Sand Batteries

[CardsFan]

There is a project in central Oregon where two reservoirs are being constructed. Solar panels pump water into the higher reservoir which is drained through turbines at night generating electricity.

Pumped storage. Been around for over 100 years. Everything old is new again.

That said, it IS an effective way to store energy (but as I recall, not very efficient). But has mostly been used in reverse. Pump the water up over night during low demand, and generate during the day during high demand. Basically using it for peaking. But in the case of solar, the reverse makes some sense.

 

[NW-Bound]

Pumped storage. Been around for over 100 years. Everything old is new again.

That said, it IS an effective way to store energy (but as I recall, not very efficient). But has mostly been used in reverse. Pump the water up over night during low demand, and generate during the day during high demand. Basically using it for peaking. But in the case of solar, the reverse makes some sense.

Pumped storage has never been out of vogue. The only problem is the world is running out of suitable places to build reservoirs and dams. And of course, environmental issues keep many potential sites from being developed.

In 1925, the Salt River Project here in AZ started building its system of reservoirs downstream of Roosevelt Dam, for use as pumped storage.

Roosevelt Dam itself was built and started to generate power in 1906. Phoenix back then was small, and excess power was sold to PG&E.

Efficiency of pumped storage is 65-70%. Not great, but when it's all that you have, it's better than nothing.

Lithium battery storage efficiency gets to 90% round trip easily. But the world does not have enough of it and cannot afford it either.

What the world actually has for energy storage is pitiful compared to what it needs. Same with water storage and transport.

 

[CardsFan]

Pumped storage has never been out of vogue. The only problem is the world is running out of suitable places to build reservoirs and dams. And of course, environmental issues keep many potential sites from being developed.

In 1925, the Salt River Project here in AZ started building its system of reservoirs downstream of Roosevelt Dam, for use as pumped storage.

Roosevelt Dam itself was built and started to generate power in 1906. Phoenix back then was small, and excess power was sold to PG&E.

Efficiency of pumped storage is 65-70%. Not great, but when it's all that you have, it's better than nothing.

Lithium battery storage efficiency gets to 90% round trip easily. But the world does not have enough of it and cannot afford it either.

What the world actually has for energy storage is pitiful compared to what it needs. Same with water storage and transport.

Thanks for the additional info. I was going to mention the environmental issue, but Porky came to mind.

It is just like the OP's topic of the sand [-]battery[/-] energy storage device. Useful some places, of no practical value elsewhere. Not quite as universally useful as the other energy storage device that we love to hate: Fossil Fuels.

 

[NW-Bound]

The title of the World's Largest Pumped Storage is still claimed by the Bath County Pumped Storage Station in Virginia. It was built in 1985.

The Bath County Station can pump up water at a rate of 12.7 million gallons per minute. The discharge rate is as high as 13.5 million gallons per minute.

For a comparison, the average flow rate of Niagara Falls is 38 million gallons per minute.

Here's the Bath County Pumped Storage.

Here are some photos of pumped storage installations around the world.

The following are some cute little ones.

 

[NW-Bound]

Thanks for the additional info. I was going to mention the environmental issue, but Porky came to mind.

It is just like the OP's topic of the sand [-]battery[/-] energy storage device. Useful some places, of no practical value elsewhere. Not quite as universally useful as the other energy storage device that we love to hate: Fossil Fuels.

Petroleum fuel stores a lot of energy, and is relatively safe to use and easy to store. What do we do without it?

I am beginning to think hydrogen is not bad. The energy conversion from solar power to hydrogen storage is 80% efficient. And then, a fuel cell to convert hydrogen to electricity is 60% efficient. Together, that's 48% efficiency.

Is that really bad? An ICE car has the efficiency of 20%. But more than that, when hydrogen is all that we have, it's a lot better than riding a donkey.

 

[skyking1]

many years ago there was a home storage system for solar heated air that used change-of-state with eutectic salts.
It was built the same way as described in this link:
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/eutectics#:~:text=Eutectic%20salts%20use%20a%20combination,through%20which%20water%20is%20circulated.

