Batteries for large scale (grid) storage

Factual Questions
21

The fundamental problem with using electrochemical batteries for wide-scale ‘grid’ energy storage and power production is that the high density batteries (e.g. lithium-ion and lithium polymer) require a lot of effort and expense to produce due to cleanliness requirements and their use of lithium, which is not an abundant material (~0.0017% in Earth’s crust, much less in ocean water) and is limited in the number of deposits that are worth mining such that it brings to question that we can even replace all liquid hydrocarbon internal combustion engine vehicles with lithium battery-based transportation unless we find some way of recycling lithium currently being used in batteries. Low density lead-acid batteries are cheaper to make but have significant environmental impacts. And of course, all electrochemical batteries are prone to fire and explosion when placed in dense matrices, and they only last for a limited number of cycles. There are better methods of bulk energy storage that can be cycled indefinitely and have good thermodynamic efficiencies when scaled up, such as hydropower storage, compressed air storage, and mechanical flywheel storage.

Stranger

22

Moderator Note

Let’s not insult other posters in this forum. “Pedantic wanker” doesn’t become less insulting just because you also apply it to yourself. No warning issued, but be civil to other posters in this forum.

Colibri
General Questions Moderator

23

What a very good observation. I wish I had noticed it. Thank you very much.

24

It turns out that there’s another source for lithium that’s much greener than mining it: geothermal brines.

This is a double win for clean energy. The brines are initially used to generate electricity, and then before being pumped back into the ground, lithium is extracted. There’s several places this is being done or at least explored: the Salton Sea area of California, Cornwall in England, the upper Rhine valley of Germany. In addition, there’s a place in Arkansas where lithium is being extracted from brines that were brought up for bromine extraction. So the supply of lithium is not limited to what’s being mined in the traditional fashion.

25

A fairly recent article on flow batteries:

If you have the space you don’t need the energy density per se, saving lithium for the applications where it’s more critical.

26

In contrast, copper, in spite of weighing ?? 20 times as much ??, makes up only ~0.008% of the weight of the earth’s crust (4 times as much).

But copper is concentrated more, which makes it easier to mine and extract.

(?? do I have my numbers right ??)

Lithium batteries are benefiting from the enormous commercial development. Tesla is building storage systems! Flow batteries require plumbing and maintenance, aren’t going into drills and cars, and aren’t benefiting from an enormous commercial market.

27
Apology

I sincerely apologize for this. No part of my text was intended to refer to anyone but myself, but the text was badly structured and expressed. I apologize for my well-intentioned but very poorly executed attempt at a self-deprecating joke.

28

Stranger brought up recycling the lithium in batteries. There’s a good deal of work going on among various companies, including Volkswagen, to recycle batteries:

29

As surmised above, these mega batteries are simply built up by paralleling many simple units. Each unit is a battery and a bi-directional power converter that attaches to the grid. The only reason you even need the units near one another is to get cost efficiencies from co-location. A suitable feed-in point on the grid being the main one.
We have had a Tesla 194MW/150MWh battery here in South Australia for a few years now. It was installed as 129/100, but upgraded a year odd ago by simply adding more units.
Worth noting, the prime use case for these relatively low power (by grid total power) systems is not to provide backup, but to provide stability. In the world of power grids a critical measure is how stable the frequency is. Things can go badly wrong real fast when the grid frequency varies. Traditionally this was not so much of a problem, as huge spinning turbines and generators have lots of inertia. So much so that the term for frequency stability is often “inertia”. Lots and lots of rotating mass. The advent of solar and wind has removed some of that stability, and there is a market for providing stability. The ability to provide a very agile power supply to the grid has value beyond its simple energy value. The owners of the grid will buy this capability. Our local battery has been turning a tidy profit addressing this market. So the addition of a battery currently enables more renewable power, not by providing days worth of backup, but by providing grid stability. If you want to store renewable energy, pumped hydro is hard to beat, so long as you have a nice big dam or high lake nearby.

On the subject for flow batteries - they are still a thing. Redflow is still about. Economies of scale keep pushing lithium batteries down in price making it hard for the flow batteries to compete directly. But their near infinite capacity (but not power) makes them interesting in specialised areas. A big one is backup of mobile phone towers.

30

Thank you. Acknowledged and appreciated.

31

Instead of using electrochemical batteries, how about we store energy by stacking concrete blocks?

32

There’s a company in Nevada that has a similar idea: winch rail cars uphill to store energy. I assume the rail cars are full of heavy stuff.

Looks like they’re still building their first site.

