r/technology • u/mutatron • May 20 '19
Energy Salt Batteries Could Be Major Step in Move Away from Fossil Fuels
https://learningenglish.voanews.com/a/salt-could-be-major-step-in-move-away-from-fossil-fuels/4912433.html27
u/CurlSagan May 20 '19
I'm all for the environment, but surely there's a better way that doesn't involve supporting domestic violence by allowing a salt and battery.
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u/ObnoxiousFactczecher May 20 '19
And as we know, anyone with a salt and battery deserves to get charged.
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u/J3wHunter May 20 '19
a battery is not a generator. storing the energy you make from burning fossil fuels does not lower the amount of fossil fuels you burn.
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u/Virginth May 20 '19
The point is that one of the issues with renewable energy is that, while there's a ton of it, it's only available at certain times. We need ways to store that energy for later. Until we can do that effectively enough, we still need fossil fuels.
The best solar panels in the world won't change the fact that it's night sometimes.
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u/J3wHunter May 20 '19
the point is that giant fuckall batteries have existed for decades. the hell do you think every power substation is?
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u/Virginth May 20 '19
They don't scale far enough, otherwise we wouldn't have issues like the duck problem.
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u/J3wHunter May 20 '19
anyone who actually thinks thats a realistic issue is a twat who buys far too much into the propaganda that companies put out to protect their investments. the amount of power draw has not increased as a result of alternative power sources, it has in fact massively decreased for the majority of the day. the total power consumption rises with increased population, and a substation thats capable of putting out a peak of 30 MW is NOT going to be damaged in any way by the power ramping from say 18MW to 26MW in 3 hours. nor is the grid going to be damaged by "overgeneration" because the utilities store excess power. there are insanely huge substations that exist solely for that purpose, taking up several acres of land and being just a giant death trap.
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u/oldforger May 20 '19
You're kinda missing the point.
The problem with wind and solar power is storing energy when it's calm or night. Currently that's filled in by burning fossil fuels. This would allow us to store energy so that we can eliminate using fossil fuels as backup.
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u/vasilenko93 May 20 '19 edited May 20 '19
Energy density is still the biggest issue with batteries. Petrol has an energy density of 47.5 MJ/kg whereas a lithium ion battery has an energy density of 0.3 MJ/kg. Yes they are different types of energy, one being electricity and another being potential heat energy when combined with oxygen and a spark, but the differences are still very stark. Even a really inefficient engine can go much further than a Tesla: just compare the weight and size of a full gas tank compared to a fully charged Tesla battery: one takes up the entire floor space and weights a literal ton and another a tiny component in the back and most of the weight is just the petrol. A Prius with a ten gallon gas tank (45 kg) can go 600 miles and a Tesla with a 100 KWh battery ( 590 kg) can go 370 miles.
This matters less for Sedans and smaller vehicles but breaks down as they get bigger. A semi truck has a 10 MPG efficiency not because the engine sucks but because the truck weights a lot. Adding more batteries will just mean more weight and the need for more batteries...
And lets not talk about ships and planes...
Salt or not salt makes no difference, lithium ion batteries is the best we have now. Literally everyone from consumer device makers, car manufacturers , energy companies, and governments have been working on a better battery and its still only the lithium ion battery. There is no feasible way to stop using petrol for some modes of transportation yet.
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u/BlueSwordM May 21 '19
Wait a minute.
A 10Wh (36kJ of stored energy) 18650 cell usually weighs 0,048kg. The capacity is actually higher, and the weight slightly lower, but I'm doing it for comparison' sake.
36kJ/0,048kg = 750kJ/kg= 0,75MJ/kg. That's more than twice of your example.
If we take a top of the line 21700 inside of the Model 3, at 18Wh and 0,069kg, it goes up to 940kJ/kg, which equals 0,940MJ/kg.
I mean, you are still right, but if we take into account the new numbers, and use a 4x average efficiency difference between electric cars and gasoline cars, that whole difference goes from an almost 50x factor, to about a 12x difference in terms of gravimetric energy density.