The salts were in stacking plastic wafers with circulation paths, and the heated air would pass through it. It would go from a solid to a liquid at a useful temperature, something near 70~90 F.
That change of state took a lot of energy. The hot air from the active collectors dumped heat into the pile all day and you took it back out at night.
The pile was several tons in insulated boxes, and typically in a basement. I remember reading about it and then like many things it just fell away.

 

[deserat]

I worked with a guy in the UK who claimed his house was about 300 years old. The stone walls were four feet thick. He said that just as the house was starting to get warm inside it would be the end of summer and the house stayed warm all winter. Same in reverse for summer. Natural thermal storage. Said he barely needed to provide supplemental heat.

I was going to comment like the above...when I took an HVAC course in mechanical engineering, we used bricks or adobe as an example of a slow heat recycler...the bricks absorbed the gear during the day and then released it at night.

 

[Chuckanut]

I saw a house in New Mexico built had walls with an interior made with bales of hay that was surrounded by a modern adobe like substance. The modern 'adobe' withstood weathering a whole lot better than traditional adobe. The builder claimed that with the judicious use of fans to cool the house at night, no A/C was needed during the day.

I'm not sure what he paid for fire insurance.

 

[Out of Steam]

I am beginning to think hydrogen is not bad. The energy conversion from solar power to hydrogen storage is 80% efficient. And then, a fuel cell to convert hydrogen to electricity is 60% efficient. Together, that's 48% efficiency.

I don't believe that we'll be driving cars directly powered by hydrogen, or piping it into our kitchens to cook with, but it will have some very important uses, especially in synthetic aviation fuels and industrial applications.

 

[mpeirce]

I don't believe that we'll be driving cars directly powered by hydrogen

Hydrogen gas is tricky to work with - it’s a very “light” molecule.

If only there was another common element that could form chains of atoms where we could hang those handy hydrogen atoms...

 

[Out of Steam]

Hydrogen gas is tricky to work with - it’s a very “light” molecule.

If only there was another common element that could form chains of atoms where we could hang those handy hydrogen atoms...

As shown by satellite monitoring, we seem to have enough problems keeping methane inside of distribution piping. Hydrogen would be much more difficult.

If the CO₂ is pulled out of the air, or out of combustion product streams from burning petroleum or methane, that's a more realistic (and safer) method of providing fuel for consumption.

 

[ERD50]

As shown by satellite monitoring, we seem to have enough problems keeping methane inside of distribution piping. Hydrogen would be much more difficult.

If the CO₂ is pulled out of the air, or out of combustion product streams from burning petroleum or methane, that's a more realistic (and safer) method of providing fuel for consumption.

I didn't follow that article. Are the satellite images detecting the flames/heat/IR of burning off the methane, or actual methane gas? This makes it sound like IR - they mention the satellites saw the giant plumes.

In oil and gas production, massive methane bursts might be the result of accidents or leaky pipelines or other facilities, Lauvaux says. But these leaks are often the result of routine maintenance practices, the team found. Rather than shut down for days to clear gas from pipelines, for example, managers might open valves on both ends of the line, releasing and burning off the gas quickly. That sort of practice stood out starkly in satellite images as “two giant plumes” along a pipeline track, Lauvaux says.

They also say this:

Methane has about 80 times the atmosphere-warming potential of carbon dioxide, though it tends to have a much shorter lifetime in the atmosphere — 10 to 20 years or so, compared with hundreds of years.

But if they burn it off, it isn't methane, it becomes CO2 and water (and other stuff with incomplete combustion, nitrogen in the air etc):

CH4 + 2O2 → CO2 + 2H2O

So if the maintenance crew didn't burn it off, what would they do? I suppose capture it and then send it back to the pipeline to use it for a productive purpose (other methane will be used for that, so this is a waste). So maybe that should be done (like we capture refrigerants)? I could guess that would be quite a procedure and time consuming and just add cost. So if it really is something that can be fixed within reason, it should.