33

There’s also pumping water into an uphill reservoir which is already fairly popular.

34

I suppose energy storage facilities like pumping water or raising rail cars uphill - does not have to be incredibly efficient as long as it can effectively take up the energy that is produced erratically from green sources. What is lacking in efficiency is made up for in cheapness and simplicity - pumping water uphill is not high tech. (It’s what many small towns have done with water towers in lieu of continuous water pressure pumps)

To rehash pedantics - a cell is one unit that produces energy from an electrochemical reaction. Battery as I understand, has its roots in the same concept of a battery of cannons… it is several (but can be one) installed together to be used together for the desired effect. Since most electrochemical reactions are limited to the electrochemical properties of the components, from 3.6V for lithium to 2V for lead acid to 1.5V for carbon and alkaline and 1.2V for NiMH - creating a battery of one or more cells is necessary to produce decent voltage.

Another cause for grid frequency unreliability is excessive load draw, or when a power plant goes offline creating the same effect. What battery farms can do is react within milliseconds to compensate for excessive draw or low supply on the grid, so yes, it’s all about stability. If a natural gas (or worse, coal) power plant is the replacement power source for the grid, it needs warning time or else there’s a wait to power up. During this time, on deregulated grids, the demand price could peak high. The battery farm prevents this, bringing stability to supply, frequency, and price. Win, win, win. (Assuming anyone considers deregulation of a necessity a “win”).

Recall that Enron’s clever marketing ploy was to take California generators offline, creating that excessive draw to profit from remaining plants. I heard about one smelter in Washington or Oregon who found it more profitable to shut down, send their employees home and resell their guaranteed power allotment south.

Tesla recently announced their new batteries were “tab-less”. A typical cylindrical battery like theirs is made from a long sandwich sheet of electrolyte between anode and cathode materials. This is then rolled up into a cylinder. The anode and cathode sheets would have metal tabs every so often along those sheets (anode tabs on top edge, cathode along bottom edge) In the rolled up battery (cell) these would be folded over to produce a metal top and bottom of the cylinder that were the contacts for the current in and out. Having a tab, say, every two inches or so along the sheet of -ode means current goes in there and spreads out to the nearby areas of the cell’s anode of cathode, so the joint from tab to anode/cathode sheet is a bit of a current bottleneck. . A simple and non-tech innovation was to make the tabs continuous along the sheets (basically - more, more, more), so there is no bottleneck point for current flow - no heat or resistance issues to limit current flow, so batteries (cells) can safely be charged much faster.

Fun fact - the electrolyte often is oil based, which is why overheating batteries can cause interesting fires. There’s research into dry electrolyte batteries, which would make the cells lighter and safer.

The other way to look at batteries - absent a catastrophic thermal failure, batteries when they are “worn out” still contain the material they were made with. Any lithium, nickel, etc. are still in the battery, unlike combustion engines, where the means of providing power is regularly dispersed to the environment. The only question is how much energy is needed to undo chemical bonds produced in the batteries and refine the contents into useable materials.

35

And in case it isn’t clear, that’s the reason for the increase from 21-70 form factor (21 mm diameter, 70 mm length) to 46-80. There is an optimal point in cell size: bigger cells have better material efficiency (more volume compared to casing material), but smaller cells are better at dissipating heat (more surface area compared to heat-generating volume). You pick the size that best balances between these two factors. The tabless design has lower electrical and thermal resistance, which means the optimum point is toward a larger cell.

There’s another advantage to the larger cell, which is that it’s big enough to use as a structural component. The small cells aren’t really stiff enough, but the 4680 cell is almost as large as those 8 oz soda cans. Glue them between two large plates and they add a ton of stiffness.

36

Another project to extract lithium from brine: Schlumberger New Energy Is Launching A Lithium Extraction Pilot Plant In Nevada

Don’t know the exact extraction method (and it’s probably proprietary anyway), but it’s supposed to be much greener than other methods.

37

This is one of those ‘disruptive’ ideas that actually make no sense but are good for divesting suckers of their money and/or fleecing governments out of ‘green’ project money.

The problems with lifting bricks like this are legion. Off the top of my head:

  • System losses are going to be WAY higher than what they claim. Cranes lose energy from lifting motors, from positioning motors, from pulleys, from bending cables over pulleys as they run, etc.

  • Concrete is one of the most CO2 intensive things to make. It’s also brittle, and if you are lifting and dropping blocks constantly, the maintenance and replacement costs will be large. A typical number for concrete is 180kg of CO2 produced per metric tonne of concrete. So a 35 tonne block of concrete will require the emission of 6300 kg of CO2. There are thousands of such blocks. And they will need constant replacement as they chip and crack from being constantly manipulated. even using recycled road crush and such will require cement stabilizer.

