Posted on 07/09/2026 6:12:26 AM PDT by MtnClimber
Advocates of generating electricity mostly with intermittent wind and sun, when challenged on how they would deal with a calm night, are always ready with the obvious answer: energy storage. Just get some batteries, store up excess power from the windy mid-days, discharge as needed, and everything will work out.
Unfortunately, the advocates never acknowledge that the problem of making an electrical grid work 24/7/365 with mostly wind and solar generation is much more difficult than just storing power from the day to discharge that night. Both wind and sun are subject to regular “droughts,” just like rain. There can be many consecutive days, or even weeks, of combined low wind and sun; let alone the entire winter has a lack of sun, and both summer and winter have less wind than spring and fall. Calculating how much energy storage will suffice to get through even a year of average wind/sun variability is a straightforward exercise, yielding an answer of as much as 1000 hours of average consumption. Meanwhile, naive politicians (those in New York being Exhibit A) regularly get duped into buying a few hours or tens of hours worth of batteries for grid backup, spending billions of dollars on amounts of storage that will be almost useless for backing up a primarily wind/sun grid.
I first wrote about this subject way back in 2018, and have had many follow-up pieces since. The conclusion of my pieces has been that to obtain sufficient battery storage to back up a primarily wind/sun grid using current lithium-ion battery technology, and even assuming best case future cost reductions and economies of scale, would cost the full GDP and more of any jurisdiction that makes the effort.
Well, who says you can only use lithium-ion technology? The massive Biden-era green energy handout statutes (e.g., the “Inflation Reduction Act”), together with green energy enthusiasm generally, have brought forth a gusher of entrepreneurialism looking for new, better and cheaper energy storage systems. Recent comments on some of my posts, as well as those of daughter Jane over at @janementonnyc on Instagram, have advocated for two new technologies of energy storage as the solution to the intermittency problem. Those two are flywheel batteries, and iron-air batteries. Could either of those really work?
As background to discussion of those two specifically, I suggest thinking about the model of the storage of drinking water. New York City stores water in a network of reservoirs located in upstate New York. The City’s water consumption is approximately 1 billion gallons per day. The storage capacity of the reservoirs is approximately 550 billion gallons, that is, approximately 550 days, or more than a year and a half of consumption. The amount stored in the reservoirs fluctuates over the course of a year, and generally drops over the summer and into the fall, but it rarely gets below about 70% of capacity, or about 380 billion gallons. And in years with serious droughts, the storage can fall below 50% of capacity, and even down to 40% of capacity. A storage level of under 40% of capacity has only happened once in my lifetime, which was about 60 years ago. In other words, most of the storage capacity is there to guard against a worst-case drought, and much of the water remains in storage for decades on end to guard against that event. Fortunately, a simple reservoir has the capability to do that.
An electrical grid without full dispatchable backup needs the same kind of storage capability. The fact that a group of generators can produce the same number of MWhs of energy in a year as the average amount demanded means little unless the energy can be matched minute by minute to the demand. To meet that criterion, a storage system must be able to store the energy from summer to winter, or from spring one year all the way to spring the next year. Preferably, there should be an ample balance stored for the long term to guard against a worst-case wind/sun drought that may occur only once a decade.
By the way, it is by no means clear that lithium-ion batteries have this level of capability. But for today, let’s consider the technologies advocated by our commenters, flywheel and iron-air.
Flywheel batteries. Flywheel batteries have lots of advantages. For example, they can discharge a very high percentage of the energy originally stored in them (90-95%), and can be charged and discharged potentially thousands or even tens of thousands of times without seriously degrading. Moreover, they can ramp up and down quickly to replace generation from intermittent sources; and they have spinning inertia, which wind and solar generators do not, and which is badly needed for grid stability.
But unfortunately flywheel batteries have very high rates of what is called “self-discharge,” that is, dissipation of the stored power over time. According to this source (something called Permanent Energy), many flywheel batteries lose as much as 12.5% per hour, and even the best ones lose about 5% per day. Other sources give me similar answers. In other words, energy stored in a flywheel battery will be long gone a month later, even if never called on. Flywheel batteries may have many uses, but for purposes of backing up the grid against any serious wind/sun drought, they are worthless. Oh, and they are expensive — currently costing in the range of $400/kWh, which is more even than lithium-ion batteries and translates to many trillions of dollars to buy amounts useful for full grid backup.
Iron-air batteries. This is a type of battery that uses only the simplest and most common of materials — iron and air. The process of storing and discharging energy takes place by repeatedly rusting and unrusting the iron. It turns out that you can store a lot of energy that way. It’s not subject to exploding or catching fire. And it’s cheap: proponents claim that they will be able to achieve a price of $20/kWh, which is a small fraction of the current price of lithium-ion batteries (~$300/kWh). So what could possibly be the problem?
Again, self-discharge is a killer. Current iron-air batteries lose about 2-5% of their stored charge per day. At that rate, all the stored charge will be gone in two months, if not one. Maybe the rate could be improved, but it would need to improve by multiple orders of magnitude to make these batteries even a little useful for large-scale grid backup against worst-case droughts.
And then there are a few other problems. Iron-air batteries can only return about 50% of the energy stored; the rest is lost. And they can only discharge about 1% of the stored energy per hour. That means that they are incapable of ramping up and down quickly to back up the intermittent wind and sun.