Related, there is what I assume is a refinery in the SW burbs of Chicago not far from us. I try to pay attention as I drive by, it's quite the operation. I've noticed one stack seems to be constantly 'flaring off' - not a huge plume (though hard to judge from that distance). I always wonder why they don't trap it and use it to run a generator or something? I suppose their just too focused on their primary job to want to dink around with it.

-ERD50

 

[Out of Steam]

Related, there is what I assume is a refinery in the SW burbs of Chicago not far from us. I try to pay attention as I drive by, it's quite the operation. I've noticed one stack seems to be constantly 'flaring off' - not a huge plume (though hard to judge from that distance). I always wonder why they don't trap it and use it to run a generator or something? I suppose their just too focused on their primary job to want to dink around with it.

It is actual methane emissions being referred to, rather than combustion products.

My understanding is that the flare stack is kept lit 24/7 in case the plant has a process interruption (called an upset) that causes a sudden large leak of flammable gases or vapors. Venting through a stack with a flame that is already lit allows them to be burned off with relative safety.

 

[NW-Bound]

I don't believe that we'll be driving cars directly powered by hydrogen, or piping it into our kitchens to cook with, but it will have some very important uses, especially in synthetic aviation fuels and industrial applications.

At this point, battery EVs lead hydrogen-fuel-cell EVs by far. A big part of it is the ability to charge at home, compared to generating your own hydrogen.

What is the state of the art for hydrogen-fuel-cell EVs?

Let's look at the 2022 Toyota Mirai which sells for $49,500 and delivers a range of 402 miles. It holds 5.6 kg of hydrogen compressed to 700 atm (10,000 psi). The car weighs 4,255 lbs, no doubt due to its 3 beefy tanks to stand the tremendous gas pressure. Fill-up time is said to be 5 minutes.

Given the above specs, I can see large commercial trucks using hydrogen-fuel-cell as being viable, compared to electric trucks hauling 10,000-lb battery.

 

[NW-Bound]

And then, there's also a thing called dual-fuel truck. What is that?

It turned out to be a diesel truck that can inject hydrogen along with diesel for burning.

That's weird, but I guess it must have some benefits for some companies to develop it. They claim the addition of hydrogen helps the diesel to burn cleaner.

From a Dutch company (note the poor English) :

The dual-fuel hydrogen truck can mix hydrogen as fuel in its converted diesel engine in order to consume less diesel and produce less CO2. If necessary, the engine can also operate entirely on diesel. In addition to the CO2, is also the NOx is reduced emissions, to -70%, but in view of the very ecological treatment in the new diesel engines, this also results in a reduction of AdBlue consumption. The existing diesel engine and drive to use, we can reduce the capital cost of the truck to 1/3 e of a zero-emission alternative.

With a full tank of hydrogen, the truck has a range of 500 km and, if necessary, the truck can drive another 3000 km on diesel.

 

[Out-to-Lunch]

I didn't follow that article. Are the satellite images detecting the flames/heat/IR of burning off the methane, or actual methane gas? This makes it sound like IR - they mention the satellites saw the giant plumes.

It is actual methane emissions being referred to, rather than combustion products.

My understanding is that the flare stack is kept lit 24/7 in case the plant has a process interruption (called an upset) that causes a sudden large leak of flammable gases or vapors. Venting through a stack with a flame that is already lit allows them to be burned off with relative safety.

As Out of Stem said, they measure the methane itself. It is done by absorption spectroscopy. You can read more here: Methane | Tropomi

 

[Oakster]

From the BBC: Sand battery could solve green energy's big problem

While you won't be able to put one in your Tesla, it does sound interesting as a cheap way to store a source of heat.

Baked potatoes store a lot of heat as well. A big hole filled with baked potatoes could be good, until they spoil.

 

[68bucks]

I saw an article about rail energy storage a while back. Looks like they are putting some into service. Sounds like a simple idea. Basically we are going to need multiple approaches to energy storage as no single idea seems to fit every application.
https://aresnorthamerica.com/

 

[NW-Bound]

I saw an article about rail energy storage a while back. Looks like they are putting some into service. Sounds like a simple idea. Basically we are going to need multiple approaches to energy storage as no single idea seems to fit every application.
https://aresnorthamerica.com/

The problem is not that these schemes don't work. As long as something does not violate the law of physics, it will work.