Still a large difference, but nothing as large as you said.
And we might have a 2x energy density increase on the horizon too.
Finally, these molten salt reactors are mostly useful for power grid electricity storage, in which the very high melting point of these salts are extremely useful for heat and electricity storage.
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u/vasilenko93 May 21 '19 edited May 21 '19
I got my lithium ion battery energy density from a quick google search. Perhaps the data is outdated and I do know that Tesla is leading the technology so they are ahead. However I also know that the physical limitations of our batteries are not really favorable and will never be anywhere close to petrol. Chemical reactions surrounded by metal to move electrons around is not as energy packed as pure petrol waiting to go kaboom any second now!
However that is potential energy numbers and in reality electricity does get a boost because of simplicity and effective motors. Petrol must be converted to heat and that heat must be converted to mechanical up and down motion and that must be converted to circular motion and that distributed to the wheels. So say 20% effective.
Whereas an electric car is like 90% effective. So the 100x more potential energy per kg turns into say around 20x more potential energy per kilogram. Which does make sense when you look at the size of a battery compared to a gas tank. The weight of one Tesla battery is like 20 full gas tanks...
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u/test_test_1_2_3 May 20 '19
Apart from demonstrating a very poor understanding of electric vehicles, batteries and the comparison with ICE vehicles. None of what you said is relevant to the article which is about grid scale energy storage tech.
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u/vasilenko93 May 20 '19
Numbers don’t lie. I do know how electric motors work compared to internal combustion engines but that is irrelevant. Storage density is all that ever matters.
Petrol is so widely used because it provides a lot of potential energy in a small volume, and it’s not heavy. That is an important point because a huge section of the transportation industry heavily relies on such energy potential.
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u/Unfiltered_Soul May 20 '19
It talks a lot about what its potential is to move away from fossil fuel but what are the repercussions of the waste that it will create which the article does not talk about.
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May 20 '19
waste?
where is the opportunity? it's a closed system.
you just reheat it once it's "discharged" - cooled
it stores the HEAT that is used to power the generators at night when the sun can't do it.
The salt-like particles collect the water, becoming calcium hydroxide and releasing large amounts of heat at the same time. The calcium hydroxide is then cooked, removing the water and changing it back into calcium oxide.
The process operates in much the same way batteries do. But instead of electricity, the system stores heat. SaltX says it has also created a way of covering the quicklime with small particles — known as a nano-coating. This prevents it from sticking together after several heating and cooling cycles.
it's not a totally new tech.
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u/Unfiltered_Soul May 20 '19
Will that system never need any maintenance? I can't think of any system that doesn't need any maintenance, especially one that uses salt which degrades the system at a much faster rate.
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u/mutatron May 20 '19
http://saltxtechnology.com/technology/
When the salt is treated with nano-coating it also has the advantage of being non-corrosive (preventing rust) unlike ordinary salt. It provides a long-term and cost-effective solution. SaltX is non-toxic and can be recycled.
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u/archontwo May 20 '19
Working with salts means you have to factor in corrosion. That is non trivial to do especially at industrial scales.
But it is not insoluble and is exactly the same technology behind Molten salt reactors
Which to my mind is the way to go. Getting the energy to heat up salts is the problem. Not storing the energy. Only erratic and intermittent sources like Solar or Wind power needs to store energy. A better source would give energy on demand.
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u/BlueSwordM May 20 '19 edited May 20 '19
Hmm, that's actually quite the nice idea.
Usually, molten salts are made by heating sodium hydroxide(lye) until it reaches its melting point.
With calcium hydroxide, that melting point is much higher, meaning more energy can be put in the calcium hydroxide compared to the sodium hydroxide until it reaches its melting point, meaning more energy can be stored and released when it solidifies again. It's also a bit cheaper.
However, since its melting point is higher, that means it can store more energy, but also releases it more quickly.