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Posted on 01/03/2008 6:04:24 AM PST by Uncledave
A newly created company called SolarReserve intends to commercialize a solar power plant capable of generating electricity and storing it in molten salt.
The venture was created by investment firm US Renewables Group, which has licensed technology from Hamilton Sundstrand, a subsidiary of United Technologies. A plant will be capable of generating 500 megawatts of peak power, the size of a typical power plant.
Solar thermal technology, which uses heat intensified by lenses and mirrors to create electricity, is being pursued by utilities because it is relatively cost-effective. It is also called concentrated solar power (CSP).
But because the sun's energy is intermittent, companies are seeking out large-scale storage techniques, from compressed air to massive batteries. Molten salt storage is already used at the Nevada Solar One plant.
SolarReserve's technology will use a tower with a holding tank of molten salt. An array of mirrors will reflect light onto the tank. The heated liquid is then pumped into a steam generator that will turn a turbine to make electricity.
The technology is expected to be available within three or four years. A representative said the company expects to realize revenue of more than $1 billion in the next 10 years.
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I don't know what's really going on here, but I suspect we have a clueless reporter. I do not think that electricity is being stored in molten salt. Doesn't make sense.
Heat energy is being stored. That can be used to generate steam, which turns a turbine, etc., etc.
Just typical bad writing by one who doesn’t know the subject matter or care to learn it.
The project proposes to store energy as heat in the molten salt and tap it to run generators, presumably by generating steam to power turbines.
in the article:
SolarReserve’s technology will use a tower with a holding tank of molten salt. An array of mirrors will reflect light onto the tank. The heated liquid is then pumped into a steam generator that will turn a turbine to make electricity.
Not sure why molten salt is a preferred heat store medium though.
And of course, the really key question IS "why is molten salt the preferred storage medium?" There's probably something interesting there. But that didn't seem to interest the reporter, because there's no information on why this was chosen.
The melting temp for NaCl is 800.8C (or 1473.4F), that’s a LOT of heat to store for using in a steam generator!
I have heard of one proposed technology years ago that could "store" solar energy in salt. How it works is that the salt solution is brought into the focus of a mirror. The heat induces a chemical phase change in the salt. The phase changed salt is chemically stable and can be stored for a long time. In order to use the stored energy, the salt is sent to a boiler and it is melted back into the lower engery state salt, which releases heat, which can be used to power a boiler. I think this method can be used to store energy all sumnmer and release it in the winter.
Are you sure? To me it says "solar power" is being stored. What is solar power but heat. The salt is storing heat or "solar power."
My initial take on that was that I wasn’t surprised that it worked, but that I would find it surprising if it would be efficient. Since water conducts electricity (the amount depending on purity), its not surprising that you would get some circulating eddy currents from the imposed electromagnetic fields, and hence some distributed electrolysis.
It strikes me as a second order effect, though, that is interesting, but unlikely to be energy-efficient.
Molten salt? Do they mean salt in solution? Or do they actually mean dry salt that has been melted?
It's not corrosive and has a much higher boiling point than water, so the same volume can hold more heat. And as opposed to other possible exotic alternatives, it's not that toxic. Spills can be left to solidify, then picked up off the ground. Unless it's raining, then you get lye, but spraying a lot of a moderate acid around will take care of that.
The byproduct will be boon to margarita lovers.
generating electricity and storing it in molten salt
So, something is being stored in molten salt. What? Well, "it" is being stored in molten salt. And what does that "it" refer to? Well, the electricity that was just generated.
Now, clearly they are using solar power to generate electricity, and clearly energy is being stored in some manner. That makes sense. But the reporter's wording is just terrible.
They should store it in potatoes. Potatoes never cool off.
Using glauber’s salt as a phase-change heat storage medium was big about 20-25 years ago and then fizzed out.
Although I read the article I forgot the part you quoted and you are correct. The reporter says that electricity is being stored in molten salt.
Sorry, thinking sodium instead of salt, forget the lye part. I guess this is just like the old Solar Two project. If the tanks burst and it spilled all over, they’d just have to bring in front loaders to pick up the salts and recycle it.
But it will hold a LOT of heat per volume, more than most other substances, so it makes for an excellent heat sink.
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