The question is whether they are cost effective. I am willing to say that this rail car scheme costs way more than pumped hydro storage for the same amount of energy storage.

Each of the rail cars needs an onboard generator/motor. To expand the system for more storage, you need more rail tracks, more cars. To scale up a pumped hydro storage, the main thing is to have bigger reservoirs.

Let's say you want to double the energy storage in the same foot print. You can dig the reservoirs twice as deep, but you cannot stack railcars easily.

Storing a volume of water of the same weight as a rail car is going to be cheaper than building and maintaining a rail car with all the moving parts, plus electrical and electronic parts.

 

[mpeirce]

What I haven’t been able to figure out is how storage really fixes the issues you get with intermittent power like solar and wind.

I understand that a huge battery complex (or other storage) can function as a replacement for some of the need for a gas powered peaking plant - namely supply electricity when there is a surge in demand or temporary shortage of some kind.

Storage supplies power until it runs out. Not only does the storage power just stop, it has to recharged before it’s useful again.

But I can’t see how it helps at all when there is a longer shortfall. Say a week of no wind or cloudy days. I just can’t imagine building storage that will supply “normal” electric usage for weeks on end when this happened.

Electric using industry will have to be shutdown. Likewise EVs use would also have to be curtailed. In winter, even heating might become an issue.

What am I missing?

 

[NW-Bound]

Storage supplies power until it runs out. Not only does the storage power just stop, it has to recharged before it’s useful again.

But I can’t see how it helps at all when there is a longer shortfall. Say a week of no wind or cloudy days. I just can’t imagine building storage that will supply “normal” electric usage for weeks on end when this happened.

Electric using industry will have to be shutdown. Likewise EVs use would also have to be curtailed. In winter, even heating might become an issue.

What am I missing?

You are not missing anything.

What is missing is a cheap battery that we can build to store power for several days.

Right now, there's no battery cheap enough to store for overnight use.

I myself can add enough battery to my DIY solar+battery system to last overnight, in the hottest day of summer. And I also must have enough space to mount more PV panels to have enough excess power during the day to charge this large battery.

Other than additional space for panels, which is hard to do unless I move out to the fringe area of the metropolitan to get more land, it's doable if I spend an additional $20k.

That's just for overnight. Forget about storing for 1 cloudy day.

It's all feasible with current technology. It only costs money.

 

[NW-Bound]

For my personal solar+storage system, I know how much I spend to save $2K in electric bills each year.

The unknown is how long this system lasts, or rather the maintenance cost to replace worn-out components, mostly the degradation of the lithium cells.

A $20K investment to save $2K in electricity is quite good, if the hardware lasts a long time. If it is thrown away after 10 years, it's not so good.

 

[OldShooter]

... What am I missing?

Not much, IMO. In any marketing effort, the bold print giveth and the fine print taketh away. You've been reading the fine print.

 

[travelover]

For my personal solar+storage system, I know how much I spend to save $2K in electric bills each year.

The unknown is how long this system lasts, or rather the maintenance cost to replace worn-out components, mostly the degradation of the lithium cells.

A $20K investment to save $2K in electricity is quite good, if the hardware lasts a long time. If it is thrown away after 10 years, it's not so good.

Don't forget that when you die, the city will have to send in a bio-hazzard team to disassemble your system.

 

[ERD50]

My big problem is with the headline:

"Climate change: 'Sand battery' could solve green energy's big problem"

As others have pointed out, various storage approaches (heat, cold, gravity, flywheel) have been around a long time, and they all 'work' to some degree. They aren't a scam, and they are practical in some applications.

But they don't "solve" anything. That's like saying the invention of the RO filter system "solved" the worlds potable water shortage problem. It works, but it takes a lot of energy, maintenance, and then you have water with ~ 25% higher salinity to deal with. Or that a hammer is the solution to homelessness.

All these things are a piece of the puzzle, another tool in the tool belt, but none are a "solution".

-ERD50