Batteries, like the other storage methods are inefficient. Lots of loss in charge and discharge. Converting AC to/from DC is very wasteful, and most electricity usage is AC. The ruthenium method is probably inefficient since it returns energy as heat, which has to be converted to electricity somehow, but could be efficient for heating purposes. Selling electricity back to the grid is probably the best choice now for small applications, unless your intent was to get off the grid in the first place, or if there is no grid.
Your reasoning is interesting. By extending your argument, we would conclude that automobiles were impractical in 1900, the personal computer was impractical in 1975 and the tablet computer was impractical in 2009.
The molten salt system is actually being used at the Andasol solar power station.
The trouble is the the feed in tariffs that are used to subsidize solar power have a perverse incentive in that the companies building the solar power plants have no incentive to generate electricity when it will be most useful, therefore they have no incentive to spend more capitol to make the generation more flexible. Their feed in tariff is the same either way.
I don’t know about your particular case, but in many places you can’t use a stream on your property for power generation, since this often requires a dam or equipment that otherwise affects the flow of water in the stream or might affect wildlife in the stream.
In many areas you also can’t put up solar panel arrays. They make solar panels that look and function a lot like roofing shingles to get around these restrictions.
Personally I think solar does have a good chance of becoming a very big thing in the future, but right now it’s not quite where it needs to be to be practical for most folks.
I expect that someday the nanotechnology will advance to the point where we will be able to open a can of solar cells and paint them on any surface with a southern exposure. As you say now, the economics doesn’t really work.
And indeed, those things were impractical at those times. It doesn’t mean they stayed impractical forever, of course.
This is what I’ll be using. Quite a few already up and running around Hilo (with county permits).
And I find your reasoning to be perplexing. The automobile and the PCs had no competing technologies when they were introduced and the tablet is just an extension of a proven technology.
The Andasol Plant which you use for example is possible due to geographic factors (practicality) and has an installed cost of over 900 million Euros. (cost) Or about $1.2B US for a 150 MW plant.
Compare that to a typical state of the art coal plant at that size with a cost of about $500M US. But coal plants are usually bigger and economies of scale for 150 MW of a larger plant (750MW) and that share price drops closer to $350M.
Considering the cost of the molten salt storage is 2 to 3 times the cost of the existing technologies then your original statement that it is cheap and practical is optimistic at best. Someday maybe, but not now.
Before you accuse me of being anti-green let me state something. I spent many hours of my life analyzing the cost of power plants, power technologies and demand side options. Nothing would please me more than to tell the coal and oil producers of the world to take a hike because a new renewable technology is here. I could justify some non-dispatchable technologies due to the ability of the power system’s other plants to compensate, but storage technologies were just too costly to implement.
In 1900 the automobile had carriages, horses by themselves, trains and boats as competing technologies for transportation. They were loud, slow, and prone to explosions and went a blazing 15 MPH. People thought automobile owners were crazy and stupid. Why buy a dangerous machine to get around that needed specialty fuel when a horse and buggy does the same thing and they can eat grass on the side of the road? In 1975 everyone used slide rules and graphing calculators and everything was paper filed, why would anyone need a computer?
Ruthenium being studied for academic reasons is one thing and might well teach us something important about how things work. But to tout it as possible storage mechanism for solar power is just plain silly.
Apparently, about 10 tons per year are produced, with a worldwide reserve estimated at 5000 tons.
So, if we had it all dug up already, each person in the USA would get a whopping 0.03 pound share. I don’t know the actual power storage ability of ruthenium or ruthenium compounds, but my guess it that much might store enough power to heat up a big burrito.
Give every person in the world their share and its more like 0.0015 pounds. The stuff is too rare by a factor of something like a 100,000 to a million times to be useful on a large scale (and thats ignoring the cost of it).
EvilTOJ, You aren’t really dismissing my point. I agree with you that all of those technologies prevailed. But they prevailed because their technology evolved as did the needs of the consumer.
My first PC cost me $3200, a price the average homeowner was unable or unwilling to pay for the work it performed (games, tax calculations etc). But the PC technology improved and got cheaper while the work it performed increased - communication, education, entertainment.
Right now,** AT THIS TIME**, energy storage technologies aren’t cost efficient - especially in the scale of individual consumers. That doesn’t mean they won’t be. It does how ever explain why there isn’t a big rush to build molten salt heat storage systems. It also indicates that any claims of it being cheap and practical technology is premature at best.
You’re missing the point by making the wrong comparisons.
Nobody is saying that an energy storage technology might not become useful. They’re saying that no one knows whether current technologies are or will become cheap and practical.
The proper comparison is to the availability of steam, electric, and gasoline-powered cars in 1900. (Plus a couple of even more exotic technologies.) Yes, it turned out that the gasoline internal combustion engine was indeed cheap and practical. But neither steam nor electric was. Both had problems that knocked them out of the marketplace, even though they had temporary successes. The world land-speed record was held by a Stanley Steamer, e.g.
Even among internal combustion, there was a competition between the two-stroke and four-stroke gas engines, diesel engines, rotary engines, gas turbines, and many other variations. The four-stroke engine won, although others later did compete in smaller numbers.
Your mistake is certainly common. It’s harmful, too. You can’t say that just because some technologies became successful, every one will. We know that’s not true. Some technologies never work outside the lab; many never become cheap and practical. And it’s even worse than that. Every single technology that has become successful won out over many competing tries that had more flaws. (Or, possibly, never got the backing needed to get it developed past those flaws.)
Technologies don’t work the way you and the others are saying they do (or at least making the implicit assumption that they work that way). It is possible that energy storage technologies will always be small-scale and luxury items. It is likely that ruthenium will never scale up. The past success of other technologies is entirely irrelevant to this issue.
I wasn’t implying that people would use molten salt for home energy storage. I was talking about large solar thermal plants. The only currently practical use for solar power at home is water heating and I’m not sure about that if you don’t have a pool.
The focal point of my exception to your statement wasn’t about scale. It was about your claim that “molten salt storage systems are cheap and practical”, which they aren’t.
The contention of a former client of mine that was a power company with significant investments in both, solar and nuclear, was that solar is really expensive in “first copy costs” (installation, system calibration… everything up to the day you’re first actually online), but AFTER you’re up and running, in the right situation, the costs are very nearly zero.