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A Tower of Molten Salt Will Deliver Solar Power After Sunset (ieee.org)
schwit1 sends this report from IEEE Spectrum: Solar power projects intended to turn solar heat into steam to generate electricity have struggled to compete amid tumbling prices for solar energy from solid-state photovoltaic (PV) panels. But the first commercial-scale implementation of an innovative solar thermal design could turn the tide. Engineered from the ground up to store some of its solar energy, the 110-megawatt plant is nearing completion in the Crescent Dunes near Tonopah, Nev. It aims to simultaneously produce the cheapest solar thermal power and to dispatch that power for up to 10 hours after the setting sun has idled photovoltaics. ... [The system] heats a molten mixture of nitrate salts that can be stored in insulated tanks and withdrawn on demand to run the plant’s steam generators and turbine when electricity is most valuable. ... Eliminating the heat exchange between oil and salts trims energy storage losses from about 7 percent to just 2 percent. The tower also heats its molten salt to 566 degrees C, whereas oil-based plants top out at 400 degrees C.
... and many more will, this is an old design, already in use.
Personally my favorite solar thermal concept is the compact linear fresnel reflector. They're much more dense (land area used per unit power generated) than pretty much all other solar tracking methods. Also, they only require single-axis tracking in long linear rows - but unlike other single-axis tracking methods like parabolic troughs, you don't need a receiver (heat pipe) running through the middle of every reflector; a reflector is *just* a reflector. The alternation of directions in which light gets reflected reduces blocking between reflectors, and thus increases how close you can space them. And the high density means less distance for the hot water to flow, and thus less heat loss, further increasing the power generation per unit area.
"Oh, goodness. Look at my wrist, I have to go." "But what about your clothes?" "I don't love these."
In TFA they mention that there's a smaller-scale demonstration plant operational right now, so it's not like they're building this plant with no working experience. One would hope that the demonstration plant is operating well enough to have justified the construction of the larger one. In projects like this, scale often works to your economic advantage, so it makes sense to start building these things bigger.
Irony: Agile development has too much intertia to be abandoned now.
My cottage is quite close, the project is described at http://ecogeek.org/2013/04/ope...
This approach is low-cost, and used in Brazil among other places: https://en.wikipedia.org/wiki/...
davecb@spamcop.net
Actually, it depends on the time of year. Demand is only highest (peaks) in the daylight hours during the summer, when air conditioning load is at its highest. During the spring and fall, when the temperatures are moderate, it's not uncommon that the peak is in the evening with lighting load (really lights + TV + commercial resteraunt use). In winter, it's definitely evening peaks with higher overnights with electric heating load. So, from a wholesale power perspective, you only need to cover that 7pm to 9pm period before load drops off (bedtimes) to smooth pricing.
Besides the flaws you cite, molten salt has been previously used e.g. in the Andasol solar (thermal) power plant in Spain.
https://en.wikipedia.org/wiki/...
reason defies logic
If this company thinks they can operate this plant, I see no reason to stop them.
I see no reason why you keep mentioning birds like it's some sort of game changer. In Canada between 16-42 million birds are killed each year through collisions with buildings. Should we stop building houses? http://www.ace-eco.org/vol8/is... North America wide that number may rise as high at 1 billion. http://www.flap.org/faqs.php Not to mention that you conveniently left out the death toll on all animals from pollution/habitat loss from the fossil fuel generators which far exceeds the numbers of 'streamers' that these plants will generate.
Improvements on all fronts, should not be abandoned because those improvements are not perfect.
They are providing power to Vegas which has the highest power usage in the evening up to midnight according to the article.
Las Vegas ... pillar of salt.
Just don't look back when you leave.
Have gnu, will travel.
We will eventually have 11 billion people consuming power at US levels - likely before the end of this century. Smart meters won't fix that. Solar is the only thing that scales (unless fusion finally stops being "just 20 years away"). Efficient PV panels and Tesla batteries are very high-tech solutions, and it's unclear that they could be available cheaply at that scale. Solar thermal, though, is quite straightforward.
This plant isn't good enough to be more than an experiment, and useful to hedge against a steep rise in fuel prices, but it's an incremental step. There seem to be many more incremental steps available for various approaches to solar thermal (I'm not the biggest fan of this exact design, but the power storage aspect is nice). Solar thermal just isn't a hyper-optimized mature field grasping for 1% improvements - there's lots of headroom here.
We're going to need a power generation solution that scales over 10x current world generation, and we're likely to need it in the lifetime of some /.ers. A solution with no exotic toolchain requirements, and no raw material requirements that won't scale, and that works for base load doesn't leave many options. (Obviously, solar isn't good for high latitudes, and gas generation isn't going away, but we're going to need something new for base load until fusion finally shows up).
Socialism: a lie told by totalitarians and believed by fools.
