I built an audio amplifier in college that had a couple of huge capacitors on the power supply (about the size of a can of soda). It would keep the amp running a few seconds after I shut off the power.
One of those "1 Farad" car stereo caps (not the classiest example) can store 72 joules (watt-seconds). So to handle a 1kW excursion for 5 seconds, would take over 70 of them. Possible, yes. But probably not worthwhile.
The frustrating thing about this article is that it keeps conflating fundamental physical problems (like needing to store energy to deal with peaks), with the limitations of currently-productized circuit topologies. It's not hard to imagine an inverter that would do something similar to MPPT without needing to pull/dump the maximum power possible, would manage a small bit of local storage (a combination of caps and abused batteries), and could intelligently load shed (with "kind" brownouts) on multiple outlets.
It's also not hard to imagine an inverter (brushless motor) air conditioner that would be a lot kinder of a load, and could even operate at variable power.
But of course with the current state of homebuilding, these are bespoke ideas better filed as "off the grid". Which is the entire larger point - an "off the grid" system fundamentally costs more in materials and also presently application engineering time, than the on-grid systems being sold to homeowners.
(Although I do have to wonder about adding a piece to the current puzzle that would generate/manage a local grid frequency, and shed excess power using off-the-shelf electric heaters.)
This doesn't sound that bad to me. Size isn't much of an issue, houses have room for them. Prices for them seem all over the place:
https://www.alibaba.com/showroom/1-farad-capacitor.html https://www.amazon.com/dp/B00381UKD0/ref=psdc_2230642011_t2_...
The idea with a capacitor is they shouldn't degrade like batteries do.
The same with an inductor, which is just a coil of wire.
Electrolytics do wear out. Lifetime hours versus temperature/ripple current is a key design parameter.
[0] And assuming stuff designed for the car stereo market actually meets its advertised specs. I just went to Youtube to verify that said devices weren't just a can with other components inside of them. A video with a freehanded jigsaw set to hip hop confirmed.
As I was saying before, the main difference from your amplifier was the amount of power involved. In general, audio amplifiers have large capacitors on the power rails to smooth out the ripple voltage, and will coast for quite some time as they don't actually need that much power for typical music and volumes.
Here's a similar example - high current USB charging bricks, with a power indicator LED. If you have no devices connected and unplug it from the wall, the LED will stay on for quite some time. The LED just doesn't draw that much current (say 10mA) compared to the capacitance, which has been designed for smoothing the full charging current of 10A. Also the LED will happily ride the voltage down from 5V to its junction voltage of 2.5V or whatever, using even less current. And due to the logarithmic nature of your eyes (ears), you don't fully perceive that dimming.
I do know that caps decay over time, but have no idea how that compares with batteries. I expect, though, that long life caps could be built.
I also wonder about using inductors instead. They are, after all, just a coil of wire.
https://electronics.stackexchange.com/questions/42084/can-yo...
https://electronics.stackexchange.com/questions/326177/energ...
Perhaps in the future we'll have supercooled inductors providing power storage, and not requiring periodic changing the way say batteries do. Alas, it's just not right now.
As an aside, it's amazing how little power it actually takes to produce worthwhile sound out of modern speakers. I once wanted to test some tower speakers without a proper receiver around, so I wired up a breadboard with some stupid opamps around poorly-heatsunk transistors, powered by a lab supply. The speakers turned out to be disappointing, but not because of the amplifier!
There's also inverter drive microwaves, and fridges even. My friend's new condo has an inverter drive fridge
Electric motors, especially the simple ones found in compressors for cooling, are running from AC. You can't put a capacitor into the AC path. You can only convert it to DC, charge the capacitor and then convert it back to AC. Where we are back to the original problem.
The output of solar panels is DC, too. The capacitors would be placed in the DC side.