Now I’m not at all saying that these two sorts of batteries cannot be useful in certain applications. For example, flywheel batteries appear to be very useful to supplement diesel engines to operate heavy cranes. The cranes go for long periods at low energy, and then have a big surge in power demand when they suddenly lift a heavy load. Pairing a flywheel battery with the diesel engine can cut the size of the needed engine by as much as half.
But why anybody, let alone our commenters, thinks that these sorts of batteries are the answer to grid backup for wind/sun generation, I do not know. Maybe some day. Meanwhile, keep working on it. As I have said before, if someone figures out a battery technology that has the needed capability and is also cost-effective to make a grid work with wind/solar generation, I will be the first to applaud.
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Good batteries-could it happen?
But only because I don't expect it to provide 100% of my power in all climates (i.e. when it rains for days in a row) and all power consumption needs (i.e. when we do spring cleaning and run the dryer a lot to wash bedclothes in guest bedrooms that haven't been used in months, while driving a lot during the day and having to charge the EV). Thus, I have the understanding that even I need a dependable grid for those hard to reach times that it'd be infeasible to set up an off-grid system for us.
The grid doesn't have a backup grid for the times solar doesn't do. The grid has to be dependable all the time, rain or shine. That's why I don't like making the grid depend on solar and wind.
“Battery Storage For Grid Backup”
Hint: They have four wheels and a license is needed to drive one on a public road.
The best battery backup for wind and solar is a nuclear reactor.
Loads can be cut by cutting off water heaters.
Houses can have zoned HVAC. Zones can be isolated to reduce grid load.
Power plants might be placed in a forest and the forest used to suck up the CO2 and supply fuel.
Maintenance costs don’t go down when the solar+windmills pull the rug out from under the grid. If it’s a public utility shouldn’t the competition be controlled like the phone companies did? Cell towers cut down the need for land lines but they, like computers sank and swam on their own. We’re much better off. Cut off the subsidies.
The copper canisters will have steel inserts. They are five metres long and one single capsule will weigh about 25 tons when it is filled with spent fuel. The outer casing consists of five-centimetre-thick copper.
The sealed copper canisters will then be placed in a system of tunnels about 500 metres deep in the solid bedrock. Here they will be embedded in Bentonite clay.
This clay will act as a buffer and protect the canister from corrosion and minor movements in the bedrock. The clay buffer will gradually absorb water and swell to fill the space around it and any cracks in the rock.
https://skb.com/future-projects/the-spent-fuel-repository/our-methodology/
Energy is — guess what — energetic. It resents being stored and will misbehave the first chance it gets. That’s why man-made storage batteries with high energy density can fail so spectacularly.
That’s also why fossil fuels are such a sweet deal, because confining energy is an expensive — and dicey — proposition. But in the case of fossil fuels, nature already has done the heavy lifting, converting fusion power transmitted from the sun into an energy-dense and relatively stable fuel. And it’s just lying there under the ground, waiting to be dug out.
All these piece-meal measures are intermittent at best and can’t supply energy with a density or cost-effectiveness to compare with nuclear. If we’re going to abandon fossil fuels wholesale, there’s nothing available except nuclear, supplemented by hydroelectric, that will allow our population to continue to grow and all of us to have a 21st-Century lifestyle. Spending on solar or wind or storage batteries for either does nothing but waste time and resources that were better spent on expanding nuclear and funding fusion research.
I like the water tower battery. Pump water to a high tower during excess generation and release it through fly wheels during down times.
Review
Of course. For example, when they invent room temperature superconductors (which could happen someday) that would go a long way.
Humans are very ingenious, especially when there is money to be made!
And since you brought up the subsidies, I'll tell you the dirty secret on why my solar works really well for me (provides 80% of my power throughout the year, for an all-electric home) but doesn't for the grid. And why my decentralized solar saves me money even though I like the physical science of hydrocarbons better.
And that's because of the word "decentralized". In other words, solar power is power I can produce on my own. We can't count on the regulators of other energy to make it efficient, but I can count on God providing the sunlight, and I can count on me to be a good steward to optimize how that sunlight is utilized.
That's not the case with the bureaucrats who get in the way of how oil and natural gas and coal are drilled/mined, and how it's transported, and how oil is refined into gasoline or how coal is burned to produce power, and how it's transported some more, or how gas is stored nearby at the gas station, and how power or natural gas is delivered to your house or how gasoline is dispensed at the pump at the gas station. That's way too many layers of selfish regulators getting in the way of how the free market can provide the energy from the ground to us.
The word "decentralized" in front of solar removes all of that for me. That's the only reason why it's cheaper for me. That would not be the case with solar on the grid. We'd still have too many regulators messing it up, even if solar was as good as hydrocarbons (which it's not).
We’re about to hit our summer weather here in So Cal - temps common above 95 for the next few months, saw 102 in the near forecast.
Waiting for the warning texts from my city about NOT plugging in EVs and/or “large appliances” because the grid is over-capacity due to all the a/c’s.
We are looking at buying solar panels. My brother installed solar panels that heat his pools and Jacuzzi and run his a/c.
I read recently that a group was proposing a 3,000ft tower for storage of water during excess peak production. The energy produced during release was impressive.
Absolutely. The math does work for that!
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