Why do you need to smooth pricing? By allowing prices to rise and fall throughout the day in response to supply and demand, you don't need to add supply between the time the sun goes down and the time people go to bed at night.
In other words, you can treat it as an economics problem and save your customers a lot of money on power plants and fuel. This is why the world is switching from flat rate pricing to time-of-use pricing.
The goal isn't to smooth pricing...it's to smooth the peaks and valleys of demand.
The grid has to be built for peak, not average...in other words, if 5% of the time, the total load of a utility's customer base is 4.5 gigawatts, then they have to be able to provide 4.5 gigawatts, even though 95% of the time the demand is half that, at most.
Ideally, power demand would be flat and constant...the same amount, all the time. Steam plants experience metal fatigue when they throttle up and down, and this is already a major problem with most utilities now. It's also way harder to regulate an efficient burn at multiple rates...which in turn, means it's harder to regulate emissions, which leads to limits on capacity if they exceed emissions of certain sorts (and, just to make it fun, those standards have just been tightened...a LOT). Those are both a big deal: too much leaking in the heat exchange coils in the boiler, and the whole plant has to come offline. Even getting close to the limit on emissions for a period, and the plant comes offline to avoid overshooting it...the plant goes into reserve mode, needed only for emergencies. And this, in turn, increases the impact of the peaks/valleys situation on the rest of the utility. And what I just described assumes 100% controllable, fuel-based generation (nuclear, petroleum, coal, gas). Now, these peaks are predictable (and predicted...there's a whole industry around the metrics and predictive load management involved), but it still poses a challenge. The steeper the walls of the peak, the faster and harder you have to spin up the generators, and the greater the stress, as well.
Renewable energy is great, except that it throws another wrench into the works. Let's say you're getting a lot of your power from solar...but then clouds move in. Effectively, for your non-renewable generation, you've just introduced a peak because it has to throttle up to take up the slack. So you end up with lots of peaks of various sizes, instead of the one or two big peaks per day. And even worse, these peaks aren't predictable.
If, however, your solar generation capacity includes a way to continue generating power after the clouds roll in, you've done two things. One, if the cloud layer is short-lived, you're able to simply disregard it and life goes on. Two, if it isn't, then you've bought more time to spin up capacity more slowly...which means less stress on the boilers, and also more options to choose from. Maybe you fire up a CT peaker, which has less trouble with variable load but takes 20-30 minutes to come online, for example. But ultimately, what you've done is taken one of the biggest problems with renewable generation and dramatically reduced it.
For your security, this post has been encrypted with ROT-13, twice.
I like seeing things like this. I'm not excited about the solar power aspect, I actually think that is a fool's errand. I'm excited about seeing people research molten salt power transfer systems and high temperature power generation.
One big problem holding up research in molten salt fission reactors is that the power generation systems it relies upon for much of its efficiency gains have not been tested fully. If we can prove to the powers that be, like the US Department of Energy, that we can handle molten salts safely then we can get that much closer to getting a molten salt reactor built.
Looking into how these concentrated solar power plants work I had to ask myself, what do they do when the sun doesn't shine enough to keep the salt molten? They claim ten hours of storage capability, that might get them through the night I suppose. What if the morning sun is obstructed by clouds? Well, I found my answer when looking at the Ivanpah Solar Power Facility.
https://en.wikipedia.org/wiki/...
To get these things started in the morning takes a lot of natural gas. I understand the need for a power plant, any power plant, to have backup power on site in the case of the need to shut down the primary electric generation when there is loss of a connection to the grid. But the need to do this every morning does sound a bit counter productive. This is a plant that is supposed to reduce our reliance on fossil fuels. That's what I thought the whole point of solar power was supposed to be.
Perhaps, after we prove molten salt solar can work when the weather agrees, then we can put a small modular thorium reactor on the site to warm up the salt in the morning and provide a base load of power for when the sun doesn't shine. Of course, once you can show that small modular reactors of about 100MW capacity can keep the solar power plant running then people will begin to wonder why they bother with the large expensive solar tower when the reactor keeps running regardless of the weather. At some point they'll tear down the tower to make room for more reactors.
That's the whole point to me, moving towards small modular thorium reactors. Of all the technologies we have out there right now I see that as the one true solution. We'll still see wind, solar, hydro, geothermal, and so on in the times and places where it is cheap but small thorium molten salt reactors can be used in so many places. Make them on an assembly line like a Boeing airliner and we should see a new one built every month. In twenty years we should see the grid powered by more than 50% nuclear fission.
I still think that nuclear fusion will prove viable within my lifetime, but only when done on a multi-gigawatt scale. That is going to be very expensive to build initially but once built it should run for a long time using common elements as fuel. Until we have a leap in technology like that we have three choices:
- Nuclear fission
- Continued fossil fuel use, with all its pros and cons
- Expensive unreliable wind and solar
So, go build your concentrated solar power plants, those would make great sites for a future thorium fission power plant.