  • The blocks at the bottom have less energy than the ones at the top, so efficiency drops off as you use the potential energy of the system. And as you stack, as the pile you are stacking grows, the potential energy drops.

  • This thing will have very low wind limits. A 35 ton block on a 400 ft rope is going to to be lots of fun to work with in high wind. And since these are proposed for places like wind farms where the wind is typically fairly high, that makes this even more problematic. If the wind is really blowing and you are generating too much power, your ‘storage’ system is likely to be shut down due to wind.

  • The weight of the giant pulleys and blocks and cables all add to the frictional losses in the system. They are not unsubstantial. 90% total efficiency is a fantasy number, probably just a regurgitation of the mechanical efficiency of the motor or something. Total system efficiency is more likely to be 25-50%.

  • if any of those blocks or cables fractures on the way or up down, that entire crane is coming down. These thing would be an inspection and maintenance nightmare. You are basically looking at the world’s biggest tower crane, except it’s running at max load 24 hours per day. Wires weaken through strain and bending arohnd pulleys, motors wear out, clutches and brakes and other hardware need constant inspection, etc. The cost of running a huge crane is high. Even moderate ones in skyscraper production and such can cost $500/hr to operate.

  • it only produces 20 MWh. that’s only 1/5 of that Tesla battery in Australia. That level of power isn’t useful for long-term storage, but only for high-speed load following. But this thing is not remotely high speed. Does anyone have a need for a 20 MWh ‘backup’ that needs 15 minutes before it can provide any power? The only use I can think of is to offset energy from low demand to high demand times, but 20MWh isn’t much for that compared to the cost and maintenance of this thing.

  • I wouldn’t want to be within a mile of this thing in an earthquake or in a hurricane.

I looked into the company a bit, and it has all the hallmarks of a scam. For example, their ‘proof of concept’ demo consisted of a bog-standard crane lifting a bog-standard load off a stack and setting it down a few feet away - something such cranes do a thousand times per day. So they spent a bunch of money on a ‘proof of concept’ designed to make it look like lots of engineering is going on, while actually proving nothing about it. In fact, the only unique things they’ve produced as far as I can tell is a bunch of rather poor 3D renders.

Just another company chasing the giant river of ‘green’ money flowing to anyone with a ‘disruptive’ idea to make foolish power sources look better. They already procured over a hundred million dollars from Softbank, so the project is already a success, even though you’ll never see one of these in commercial operation unless it is massively subsidized.

38

In the meantime, the NRC has fully approved the NuScale Small Modular Reactor. A single module produces 60MW, and nuclear runs close to 90% of baseplate capacity, Call it 50 MWh per day. An approved power station design uses 12 of these modules and could produce 600 MWh of sweet, consistent baseload power 24/7 in a facility about the size of a medium sized factory, regardless of whether the wind is blowing or the sun is shining.

We should be all-in on nuclear, or we aren’t serious about global warming. We are wasting decades chasing miracle power sources or figuring out how to use low density intermittent power, when the perfect solution has been staring us in the face for 50 years, and has gotten immeasurably better since.

France managed to build enough nuclear for 80% of its electricity in about a decade, and has the lowest power prices in Europe without a single major incident over 30 years. We have improved nuclear tech immensely since then.

We are dealing with climate change like idiots.

39

Given the economies of scale with lithium battery production today, how well do these each compete for utility level storage?

I’ve been a long time fan of flywheels but they don’t really seem to be taking off much. Why not?

40

Flywheels have a place in the energy storage ecosystem. As usual Wikipedia has a good overview:

From the Wiki page, it looks like they’ve installed flywheel storage in the grid as recently as 2014. From experience, I know that flywheels are always in the mix for spacecraft (with an added bonus of use for fuel-free attitude control). This page has a nice listing of “alternative energy storage”.

If you’re wondering why flywheels aren’t ubiquitous, here’s a quote from the link:

The magnitude of the engineering challenge should not be underestimated. A 1 foot diameter flywheel, one foot in length, weighing 23 pounds spinning at 100,000 rpm will store 3 kWh of energy. However at this rotational speed the surface speed at the rim of the flywheel will be 3570 mph. or 4.8 times the speed of sound and the centrifugal force on particles at the rim is equivalent to 1.7 million G. The tensile strength of material used for the flywheel rim must be over 500,000 psi to stop the rotor from flying apart.