to build about 100 of these to get the power of, for example, the 9GW Jaitapur project in India. The Jaitapur project will have a long build/approval time also, but you don't need to do it 100 times. Of course you can cut approval times for solar and nuclear by just deciding that wildlife/environmental/safety issues don't count. But nobody wants either technology to be rushed.
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Post by prismsuk on Jul 16, 2013 19:52:32 GMT 9.5
There seems to be a correlation (not necessarily causation) between big gaps in wind resources and big gaps in the clarion calls for more and more wind turbines, from (purported) environmentalists. As we speak, over here in the UK, where we have 8 GW of onshore and offshore wind farms, 0.6 GW of electricity from wind is trickling into the National Grid - www.gridwatch.templar.co.uk/ - For 10 days, electricity from wind has crept over 1 GW on only 3 occasions, totalling about 12 hours - and these conditions are set to go on for another few days of a gorgeous hot-spell, thanks to a slow moving anticyclone. Even if we had 10 times as many wind turbines, we wouldn't be able to power the Isle of Wight from renewables, let alone the whole of the UK. Thank goodness we have a steady 24/7, on demand, emission-free, 8 GW supply of nuclear power, to make up the difference. There's no chance of keeping the lights on or saving the planet with renewables, is there?
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Post by anonposter on Jul 16, 2013 21:29:25 GMT 9.5
To help determine whether renewables would actually do the job, sensors could be installed at every location where it would be reasonable to instal solar or wind power generation stations. The sensors could be connected (perhaps by radio) to a central site where the information would be recorded and analyzed. The results, collected over a long enough period (at least several years) would indicate just how practical renewable systems would be. We've pretty much already got them.
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Post by Gene Preston on Jul 16, 2013 23:35:21 GMT 9.5
ERCOT (see www.ercot.com ) is a system similar in size to AEMO and is nearly isolated from other systems in the US and Mexico, connecting only through a few small DC tie lines. Ever larger amounts of wind are being studied in ERCOT. The electrical stability and the dispatching stability of the ERCOT system is becoming a rather severe problem as wind is being pushed to higher and higher levels. These higher wind levels are very far from being able to have 100% renewable energy. Solar has yet to make a significant impact in Texas. Other renewable energy sources are insignificant. As wind is being pushed to higher levels it's becoming apparent that gas energy is being reduced to the point that gas generators are not generating enough revenue to continue their operations and they are being retired. Every week there is an announcement of another gas plant being retired. This is creating a capacity shortfall since there are times when there is little wind and the load is dependent on wind being there because of a lack of backup fossil fuel capacity. ERCOT is desperate to keep the gas capacity and it having to strike unusual deals to bring back on line the shut down gas plants. ERCOT has nuclear capacity, but its only a small fraction of the total capacity of the system and its static. The public utility commission is struggling with the capacity issue. The ex chairman of the PUC, Pat Wood, who oversaw the deregulation of the ERCOT grid in the 1990's has recently become notoriously famous in Texas for saying that the deregulated energy market he helped implement is now known to be a failure. Yet the energy market believers cling on believing the energy only market can be patched up and made to work. If Australians try to implement a renewables only plan it will certainly fall into the same problems we are experiencing here in Texas. And as Dr Ted Trainer has pointed out, financing renewables is a huge problem because of the overbuilding of the system that is required. Dr Eugene Preston www.egpreston.com
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Post by Keith Pickering on Jul 17, 2013 13:48:26 GMT 9.5
A recent study by Budishak et. al., covering a part of the US Eastern seaboard and using actual weather data for several years, concluded that the cheapest 99.9% renewable system would be almost no solar, and overbuild wind by a factor of 3. www.sciencedirect.com/science/article/pii/S0378775312014759Regarding the EROI of solar (and other sources), a recent study by Weißbach et. al. (http://dx.doi.org/10.1016/j.energy.2013.01.029) gives EROI of 3.9 for photovoltaic and 19 for CSP, putting the "breakeven" EROI at 7, based on the ratio of energy price to GDP generated.
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Post by Evcricket on Jul 17, 2013 13:55:11 GMT 9.5
I've got a pretty good idea what the response to this is going to be but I'll type it out anyway.
I think the "idle plant" consideration is an absolute furphy. Gas turbines are cheap, the fuel is expensive. The operating conditions you describe now are very similar to what we have today. What is the negative outcome of a gas turbine being used infrequently? It's obviously cost effective enough now for many companies to pursue it, even with use below ten days a year. AEMO considered the total cost of supplying electricity including these idle gas turbines and renewables and found the cost to be tolerable.