I am armed because I am free. I am free because I am armed.
Thorium fission can scale.
Thorium (specifically Th-232) doesn't fission. It has to be bred up into U-233 by absorbing a neutron which can then fission by being hit by another neutron releasing energy. Fission of U-233 releases an average of about 2.2 neutrons to carry out further breeding and fission. This breeding-fission process is a bit knife-edge compared to regular PWRs, BWRs and other uranium-fuelled reactors where only one neutron is required to fission a U-235 nucleus and produce 2+ more.
What recent developments in "thorium fission" can you point us at? There's a lot of Powerpoint presentations and glossy brochures being waved around by folks looking to make a buck from research funding and subsidies but no-one is bending metal and pouring concrete right now on anything based on thorium as a primary source of nuclear energy. There ARE some experiments with thorium going on; PWR-style fuel pellets with thorium mixed in with uranium and plutonium are being exposed in a test reactor in Norway at the moment and there's an experimental Chinese pebble-bed reactor which can use some thorium in the fuel pebbles but that's about it.
As for modularity, it's not a new thing in regular uranium reactors -- see the units used in submarines, icebreakers and large aircraft carriers for the past fifty years and more as a worked example. The Russians are building a "power barge" carrying a ship reactor to produce about 40MW of electricity for coastal communities in Siberia and the Chinese are pouring concrete on a commercial modular power reactor (about 105MWe) but it's going to be a pebble-bed design fuelled entirely by uranium and plutonium to begin with. It might use a small amount of thorium in the future but that's a long way off and its commercial viability is still to be proven. Previous attempts to commercialise pebble-bed reactors capable of using some thorium such as the German THTR-300 were not a success.
Thorium (specifically Th-232) doesn't fission.
I am well aware of that but using "thorium fission" as a shorthand for "thorium cycle fission" seems common enough that I thought it would not need explanation. I assumed that people that knew what LFTR was would know what I meant and everyone else could search on "thorium fission" in Google, Wikipedia, or wherever and figure it out by clicking on the first link that shows up.
This breeding-fission process is a bit knife-edge compared to regular PWRs, BWRs and other uranium-fuelled reactors where only one neutron is required to fission a U-235 nucleus and produce 2+ more.
A lot of nuclear engineers seem to disagree with you. There are several techniques to make thorium cycle viable, the most popular are molten salt variations. Molten salt allows poisons that would normally accumulate in solid fuel to boil out. Iodine and xenon are the biggest concerns and those simply cannot remain in solution for long, and there are techniques to speed the removal from the core adding efficiency.
What recent developments in "thorium fission" can you point us at?
Here's a good place to start:
https://www.youtube.com/user/g...
There's a lot of Powerpoint presentations and glossy brochures being waved around by folks looking to make a buck from research funding and subsidies but no-one is bending metal and pouring concrete right now on anything based on thorium as a primary source of nuclear energy.
I believe that China and India would disagree with you. Right now in the USA and Canada thorium fission is being held up by regulators that don't know what to do with thorium yet. I suspect we'll see a boom in LFTR and DMSR shortly after China demonstrates their first MSR. It used to be that the USA was first in technology, now we race to be second place.
Previous attempts to commercialise pebble-bed reactors capable of using some thorium such as the German THTR-300 were not a success.
Let's see, steam turbines, helium cooled core, small manufactured fuel pebbles, and a one off design. What could possibly go wrong? Water creeping into the helium coolant. Pebbled fuel breaking in the reactor and getting lodged in piping. Difficulty in sourcing fuel. Not a high point of thorium as a fuel.
LFTR uses molten salt as coolant and fuel carrier, any leaking between them does cause contamination but it will not stop operation. Leaks can be repaired and operation resumed. There is no water cooling to create concerns over flash boiling, corrosion of metals, or contamination of fuel. LFTR does not require "manufacture" of the fuel, it's a stable salt with very low chemical and nuclear reactivity. Once melted it can be simply poured into the core. Waste products are removed as part of normal operation, they won't accumulate to levels that would cause massive release if there is a catastrophic failure. Any kind of large failure would be limited to destruction of the core, it can't "blow it's top" like water cooled and solid fuel reactors of the past.
This design was tested and operating fifty years ago. However, because we've learned a lot in the last fifty years in material science, manufacturing, and so forth that design would not be considered viable today. What it does do is show the physics work and if we can only get the DOE to get their assess off their thumbs then maybe we can see thorium as a fuel before another fifty years pass.
I am armed because I am free. I am free because I am armed.
> The problem today is that solar costs three times what it needs to cost to be competitive.
Read this article and say that solar is still 3x competitive range:
http://www.pv-tech.org/news/buffett_projects_record_low_cost_is_part_of_pricing_trend_says_first_solar
Same company as the original story, by the way, NV Energy.