Remember too that any nuclear system will also need gas back up, as the generation side must be able respond as quickly as the demand side. Nuclear plants are big, slow Rankine cycles, just like coal plants and they can't ramp fast enough to meet all the demand in a day.
I thought this analysis of renewables capability could have done with a bit more work too. That study of solar power was interesting, but the argument against that has always been geographically diverse wind power will solve that problem, yet the author dismisses it with this: "It is highly likely that within those 48 days aggregate wind input would also have been very low." AEMO modeled 5000 random days of weather and found it feasible to meet reliability conditions. I'm remain more convinced of the AEMO study, but I must admit I didn't read much more after that.
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Post by edireland on Jul 18, 2013 1:59:45 GMT 9.5
Remember too that any nuclear system will also need gas back up, as the generation side must be able respond as quickly as the demand side. Nuclear plants are big, slow Rankine cycles, just like coal plants and they can't ramp fast enough to meet all the demand in a day.
Read more: bravenewclimate.proboards.com/index.cgi?board=bncblogposts&action=display&thread=416#ixzz2ZJy8nyzs
Why does it need gas backup? The marginal cost of operating a modern BWR (see an ESBWR) in terms of staffing and fuel comes out at about one US cent per kWh. One. That is so cheap that it would be better to leave the plant running at full throttle at all times and when you have spare capacity, route the electricity into some insanely energy intensive process that doesn't require large capital cost equipment. For instance very cheap alkaline electrolysers could easily breach $1/kg for hydrogen using one cent per kWh electricity. I imagine you could easily sell such hydrogen at that price, additionally there are things like Solid State Ammonia Synthesis to consider, especially since the top of the peak is only required for 10% of the day, meaning that your "power sink" can run 90% of the time. Since nuclear plant is cheaper per GWe than solar is for the same average output it is cheaper to build a 100% nuclear system and simply use electrolysers or similar equipment to soak up the "waste" electricity. Gas backup would be unnecessary, and since the electrolysers would be at room temperature and can thus go from 100% to 0% output in seconds, spinning reserve would also be redundant.
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Post by trag on Jul 18, 2013 2:14:12 GMT 9.5
The public utility commission is struggling with the capacity issue. The ex chairman of the PUC, Pat Wood, who oversaw the deregulation of the ERCOT grid in the 1990's has recently become notoriously famous in Texas for saying that the deregulated energy market he helped implement is now known to be a failure. Dr. Preston, I also live in Austin, TX. Are you aware of any movement or useful activity one can take to encourage the city to stop subscribing to ever greater amounts of expensive unreliables? I suspect the recent price hike we've experienced is a direct result of those actions, and not a "long overdue price increase". It doesn't make sense that prices would be stable for 18 years and then suddenly go up 20% when natural gas prices are at an all time low. I suspect, but have not checked the records (might make a good student research project) , that while the cost of wind in Austin is only charged to "subscribers", that the reality is that increased wind subscriptions causes a need for increased purchases of electricity on the spot market, which is many times as expensive as base load purchases. Then the cost of the increase in spot market purchases, which were caused by having unreliable wind on our grid are charged to all the customers at Austin Energy, not just the wind subscribers. Looking for correlations between increases in spot market purchases and wind subscriptions would be a good place to start. [Now I'm just ranting] The other thing I wish the Austin public would realize is that when the city council refused to participate in the STNP expansion back in 2009 it was because a consultant risk assessment showed a worst case in which electricity from the expansion might cost $.12/KWHr instead of $.08, but the study also concluded that the worst case was very unlikely. Yet, every purchase of unreliable energy they've made since then, instead of the STNP expansion, has been at prices higher than the worst case for STNP. How does that make any sense? Is there any way or group that you are aware of which is trying to make the Austin public aware of the lack of sense in Austin's electricity supply decisions? Thank you for your time and attention, Jeff Walther 78759
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Post by dwalters on Jul 19, 2013 2:34:56 GMT 9.5
Great essay/Great discussion!
A few points. GTs are NOT cheap. They are cheapER than any other base load (some hydro is cheaper) but that's it. When you spend $500,000,000 on a pair of GE FE GTs you want your money back. Many of these plants run only 10 days a year (actually FEW do, most run or start up at least 240 days a year!) the costs to the rate payer for idle equipment goes up and up. The rate case for each GT is justified on *potential* need, and thus in fact in Texas the point at which these two blades of the scissors meet is becoming untenable. Someone will pay for this idle equipment. The ERCOT is correct: this is a serious problem.
Yes, a 100% atomic generation system is easy to configure with the timely shunting of power to other high energy uses. Since we are talking Australia, that 'something' should be obvious. Nuclear desal is a great way to off excess generation and balance the high gen/low load periods of the evening.
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Post by Graham Palmer on Jul 20, 2013 20:44:03 GMT 9.5
I think the idle plant consideration is an absolute furphy. Gas turbines are cheap, the fuel is expensive. The operating conditions you describe now are very similar to what we have today. What is the negative outcome of a gas turbine being used infrequently? The current use of OCGT is based on accessing the nearest gas main, which is a sunk cost, hence the very low capital cost. But using OCGT with biofuels is completely different - it requires building the biofuel infrastructure, harvesting, processing, storing, transporting - this is a completely different business model. Lang covered some of this in Elliston et al's proposal. Some of these proposals produce very big numbers for costs and tonnage, compared to very low costs to access the existing natural gas network. bravenewclimate.com/2012/02/09/100-renewable-electricity-for-australia-the-cost/I'm not sure whether AEMO have assumed the use of gas turbines running on biofuel or boilers and combined heat and power (CHP) plants similar to the Scandinavian countries. No doubt biomass has some potential, but within the literature, apart from the Brazillian ethanol, there seems very few instances where large-scale biofuel systems have proven "sustainable" or resulted in a strong positive EROI.
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Post by David B. Benson on Jul 21, 2013 9:32:08 GMT 9.5
Biogas is readily refined into separate CO2 and CH4 components. Simply introduce the CH4 into existing natgas piping. This is currently being done in St. Louis, for example.
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Post by evcricket on Jul 23, 2013 6:34:31 GMT 9.5
"Nuclear desal is a great way to off excess generation and balance the high gen/low load periods of the evening."
This idea is broadly okay, but the choice of technology is not ideal.
For frequency control supply response (where generators ramp up and down to cover changes in demand) the grid needs either rapid switch off or switch on. We have a grid which traditionally has been demand driven (which might change a bit as Smart Meters roll out) and changes in demand are not challenged. Anyone can switch on or off at will.
To respond to this at the moment we use the coal plants for small changes and gas turbines for larger ones. It's a rate of change problem, not a magnitude of change problem.
I've been doing some work recently on demand side participation, considering the existing loads that can switch off quickly to assist with this frequency response (in the NEM it's called FCAS Frequency Correction Ancillary Services).
Feedback from desal owners is that they can't participate. They really don't like changing their use and are essentially a baseload user. The changes in pressure associated with powering up and down wreck their membranes but worse throw out the calibration on the pressure gauges.
So I agree it is feasible that you could just dump the power from a nuke into something else, but we'll need a better something else. And I don't know what that might be.
You need something that can take as large a variation in load as the maximum possible change in demand, that can turn on and off without getting wrecked, and driving a process which can be stopped and started at will. I don't believe such a process exists.
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Post by edireland on Jul 23, 2013 7:09:09 GMT 9.5
Low temperature hydrogen electrolysis. (It has no thermal cycling and with proper control there is little issue with compressors being damaged by spooling up and down).
Additionally you don't have to power down systems completely. So you can keep things like SSAS banks hot but only at fractional output.
Smart meters are a great social evil because they will damage the freedom of the poorer members of society.
EDIT:
The marginal costs of nuclear steam are so low that you could just bleed steam to an accumulator during times of low demand and use it for a variety of secondary industrial tasks (including MED-TVC)
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Post by Quite Frankly on Jul 23, 2013 7:45:46 GMT 9.5
I don't see any evidence that the upwardly-revised costs mentioned in this article would in fact be unaffordable. Australia is an incredibly wealthy nation with a significant amount of expendable and far from optimally-invested income. I agree with the sentiment and the analysis, but don't underestimate the ability of a highly developed nation rich in exportable mineral and intellectual resources to pay what amounts to a relatively modest sum in GDP terms over a several-decadal period.
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Post by David B. Benson on Jul 23, 2013 13:23:28 GMT 9.5
evcricket --- Consider adding a thermal store to accept the heat which is not to go through the main electricity generation turbine. The output side of the thermal store can then be maintained as a steady supply even though the input side varies over a rather wide range.
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Post by jagdish on Jul 23, 2013 14:54:22 GMT 9.5
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Post by James Greenidge on Jul 23, 2013 21:39:14 GMT 9.5
Gee. It's incredible how much of their pristine environment they're willing to mow under and despoil just to run away from low footprint clean nuclear power to prove a largely philosophical point. I wish these environmentalists just swallowed a little of their beef with nuclear and gave it a break. If they REALLY want to be fair, allow a nuke or two to run and see whether it sinks or swims like any other business. Their points would hold more credence then.
James Greenidge Queens New York
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Post by RogerClifton on Jul 23, 2013 22:50:52 GMT 9.5
evcricket says - "It's a rate of change problem, not a magnitude of change problem." - referring to power levels in the grid being taken up by consumers. But RO desal operators dont enthuse.
RO desalination is an elec user rather than heat, which is easier to buffer than elec.
If secondary coolant at the NPP could be switched between the steam generator and an alternate heat use, on the timescale required (seconds?), the elec power output can rise and fall while the nuke just keeps on grunting.
On-site MSFD (flash distillation desal) could buffer up its heat inflow in extra volumes for its heated feedwater. Pressurized hot water tanks would then take up so-many minutes of power. If the MSFD output can respond within those minutes, its cleaned water outflow into reservoirs would buffer thermal power across the longer timescales. It is routine for water suppliers to pump water beween dams, allowing buffering on the scale of months.
(Typed slowly in a darkened internet cafe in Geylang, Singapore, not that I need to be furtive...).
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Post by dwalters on Jul 24, 2013 0:06:15 GMT 9.5
Nuclear desal can be accomplished in several ways. With, as suggested, steam from the secondary loop (of a LWR) can be shunted to the desal, it's the ideal way of load controlling. Very fast load shifting, at that. When load goes down, a valve opens and allows how steam to (or pressurized water which is a lot more efficient) to go to the desal flash coolers. Or it can drive a steam turbine-pump to do RO. I don't know which is best.
On an IFR or LFTR, with far hotter temps, then such desal shunting allows for a vaster quantiy of water with the addition of a flash distiller desal at the low end of the turbine, assuming Brayton cycle GTs are used. Either way, low following is made very easy, as easy as hydro, and massive amounts of potable water are created. This scheme also allows for a slight overbuild...say 10% of the entire systems load needs, that is 110% of all generation is possible this way with the extra 10% used as back up for reactors out of service.
David
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Post by evcricket on Jul 24, 2013 7:16:39 GMT 9.5
Some interesting ideas for load shedding, thanks. Have any of these been tried or demonstrated yet?
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Post by edireland on Jul 24, 2013 7:26:14 GMT 9.5
Well a couple of reactors at Bruce NPP stayed at 60% reactor load (I believe the minimum sustainable load) throughout a complete blackout that would normally have required a shutdown simply by dumping steam directly to the condensers, only spinning the turbines with enough steam to cover plant power requirements.
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Post by dwalters on Jul 25, 2013 23:44:13 GMT 9.5
evcricket, not but it is basic physics. Combined Cycle Gas Turbines or OCGTs that use a Heat Recovery Steam Generator (HRSG) use a diverter valve to move hot exhaust away from the HTSG so it can run in a simple cycle. This hasn't been tried as the way I described because all our nukes are LWR (or HWR) and run on a lower temperature Rankine steam cycle. The idea however, could be applicable here too, run the nukes flat out, use excess generation to run something like desal. Obviously not very efficient but it can work. Diablo Canyon nuclear power plant in California does this via a massive 1200 MW pump storage site that was built along with the plant by using excess evening generation to pump water up 1,000 feet to the upper level pump storage at Helms, about 100 miles away. If we had LFTR and IFRs deployed now, then I have no doubt that "Process Heat Load Following" would...follow along as an integrated part of the generation scheme for the plant. We could plop down dozens of 200 MW IFRs or LFTRs around the coast of Australia, for example, and produce tremendous amounts of potable water. Create little green-house agricultural "nuplexes" *anywhere*...and send power into the grid in a distributed manner.
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Post by jagdish on Jul 26, 2013 22:30:55 GMT 9.5
Gee. It's incredible how much of their pristine environment they're willing to mow under and despoil just to run away from low footprint clean nuclear power to prove a largely philosophical point. I wish these environmentalists just swallowed a little of their beef with nuclear and gave it a break. If they REALLY want to be fair, allow a nuke or two to run and see whether it sinks or swims like any other business. Their points would hold more credence then. James Greenidge Queens New York There is always a small section of population who stay isolated with or without electricity from own diesel generators. They are the right niche for wind or solar power. Hugh wind farms feeding power intermittently to grid are no doubt an absurdity but the distributed lot have to use the technology appropriate to them. I am a great votary of IFR with a further modification of using fast MSR. Even the Fukushimas can also benefit from solar energy just as they use diesel generators.
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